Maternal slow-release nitrogen diets during late gestation optimize the energy metabolism in calves' skeletal muscle

The current study aimed to determine the enriched biological process, through proteomic and transcriptome data, associated with maternal slow-release nitrogen diets received during late gestation on the skeletal muscle of the offspring. At day 180 to day 268 of gestation a total of 16 pregnant Brahman cows, were assigned into Control treatment (CON; n = 7), where cows were fed ad libitum a low crude protein basal diet plus mineral mixture; or Slow-released nitrogen (SRN, n = 9) based diet, where cows were fed a basal diet plus a slow-release nitrogen supplement. Muscle biopsy was performed at day 45 of age in calves and used to perform RNA sequencing (RNA-seq) and proteomic (HPLC-MS/MS) analyses. Although the experimental treatment did not show effects on transcript abundance, proteomic analysis revealed significant differences in protein expression. Enriched (adjusted p-value ≤ 0.05) biological processes from the exclusive proteins identified in calves' skeletal muscle from SRN group are related to central energy metabolism (synthesis of Acetyl-CoA, tricarboxylic acid cycle, isocitrate metabolic process), regulation of calcium and nitrogen transport, and protein folding. Protein-protein interaction network assessed in the differentially abundant proteins (DAPs) revealed 4 main enriched biological processes, including ATP metabolic process, glucose metabolism, tricarboxylic acid cycle, and sarcomere organization. These findings suggest that maternal supplementation whit slow-release nitrogen during late gestation can positively influence postnatal energy metabolism in calf skeletal muscle.