Ciência Rural (Feb 2013)
Período de suplementação de ractopamina em dietas para suínos machos castrados em terminação Lenght of ractopamine supplementation in diets for finishing barrows
Abstract
O objetivo do estudo foi determinar o período ideal de suplementação de 20ppm de ractopamina nas dietas de suínos machos castrados em terminação. Foram utilizados 50 suínos machos castrados com peso inicial de 65,85±4,34kg, distribuídos em delineamento de blocos ao acaso, com seis tratamentos (0, 7, 14, 21, 28 e 35 dias de suplementação de ractopamina pré-abate), sendo quatro repetições para os tratamentos 0, 7, 14, 21 e 28 dias e cinco repetições para o tratamento com suplementação por 35 dias. A unidade experimental foi composta por dois animais. A conversão alimentar melhorou (PThe study was conducted to determine the optimal period of supplementation of 20ppm of ractopamine in diets of finishing barrows. Fifty pigs, with initial weight of 65.85±4.34kg were used. The pigs were distributed in randomized blocks design of six treatments (supplementation of ractopamine for 0, 7, 14, 21, 28 and 35 days pre-slaughter), with four replications for treatments 0, 7, 14, 21 and 28 days and five replicates for the treatment supplemented by 35 days. Each experimental unit consisted of two animals. The feed conversion improved (P<0.05) and the hot carcass weight, the amount of lean meat and the index of carcasses increased linearly (P<0.05) with increasing period of ractopamine supplementation. The economic return for the amount of lean meat produced per animal improved linearly until the period of seven days of supplementation with ractopamine, from which remained at a plateau (P<0.05). Supplementation of 20ppm of ractopamine in the diet of finishing barrows during the 35 days improved feed conversion, increases the hot carcass weight, the amount of lean meat and the index of carcasses. The supplementation of 20ppm ractopamine in the diet of finishing barrows results in economic return for the amount of lean meat produced per animal regardless of the length of supplementation.
