Alterations in Skeletal Muscle mRNA Abundance in Response to Ethyl-Cellulose Rumen-Protected Methionine during the Periparturient Period in Dairy Cows.

This study aimed to evaluate the effect of feeding ethyl cellulose rumen-protected methionine (RPM) on skeletal muscle mRNA abundance during the periparturient period. Sixty multiparous Holstein cows were used in a block design and assigned to either a control or RPM diet. The RPM was supplied from -28 to 60 days in milk (DIM) at a rate of 0.09% (prepartum) or 0.10% (postpartum) of dry matter (DM), ensuring a Lys:Met in the metabolizable protein of ~2.8:1. Muscle biopsies were collected at -21, 1, and 21 DIM. Thirty-five target genes associated with nutrient metabolism and biochemical pathways were measured via RT-qPCR. The mRNA abundance of genes associated with amino acid (AA) transport ( SLC7A8 , SLC43A2 ), carnitine transport ( SLC22A5 ), insulin signaling ( IRS1 ), and antioxidant response ( NFE2L2 ) had diet × time effect ( p < 0.05) due to greater abundance in RPM versus CON cows, especially at 1 and 21 DIM. Members of the AA transport ( SLC7A8 , SLC25A29 , SCL38A9 ), fatty acid β-oxidation ( ACADVL ), vitamin transport ( SLC5A6 , SLC19A2 ), mTOR pathway ( AKT1 and mTOR ), antioxidant response ( KEAP1 , CUL3 ), CDP-Choline pathway and arginine metabolism had overall greater abundance ( p < 0.05) in RPM versus CON cows. Overall, data indicate that RPM can alter nutrient metabolism in the skeletal muscle around parturition partly through alterations in mRNA abundance.