Effect of dietary protein level and lamb breed on meat physicochemical traits, fatty acid profile and nutritional indices

Abstract

Special attention is increasingly given to food characteristics, particularly fatty acid (FA) profile. The quality of meat, as food of animal origin, depends on animal genotype and feeding. This study evaluated the meat quality and FA profile of three Tunisian sheep breeds, i.e. Barbarine (BB), Queue Fine de l'Ouest (QFO) and Noire de Thibar (NT), under diets with low (11 %) or high (16 %) crude protein (CP) levels, aiming to optimize feeding strategies for Tunisian sheep production. Lambs were slaughtered at 51 kg body weight. The longissimus-thoracis et lumborum muscle was extracted for meat quality analysis. The intramuscular fat was higher for QFO than other breeds. The meat FA profile was not affected by CP level but was affected by sheep breed. The C16:0 FA was higher for QFO than the two other breeds, which had higher C18:0 FA (17.7 vs. 14.6 %). The n−3 and n−6 polyunsaturated FA (PUFA) contents were higher (P<0.001) for meat of fat-tailed BB than other breeds, resulting in a higher total PUFA and higher PUFA / SFA ratio (0.135 vs. 0.09, where SFA represents saturated fatty acid). The atherogenic index (AI) and cholesterolemic index (h/H) of the meat were in the recommended ranges, being in favour of BB and NT breeds with, respectively, lower and higher values than QFO. However, the thrombogenic index (TI) was high and similar among breeds. In conclusion, the FA profile and lipid indices in sheep meat were primarily influenced by breed, with no significant effect from crude protein level, suggesting that a low-protein diet can yield comparable meat quality to a high-protein diet.