Background: Under fasting conditions, the pathway converting gluconeogenesis precursors into muscle glycogen becomes crucial due to reduced glycogen reserves. However, there is limited research on skeletal muscle gluconeogenesis and the impact of fasting on gluconeogenic gene expression. Methods: Sheep fetal skeletal muscle cells cultured in vitro were used to study the effects of varying lactic acid concentrations (0 to 30 mM) and 2.5 mM glucose on the expression of gluconeogenesis-related genes after 6 h of fasting. The effects on mRNA and protein expression of key genes involved in skeletal muscle gluconeogenesis were measured by quantitative real time polymerase chain reaction (qRT-PCR), immunofluorescence, and western blotting at 48 h. Results: Fasting increased the expression of key gluconeogenic genes, fructose-1,6-bisphosphatase 2 (FBP2), glucose-6-phosphatase 3 (G6PC3), pyruvate kinase M (PKM), monocarboxylate transporter1 (MCTS1), glucose transporter type 4 (GLUT4), pyruvate carboxylase (PC), and lactate dehydrogenase A (LDHA). The mRNA levels of FBP2, G6PC3, and MCTS1 significantly decreased with glucose addition. Additionally, 10 mM lactic acid significantly promoted the expression of FBP2, PC, MCTS1, LDHA, GLUT4, and PKM while inhibiting phosphoenolpyruvate carboxykinase (PEPCK) expression. At the protein level, 10 mM lactic acid significantly increased FBP2 and PKM protein expression. Conclusions: This study shows that fasting regulates key gluconeogenic gene expression in sheep skeletal muscle cells and highlights the role of lactic acid in inducing these gene expressions.

饲料的营养成分可直接影响家畜的屠宰性能与肉品质,试验旨在研究高纤维牧草和高蛋白牧草对羔羊肉品质的影响.试验分别选取高纤维牧草驼绒藜和高蛋白牧草苜蓿作为饲料主要成分.选取4对(共8只)3月龄、体重(24±2.3) kg、健康的双胞胎羔羊为试验对象,分析了两种饲料对羔羊屠宰性能与羊肉品质指标的影响.结果 表明,饲喂苜蓿颗粒饲料对羔羊增重效果极显著,达到0.187 kg/d,显著高于驼绒藜为主的颗粒饲料(0.097 kg/d,P＜0.01).同时,苜蓿饲料也显著增加了肌肉中脂肪的含量,而驼绒藜饲料显著增加了羊肉的水分含量(P＜0.05),提高羊肉的嫩度.虽然两种饲料对屠宰率、骨重、净肉率、肉骨比、净肉重、系水力、眼肌面积等指标的影响均差异不显著(P＞0.05),但是对宰前活重、胴体重、GR值的影响显著(P＜0.05).与苜蓿组相比,驼绒藜可增加羔羊肌肉中对人体有益的必需脂肪酸亚油酸和花生四烯酸的含量.该研究结果为畜牧业生产功能性肉品提供了新的思路.