Farinha de larvas na nutrição de aves

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Universidade de São Paulo 
Escola Superior de Agricultura “Luiz de Queiroz” 
Farinha de larva de inseto (Tenebrio molitor) na alimentação de frangos de corte: 
preferência alimentar, energia metabolizável e digestibilidade de aminoácidos 
Marcos Antonio Nascimento Filho 
Dissertação apresentada para obtenção do título de 
Mestre em Ciências. Área de concentração: Ciência 
Animal e Pastagens 
 
 
 
 
 
 
 
 
 
 
Piracicaba 
2020 
 
 
Marcos Antonio Nascimento Filho 
Zootecnista 
Farinha de larva de inseto (Tenebrio molitor) na alimentação de frangos de corte: preferência 
alimentar, energia metabolizável e digestibilidade de aminoácidos 
versão revisada de acordo com a resolução CoPGr 6018 de 2011 
Orientador: 
Prof. Dr. JOSÉ FERNANDO MACHADO MENTEN 
Dissertação apresentada para obtenção do título de 
Mestre em Ciências. Área de concentração: Ciência 
Animal e Pastagens 
 
 
 
 
 
 
 
 
 
 
 
 
 
Piracicaba 
2020 
2 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Dados Internacionais de Catalogação na Publicação 
DIVISÃO DE BIBLIOTECA – DIBD/ESALQ/USP 
Nascimento Filho, Marcos Antonio 
Farinha de larva de inseto (Tenebrio molitor) na alimentação de frangos 
de corte: preferência alimentar, energia metabolizável e digestibilidade de 
aminoácidos / Marcos Antonio Nascimento Filho. - - versão revisada de 
acordo com a resolução CoPGr 6018 de 2011. - - Piracicaba, 2020. 
72 p. 
Dissertação (Mestrado) - - USP / Escola Superior de Agricultura “Luiz 
de Queiroz”. 
1. Farinha de inseto 2. Frangos de corte 3. Ingrediente alternativo 4. 
Energia metabolizável 5. Digestibilidade de aminoácidos I. Título 
 
3 
 
AGRADECIMENTOS 
 
À Deus, por me guiar e ser meu abrigo maior. 
Aos meus pais, Silvana de Melo Moscoso e Marcos Antonio Nascimento, obrigado pelo 
amor incondicional e os princípios ensinados que me fizeram ser uma pessoa feliz e confiante na 
busca dos meus sonhos. 
Ao Professor Doutor José Fernando Machado Menten, por todo o apoio, motivação, 
amizade e conhecimento compartilhado como orientador para o meu aperfeiçoamento 
profissional. 
Aos amigos do grupo de experimentação avícola “Luiz de Queiroz” (EALQ), Ana Beatriz 
Santos de Oliveira, Diana Suckeveris, Raquel Tatiane Pereira, Alvaro Mario Burin Junior e Rafaela 
Pereira que sempre estiveram presentes nesta jornada de experimentos e que, como grandes 
amigos formamos uma familía ao qual serei sempre grato pelos conselhos e os momentos alegres 
que passamos juntos. 
Aos estagiários e funcionários do setor de avicultura da Escola Superior de Agricultura 
“Luiz de Queiroz” que participaram das atividades nos experimentos para a obtenção do meu 
título de mestre, agradeço pela amizade e suporte nas horas de trabalho. 
Ao meu grande amigo, Vinicius Ricardo Cambito de Paula, que durante estes anos me fez 
confirmar que pessoas importantes sempre deixam uma marca em nossa vida, e você deixou a 
sua mostrando que nossa amizade é sem divisões ou fim! Muito obrigado pelo suporte, carinho e 
por sempre estar ao meu lado em todas as horas! 
Ao meu amigo, Shilton Reino Cavalcante, agradeço por sua amizade, companheirismo e 
todas as risadas na República Paiol. 
Ao meu grande amigo e irmão, Jonathan Santos, que desde que nos conhecemos 
sempre esteve ao meu lado me apoiando. Compartilho esta alegria dizendo muito obrigado pelo 
carinho e por se fazer presente na minha vida, fortalecendo cada vez mais esta nossa amizade! 
À Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), pela concessão da 
bolsa de estudos (processo nº 2017/19751-7) e auxílio a pesquisa (processo nº 2017/05423-8). 
Aos professores do Departamento de Zootecnia da Escola Superior de Agricultura “Luiz 
de Queiroz”, agradeço todo o conhecimento compartilhado durante toda a jornada acadêmica. 
À Escola Superior de Agricultura “Luiz de Queiroz”, obrigado. 
À Universidade de São Paulo, obrigado. 
 
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SUMÁRIO 
RESUMO ........................................................................................................................................................... 5 
ABSTRACT ......................................................................................................................................................... 6 
1. INTRODUÇÃO ............................................................................................................................................... 7 
1.1. FARINHA DE LARVA DE INSETO (TENEBRIO MOLITOR): CARACTERÍSTICAS E VALOR NUTRITIVO ................................................ 9 
1.2. INSETOS EM DIETAS PARA FRANGOS DE CORTE ............................................................................................................. 11 
1.3. JUSTIFICATIVA E PRINCIPAIS OBJETIVOS ....................................................................................................................... 13 
REFERÊNCIAS .................................................................................................................................................15 
2. CAFETERIA-TYPE FEEDING OF CHICKENS INDICATES A PREFERENCE FOR INSECT (TENEBRIO MOLITOR) 
LARVAE MEAL.................................................................................................................................................21 
SIMPLE SUMMARY .........................................................................................................................................21 
ABSTRACT .......................................................................................................................................................22 
2.1. INTRODUCTION....................................................................................................................................................... 22 
2.2. MATERIAL AND METHODS ....................................................................................................................................... 24 
2.2.1. Animals, diets, and experimental procedures ......................................................................................... 24 
2.2.2. Measurements and analytical methods................................................................................................... 25 
2.2.3. Statistical Analysis ..................................................................................................................................... 27 
2.3. RESULTS ................................................................................................................................................................ 27 
2.4. DISCUSSION ........................................................................................................................................................... 32 
2.5. CONCLUSIONS ........................................................................................................................................................ 36 
AUTHOR CONTRIBUTIONS..............................................................................................................................36 
ACKNOWLEDGMENTS ....................................................................................................................................36 
CONFLICT OF INTEREST ..................................................................................................................................36 
REFERENCES ...................................................................................................................................................36 
3. NUTRITIONAL VALUE OF TENEBRIO MOLITOR MEAL FOR CHICKENS: METABOLIZABLE ENERGY AND 
STANDARDIZED ILEAL AMINO ACID DIGESTIBILITY .........................................................................................43 
ABSTRACT .......................................................................................................................................................43 
3.1.INTRODUCTION....................................................................................................................................................... 44 
3.2. MATERIAL AND METHODS ....................................................................................................................................... 46 
3.2.1. Metabolizable energy assay ..................................................................................................................... 46 
3.2.1.1. Animals, diets and experimental procedures..................................................................................................... 46 
3.2.1.2. Measurements and analytical methods ............................................................................................................. 47 
3.2.2. Amino acid digestibility assay ................................................................................................................... 48 
3.2.2.1. Animals, diets and experimental procedures..................................................................................................... 48 
3.2.2.2. Measurements and analytical methods ............................................................................................................. 49 
3.3. RESULTS AND DISCUSSION ....................................................................................................................................... 50 
3.4. CONCLUSION ......................................................................................................................................................... 54 
ACKNOWLEDGMENTS ....................................................................................................................................54 
CONFLICT OF INTEREST ..................................................................................................................................54 
REFERENCES ...................................................................................................................................................54 
4. CONSIDERAÇÕES FINAIS .............................................................................................................................67 
APÊNDICES .....................................................................................................................................................68 
5 
 
RESUMO 
Farinha de larva de inseto (Tenebrio molitor) na alimentação de frangos de corte: preferência 
alimentar, energia metabolizável e digestibilidade de aminoácidos 
O uso de insetos como alimento é considerado uma alternativa promissora para a 
indústria animal por aliar alto valor nutritivo e propriedades nutracêuticas em um 
sistema sustentável de produção sob o ponto de vista econômico-ambiental. 
Considerando que as aves criadas soltas têm o hábito natural de consumir insetos, 
a introdução de ingredientes, como por exemplo a farinha de larva de tenébrio, 
na formulação de dietas pode contribuir para otimizar esta cadeia produtiva. 
Sendo assim, com o objetivo de caracterizar a composição nutricional e fornecer 
bases científicas para iniciar discussões da viabilidade do uso de insetos em dietas 
para animais no Brasil, este projeto de pesquisa investigou os efeitos do tenébrio, 
na forma de farinha, em rações para frangos de corte. O projeto realizou duas 
diferentes abordagens do uso da farinha de larva de tenébrio na alimentação de 
frangos: a) ensaio de preferência e consumo alimentar (experimento 1); e b) valor 
nutritivo da farinha de inseto (experimentos 2 e 3). O consumo e a preferência 
alimentar entre farinha de larva de tenébrio, milho, soja semi-integral extrusada e 
suplemento (minerais, vitaminas e aminoácidos) foram investigados a fim de 
verificar o interesse dos frangos de corte pela farinha de inseto e posteriormente 
nortear sua inclusão em dietas para aves de produção. Em seguida, foi 
determinada a composição nutricional e os valores de energia metabolizável e de 
aminoácidos digestíveis estandardizados da farinha de larva de tenébrio. No 
experimento 1, os frangos de corte apresentaram alta aceitabilidade pela farinha 
de inseto, consumindo em média 50% do total durante o período experimental. 
Foi observado um aumento gradual no consumo da farinha de tenébrio, que se 
estabilizou a partir do 11º dia do período experimental. No período de 
estabilização, a farinha de larva de tenébrio foi o ingrediente preferido pelos 
frangos, gerando uma melhora na conversão alimentar das aves. Nos 
experimentos 2 e 3, a composição nutricional da farinha de larva de tenébrio 
indica que este ingrediente alternativo é uma fonte rica em proteína bruta (500,0 
g/kg), extrato etéreo (297,3 g/kg), e energia bruta (6.336 kcal/kg) com base na 
matéria natural. O valor de energia metabolizável aparente corrigida para o 
balanço determinado foi de 5.004 ± 121 kcal/kg na matéria seca e os coeficientes 
de digestibilidade ileal estandardizada de aminoácidos foram: Met, 0,87; Lys, 
0,89; Thr, 0,82; Val, 0,86; Ile, 0,86; Arg, 0,92; Phe, 0,90; Leu, 0,88; His, 0,81. Os 
resultados deste projeto evidenciam o potencial nutricional e/ou nutracêutico da 
farinha de larva de tenébrio a ser explorado, sendo guia para a formulação 
adequada de dietas quando este ingrediente alternativo é incorporado a rações 
de aves. 
Palavras-chave: Farinha de inseto; Frangos de corte; Ingrediente alternativo; 
Energia metabolizável; Digestibilidade de aminoácidos 
 
