Abstract
The decline in sheep health and meat quality caused by seasonal nutritional deficiencies has always been an important problem in the production of naturally grazing sheep. Glucose metabolism is crucial in ruminants for adequate cell function and maintenance of the body tissues and systems. However, whether glucose metabolism, especially gluconeogenesis, is affected by seasonal grazing conditions has not been fully uncovered. Thus, twelve sheep from two seasons (dry and green grass periods) in natural grazing areas of Inner Mongolia, China, were selected for this study. Their serum glucose, insulin, PC, and PEPCK levels and volatile fatty acid (gluconeogenesis material) concentrations in rumen fluid were analyzed. The expression of key enzymes including PC, PEPCK, GLUT2, and G6P of gluconeogenesis and their regulators INSR, PI3K/AKT and p53-SIRT6-Fox01 in the liver was detected by real-time PCR and western blotting. The results revealed significant variances in gluconeogenesis and its indicators and showed p53-SIRT6-Fox01 as having potential regulation in different grazing periods. This study offers new insights into the mechanism of gluconeogenesis and adaptive regulation between dry grass period and green grass period and also provides a reference for maintaining the health of sheep and meat quality despite seasonal nutritional deficiencies.