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

SIMPLE SUMMARY: Improvements in performance around parturition by feeding ethyl-cellulose rumen-protected methionine (RPM) have been reported. Hepatic and adipose gene transcription effects have been a key focus of studies dealing with RPM. It is unknown, however, if RPM alters the abundance of genes associated with nutrient metabolism and biochemical pathways in skeletal muscle. This tissue also experiences dynamic biological changes around parturition. The objective was to use skeletal muscle biopsies from cows fed a control or RPM-supplemented diet around parturition to investigate alterations in mRNA abundance. Compared with controls, feeding RPM led to overall upregulation of genes associated with amino acid transport, carnitine transport, β-oxidation, vitamin transport, mTOR pathway, insulin signaling, antioxidant response, CDP-Choline pathway, and arginine metabolism. Thus, besides positive effects at the level of performance, RPM can help skeletal muscle maintain homeostasis around parturition partly through alterations in mRNA abundance. ABSTRACT: 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.