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ABSTRACT 
Insect larva meal (Tenebrio molitor) in broiler chickens’ diet: feed preference, metabolizable 
energy and digestibility of amino acids 
The use of insects in the animal industry is a promising alternative because it 
combines high nutritional value and nutraceutical proprieties in a sustainable 
production system from an economic and environmental point of view. 
Considering that free-range birds have a natural behavior to pick up a variety of 
insects during their entire lifecycle and eat them voluntarily, the introduction of 
ingredients, such as Tenebrio molitor larva meal, in the formulation of diets can 
contribute to optimize this production chain. Therefore, in order to characterize 
the nutritional composition and provide a scientific framework to rise the 
discussion on the use of insects for animals in Brazil, this research project 
investigated the effects of tenebrio meal in broiler chickens diet. This research 
was divided in two approaches of using insect meal for chickens: a) ingredient 
preference and feed intake (experiment 1); and b) metabolizable energy and 
amino acid digestibility assays (experiments 2 and 3). The feeding behavior among 
tenebrio meal, ground corn, extruded semi-whole soybean meal, and supplement 
mixture (minerals, vitamins, amino acids) was investigated to verify the interest by 
the chickens for insect meal and guide the amount of tenebrio meal inclusion in 
poultry diets. Following, the nutritional composition, metabolizable energy and 
standardized ileal digestibility of amino acids of tenebrio meal were quantified. In 
experiment 1, broiler chickens showed high acceptability for tenebrio larva meal, 
consuming on average 50% of the total intake during the experimental period. 
There was a gradual increase in the consumption of tenebrio meal, which 
stabilized from day 11 of the experimental period. In the stabilization period, 
tenebrio meal was the most preffered ingredient by the chickens, in which also 
generated an improvement in feed conversion of the birds. In experiments 2 and 
3, the nutritional composition of tenebrio meal indicates that this alternative 
ingredient is a rich source of crude protein (500.0 g/kg), ether extract (297.3 
g/kg), and crude energy (6,336 kcal/kg), as fed basis. Determined apparent 
metabolizable energy corrected for nitrogen balance was 5,004 ± 121 kcal/kg in 
dry matter basis, and the standardized ileal amino acid digestibility coefficients 
were: Met, 0.87; Lys, 0.89;Thr, 0.82; Val, 0.86; Ile, 0.86; Arg, 0.92; Phe, 0.90; Leu, 
0.88; His, 0.81. The results of this project indicate the nutritional and/or 
nutraceutical potential of the Tenebrio molitor larva meal to be exploited, being a 
guide for adequate formulation of diets when this novel ingredient is incorporated 
into poultry feeding. 
Keywords: Insect meal; Broiler chickens; Alternative ingredient; Metabolizable 
energy; Digestibility of amino acids 
 
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1. INTRODUÇÃO 
A nutrição é um dos pilares para o desenvolvimento da indústria avícola devido a seu 
impacto no desempenho e saúde das aves e aos gastos com ingredientes e aditivos nos 
custos de produção. Paralelamente a essa questão, a avicultura vive uma corrida apressada 
desde 2006 por alternativas ao uso de antimicrobianos como melhoradores de desempenho. 
Neste sentido, é importante garantir a competitividade e o suprimento de ingredientes em 
quantidade e qualidade para rações, permitindo e encorajando novas abordagens para que o 
sistema opere de forma cada vez mais sustentável nos quesitos sociais, ambientais e 
econômicos. 
Aves têm naturalmente o hábito de selecionar insetos de diversos tipos e consumir 
voluntariamente, e, a entomofagia pode representar uma boa parte de todo o alimento 
ingerido ao longo da vida. (Khan, 2018). Mesmo assim, até o presente, informações sobre os 
efeitos da farinha de insetos na saúde, no aproveitamento dos nutrientes e no desempenho 
produtivo de aves são escassas e pouco exploradas (Józefiak e Engberg, 2015), especialmente 
no Brasil. Os recentes estudos realizados nesse campo obtiveram bons resultados e 
encorajam cada vez mais a produção de insetos em escala industrial assim como seu uso na 
alimentação animal e humana (Veldkamp et al., 2012; Veldkamp e Bosch, 2015). 
Ainda que o uso de insetos na alimentação animal e/ou humana soe como exótico 
no mundo ocidental, esta é uma prática milenar no oriente que alimenta mais de dois bilhões 
de pessoas. De fato, não se trata de introduzir a ideia de insetos como alimento, mas de 
modificar o conceito inserido na sociedade ocidental (Van Huis et al., 2013). 
A classe dos insetos (filo Artropoda) hospeda a maior diversidade da vida animal 
(cerca de 90%) existente no planeta Terra com mais de um milhão de espécies de insetos 
descritas e catalogadas (Van Huis et al., 2013). Uma lista de mais de 2.000 espécies ao redor 
do mundo são reconhecidas como ‘‘insetos comestíveis’’ por apresentarem rico valor 
nutricional, propriedades nutracêuticas (peptídeos antimicrobianos) e por não transmitirem 
doenças ou serem venenosos, tornando aptos para consumo (Jongema, 2017; Glover & 
Sexton, 2015; Van Huis, 2015). 
O sistema de produção de insetos, em geral com ciclo curto de vida, envolve alta 
eficiência alimentar agregado a robustez e a capacidade recicladora de resíduos, 
8 
aproveitando estes como alimento (Van Huis et al., 2013; Makkar et al., 2014). Da mesma 
forma, uma grande vantagem na produção de insetos está relacionada à baixa necessidade de 
consumo de água potável. Insetos são muito eficientes na utilização da água e na maioria dos 
casos o alimento (substrato) constitui a principal fonte de água (Oonincx et al., 2015a; van 
Broekhoven et al., 2015). 
As espécies de insetos mais adequadas à produção em escala industrial são o 
tenébrio (Tenebrio molitor), a mosca soldado-negro (Hermetia illucens), a mosca-doméstica 
(Musca domestica), e o bicho da seda (Bombyx mori). Essas espécies apresentam conteúdo 
proteico de 42-62% e são ricas em ácidos graxos insaturados e micronutrientes. Além disso, 
estes insetos são de fácil criação do ponto de vista social, econômico e ambiental, pois 
necessitam de menores investimentos para se desenvolver de forma sustentável comparado 
a outros sistemas do ramo. Também, são recicladores de nutrientes por serem capazes de se 
desenvolver utilizando substratos como sub-produtos e/ou resíduos orgânicos vegetais 
diversos (Oonincx et al., 2015a) e até mesmo esterco (Sheppard et al., 1994; Oonincx et al., 
2015b; Hussein et al., 2017), podendo contribuir positivamente para a questão de desperdício 
de alimentos de cerca de 30% que a sociedade moderna enfrenta (Van Huis et al., 2013; 
Makkar et al., 2014). 
Considerando o potencial deste ingrediente em rações, estudos também destacam a 
produção de peptídeos antimicrobianos pelos insetos, que pode agregar efeitos benéficos 
sobre o desempenho e a saúde das aves. Os peptídeos antimicrobianos são proteínas (menor 
que 100 unidades de aminoácidos) que compõem o sistema imune dos insetos e são muito 
efetivos contra bactérias, fungos, parasitas e até mesmo vírus (Jenssen et al., 2006; Yi et al., 
2014; Mylonakis et al., 2016). Isto tem gerado muito interesse por parte da indústria 
farmacêutica animal pela possibilidade em obter um substituto ao uso de antimicrobianos 
como aditivos melhoradores de desempenho (Ratcliffe et al., 2014; Van Huis, 2015). 
Até o momento, o obstáculo mais significativo ao uso dos insetos na nutrição animal 
é sua produção limitada em escala industrial o que culmina em alto custo e oscilações no 
suprimento do produto à indústria de rações (Veldkamp et al., 2012). Esse obstáculo vem 
sendo rapidamente superado à medida que o interesse na produção em escala industrial 
ganha notoriedade no mundo, especialmente na Europa. Paralelamente à expansão da 
indústria de insetos, a legislação do seu uso na nutrição animal e humana vem sendo 
reformulada e atualizada. Em novembro de 2015 a União Européia reconheceu insetos como 
9 
 
