Restrição alimentar em ovinos deslanados em crescimento, efeitos sobre digestão, metabolismo de nitrogênio e qualidade de carcaça

Abstract

With an irregular rainfall, ruminant production in extensive systems based on native pasture in the semi-arid northeastern region is affected by long periods of quantitative feed restriction, which impacts the performance and carcass traits, affecting the commercialization of their products. This study aimed to evaluate the effects of different levels of feed restriction on the performance, nutrient digestibility, purine derivative (PD), physicochemical properties and fatty acid (FA) profile of crossbred lamb meat. Thirty Dorper x Santa Ines intact, male, lambs (31 ± 1.28 kg initial body weight (BW) and 4 months of age) were distributed in a completely randomized design and were subjected to three levels of feed restriction (0, 30 and 60% dry matter (DM)) for 84 days. The DM, organic matter, crude protein, neutral detergent fiber and total carbohydrate digestibility were higher in animals subjected to 60% DM feed restriction. The microbial crude protein (MCP) synthesis efficiency was highest for animals subjected to 60% DM feed restriction. The average daily gain decreased from 192.2 to -31.0 g/day with increasing levels of feed restriction. Meat fat content was lower in animals under 60% feed restriction. The pH decreased from 5.72 to 5.57 with increasing feed restriction. Animals under 60% DM feed restriction had increased concentrations of saturated FA, C14:0, n6:n3 and thrombogenicity index in meat; however, this level of feed restriction resulted in higher levels of monounsaturated and polyunsaturated FA. In conclusion, lambs subjected to feed restriction at 60% DM showed greater DM digestibility and MCP. Meat of lambs subjected to 60% DM feed restriction had higher contents of C12:0, C14:0, and C16:0, which are considered less beneficial for consumers’ health.