Early life nutrition affects  the molecular ontogeny  of testicular development  in the young bull calf

Enhanced early life nutrition accelerates sexual development in the bull calf through neuroendocrine-signalling mediated via the hypothalamic–pituitary–testicular axis. Our aim was to assess the  impact of contrasting feeding regimes in bull calves during the frst 12 weeks of life on the testes  transcriptome and proteome. Holstein–Friesian bull calves were ofered either a high (HI) or  moderate (MOD) plane of nutrition, designed to support target growth rates of 1.0 and 0.5 kg/day,  respectively. At 12 weeks of age all calves were euthanized, testicular parenchyma sampled, and  global transcriptome (miRNAseq and mRNAseq) and proteome analyses undertaken. Bioinformatic  analyses revealed 7 diferentially expressed (DE) miRNA and 20 DE mRNA. There were no diferentially  abundant proteins between the two dietary groups. Integration of omics results highlighted a  potential role for the cadherin gene, CDH13, in earlier reproductive development. Furthermore,  co-regulatory network analysis of the proteomic data revealed CDH13 as a hub protein within a  network enriched for processes related to insulin, IGF-1, androgen and Sertoli cell junction signalling  pathways as well as cholesterol biosynthesis. Overall, results highlight a potential role for CDH13 in  mediating earlier reproductive development as a consequence of enhanced early life nutrition in the  bull calf.