College of Animal Science and Technology/Gansu Key Laboratory of Herbivorous Animal Biotechnology, Gansu Agricultural University, Lanzhou 730070, China.
School of Fundamental Sciences, Massey University, Palmerston North 4410, New Zealand.
J Appl Microbiol. 2023 Aug 1;134(8). doi: 10.1093/jambio/lxad182.
The meat of Tibetan sheep has a unique flavor, delicious taste, and superior nutritional value. However, the change of grass will lead to a change in meat quality. This study aimed to explore the potential regulatory mechanisms of microbial metabolites with respect to meat quality traits of Tibetan sheep under nutrient stress in the cold season.
We determined and analyzed the longissimus dorsi quality, fatty acid composition, expression of genes, and rumen microbial metabolites of Tibetan sheep in cold and warm seasons. The shear force was decreased (P < .05), the meat color a*24 h value was increased (P < .05), and the contents of crude fat (EE) and protein (CP) were decreased in the cold season. Polyunsaturated fatty acids (PUFAs)-linoleic acid and docosahexaenoic acid increased significantly in the cold season (P < .05). The expressions of meat quality genes MC4R, CAPN1, H-FABP, and LPL were significantly higher in the warm season (P < .05), and the CAST gene was significantly expressed in the cold season (P < .01). The different microbial metabolites of Tibetan sheep in the cold and warm seasons were mainly involved in amino acid metabolism, lipid metabolism, and digestive system pathway, and there was some correlation between microbiota and meat quality traits. There are similarities between microbial metabolites enriched in the lipid metabolism pathway and muscle metabolites.
Under nutritional stress in the cold season, the muscle tenderness of Tibetan sheep was improved, and the fat deposition capacity was weakened, but the levels of beneficial fatty acids were higher than those in the warm season, which was more conducive to healthy eating.
藏羊肉具有独特的风味、美味的口感和卓越的营养价值。然而，草料的变化会导致肉质的变化。本研究旨在探索微生物代谢物在冷季营养胁迫下对藏羊肉质特性的潜在调控机制。
我们测定和分析了冷、暖季藏羊背最长肌品质、脂肪酸组成、基因表达和瘤胃微生物代谢物。冷季剪切力降低（P<.05），肉色 a*24h 值升高（P<.05），粗脂肪（EE）和蛋白质（CP）含量降低。冷季多不饱和脂肪酸（PUFAs）-亚油酸和二十二碳六烯酸显著增加（P<.05）。冷季肉质基因 MC4R、CAPN1、H-FABP 和 LPL 的表达显著升高（P<.05），CAST 基因在冷季表达显著（P<.01）。冷、暖季藏羊的不同微生物代谢物主要参与氨基酸代谢、脂质代谢和消化系统途径，微生物群与肉质性状之间存在一定的相关性。在脂质代谢途径中富集的微生物代谢物与肌肉代谢物之间存在相似性。
在冷季营养胁迫下，藏羊肌肉嫩度提高，脂肪沉积能力减弱，但有益脂肪酸水平高于暖季，更有利于健康饮食。
