Estratégias nutricionais para terminação de cordeiros em pastagem ou em confinamento

Abstract

The aim this study was to evaluate nutrient intake, feed conversion (FC), incidence of verminoses and weight gain (GW) over time. Digestibility, glucose (GLI), triacylglycerides (TAG), cholesterol (COL) and insulin (INS) concentrations, ruminal histology, carcass and cuts evaluation, physicochemical and sensorial meat characteristics, fatty acid profile present on meat and expression of genes linked to lipid metabolism of lambs managed in three feed management systems: feedlot (FL) to pasture (PAS) and receiving high grain diets with 85% whole corn grain (WCG). The intake of dry matter, crude protein, ethereal extract, organic matter and ash was linear intake during the experimental period (P> 0.005). The highest dry matter digestibility was observed for the MGI feed management. The incidence of verminoses was higher for PAS feed m management. The lower CA and higher GPD were for WGC (P <0.005). FL feed management showed higher intake of dry matter. The levels of triglycerides and cholesterol were similar for all treatments, glucose and insulin concentrations were higher for MGI feed management as well as the area and height of ruminal papillae. The slaughter weight was higher than the MGI animals, the warm and cold carcass weight were lower for PAS feed management, as well as loin eye area and subcutaneous fat thickness. The cut leg and chest were higher proportions (P> 0.005) for the FL and WGC dietary management, and palette was higher proportion for PAS animals. The pH and shear force of the meat were similar for the three treatments. There was an increase in the fat content on meat for the WGC food management, accompanied by a reduction in the moisture content. There was a higher proportion of polyunsaturated fatty acids and conjugated linolenic acid in sheep meat from food management PAS.The proportion of saturated fatty acids was similar in all treatments and the lower monounsaturated content for PAS management. The ratio n6: n3 was higher for animals from the FL and MGI treatments (P = 0.159). The activity of Δ-9 desaturase enzyme was higher for WGC management and elongase activity was higher for PAS feed management. The PPARalpha expression was similar for all treatments, the SCD1 gene lower expression for FL (P = 0.0375). The SREBP1 gene was higher for MGI and ELOVL6 management for PAS animals. Attributes of sensory evaluation and overall impression appearance were similar for all treatments. The texture presented a lower note for the FL. The best meat flavor was observed for PAS food management (P = 0.0023).