PSII-2 Different levels of herbage allowance during the gestation of Nellore cows result in differentially abundant proteins on skeletal muscle of offspring at slaughter.

Abstract Maternal nutrition during pregnancy can significantly impact the development of offspring, as well as affect physiology and metabolism. Although several studies have described the effects of maternal nutrition on fetal skeletal muscle development, little is known about the metabolic pathway’s regulation. Thus, this study aimed to identify proteins and metabolic pathways differently regulated in the Longissimus thoracis muscle of Nellore offspring in response to different levels of herbage allowance during the gestation of Nellore cows. Seventy-two multiparous lactating cows pregnant with male calves on day -151 were divided into two experimental groups: low herbage allowance (LHA) and high herbage allowance (HHA), which received 2.81 kg and 7.58 kg of forage dry matter per kg body weight, respectively. The cows were kept in paddocks with Urochloa brizantha cv. Marandu. After calving, the cow-calf pairs were handled together until weaning. After the growing phase, offspring were kept in feedlot pens for 101 days and slaughtered at 562 days old. Offspring from the HHA group exhibited better feed conversion and efficiency (P < 0.05) in the finishing phase, higher body weight at weaning (17 kg) and at slaughter (37 kg), as well as higher hot carcass weight (18 kg) in comparison to offspring from the LHA group. Samples from L. thoracis muscle were collected during the slaughter, and a subset of 16 samples (8 from LHA group and 8 from HHA group) were used for proteomic analysis by liquid chromatography coupled to tandem mass spectrometry in a data-dependent acquisition mode. The trans-proteomic pipeline was employed for the processing, validation, and quantification of mass spectrometry-based omics data. Database searches were performed using the Comet v.2019 and the bovine UniProt database. The high confidence peptide identification (FDR ≤ 0.05) and quantitation were obtained through the Peptide Prophet and the XPRESS algorithm, respectively. Proteins with fold-change ratios ≥ 1.5 and ≤ 0.67 were considered as differentially abundant (P < 0.05). The differentially abundant proteins detected between LHA and HHA groups were used to perform functional enrichment analysis by DAVID v.2024q4 to detect molecular functions and pathways that contribute to phenotypic differences observed between LHA and HHA groups. After quality control, 30 differentially abundant proteins were identified between the two experimental groups. Among the differentially regulated proteins, those related to biosynthesis of amino acids (PKM, GPT), metabolism of carbohydrates (PKM, BGN), structural constituent of muscle (MYL2, BGN), and immune system (ARIH1, NFIL3, STAT5B) were highlighted. Identifying differentially abundant proteins and their roles in critical pathways contributes to improving the knowledge of the mechanisms behind the effects of maternal nutrition in skeletal muscle of Nellore offspring.