Maternal Plane of Nutrition during Mid-Gestation Affects the Skeletal Muscle Transcriptome in Beef Cattle Progeny

The objective was to determine the effect of maternal nutrition management during mid-gestation on the skeletal muscle transcriptome in progeny using 3 dietary treatments. Spring-calving, multiparous cows (n = 25) were limit-fed a common diet at three levels of intake to achieve 70% NRC requirement (70%REQ; 5.2. kg DMI), 100% NRC energy and protein requirements (REQ; 7.4 kg DMI), and 130% NRC requirements (130%REQ; 9.7 kg DMI). Diet composition included soy hulls, corn silage, and alfalfa haylage. Treatment diets were fed during mid-gestation (d 88 - 171 of gestation), and a common diet formulated to meet 100% NRC requirements was fed during the remainder of gestation. After calving, all cows and calves were managed similarly as a single contemporary group. Longissimus muscles biopsies were taken on 99 and 392 d of age. Extracted RNA was used in paired-end RNA sequencing on the Illumina HISeq2500 platform to analyze the transcriptome at d 99 and 392. Transcriptomic data were mapped to the UMD3.1.1 bovine reference genome and analyzed using a mixed model approach within the R-package limma. Over 7,000 expressed genes were included in weighted gene co-expression network analysis (WGCNA) which clustered genes into 11 modules including 4 that correlated to phenotypic measures. The largest module included over 2,000 co-expressed genes and was downregulated (P < 0.01) in progeny born to 130%REQ-fed compared with REQ-fed dams. The Dynamic Impact Approach annotated genes within this module to KEGG pathways. The pathways most impacted by maternal plane of nutrition were mainly lipid-associated including steroid and steroid hormone biosynthesis, sulfur metabolism, retinol metabolism, ketone synthesis and degradation, fat digestion and absorption, and PPAR signaling pathways. Module 7 (342 genes) was correlated positively with Warner-Bratzler shear force and negatively with marbling score. Major pathways in module 7 centered on glycolysis/gluconeogenesis, energy metabolism, and calcium signaling. These genes and associated pathways support increased glycolytic muscle fibers (type 2x) in progeny born to 130%REQ-fed compared with 70%REQ-fed dams. Results indicate the skeletal muscle transcriptome and associated metabolic functions prior to slaughter are affected by mid-gestation maternal plane of nutrition and may be regulated by epigenetic factors.