Transcriptome and metabolome analyses reveal muscle changes in Tan sheep (Ovis aries) at different ages

Tan sheep (Ovis aries) are one of the most important breeds of sheep in China, known for their high-quality wool and long-term adaptation to northwestern China's dry, cold, and windy climate. The present study aimed to reveal the mRNA and metabolite profiles of lambs of different ages. Thirty female lambs were randomly selected and divided into three groups: 6, 9, and 12 months of age. Muscle tissues were sampled and subsequently analyzed via transcriptome and metabolome analyses. There were significant differences found in mRNA expression and metabolite levels in lamb muscle at different ages. Differentially expressed genes (DEGs) were significantly enriched in the “fatty acid metabolism” pathway, indicating the critical role of fatty acids in the development of lamb muscle. Some DEGs, such as COL1A1, COL1A2, and MYH4, showed interactions with metabolites. Levels of 4-pyridoxic acid and pyridoxine in muscle tissues decreased with age. Further, the results indicated that the ability of lamb muscle to maintain vitamin B6 levels decreases with age. The study findings provide new insight into the muscle building and development processes of Tan sheep.