Diferentes sistemas nutricionais influenciam na maciez da carne de borregas sem alterar a expressão gênica

Abstract

Feeding is a determining factor in the various characteristics of sheep meat, and animals fed with higher proportions of concentrate have meats with higher fat content, which in turn increases the tenderness sensation, with the enzyme complex calpain and calpastatin being the main one mechanism that leads to tenderization of the meat. The objective were to evaluate the effect of supplementation of lambs finished in different nutritional plans on the gene expression of caspase-3, μ-calpain, m-calpain and calpastatin and its possible association with meat quality. Samples of the Longissimus lumborum muscle from 24 ewes were used, divided into 3 groups: P (pasture - 70 to 80% of the nutritional requirement), PS (pasture and supplement - 100 to 110% of the nutritional requirement) and C (feedlot, provided 140% of the requirement). Physicochemical analyzes were performed for proximate analysis, pH, marbling, lipid oxidation and shear force and also RT-qPCR for the analysis of relative gene expression of the following genes: CASP3 (caspase 3), CAST (calpastatin), CAPN1 (μ-calpain) and CAPN2 (m-calpain).There was statistical difference for ether extract, shear force and lipid oxidation between treatments, on the other hand, there was no difference in gene expression. There is an increase in the ether extract in the meat of confined animals, as the greater energy input in nutrition increases this variable. Animals kept only on pasture have lower lipid oxidation in meat than other treatments due to the higher intake of vitamin E from pasture. The shear force is considerably higher in the meat of animals kept only on pasture, but it’s still considered soft. The nutrition of lambs does not interfere with the gene expression of CASP3, CAPN1, CAPN2 and CAST.