‘‘novel food’’, iniciativa que regulamenta seu consumo como ingrediente para animais e 
humanos (EU Regulation 2015/2283). Posteriormente, em julho de 2017 (Comission 
Regulation, 2017) foi liberado o uso de insetos na alimentação de peixes de produção e 'pets'. 
Países como Estados Unidos da América, Canadá e Austrália, por exemplo, começaram a 
discutir e implementar regulamentações para o uso de insetos na alimentação animal 
(Lähteenmäki-Uutela et al., 2017), demonstrando o interesse da aplicação prática destes 
produtos e expansão da indústria neste mercado. 
Dentre as maiores empresas mundiais que produzem, processam e comercializam 
insetos para nutrição animal e humana estão: Kreca-Holanda, Ynsect-França, Protix 
Biosystems-Holanda, AgriProtein-África do Sul, Enviroflight-Estados Unidos, Bioflytech-
Espanha e Entomotech-Espanha. A mais antiga é a Kreca com mais de 35 anos no mercado e 
oferecendo 15 diferentes espécies de insetos na divisão de nutrição animal. No Brasil, a única 
empresa regulamentada é a Nutrinsecta (do grupo Megazoo) na qual a produção de insetos é 
destinada principalmente à alimentação de aves ornamentais (mercado 'pet'), aves e peixes 
de produção e eventualmente fornecida a outros consumidores com propósitos de pesquisa. 
A Nutrinsecta está no mercado há 15 anos e produz 3 diferentes espécies, tenébrio, barata 
cenérea e grilo preto, que somam cerca de 4 toneladas de insetos a cada mês com 
perspectivas otimistas de aumento da produção. 
Uso de insetos na indústria animal é extremamente promissor por aliar valor 
nutritivo, saúde e sustentabilidade de forma nunca antes vista. Diante das potenciais 
vantagens do uso de insetos na nutrição animal enfatizados acima, alguns dos autores que 
têm trabalhado recentemente com insetos especulam que a explicação para a não ocorrência 
de seu uso generalizado reside no fato de este segmento industrial não ter sido considerado 
antes. 
1.1. Farinha de larva de inseto (Tenebrio molitor): características e valor nutritivo 
O ciclo de vida total do tenébrio, também conhecido com os termos em inglês 
“mealworm” ou “yellow mealworm’’, varia de 280 a 630 dias. As larvas eclodem em torno de 
uma semana e após vários estágios se transformam em larvas maduras tipicamente ao 
alcançar 3-4 meses em temperatura ambiente (Makkar et al., 2014). Entretanto, o estágio 
larval podedurar 5-18 meses, enquanto o tenébrio adulto vive por cerca de 2-3 meses 
10 
(Morales-Ramos et al., 2012). De forma geral, a fase larval de tenébrios é composta por ≈12 
ínstars e dura cerca de 90-120 dias (Morales-Ramos et al., 2010). A larva madura tem 
coloração amarelo-marrom claro, 20-32 mm de comprimento e pesa entre 120-160 mg 
(Makkar et al., 2014). 
Tenébrios se reproduzem facilmente e são altamente prolíficos, gerando uma grande 
número de descendentes durante o ciclo de vida. Por essas razões eles são produzidos 
industrialmente para animais de zoológico e 'pets', incluindo pássaros, répteis, pequenos 
mamíferos, anfíbios e peixes (Veldkamp et al., 2012). Eles são usualmente fornecidos vivos, 
mas também enlatados, desidratados, ou na forma de farinhas (Ortiz et al., 2016). 
O tenébrio tem a capacidade de converter resíduos vegetais de baixa qualidade em 
alimentos de alta qualidade em termos de energia, proteína e gorduras em um tempo 
relativamente curto (Józefiak et al., 2016). Tenébrios podem utilizar grãos contaminados com 
micotoxinas sem serem prejudicados porque são capazes de detoxificar (modificar 
enzimaticamente) zearalenona em um metabólito particular, o alfa-zearalenol (Van 
Broekhoven et al., 2017). Não há riscos de acumulação de zearalenona nas larvas de tenébrio 
e nem nos animais que se alimentam deles (Hornung, 1991). Este inseto é onívoro e em vida 
livre se alimenta tipicamente de grãos de cereais ou farinhas diversas. Em sistemas de 
produção comercial, o substrato alimentar de tenébrios é constituído por sub-produtos, 
sobras variadas de origem vegetal e animal oriundos da indústria de alimentos citando-se 
fábricas de pães e macarrão, varredura de fábrica de ração animal, assim como hortaliças 
(cenoura, beterrada, alface) e levedura de cerveja (Aguilar-Miranda et al., 2002). 
A larva de tenébrio contém alta quantidade de proteína bruta (47-60%) e de lipídeos 
(30-43%) na matéria seca. Além disso, quando frescas contêm cerca de 60-70% de água. O 
tenébrio tem apenas cerca de 5% da matéria seca em cinzas e é similar a outros insetos que 
têm baixo conteúdo de cálcio e baixa relação Ca:P. A farinha de larva de tenébrio é rica em 
aminoácidos essenciais e composição de lipídeos inclui valores altos de ácidos graxos mono e 
poli-insaturados (Makkar et al., 2014). A Tabela 1 apresenta a composição química da farinha 
de larva de tenébrio. 
 
 
 
 
11 
 
Tabela 1. Composição química e valor energético da farinha de larva de tenébrio 
Valor nutritivo 
Farinha de tenébrio (Tenebrio molitor) 
Unidade Média ± desvio padrão 
Composição centesimal 
Matéria seca % da materia natural 39,65 ± 3,6 
Proteína bruta % da matéria seca 52.35 ± 1,1 
Energia bruta kcal/kg de matéria seca 4.438 ± 4,0 
Extrato etéreo % da matéria seca 24,7 ± 1,5 
Fibra bruta % da matéria seca 1,97 ± 0,3 
Cinzas % da matéria seca 3,62 ± 0,6 
Quitina* % da matéria seca 13,00 
Fonte: Zielińska et al., 2015; *Adámková et al. (2017) 
 
A fonte de proteína constitui uma das principais preocupações dos nutricionistas 
tanto pelo alto custo desse ingrediente quanto pela sua necessidade e importância fisiológica 
ao animal. Por isso, a busca por fontes protéicas alternativas de valor nutricional comparável 
ou superior ao dos tradicionais ingredientes é necessária para garantir à avicultura mais 
opções de ingredientes e assim assegurar a viabilidade da atividade em todos os sentidos. 
Neste contexto, o uso de insetos em dietas para frangos merece atenção por ter 
características suficientes para ser considerado uma solução alternativa, uma vez que a 
qualidade proteica e energética geralmente é similar e/ou superior à do farelo de soja e 
farinha de peixes, fontes comumente utilizadas pela indústria animal (Veldkamp and Bosch, 
2015). 
1.2. Insetos em dietas para frangos de corte 
Insetos representam o alimento mais ingerido por frangos criados livres, 
representando 37% do total. Dentre os demais alimentos consumidos pelas aves, gramíneas 
representam 25%, grãos 16%, vegetais/frutas 4%, material fecal 6% e outros 12% (Vries, 
2000). Além do papel nutritivo, o comportamento de procurar e comer insetos pode resultar 
no melhor bem-estar das aves (Józefiak et al., 2016). 
Estudos recentes abordaram os efeitos da utilização de farinha de insetos na 
nutrição de aves e resultados positivos foram encontrados. Ao mesmo tempo, a escassez de 
12 
informação sobre a digestibilidade da farinha de insetos em aves dificulta a discussão quanto 
a viabilidade do uso de insetos por impossibilitar a comparação entre resultados, ou seja, 
entre os ingredientes tradicionais e a farinha de insetos. Dentre os trabalhos encontrados, a 
mosca soldado-negro é o inseto mais estudado (Cullere et al., 2016; Schiavone et al., 2017; 
Mwaniki e Kiarie, 2018; Velten et al., 2018). Também, existem resultados na literatura sobre a 
energia metabolizável e digestibilidade de aminoácidos da mosca-doméstica, tenébrio, grilo e 
gafanhoto (Hall et al., 2018; De Marco et al., 2015; Wang et al., 2005; Wang et al., 2007), que 
variam a metodologia aplicada, tal como a idade das aves, tipo de alimentação e método de 
coleta de amostras. 
Hwangbo et al. (2009) compararam a farinha de mosca-doméstica (300 g/kg) ao 
farelo de soja e reportaram alto coeficiente de digestibilidade da proteína bruta (98%) da 
farinha de inseto. Avaliando o potencial da farinha de mosca-doméstica como ingrediente 
alternativo na alimentação de frangos de corte, Hall et al. (2018) determinaram o coeficiente 
de digestibilidade verdadeira de aminoácidos de 89%, indicando que esta pode ser utilizada 
como uma proteína alternativa interessante. De Marco et al. (2015) utilizaram farinha de 
tenébrio (250 g/kg) e uma dieta referência (milho e farelo de soja) para frangos de corte e 
obtiveram coeficiente de digestibilidade aparente da proteína de 60%, extrato etéreo 88% e 
valor de energia metabolizável aparente (EMA) e corrigida (EMAn) de 4.027 e 3.826 kcal/kg 
de ração, respectivamente. Também, realizando dois estudos pararelos, Wang et al. (2005 e 
2007) reportaram alto coeficiente de digestibilidade de aminoácidos para grilos e gafanhotos, 
e valores moderados para o conteúdo de energia metabolizável comparados a farinha de 
peixes. Alguns pesquisadores acreditam que a digestibilidade pode ser afetada devido às 
dificuldades das aves em digerir quitina. Entretanto, especula-se que a quitina poderia ser 
substrato para a fermentação microbiana e assim exercer efeitos positivos no balanço da 
microbiota do sistema gastrointestinal de aves similar aos efeitos de probióticos e/ou 
prebióticos (Józefiak and Engberg, 2015). 
Outros estudos reportam os efeitos da inclusão de farinha de insetos 
especificamente em dietas para frangos. Pretorius (2011) conduziu um experimento de 
desempenho com frangos usando sete dietas comerciais (milho-farelo de soja) 
suplementadas com 10% a 50% de larva de mosca-doméstica ou farinha de peixe. Nenhuma 
diferença significativa foi observada no desempenho ou peso de carcaça nas aves alimentadas 
com 10% de larva de mosca-doméstica ou 10% de farinha de peixe. Por outro lado, frangos 
13 
 
