Analyses of widely targeted metabolic profiling reveal enhanced energy metabolism in well-developed testicular tissue of Hu sheep.

Energy supply is crucial for testicular development. Nevertheless, the specific alterations in the energy metabolic pathways that affect testicular development have not been extensively investigated. This study aimed to investigate the variations in metabolites and alterations in energy metabolic pathways in the testes of Hu sheep with different developmental status at 6 months of age. Twelve rams with similar body weights but distinct testis developmental status were selected among 345 Hu sheep based on testis size and histomorphology results, and they were divided into the well-developed (L group, n = 6) and developmentally delayed group (S group, n = 6). A total of 660 metabolites were identified via widely targeted metabolic analysis. Among 148 differentially expressed metabolites, 78 were up-regulated and 70 were downregulated in the L group compared with the S group. Functional enrichment analysis indicated that a significant proportion of the identified differential metabolites was implicated in energy metabolism-related pathways. Moreover, the L group exhibited significantly higher expression levels of genes involved in glycolysis (GLTU8 and LDH), TCA (PDHA2, CS and IDH3G), gluconeogenesis (PCK1), pentose phosphate (G6PD), and fatty acid degradation (GK, ACSL1, FABP3, CPT1 and CTP2). The activity enzymes such as citrate synthase, pyruvate dehydrogenase, and lactate dehydrogenase also increased in the L group. In summary, this observation implied that the augmentation of energy metabolic pathways plays a crucial role in facilitating testicular development. The upregulation of energy metabolic pathways collectively facilitates the testicular development in Hu sheep.