Avaliação do uso da ractopamina na gestação de fêmeas suínas e o efeito no desempenho dos leitões

Abstract

Meat is made up of adipose, connective and muscle tissue, the last being the largest of the components. The muscle mass produced by an animal, as well as its speed of growth depend on the number of muscle fibers (hyperplasia) which compose a muscle and the diameter of each fiber (hypertrophy) (HOSHI, 2008). Besides its functions of carcass improvement, ractopamine may be used in pregnant swine. Because of that, the influence of both nutrition and hormone supply on the number of fetal secondary muscle cells has been studied, and it has been questioned whether this hyperplasic process will render modifications in the number of muscle fibers at birth (HAESEL & BUZEN, 2005). This study aims to evaluate the use of ractopamine in the diet during pregnancyinfluences the weight of piglets at birth and at weaning. The experiment was conducted in a commercial farm pigs, producing piglets in the city of Redentora-RS, part of the Cooperative Agricultural & Industrial (COTRIJUI). We used 18 females, distributed in two treatments, 10 arrays and the control (noractopamine) and 8 arrays containing 20 ppm of ractopamine in the diet. Females consumed the experimental diets from 25 to 50 days of gestation, thus totaling 50 kg of feed per female. The variables were: birth weight of piglets borntotal, born alive, number of stillbirths, number of mummified, total weight of the litter, total number of weaned piglet weight at weaning. The experimental design was completely randomized with different numbers of repetitions. The data obtained were analyzed by Tukey test, with the aid of the computer program Assistat. For the study took into account the average number of piglets weaned per female and the average individual weight, since there were heavylitters. Under the conditions of the present study was conducted, adding 20 ppm ofractopamine in the diet, provided 25 to 50 days gestation improved the weight of piglets at birth and therefore weaning.