alimentados com 25% de larva de inseto apresentaram melhores resultados para o peso vivo 
e ingestão de alimentos quando comparados com com frangos que receberam 25% de 
farinha de peixe. Em outro estudo, a inclusão de 0, 5 e 10% de farinha de tenébrio em 
substituição ao farelo de soja em rações para frangos de corte não resultou em diferenças no 
desempenho (Ramos-Elorduy et al., 2002). 
Makkar et al. (2014) verificou que a mosca soldado-negro como substituto do farelo 
de soja resultou em similar ganho de peso e menor ingestão de alimentos que dietas 
controle, indicando melhora na conversão alimentar. 
Até o presente, nenhum estudo sobre o conteúdo digestível de aminoácidos e a 
energia metabolizável da farinha de tenébrio em dietas para frangosde corte no Brasil foi 
publicado. Os benefícios do uso de farinha de inseto na nutrição animal parecem ser 
inúmeros ainda mais considerando o seu valor nutricional, todavia estas características ainda 
são pouco exploradas e precisam ser estudadas do ponto de vista de digestibilidade e efeitos 
sobre o desempenho zootécnico das aves. 
1.3. Justificativa e principais objetivos 
Para que um novo ingrediente ou aditivo seja disponibilizado para uso em rações de 
frangos, é necessário compreender as propriedades nutracêuticas e quantidade (mínima e 
máxima) a ser utilizada para obter os efeitos desejados. No caso do tenébrio, diversos fatores 
precisam ser explorados a fim de entender os efeitos deste produto sobre as aves. As 
pesquisas mais importantes ganharam força nos últimos 5 anos e ocorreram na Europa e, até 
o momento, poucos dados foram apresentados sobre a digestibilidade de nutrientes da 
farinha de tenébrio, a preferência alimentar, desempenho e respostas do sistema imune de 
frangos de corte alimentados com este ingrediente alternativo. 
Portanto, este estudo foi proposto para fornecer informações indispensáveis para 
uso da farinha de larva de tenébrio em rações para frangos de corte no Brasil. No caso do tipo 
de inseto, o presente estudo optou pelo tenébrio por a) estar disponível no mercado nacional 
e internacional (acessibilidade), b) por estar entre as três espécies de insetos mais 
promissoras para uso na nutrição animal, e c) por seu valor nutritivo (especialmente proteína 
e gordura). 
14 
O experimento 1 (preferência alimentar baseado em ‘‘sabedoria nutricional’’, uma 
capacidade intrínseca de todo animal) foi desenhado para obter informações de quanto as 
aves consomem de farinha de tenébrio. A ideia central foi disponibilizar os ingredientes 
separadamente (farinha de larva de inseto, milho e farelo de soja) e assim investigar o quanto 
voluntariamente a ave consumirá de cada. Uma vez que a ave auto-balanceie sua dieta 
escolhendo entre milho, farelo de soja e tenébrio, será possível avaliar o quanto de inseto é 
fisiológico/inato da ave consumir. 
O experimento 2 consistiu de um ensaio de metabolismo e outro de digestibilidade 
ileal estandardizada da farinha de tenébrio realizados para obter dados sobre o 
aproveitamento dos nutrientes, tais como a digestibilidade de aminoácidos, da matéria seca, 
dos lipídeos e da energia bruta, além da energia metabolizável, fundamentais para uso da 
farinha de inseto como ingrediente em dietas para frangos. 
Por fim, os resultados de preferência alimentar e digestibilidade irão fornecer bases 
científicas para iniciar discussões da viabilidade do uso de farinha de larva de tenébrio em 
dietas para frangos de corte no Brasil. 
15 
 
REFERÊNCIAS 
Aguilar-Miranda, E. D., López, M. G., Escamilla-Santana, C., Barba de la Rosa, A. P. 
(2002). Characteristics of maize flour tortilla supplemented with ground Tenebrio molitor larvae. 
Journal of Agricultural and Food Chemistry, 50, 192-195. doi:10.1021/jf010691y 
Adámková, A., Mlček, J., Kouřimská, L., Borkovcová, M., Bušina, T., Adámek, M., . . . & 
Krajsa, J. (2017). Nutritional potential of selected insect species reared on the island of Sumatra. 
International Journal of Environmental Research and Public Health, 14(5), 521. 
doi:10.3390/ijerph14050521 
Commission Regulation (2017). 2017/893 of 24 May 2017 amending Annexes I and IV 
to Regulation (EC) No 999/2001 of the European Parliament and of the Council and Annexes X, 
XIV and XV to Commission Regulation (EU) No 142/2011 as regards the provisions on processed 
animal protein. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32017R0893. 
Accessed 15/05/18. 
Cullere, M., Tasoniero, G., Giaccone, V., Miotti-Scapin, R., Claeys, E., De Smet, S., Dalle 
Zotte, A. (2016). Black soldier fly as dietary protein source for broiler quails: apparent 
digestibility, excreta microbial load, feed choice, performance, carcass and meat traits. Animal, 
10(12), 1923-1930. doi:10.1017/S1751731116001270 
De Marco, M., Martínez, S., Hernandez, F., Madrid, J., Gai, F., Rotolo, L., . . . 
Schiavone, A. (2015). Nutritional value of two insect larval meals (Tenebrio molitor and 
Hermetia illucens) for broiler chickens: Apparent nutrient digestibility, apparent ileal amino 
acid digestibility and apparent metabolizable energy. Animal Feed Science and Technology, 
209, 211-218. doi:10.1016/j.anifeedsci.2015.08.006 
Glover, D., and Sexton, A. (2015) Edible insects and the future of food: A foresight 
scenario exercise on entomophagy and global food security (No. IDS Evidence Report; 149). 
IDS, 2015. https://opendocs.ids.ac.uk/opendocs/handle/20.500.12413/7063. Accessed 
18/11/18. 
Hall, H. N., O’Neill, H. V. M., Scholey, D., Burton, E., Dickinson, M., Fitches, E. C. 
(2018). Amino acid digestibility of larval meal (Musca domestica) for broiler chickens. Poultry 
Science, 97(4), 1290-1297. doi:10.3382/ps/pex433 
16 
Hornung, B. (1991). The importance of mealworm larvae (Tenebrio molitor, L. 1758) as 
carriers of zearalenone when fed to insectivorous birds and other pet animals. In: Die Bedeutung 
der Larven des Mehlkafers (Tenebrio molitor, L. 1758) als Ubertrager von Zearalenon in der 
Futterung von insektivoren Vogeln und anderen Heimtieren.), pp. 81. 
Hussein, M., Pillai, V. V., Goddard, J. M., Park, H. G., Kothapalli, K. S., Ross, D. A., ... 
Johnson, P. A. (2017). Sustainable production of housefly (Musca domestica) larvae as a protein-
rich feed ingredient by utilizing cattle manure. PloS one, 12(2), e0171708. 
doi:10.1371/journal.pone.0171708 
Jenssen, H., Hamill, P., and Hancock, R. E. (2006). Peptide antimicrobial agents. Clinical 
microbiology reviews, 19(3), 491-511. doi:10.1128/CMR.00056-05 
Jongema Y. (2017) Worldwide list of recorded edible insects. Department of 
Entomology, Wageningen University & Research, The Netherlands. 
https://www.wur.nl/en/Expertise-Services/Chair-groups/Plant-Sciences/Laboratory-of-
Entomology/Edible-insects/Worldwidespecies-list.htm. Accessed 20/04/18. 
Józefiak, D., Engberg, R. M. (2015) Insects as poultry feed. 20th European Symposium 
on Poultry Nutrition, 24-27 August 2015, Prague, Czech Republic. 
Józefiak, D., Józefiak, A., Kierończyk, B., Rawski, M., Świątkiewicz, S., Długosz, J., 
Engberg, R. M. (2016). Insects - A natural nutrient source for poultry - A review. Annals of Animal 
Science, 16, 297-313. doi: 10.1515/aoas-2016-0010 
Khan, S. H. (2018). Recent advances in role of insects as alternative protein source in 
poultry nutrition. Journal of Applied Animal Research, 46(1), 1144-1157. 
doi:10.1080/09712119.2018.1474743 
Lähteenmäki-Uutela, A., Grmelová, N., Hénault-Ethier, L., Deschamps, M. H., 
Vandenberg, G. W., Zhao, A., ... Nemane, V. (2017). Insects as food and feed: laws of the 
European Union, United States, Canada, Mexico, Australia, and China. European Food and Feed 
Law Review, 12(1), 22-36. 
Makkar, H. P. S., Tran, G., Heuzé, V., Ankers, P. (2014). State-of-the-art on use of 
insects as animal feed. Animal Feed Science and Technology, 197, 1-33. 
doi:10.1016/j.anifeedsci.2014.07.008 
Mwaniki, Z. N., and Kiarie, E. (2018). Standardized ileal digestible amino acids and 
apparent metabolizable energy content in defatted black soldier fly larvae meal fed to broiler 
chickens. Canadian Journal of Animal Science, 99(2), 211-217. doi:10.1139/cjas-2018-0111 
17 
 
