Composition biochimique et propriétés organoleptiques de la viande d’agneaux nourris aux glands de chêne vert (Quercus ilex)

Abstract

Growth performances, carcasses parameters and meat fatty acid composition of lamb fed green oak acorns (Quercus ilex) based diet. The aim of this experiment is to compare the effects of diets containing green oak acorns (GO) and barley (BL) on the growth performances, carcasses parameters and the composition in fatty acids of lambs. Two groups of five lambs each were fed, respectively, during 105 days with diets containing 50% of oaks acorns and 50% of barley. At the end of the test, the animals of the two diets expressed comparable body weights and weight gain. A significant difference (P < 0.05) was observed for the thickness of fat cover which is 3 mm for the BL group against 1.6 mm for GO group even if no significant difference was revealed concerning the output with slaughtering. The intramuscular lipids were significantly higher (P < 0.05) in the group of animals fed with GO diet compared to the BL diet (3.88 vs 2.83 g.100-1 g of muscle). Among the saturated fatty acids (SFA), the stearic acid significantly appeared in higher proportion (P < 0.05) in GO diet (20.8 vs. 18.1%) whereas the palmitic acid is prevalent in the group of animals fed with the BL diet (25 vs 30%). For the polyunsaturated fatty acid (PUFA), no significant difference was observed between the two groups. The linoleic acid is prevalent among the PUFA of two groups without significant difference. The linolenic acid is higher in theanimal fed BL. The n-6: n-3 ratio is higher in the BL group (8.9 vs 7.3). At the end, the low level of incorporation of PUFA in muscle of the lamb because of biohydrogenation, suggests us supplementing the diet by green grass. Not effect was not observed on Muscle proteins between the two group ( 18.98 % vs18.31 %) Cooking meat has reduced to a considerable extent (20.50 %), the contents of AGS meat lot barley (55.28 % to 43.96 %), in contrast to the batch or GCV relative stability is noticed. An insignificant change (2.24 %) was observed (51.56 % to 50.28 %). On the sensory properties, 85% of tasters found that the meat of the control leg is tender, against 58 % for the batch GOA. However, over 70 % believe that meat from the GOA batch and barley are tender (75%vs.73percentage), respectively. The lamb meat is considered soft by more than 70 % of the panel for barley batch and only 48.50 % for GOA batch. For ribs meat, opinions are divided (81.68 % vs68.34 %). For flavor, 82% vs 62 % of tasters felt that the taste of the meat lot barley intense than the experimental group. In this setting, the opinions are also shared for ribs meat of two batches (80%vs.73). Ultimately, the sensory characteristics of the meat roast lot GOA were acceptable for tenderness (58.35 %), flavor (61.67 %) and juiciness (48.35 %). For ribs meat, it was better appreciated for each of the parameters already mentioned. 73% of tasters found that the meat is tender, juicy 68% and 73 % soft.