Integrative analysis of the hypothalamic-pituitary-testicular axis reveals molecular mechanisms underlying sperm motility differences in Landes ganders.

Abstract

This study aims to investigate the differences in semen quality between the high- and low-sperm motility group in Landes ganders, and to elucidate the regulatory role of the hypothalamic-pituitary-testicular (HPT) axis. Based on sperm motility values, the Landes ganders were divided into the high-sperm motility group (HSM,&#x202f;=&#x202f;3, 51.76&#x202f;&#xb1;&#x202f;2.53) and the low-sperm motility group (LSM,&#x202f;=&#x202f;3, 39.39&#x202f;&#xb1;&#x202f;2.52). Semen quality parameters, serum antioxidant indices, testosterone concentrations, and testicular histomorphology were assessed. Transcriptome sequencing (RNA-seq) was conducted on hypothalamic, pituitary, and testicular tissues to identify differentially expressed genes (DEGs), followed by Gene Ontology (GO) and KEGG pathway enrichment analyses. Sperm concentration and motility were significantly higher in the HSM group compared with the LSM group (&#x202f;<&#x202f;0.01). Ganders with low-sperm motility group exhibited increased serum malondialdehyde levels and decreased total antioxidant capacity and superoxide dismutase activity (&#x202f;<&#x202f;0.01), along with reduced testosterone concentrations (&#x202f;<&#x202f;0.05). Histological examination revealed that HSM ganders displayed well-developed seminiferous tubules with larger diameters, increased germ cell layers, and abundant mature spermatozoa, whereas LSM ganders showed impaired spermatogenesis and reduced tubular development (&#x202f;<&#x202f;0.01). Key genes associated with spermatogenesis (,) and steroidogenesis (,,) were significantly upregulated in the HSM group. Transcriptomic profiling identified 1,189, 2,126, and 1,538 DEGs in the hypothalamus, pituitary, and testis, respectively. These DEGs were significantly enriched in pathways related to GnRH signaling, steroid hormone biosynthesis, neuroactive ligand-receptor interaction, and Wnt signaling. Differences in sperm motility among Landes ganders are closely associated with antioxidant status, endocrine regulation, testicular development, and coordinated gene expression along the HPT axis. These findings provide mechanistic insights into spermatogenesis and offer a theoretical basis for improving reproductive performance in geese.