Morales-Ramos, J. A., Rojas, M. G., Shapiro-Ilan, D. I., Tedders, W. L. (2010). 
Developmental plasticity in Tenebrio molitor (Coleoptera: Tenebrionidae): analysis of instar 
variation in number and development time under different diets. Journal of Entomological 
Science, 45, 75-90. doi: 10.18474/0749-8004-45.2.75 
Morales-Ramos, J. A., Rojas, M. G., Kay, S., Shapiro-Ilan, D. I., Tedders, W. L. (2012). 
Impact of adult weight, density, and age on reproduction of Tenebrio molitor (Coleoptera: 
Tenebrionidae). Journal of EntomologicalScience, 47, 208-220. doi: 10.18474/0749-8004-
47.3.208 
Mylonakis, E., Podsiadlowski, L., Muhammed, M., Vilcinskas, A. (2016). Diversity, 
evolution and medical applications of insect antimicrobial peptides. Philosophical Transactions of 
the Royal Society B: Biological Sciences, 371(1695), 20150290. doi:10.1098/rstb.2015.0290 
Oonincx, D. G. A. B., Van Broekhoven, S., Van Huis, A., Van Loon, J. J. A. (2015a). Feed 
conversion, survival and development, and composition of four insect species on diets composed 
of food by-products. PLoS One, 10(12), e0144601. doi: 10.1371/journal.pone.0144601 
Oonincx, D. G. A. B., Van Huis, A., and Van Loon, J. J. A. (2015b). Nutrient utilisation by 
black soldier flies fed with chicken, pig, or cow manure. Journal of Insects as Food and Feed, 1(2), 
131-139. doi:10.3920/JIFF2014.0023 
Ortiz, J. C., Ruiz, A. T., Morales-Ramos, J. A., Thomas, M., Rojas, M. G., Tomberlin, J. K., … 
Jullien, R. L. (2016). Insect mass production technologies. In Insects as Sustainable Food 
Ingredients (pp. 153-201). Academic Press. doi:10.1016/B978-0-12-802856-8.00006-5 
Pretorius, Q. (2011). The evaluation of larvae of Musca domestica (common house fly) 
as protein source for broiler production. MSc. thesis, Department of Animal Science, 
Stellenbosch University, Stellenbosch, South Africa, 94p. 
https://scholar.sun.ac.za/bitstream/handle/10019.1/6667/pretorius_evaluation_2011.pdf?sequ
ence=1. Accessed 11/06/18. 
Ramos-Elorduy, J., Avila Gonzalez, E., Rocha Hernandez, A., Pino, J. M. (2002). Use of 
Tenebrio molitor (Coleoptera: Tenebrionidae) to recycle organic wastes and as feed for broiler 
chickens. Journal of Economic Entomology, 95,214-220. doi:10.1603/0022-0493-95.1.214 
Ratcliffe, N., Azambuja, P., and Mello, C. B. (2014). Recent advances in developing insect 
natural products as potential modern day medicines. Evidence-based complementary and 
alternative medicine. doi:10.1155/2014/904958 
18 
Regulation (EU) 2015/2283 of the European Parliament and of the Council of 25 
November 2015 on novel foods, amending Regulation (EU) No 1169/2011 of the European 
Parliament and of the Council and repealing Regulation (EC) No 258/97 of the European 
Parliament and of the Council and Commission Regulation (EC) No 1852/2001 (OJ L 
327,11/12/15, pp. 1-22). https://eur-lex.europa.eu/eli/reg/2015/2283/oj. Accessed 07/06/19. 
Schiavone, A., De Marco, M., Martínez, S., Dabbou, S., Renna, M., Madrid, J., ... Gasco, L. 
(2017). Nutritional value of a partially defatted and a highly defatted black soldier fly larvae 
(Hermetia illucens L.) meal for broiler chickens: Apparent nutrient digestibility, apparent 
metabolizable energy and apparent ileal amino acid digestibility. Journal of Animal Science and 
Biotechnology, 8(1), 51. doi:10.1186/s40104-017-0181-5. 
Van Broekhoven, S., Oonincx, D. G. A. B., Van Huis, A., Van Loon, J. J. A. (2015). Growth 
performance and feed conversion efficiency of three edible mealworm species (Coleoptera: 
Tenebrionidae) on diets composed of organic by-products. Journal of Insect Physiology, 73, 1-10. 
doi:10.1016/j.jinsphys.2014.12.005 
Van Broekhoven, S., Gutierrez, J. M., De Rijk, T. C., De Nijs, W. C. M., Van Loon, J. J. A. 
(2017). Degradation and excretion of the fusarium toxin deoxynivalenol by an edible insect, the 
yellow mealworm (Tenebrio molitor L.). World Mycotoxin Journal, 26(2), 163-9. 
doi:10.3920/WMJ2016.2102 
Van Huis, A., Van Itterbeeck, J., Klunder, H., Mertens, E., Halloran, A., Muir, G., 
Vantomme, P. (2013). Edible insects. Future prospects for food and feed security. FAO (No. 171). 
https://library.wur.nl/WebQuery/wurpubs/fulltext/258042 Accessed 23/01/18. 
Van Huis, A. (2015). Edible insects contributing to food security? Agriculture & Food 
Security, 4(1), 20. doi: 10.1186/s40066-015-0041-5 
Veldkamp, T., Van Duinkerken, G., Van Huis, A., Lakemond, C. M., Ottevanger, E., Bosch, 
G., Van Boekel, T. (2012). Insects as a sustainable feed ingredient in pig and poultry diets - A 
feasibility study. (No. 638). Wageningen UR Livestock Research. 
https://library.wur.nl/WebQuery/wurpubs/fulltext/234247 Accessed 23/01/18. 
Veldkamp, T., Bosch, G. (2015). Insects : A protein-rich feed ingredient in pig and 
poultry diets. Animal Frontiers, 5(2), 45-50. doi: 10.2527/af.2015-0019 
Velten, S., Neumann, C., Schäfer, J., Liebert, F. (2018). Effects of the partial replacement 
of soybean meal by insect or algae meal in chicken diets with graded amino acid supply on 
19 
 
parameters of gut microbiology and dietary protein quality. Open Journal of Animal Sciences, 
8(03), 259. doi:10.4236/ojas.2018.83020 
Vries, D. (2000). Observations on behaviour and feed intake of chickens kept on free 
range in Muy Muy, Nicaragua. In: Proceedings of the 21st Word's Poultry Congress, Montreal, p. 
1-3. 
Wang, D., Zhai, S. W., Zhang, C. X., Bai, Y. Y., An, S. H., Xu, Y. N. (2005). Evaluation on 
nutritional value of field crickets as a poultry feedstuff. Asian-Australasian Journal of Animal 
Sciences, 18(5), 667-670. doi:10.5713/ajas.2005.667 
Wang, D., Zhai, S. W., Zhang, C. X., Zhang, Q., Chen, H. (2007). Nutrition value of the 
Chinese grasshopper Acrida cinerea (Thunberg) for broilers. Animal Feed Science and 
Technology, 135(1-2), 66-74. doi:10.1016/j.anifeedsci.2006.05.013 
Yi, H. Y., Chowdhury, M., Huang, Y. D., Yu, X. Q. (2014). Insect antimicrobial peptides 
and their applications. Applied microbiology and biotechnology, 98(13), 5807-5822. 
Zielińska, E., Baraniak, B., Karaś, M., Rybczyńska, K., Jakubczyk, A. (2015). Selected 
species of edible insects as a source of nutrient composition. Food Research International, 77, 
460-466. doi:10.1016/j.foodres.2015.09.008 
20 
 
21 
 
2. CAFETERIA-TYPE FEEDING OF CHICKENS INDICATES A PREFERENCE FOR 
INSECT (Tenebrio molitor) LARVAE MEAL 
Marcos Antonio Nascimento Filho1,*, Raquel Tatiane Pereira1, Ana Beatriz Santos de 
Oliveira1, Diana Suckeveris1, Alvaro Mario Burin Junior1, Thiago de Araújo Mastrangelo2, Diego 
Vicente da Costa3, José Fernando Machado Menten1 
 
 
1Department of Animal Science, University of São Paulo, Piracicaba, SP, 13418-900, 
Brazil 
2Radioentomology and Food Irradiation Laboratory, Center of Nuclear Energy in 
Agriculture, Piracicaba, SP, 13416-000, Brazil 
3Agricultural Sciences Institute, Federal University of Minas Gerais, Montes Claros, 
MG, 39404-547, Brazil 
 
Manuscript prepared according to the guidelines of Animals - accepted article 
 
SIMPLE SUMMARY 
The use of insects as an alternative ingredient in the feed industry is a 
promising solution to optimize animal production systems worldwide. These 
insect-derived products are seen as novel sources of animal origin protein, 
especially in avian and aquatic species diets, which are sustainable in production 
and desirable as nutrient-rich feed ingredients. In order to be used in feed 
formulations for poultry, the nutritional composition of the insect products and 
the effects on performance of chickens must be known. In the present study, we 
investigated whether broilers displayed a preference (or not) for Tenebrio molitor 
larvae meal, evaluating ingredient acceptability and birds’ performance. After a 
few days of being offered insect meal in a cafeteria-type study, chickens 
developed a clear preference for this ingredient compared to usual feed 
ingredients, especially extruded semi-whole soybean meal (high protein content). 
Additionally, there was an indication that T. molitor meal consumption by the 
chickens improved feed conversion. We conclude that T. molitor meal is a 
promising protein ingredient for poultry diets. Overall, although insect-derived 
products are still under regulation processes all around the world, the increasing 
knowledge concerning this topic indicates that insects could be a suitable 
alternative as feed source in the animal industry. 
22 
ABSTRACT 
This study aimed to determine whether broilerchickens display a 
preference for Tenebrio molitor larvae (TM) meal by evaluating ingredient 
acceptability and birds’ performance. Sixty 14-day-old male chickens were 
assigned into two treatment groups (5 birds/pen, n = 6) in a cafeteria-type study: 
the control (C) group, and the TM group. Each pen was equipped with one bell 
drinker and four through feeders allocated side by side; all feeders of the C group 
contained a complete standard diet whereas each feeder of the TM group 
contained one of the following ingredients: ground corn, extruded semi-whole 
soybean, vitamin-mineral supplement mixture, and TM meal. Feed intake was 
recorded daily and growth was monitored periodically up to day 32. Chickens 
which had access to individual feed components showed a delay to display 
preference for TM, but consumed, overall, up to 50% of the total intake as TM 
meal. Feed intake and growth performance were lower in all periods for TM group 
(P < 0.02), whereas feed conversion ratio was improved on days 22–28 and days 
29–32 of age (P < 0.01). Data from bivariate and multidimensional analysis 
indicate that birds started to reach a balance of ingredient intake at 25 days of 
age, showing a high correlation between consumption of each ingredient and the 
day of the experiment. Chickens exhibited a preference for T. molitor meal, 
resulting in improved feed efficiency, which allows us to conclude that it can be a 
suitable feed alternative for poultry. 
Keywords: insect meal; Tenebrio molitor; broiler; alternative ingredient; 
acceptability; nutritional value; performance 
 
2.1. Introduction 
The use of insects in animal nutrition is a promising alternative in order to obtain a 
sustainable protein source to feed the world. Considering the current challenges of 
overpopulation and feed supply for animals and humans, new feed ingredients are needed to 
provide a secure food production chain in the future [1]. 
Edible insects have been shown to be highly nutritious and healthy food sources (rich 
in protein and fat), with beneficial nutraceutical properties. Moreover, by seeking animal 
production systems that are more environmentally friendly, insect rearing has contributed 
positively to new sustainable ecosystems, requiring less water, food, space, and, most 
interesting, recycling organic by-products as substrate for growth [2–4]. 
23 
 
