Lipídeos na dieta de cordeiros de diferentes cruzamentos para produção de carne

Abstract

The aim was to evaluate the use of protected fat (PF) in the finishing diet of lambs from five genetic groups and its effect on: performance, chemical composition of meat and fatty acid profile of the muscle lipids. Two diets were evaluated, which were distributed randomly for the lambs, one was the control and the other with 5.4% PF replacing corn meal, both with 85.1% concentrate and 14.9% forage. In this study, 75 lambs with initial weight of 25.8 ± 3.50 kg were confined until they reached slaughter weight of 44.0 ± 2.76 kg. Of the five genetic groups, one was Santa Inês pure and the other four were from the crossing of Santa Ines sheeps with Black Dorper; White Dorper; Texel; and Lacaune rams. It was used a completely randomized design in a factorial 5 x 2 (five genetic groups and two diets). With the statistical model, it was evaluated the effects of the interaction between the two factors. The crossbred Texel x Santa Inês lambs gained 307 grams / day, being the top gain among all genetic groups, while crossbred White Dorper x Santa Inês lambs gained 256 grams / day, with the lower gain among all genetic groups (P = 0.01). The inclusion of protected fat in the diet increased the dry matter (P = 0.06), ether extract (P <0.01) and crude protein (P <0.01) intake. Weights and carcass yield, as well as the carcass cuts were not affected (P> 0.05) by the evaluated factors. The internal fat (mesenteric and omental) was higher (P <0.01) in lambs receiving protected fat. The chemical composition of meat was not affected (P> 0.05) by the evaluated factors. The proportion of saturated fatty acids in the lipid fraction of meat from lambs of all genetic groups was higher when the protected fat was included in the diet. The inclusion of protected fat in the diet reduced the levels of conjugated linoleic acid (CLA) C18: 2c9t11 in meat from crossbred Texel x Santa Inês, Lacaune x Santa Inês and Santa Inês pure lambs. However, this effect was not observed in the crossbred Black Dorper x Santa Inês and White Dorper x Santa Inês lambs (P = 0.07). While the levels of CLA C18: 2t10c12 were higher only in crossbred Black Dorper x Santa Inês and White Dorper x Santa Inês lambs (p = 0.04) when the protected fat was included in the diet. Since meat with minor proportions of saturated fatty acids and higher proportions of CLA C18: 2c9t11 is desirable by consumers, replacing 5.4% corn flour by 5.4% protected fat in finishing diet with high concentrate is not advantageous for crossbred Texel x Santa Inês, Lacaune x Santa Inês and Santa Inês pure lambs.