Lasia spinosa supplementation improves semen quality and sperm cryosurvival in subfertile beef bulls: An exploratory testicular transcriptomic analysis.

Heat stress can impair semen quality in imported bull sires. Recent research has shown the potential of Lasia spinosa Thw. (LST) to improve semen quality in boars, so we aimed to investigate the effect of LST supplementation on semen quality in subfertile bulls, focusing on semen characteristics in both fresh and frozen-thawed ejaculates as well as the transcriptomic changes in testicular tissues. Six imported beef bull sires presenting poor semen quality for > 5 months at the Bull Semen Production Center were included in the experiment. They received daily supplementation with LST (5 g/100 kg body weight). Semen and serum testosterone evaluations were performed weekly for 24 weeks. For histologic and transcriptomic evaluations, testicular biopsies were performed on three LST-supplemented bulls, pre- and post-supplementation, and three control bulls. We observed significant improvements in movement kinetics, viability, acrosome integrity, membrane integrity, and sperm head morphology in LST-supplemented bulls. Frozen-thawed semen presented significant enhancements in parameters such as motility and mitochondrial activity. Serum testosterone significantly increased after supplementation, correlating significantly with sperm motility and mitochondrial activity. Transcriptomic analysis identified 16 downregulated genes in subfertile bulls; LST supplementation induced upregulation of 11 genes related to germ cell structure, spermatogenesis, and sperm quality, including CNFN, KRT17, KRT1, KRT19, DSC3, KLK8, SPRR4, SPRR2E-like, Serpin B4-like, and WFDC18-like. Our findings highlight the potential of LST supplementation as a promising intervention for enhancing reproductive performance in subfertile bulls.