Braña_2012_Diverse sources of Ractopamine affect growth performance differently_pag 130

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IPVS
2012 KOREA
22nd INTERNATIONAL PIG
VETERINARY SOCIETY CONGRESS
Jeju, Korea
June 10-13, 2012 
Oral Sessions
June 11 (Mon)
IPVS
2012 KOREA
22nd INTERNATIONAL PIG
VETERINARY SOCIETY CONGRESS
 NO-049 
 
| Swine Production/Nutrition/Feed-NUTRITION | 
Diverse sources of Ractopamine affect growth performance differently 
 
D Braña1, JR Gabriel2, JA Cuaron1 
1CENID-Fisiologia, INIFAP, Queretaro, Mexico, 2FES-C, UNAM, Edo. de Mexico, Mexico, yeyobv@yahoo.com.mx 
 
Introduction 
Ractopamine (RAC) is a phenethanolamine, β-adrenergic 
receptor agonist that is commercially available 
(Paylean®, PLN, Elanco, Greenfield, IN, USA), for 
enhanced muscle protein growth in pigs. After the 
success of PLN, several companies have developed 
commercial RAC products of obscure origin and 
practically nil basic and safety data, presuming that the 
molecules and their effects would be identical to PLN. 
The food safety issues are on the verge of responsibility 
of public health authorities, but effectiveness for pork 
production is an industry matter that has not been 
appropriately addressed. The herein experiments were 
designed to compare growth performance of finishing 
pigs fed PLN and two commercially available “generic” 
RAC products (GEN), in two identical independent trials, 
where consistency of response within batches was also 
tested. 
 
Materials and Methods 
Trials were two repeated Randomized Complete Block 
experiments, blocks being consecutive weaning rounds. 
Within trial, there were 9 Treatments: a Control diet 
(CON), and 4 different batches (randomly bought) of 
each RAC source (PLN or GEN), included at 5 ppm in 
an adequate diet for PLN, to maximize lean growth rate. 
A total of 528 pigs (half gilts), 238 and 290 in each 
experiment, were assigned as follow: 106 pigs for the 
CON, 213 and 209 for PLN or GEN. Animals were 
individually housed and managed (2.09 m2/pig), fed 
twice a day and weighed weekly; average daily fat free 
lean growth (FFL) was estimated by means of real time 
ultrasound (Aloka 550 SD) measurements. Data were 
statistically analyzed under the restrictions of the 
described model, with 9 treatments (CON, 4 PLN and 4 
GEN) and 4 blocks. Analyses of variance were facilitated 
by the General Linear and Mixed Models (SAS) and data 
are presented as the least square means. 
 
Results 
Initial body weight (Trial 1: 76.6 ±8.32; Trial 2: 84±7.36 
kg) was similar (P