Among circa 2000 species of known edible insects, Tenebrio molitor (TM) is one used 
to produce larvae meal for animal feeding [5,6]. The dried meal derived from TM larvae is rich 
in protein (47%–60%) and fat (31%–43%) content, and has been introduced in commercial 
pet and zoo animals’ diet [4,7]. 
Chickens have the natural behavior of picking up a variety of insects during their 
entire lifecycle and eating them voluntarily, and these insects may represent a part of the 
bird’s ingested food [3]. Moreover, studies have shown that birds are able to self-select 
available feedstuffs in order to balance their own diet, meeting nutritional requirements [8]. 
Considering that insect meal has a similar protein content to soybean meal, and soy 
cultivation requires vast arable land areas and leads to some environmental damage [9], it is 
feasible to suggest that insects can be introduced in feed formulation for chickens. 
In addition to concerns about land usage, greenhouse gas emissions, public health, 
and water pollution [10,11], recent studies reveal how insect rearing systems can produce a 
beneficial food and feed source throughout the next years [12]. In 2017 the European 
Commission authorized the application of insect protein in aquaculture feed (EU 2017/893) 
[13], and it is expected that a new revision of the feed ban rules will allow insect protein in 
poultry and swine feed by 2020 [14]. In many countries there have been investments to 
support this alternative feed ingredient on the market for commercial-scale production, and 
animals might favor insects once they become a regular component of their diet [15]. 
Regarding its nutritional value, some studies have investigated amino acid profile, 
fatty acid content, nutrient digestibility, and health benefits of this alternative protein 
ingredient and demonstrated promising results, but the information is still limited and 
additional research is under development [16–20]. In order to provide new useful and 
accurate information on TM meal in practical diets for poultry, this study aimed to determine 
whether chickens display a preference for TM meal when offered simultaneously to corn, 
extruded semi-whole soybean, and supplement mixture, in a cafeteria-type trial, by 
evaluating ingredient acceptability and birds’ performance during the period from 14 to 32 
days of age. 
 
 
 
24 
2.2. Material and Methods 
The experimental procedures were approved by the Institutional Animal Care and 
Use Committee, University of São Paulo, Piracicaba, SP, Brazil (protocol number: 
2017.5.2568.11.5; 17/11/2017). 
2.2.1. Animals, diets, and experimental procedures 
A cafeteria-type feeding (free-choice) study was conducted at the Department of 
Animal Science, University of São Paulo, Piracicaba, São Paulo, Brazil. A total of 100 one-day-
old male broiler chickens (individual body weight ~52 g) of a commercial strain (Ross AP95) 
were raised in floor pens (wood shavings as bedding material) and fed a corn-soybean meal 
starter diet. At day 14, 60 birds of uniform body weight (~459 g) were chosen and randomly 
distributed into two dietary treatments: a control (C) group, and a TM group (test group). 
Each pen was equipped with one bell drinker and four through feeders allocated side by side; 
all feeders of the C group contained a complete standard diet (Table 1) to meet birds’ 
nutritional requirements for standard performance [21], whereas each feeder of the TM 
group contained one of the following ingredients: ground corn, extruded semi-whole 
soybean, supplement mixture (vitamin–mineral premix, limestone, dicalcium phosphate, salt, 
choline chloride, amino acids, salinomycin), and TM meal. Each group consisted of six 
replicate floor pens (five birds/pen) assigned to a completely randomized design. The insect 
meal was obtained from Vida Proteína Cia. Ltd.a., Neirópolis, Goiás, Brazil. Feed and water 
were available ad libitum. All feeders were rotated of position daily to avoid eventual 
laterality of the animals. Supplement mixture was composed of one part of the mix of the 
minor components and three parts of sand in order to dilute and encourage consumption. 
The C group was used as a reference for total feed and nutrient consumption by the birds. 
 
 
 
 
 
 
 
25 
 
Table 1. Composition of the standard diet of control group, as fed basis. 
Ingredients (g/kg, Unless Noted) 14–32 Days 
Corn 544.5 
Extruded semi-whole soybean 41.7% CP 422.0 
Dicalcium phosphate 14.1 
Limestone 7.9 
Salt 5.0 
DL-Methionine 2.5 
Vitamin premix 1 1.2 
L-Lysine 77% 1.1 
Choline chloride 70% 0.6 
Salinomycin 12% 0.6 
Mineral premix 2 0.5 
Total 1,000 
Nutrient profile 3 
Crude protein 233.4 
Ether extract 60.9 
Crude fiber 24.8 
Available phosphorus 3.7 
Calcium 7.6 
Methionine 5.4 
Lysine 11.2 
Methionine + Cysteine 8.3 
Threonine 7.5 
AMEn (MJ/kg) 12.71 
1 DSM Nutritional Products, Composition per kg of diet: Vit. A—10,800 UI; Vit. D3—3000 UI; Vit. E—24 UI; Vit. 
K3—3 mg; Vit. B1—2.4 mg; Vit. B2—7.2 mg; Vit. B6—3.6 mg; Vit. B12—18 μg; Nicotinic acid—42 mg; Pantothenic acid—21.6 
mg; Biotin—0.12 mg; Folic acid—1.8 mg; Selenium—0.3 mg. 2 DSM Nutritional Products, Composition per kg of diet: 
Manganese—80 mg; Iron—50 mg; Zinc—50 mg; Copper—10 mg; Cobalt—1 mg; Iodine—1 mg. 3 On a 88.9% dry matter 
basis, the crude protein, ether extract, and crude fiber are analyzed values, others are calculated values. 
2.2.2. Measurements and analytical methods 
Samples of TM meal, corn, extruded semi-whole soybean, and the standard dietwere ground to pass through a 1-mm sieve and stored in plastic bags. Analyses were carried 
out to determine the dry matter (DM), ether extract (EE), and crude protein (CP). Additionally, 
ash, gross energy (GE), amino acid composition (AA), fatty acid profile (FA), calcium, 
phosphorus, copper, iron, manganese, and zinc content of TM meal were determined to 
characterize the ingredient. According to standard procedures proposed by Association of 
Official Analytical Chemists (AOAC) [22], the samples were dried to a constant weight at 105 
26 
°C for 24 h to determine the DM content (procedure 930.15). GE was measured using an 
oxygen bomb calorimeter (Parr 6200; Parr Instrument Co., Moline, IL, USA). Nitrogen was 
determined in order to calculate CP (N*6.25) using AOAC [22] procedure 984.13, ash content 
using the furnace muffler at 550–600 °C, procedure 924.05, and EE by Soxhlet extraction 
method, procedure 920.39. Quantitative measurement of AA (except tryptophan) was 
performed by AMINOLab® (Evonik Industries, Hanau, Germany) using a HPLC procedure with 
sample preparation by hydrolysis with the hydrochloric acid method for most amino acids, or 
by performic acid oxidation prior to the hydrolysis for methionine and cystine analysis [23] 
(procedure 994.12). 
FA methyl esters (FAMEs) were analyzed using Focus gas chromatography (Thermo-
Finnigan, San Jose, CA, USA) equipped with a flame ionization detector (FID) and a CP-Sil 88 
capillary column (100 m length * 0.25 μm i.d. * 0.20 μm film thickness; Supelco, Bellefonte, 
PA, USA). The following temperature program was used: initial hold of 4 min at 70 °C; 
followed by rise at 13 °C/min to 175 °C and rise at 4 °C/min from 175 to 215 °C; and a final 
hold of 5 min followed by rise at 7 °C/min to 230 °C. The injector temperature was 250 °C. 
The injection volume was 1 μm. The detector temperature was 260 °C. Peaks were identified 
by comparison of retention times for known FAME standards with software (Chromquest 4.1, 
Thermo Electron, Monza, Italy) and FA contents were estimated by an area normalization 
method from Sigma as internal standard. The FA profile was expressed as % of total lipids. 
Mineral samples were determined by the CBO Laboratory (Campinas, São Paulo, Brazil) 
following AOAC [24] procedure method 927.02 for calcium, copper, iron, manganese, and 
zinc, and procedure method 965.17 for phosphorus. Similarly, corn, extruded semi-whole 
soybean, and the standard diet were analyzed for DM and CP, and the supplement mixture 
for calcium and phosphorus following the procedures mentioned above. 
Broiler growth performance was measured starting on day 15 until 32 days of age. 
Due to the limited amount of insect meal available, the experiment was terminated when the 
supply of the product was finished. Feeders were weighed and refilled daily to determine the 
feed intake of each individual component per treatment pen. The consumption of sand used 
as an inert substance in the supplement mixture was not taken into account in the 
calculations. Birds were weighed on days 21, 28, and 32 to determine body weight gain and 
feed conversion ratio. 
27 
 
