Susceptibility to stress, performance and meat quality of swines of differents castration categories and levels of ractopamine

Abstract

A total of 640 animals, weighing initial average of 23 kg (± 1 kg) will be housed in phases growing and finishing within 120 days and weighing slaughter average of 115 Kg (± 5 kg). These animals will be divided into 64 pens (10 pigs / pen), according to the following treatments: two types of castration (Surgical castration and imunocastration) x 4 levels of ractopamine administered for 28 days before slaughter (0, 5, 10 and 15 ppm) representing 8 treatments. The blocks are defined according to the weight of pigs at weaning (with 21 days) and out the nursery (63 days). Will be analyzed the performance (weight gain, feed intake and feed conversion), welfare (carcass and skin damages and parameters physiological of stress) and meat quality (pH, color, drip loss, cooking loss, texture, fat intramuscular and carcass traits). Animals will undergo a fast of 12 hours before slaughter. The experimental design will be blocks with 8 treatments and 4 repetitions. The data will be submitted for analysis univariate and multivariate analysis of variance involving an full factorial design with two factors (2 categories of castration and 4 levels of ractopamine). Analyses will be implemented through the SAS statistical software (2008). The aim of this study was evaluate the effect of interaction between categories of castration and levels of ractopamine on susceptibility to stress, performance and pork meat quality. (AU)