DIFFERENT SOURCES AND LEVELS OF ENERGY IN SHEEP DIETS AND THEIR EFFECTS ON PROGENY

Abstract

Energy influences the reproduction of sheep, but little is known how levels and different sources can affect this characteristic. There is evidence that maternal nutrition can affect the future production and reproduction of offspring. The objective of the project is to evaluate different levels of energy in the diet (below the requirement at the level and above) according to the recommendations of the NRC (2007), as well as to compare the different sources of energy (cellulose, starch, diets of pregnant sheep and the consequences on their offspring. In order to carry out the project, it will be divided into two experiments: the first one focuses on the nutrition of the sheep and their reproductive indexes and the second one evaluating the fetal programming with evaluations of the reproductive performance of the lambs and the zootechnical of the lambs. The experiments will take place in the Sheep Sector of the prefecture of Campus of the Faculty of Animal Science and Food Engineering of FZEA - USP. It will be used 73 ewes, in a randomized block design, synchronized to the mating season, covered with controlled natural mating and fed with 3 energy levels, being maintenance, gestation and above pregnancy energy by 25% more. In the diets above the maintenance will be used three different sources of energy: starch, protected fat and chromium. The reproductive indices, hormonal parameters, genomic and lipidic parameters will be evaluated in the matrices. In a second experiment, a study of the effect of the mother on the progeny (fetal programming) on the beginning of the reproductive life of the lambs and on the zootechnical performance of the lambs in the confinement will be made. Also will be evaluated characteristic of the carcass as yields, in addition to ruminal parameters such as papilla. In the meat will be made morphological and histological analysis of muscle fibers, in addition to other quality parameters such as softness, water loss, myofibril index, collagen. The statistical design will be in randomized blocks, where the block will be the age of the sheep. Statistical analyzes will be performed using PROC MIXED from SAS statistical package 9.1.2 for Windows (SAS Institute Cary, NC, USA). Non-parametric analyzes will be assessed using the chi-square, and urinalysis will be done with descriptive statistics. The normality of the residues will be verified by the Shapiro Wilk test and homogeneity of the variances by the Levene tests. Data that does not meet these assumptions will be transformed for verification. The original or transformed data will be submitted to the Tukey Test 5% if there is interaction of the factors. (AU)