2.2.3. Statistical Analysis 
Performance data were submitted to ANOVA by PROC GLM (General Linear Models) 
of SAS 9.4 [25]. When a significant effect was verified, the variables were submitted to mean 
comparison by t test within each evaluation period. For the test group, data of daily individual 
ingredient consumption were compared by Tukey test. In addition, these data of each feed 
ingredient in the six replicates of the test group were submitted to a parametric analysis 
(Pearson’s correlation coefficient) with descriptive statistics by PROC CORR of the SAS 
software to establish the day on which the intakes tended to plateau; in other words, when 
the consumption of TM meal was constant. In order to rate the preference of each ingredient 
consumed by the birds, a nonmetric multidimensional preference analysis (MDPREF) was 
performed through PROC PRINQUAL of the SAS program to identify whether or not there was 
preference for TM meal by the birds. When pertinent, data were evaluated considering the 
level of 5% of significance. 
2.3. Results 
The analyzed values for DM, EE, and CP were 868.9 g/kg, 29.6 g/kg, and 86.1 g/kg in 
corn and 931.1 g/kg, 125.3 g/kg, and 416.8 g/kg in extruded semi-whole soybean, 
respectively. The nutritional profile and mineral content of TM meal used in this study are 
summarized in Table 2 and compared to average values found in the literature. The total 
protein and fat content in TM larvae were 521 g/kg DM, and 317.4 g/kg DM, respectively. The 
GE content of TM meal on a dry matter basis was 28.45 MJ/kg. The mineral contents of TM 
meal were calcium (1228 mg/kg DM), phosphorus (6058 mg/kg DM), copper (6.8 mg/kg DM), 
iron (62.4 mg/kg DM), manganese (12.9 mg/kg DM), and zinc (115.1 mg/kg DM). For amino 
acid composition (Table 3), high values were found for valine (32.5 g/kg DM) and histidine 
(17.5 g/kg DM) in TM meal. Among the essencial amino acids, leucine was the most abundant, 
whereas glutamic acid was the most abundant non-essential amino acid. 
The fatty acid profile of TM meal is reported in Table 4. Concerning the main fatty 
acids in the test ingredient, significant amounts of palmitic, oleic, linoleic, and α-linolenic acid 
were observed, with values of 15.4, 45.3, 26.2, and 1.1 g/100 g of fat, respectively. 
The results for daily average feed intake of each component offered to the birds in 
the six replicates for the test group are shown in Table 5. Up to day 17, corn was the 
28 
ingredient consumed in greatest amount by the birds (P < 0.001). From day 18 until day 24, 
there was a shift in this trend and after that (day 25) the intake of TM meal was superior 
compared to all other components (P < 0.001). In Table 6 the Pearson’s correlation coefficient 
of feed intake of all ingredients between the ages of the birds at 23, 25, 27, 29, and 30 days of 
age is shown. Starting on day 25, there was a very high positive correlation (r = 0.93–0.98) 
among variables; on the other hand, r values for day 23 and the prior days of the experiment 
were lower (0.68–0.72), although significant. 
 
Table 2. Chemical composition and mineral content of T. molitor (TM) meal used in the study 
compared to range values in the literature (dry matter basis). 
 TM Meal Literature 1 
Dry matter (g/kg) 936.7 946.7–962.8 
Crude protein (g/kg) 521.0 492.0–555.8 
Gross energy (MJ/kg) 28.45 24.40–32.42 
Ash (g/kg) 41.2 28.6–31.0 
Ether extract (g/kg) 317.4 280.0–361.0 
Calcium (mg/kg) 1228 169–2700 
Phosphorus (mg/kg) 6058 2850–7800 
Cu (mg/kg) 6.8 6.1–16.0 
Fe (mg/kg) 62.4 20.6–66.9 
Mn (mg/kg) 12.9 5.2–9.0 
Zn (mg/kg) 115.1 52.0–116.0 
1 References: [4,5,7,16,17,26–28]. 
 
 
 
 
 
 
 
 
 
 
29 
 
Table 3. Amino acid profile of T. molitor (TM) meal used in the study compared to range 
values in the literature (g/kg of dry matter basis). AA: amino acid composition; DM: dry 
matter. 
 TM Meal Literature 1 
Essential AA (g/kg of DM) 
Arginine 28.2 23.6–34.5 
Histidine 17.5 14.2–20.1 
Isoleucine 22.5 21.0–35.6 
Leucine 38.0 31.5–45.8 
Lysine 30.0 25.7–35.9 
Methionine 7.4 6.3–10.1 
Methionine + Cysteine 12.2 9.4–22.6 
Phenylalanine 23.9 16.1–23.0 
Threonine 20.2 18.1–26.1 
Valine 32.5 24.4–39.7 
Non-essential AA (g/kg of DM) 
Alanine 38.0 36.8–44.3 
Aspartic acid 44.2 35.9–50.5 
Cysteine 4.8 3.1–12.5 
Glycine 27.0 22.1–31.8 
Glutamic acid 62.9 56.8–79.7 
Proline 30.9 30.2–43.4 
Serine 23.3 20.9–37.0 
Tyrosine 45.9 28.4–39.1 
1 References: [7,17,26–28]. 
 
Table 4. Fatty acid content of T. molitor (TM) meal used in the study compared to the 
literature (g/100 g of EE). 
Fatty Acid TM Meal Literature 1 
Myristic acid (C14:0) 3.1 2.9–4.0 
Palmitic acid (C16:0) 15.4 16.7–22.9 
Stearic acid (C18:0) 2.3 2.5–3.9 
Oleic acid (C18:1) 45.337.7–53.9 
Linoleic acid (C18:2n6) 26.2 27.4–34.8 
α-Linolenic acid (18:3n3) 1.1 1.3–1.4 
1 References: [4,5,16,26,28]. 
 
 
30 
Table 5. Daily consumption of ground corn, extruded semi-whole soybean, T. molitor (TM) 
meal, and supplement mixture of the test group from day 15 to day 32, data in grams per pen 
(five chickens) ± standard deviation. 
Days Corn Extruded s-w Soybean TM Meal Supplement Mixture P Value 
D15 250 ± 31 a 12 ± 16 b 8 ± 2 b 3 ± 3 b <0.0001 
D16 284 ± 35 a 35 ± 29 b 19 ± 27 b 14 ± 13 b <0.0001 
D17 254 ± 128 a 21 ± 32 b 102 ± 126 b 21 ± 28 b <0.001 
D18 225 ± 118 a 19 ± 27 c 207 ± 180 ab 31 ± 19 bc <0.005 
D19 174 ± 157 a 18 ± 27 a 193 ± 147 a 24 ± 22 a <0.05 
D20 136 ± 106 ab 33 ± 62 b 209 ± 163 a 21 ± 13 b <0.05 
D21 138 ± 118 ab 37 ± 76 b 268 ± 129 a 22 ± 16 b <0.001 
D22 116 ± 108 ab 37 ± 87 b 270 ± 135 a 19 ± 12 b <0.001 
D23 148 ± 104 ab 31 ± 68 b 240 ± 120 a 20 ± 18 b <0.001 
D24 139 ± 77 ab 35 ± 83 b 239 ± 98 a 29 ± 25 b <0.001 
D25 147 ± 49 b 14 ± 17 c 307 ± 43 a 26 ± 15 c <0.0001 
D26 133 ± 69 b 18 ± 18 c 312 ± 37 a 42 ± 22 c <0.0001 
D27 135 ± 64 b 7 ± 6 c 296 ± 42 a 59 ± 59 bc <0.0001 
D28 143 ± 68 b 12 ± 7 c 336 ± 48 a 48 ± 19 c <0.0001 
D29 148 ± 74 b 12 ± 7 c 339 ± 41 a 37 ± 13 c <0.0001 
D30 173 ± 76 b 20 ± 24 c 296 ± 34 a 37 ± 13 c <0.0001 
D31 196 ± 72 b 9 ± 9 c 293 ± 61 a 38 ± 15 c <0.0001 
D32 210 ± 90 b 20 ± 19 c 308 ± 55 a 31 ± 8 c <0.0001 
a,b,c Mean values within a row having different superscripts are statistically different by Tukey test (P < 
0.05). 
 
Table 6. Pearson’s correlation coefficient and P value of feed intake of all ingredients between 
the ages of the birds at 23, 25, 27, 29, and 30 days of age. 
Intake of Feed Components Correlation Coefficient (r) P Value 
d23 vs. d25 0.71817 <0.0001 
d23 vs. d27 0.72751 <0.0001 
d23 vs. d29 0.68919 0.0002 
d23 vs. d30 0.71423 <0.0001 
d25 vs. d27 0.93712 <0.0001 
d25 vs. d29 0.96498 <0.0001 
d25 vs. d30 0.95711 <0.0001 
d27 vs. d29 0.95661 <0.0001 
d27 vs. d30 0.93542 <0.0001 
d29 vs. d30 0.98022 <0.0001 
 
31 
 
In order to endorse the justification whether or not broilers have preference for TM 
meal or other food component in this study, a multivariate analysis graph for the feed 
consumption of the test group is presented in Figure 1. The graph shows a matrix containing 
the reference classification of the four components (represented as circles) for the 18 days of 
experimentation (represented as vectors). Regarding the preference of the birds for TM meal 
in a scale of daily intake, in which the amount of consumption means high or low preference 
for the ingredient, it is possible to verify that the vectors for days 25 to 32 of birds’ age point 
in the direction of the most preferred ingredient, TM meal, in four out of six circles 
(replicates) of the test group. In the graph, bird preference increases as the vectors move in a 
positive direction from the origin to the arrow. This finding evidences the higher consumption 
of TM meal compared to the other components in the last days of the trial. In contrast, the 
graph allows us to infer that at the beginning of the trial (from days 15–19 of age), ground 
corn was the most preferred ingredient. From days 20 to 24 of age there was no clear 
preference, indicating the period of shift between ground corn and TM meal. Extruded semi-
whole soybean meal and supplement mixture were the least preferred ingredients by the 
birds during the experiment. 
Figure 1. Biplot of multidimensional preference analysis for the consumption of test 
ingredients from day 15 to 32 of birds’ age (S = Extruded semi-whole soybean meal, N = 
Supplement mixture, M = Ground corn, T = TM meal). 
32 
Data for growth performance are summarized in Table 7. Feed intake of the 
balanced complete diet and weight gain of the birds of C group in the three evaluation 
periods were higher than in the test group (P < 0.02), in which the birds had the choice of 
ingredients. For feed conversion ratio, no difference was observed between birds of the C 
group (1.76) and those of the test group (2.15) in the period from days 15 to 21 (p = 0.418). 
Interestingly, the feed conversions from days 22 to 28 of age were statistically different, with 
average values of 1.22 for the TM group vs. 1.59 for the C group (p = 0.004), and the same 
trend was observed from days 29 to 32, in which the feed conversion of the test group (1.36) 
was better than that of the control group (1.63, p = 0.014). 
 
