Effects of diets differing in the concentrate-to-roughage ratio on meat quality and fatty acids composition in abomasal digesta and meat from thin-tail and fat-tail Brazilian ovine breeds

Fat-tail ovine breeds are known proposed to have distinctive lipid metabolism compared with thin-tail breeds. This hypothesis was investigated evaluating the effects of two types of diets (high vs low concentrate diet - HC vs LC) fed to two sheep breeds (fat-tail or thin-tail sheep) on fatty acid (FA) composition of abomasal digesta and meat quality. Forty lambs (20 fat-tail lambs and 20 thin-tail lambs) distributed in a randomized complete block design and fed two diets with different roughage: concentrate proportion. Breed slightly modified the FA profile of abomasal digesta and meat, but the 18:3 n-3 rumen biohydrogenation was increased in fat-tail lambs, resulting in a reduction of 18:3 n-3 meat proportion of fat-tail lambs fed HC diet and increased it in meat from thin tail lambs fed LC diet. The HC diet increased dry matter intake, and consequently FA intake, changing extensively the FA abomasal content and profile and increased the fat and protein content in meat. However, breed did not affect the meat fat content and BCFA, as proposed, but the fat-tail lambs decreased n-3 PUFA content and increased n-6 PUFA and t10-18:1 content (mg/100 g fresh meat), reducing the nutritional value of meat.