Table 7. Feed intake, weight gain, and feed conversion ratio of the C group and TM group per 
period (average/bird ± standard deviation). 
Variables 
Treatments 1 
P Value 
C TM 
Days 15–21 
 Feed Intake (g) 799 a ± 67 537 b ± 54 <0.0001 
 Weight Gain (g) 455 a ± 11 297 b ± 111 0.006 
Feed Conversion Ratio 1.76 a ± 0.14 2.15 a ± 1.14 0.418 
Days 22–28 
 Feed Intake (g) 966 a ± 72 638 b ± 77 <0.0001 
 Weight Gain (g) 611 a ± 37 528 b ± 60 0.016 
Feed Conversion Ratio 1.59 a ± 0.16 1.22 b ± 0.18 0.004 
Days 29–32 
 Feed Intake (g) 699 a ± 60 414 b ± 68 <0.0001 
 Weight Gain (g) 430 a ± 37 311 b ± 72 0.005 
Feed Conversion Ratio 1.63 a ± 0.07 1.36 b ± 0.22 0.014 
1 Treatments: C = Control group; TM = T. molitor group. a,b Mean values within a row having 
different superscripts are statistically different by the t test (P < 0.05). 
 
2.4. Discussion 
The data on nutrient composition of TM larvae meal indicate that protein value is 
similar to those found in other studies showing that insects are a good source this nutrient; in 
particular, T. molitor has an average protein content of 526 g/kg DM [4,17,28,29]. Moreover, 
Finke [16] mentioned that T. molitor has a sufficient amount of protein for the growth of rats 
and chickens, being nutritionally equivalent to fish meal and soybean meal. Regarding the 
33 
 
composition of essential amino acids, the TM meal used in this study showed higher values 
for valine and histidine compared to animal protein sources utilized in the feed industry, e.g., 
meat meal (24.5 and 9.5 g/kg DM, respectively) and fish meal (28.2 and 11.2 g/kg DM, 
respectively). In addition, it has similar or slightly higher contents of all amino acids compared 
to vegetable protein sources [5]. For Bukkens [30], in most cases, insect protein is better 
balanced than that of plants. 
Differences observed between values of amino acids in the literature and the 
present study appear as a consequence of a wide variation in composition for TM meal from 
different databases. The variable content of amino acids may be due to factors such as 
methodology employed, local food availability, and larval stage [4,31,32]. Overall, our results 
are in agreement with those reported by Ravzanaadii et al. [26], evaluating the nutritional 
value of T. molitor as a food and feed source, as well as De Marco et al. [17] and Elahi et al. 
[33], who evaluated the potential use of T. molitor for broiler chickens. 
For mineral composition, the analyzed values are within the range found in the 
literature. The concentrations of calcium and phosphorus are much lower than those in the 
usual ingredients of animal origin used in feeds, because insects have a soft structural body, 
not including bones. Phosphorus concentration is similar to that of soybean meal, but it is 
considered totally available [16,34]. Moreover, TM meal seems to be a very good source of 
trace minerals such as copper, iron, manganese, and zinc, in agreement with data reported by 
Finke [16]. These trace minerals are essential for biochemical processes in the body, 
participating actively in metabolic and immune responses for production [3]. According to 
Rumpold and Schluter [35], regarding the amount of zinc and iron for nutritional 
requirements, edible insects could be considered a food mineral supplement as they normally 
have high content of these minerals compared to animal protein sources. 
Insect larvaemeal is a rich source of energy due to its high fat content. Insects have a 
very relevant plasticity to modulate body fat composition. The main factor influencing it is the 
substrate in which the larvae are grown [36,37]. 
For fatty acid composition, it was observed that TM meal has a significant amount of 
palmitic, oleic, linoleic, and α-linolenic acid. Despite the variation in composition of fatty 
acids, these data are in close agreement with prior reports [7,26,35]. Unsaturated fatty acids 
seem to have biological importance as functional nutrients, modulating health effects in 
34 
humans [38]. As TM meal shows good amounts of unsaturated fatty acids, it opens other 
possible applications to this novel alternative feed ingredient. 
Measuring daily average feed intake, it was observed that in the first few days a wide 
variation in consumption occurred in the four components of all pens in the test group, 
indicating a peculiar feeding behavior of the birds. In addition, corn was the ingredient 
consumed in greatest amount by the birds (up to day 17 of age). From day 18 to day 24, there 
was a shift in this trend, showing that, among the protein ingredients, there was a preference 
for the TM meal compared to extruded semi-whole soybean meal. Starting at 25 days of age 
the intake of TM meal was superior compared to all other components, which evidences the 
acceptability and choice of this ingredient by the birds. Along the trial, the intake of TM meal 
in the test group increased considerably, reaching 34% of total consumption during the first 
seven days of experiment, 62% during the following seven days and, in the last four days, 
58%. This preference may be based on the food habit of birds, once they have the practice of 
entomophagy [3]. Moreover, the birds’ intense craving for TM meal might be also related to 
its nutritional composition (high energy and protein values) and may be associated with other 
undetermined properties. 
Through a parametric evaluation of linear relationship for feed intake of all 
ingredients between the ages of the birds at 23, 25, 27, 29, and 30 days of age, it is possible 
to assume, based on very high positive correlations, that birds started to reach a constant 
balance of ingredient intake from the 11th day of the experiment, which refers to day 25 of 
bird age. The multidimensional preference analysis corroborates the explanation about the 
uniformity for consumption of the ingredients by the birds of test group from the 11th day of 
experimentation (day 25 of bird age). Once TM meal preference was established, the birds 
had also adapted to the choice of the other components, which reduced the variation of 
intake among them, as can be seen in Table 6. To the best of the authors’ knowledge, there 
are no data reported in the literature evaluating feed preference of birds for insect meal to be 
compared to the findings described. 
In the present study, the data for feed intake showed a difference in consumption up 
to 30% between groups. During the first two days of the experiment, the diet of the test 
group was clearly unbalanced (Table 5), with the chickens consuming 80–90% corn; in 
addition, during the first week, total feed intake and weight gain of the test group were 
reduced by 33–35%. The low initial weight gain due to the unbalanced diet may have been 
35 
 
harmful for further growth of the chickens. According to Yo et al. [39], sensory factors (e.g., 
color) play an important role in ingredient intake and regulation; thus, birds fed a basal diet 
(corn–soybean meal) before the initiation of the trial might have found ground corn similar to 
it, unleashing a preference for this component. Along the days, birds instigated by their active 
and curious behavior were able to self-select other components to promote regular growth. 
Interestingly, the most consumed component reverted to be TM meal (protein- and energy-
rich), followed by ground corn (energy content), which indicates the capability of birds to 
regulate the consumption of ingredients to maintain the energy: protein ratio according to 
their nutritional needs [40]. Moreover, the unquestionable shift from a conventional protein 
source (soybean) to TM meal was observed and it may demonstrate that birds opted to feed 
on TM meal because of its sensory characteristics as well as good nutritional profile. 
Accordingly, Biasato et al. [41] suggested that improved diet palatability might be responsible 
for the increased feed intake and weight gain when chickens were fed TM meal in their study. 
Although birds of the test group had the capacity to balance their consumption as 
the trial advanced, weight gain was also proportionally lower compared to the C group. This 
can be explained by the cafeteria-type feeding system (free-choice), as during a period of 
time (days 15–25 of age) birds were trying to adjust an appropriate diet to meet daily 
requirements [42], which affected the weight gain of the test group. It must be noted that 
measurable TM meal intake took up to 10 days in some pens and its consumption was 
immediate in other pens (data not shown). This fact resulted in great differences among pens 
for nutrient intake and expected differences in feed efficiency. Therefore, the values of feed 
conversion encountered may be impaired, especially in the period from days 15 to 21. Once 
birds of the TM group started to better balance their diets, it was possible to verify a great 
improvement in feed conversion from days 22 to 28 and days 29 to 32 of age, in which this 
variable was better for the test group compared to the control group. Even though it is known 
that a balanced complete diet supplies an adequate mixture of all nutrients required to 
improve efficiency [43], this current study shows interesting features about TM meal in its 
capacity to improve feed conversion in a free-choice feeding trial. It is possible to notice that 
as birds were adapting to the free-choice diet, they started to recover in performance 
continuously. 
36 
The present findings about feed preference with TM meal are the first data available, 
which might aggregate information in the literature to indicate that birds have a great 
preference for insect meal-based products. New studies must be done in order to gather data 
on the digestibility, performance, and immune system of birds fed insect meal for future 
global applications as a feed. 
 
2.5. Conclusions 
Chickens exhibited a preference for Tenebrio molitor meal, resulting in improved 
feed efficiency, which allows to conclude that it can be a suitable feed alternative for poultry. 
 
Author Contributions 
M.A.N.F. conceptualization, data curation, formal analysis, investigation, writing—
original draft preparation, visualization; R.T.P. conceptualization, methodology, project 
administration; A.B.S.d.O. investigation; D.S. investigation; A.M.B.J. investigation; T.d.A.M. 
investigation, resources; D.V.d.C. investigation, resources; J.F.M.M. conceptualization, 
writing—original draft preparation, project administration, supervision. 
 
Acknowledgments 
This research was funded by FAPESP, São Paulo Research Foundation, project grant 
number 2017/05423-8 and master’s scholarship grant number 2017/19751-7. The authors 
kindly acknowledge Banco do Nordeste do Brasil (BNB), Vida Proteína for the insect meal 
supply, and Evonik Brasil for the amino acid analyses. 
 
Conflict of Interest 
The authors declare no conflict of interest. 
 
References 
1. Grau, T.; Vilcinskas, A.; Joop, G. Sustainable farming of the mealworm Tenebrio molitor 
for the production of food and feed. Z. Nat. 2017, 72, 337–349, doi:10.1515/znc-2017-
0033. 
37 
 
2. Veldkamp, T.; van Duinkerken, G.; van Huis, A.; Lakemond, C.M.M.; Ottevanger, E.; 
Bosch, G.; van Boekel, M.A.J.S. Insects as a Sustainable Feed Ingredient in Pig and 
Poultry Diets: A Feasibility Study;