Dietary Pediococcus acidilactici supplementation enhances sperm quality and testicular function in roosters

The ban on the use of antibiotics as growth promoters due to resistance issues has urged scientists to find alternatives to antibiotics. In recent years, probiotics have gained widespread attention for their potential benefits on systemic physiological functions. However, little is known about how Pediococcus acidilactici supplementation specifically influences sperm quality, testicular development, and the molecular mechanisms underlying male reproductive performance in roosters. Therefore, this study aimed to evaluate the effects of different levels of Pediococcus acidilactici supplementation on the reproductive performance of roosters. Roosters were randomly assigned to four groups: a control group (fed a basal diet) and three treatment groups supplemented with Pediococcus acidilactici at P1 (1 × 10⁸), P2 (1 × 10⁹), and P3 (1 × 10¹⁰) CFU/mL. Over a five-week trial period, semen parameters, motility, viability, mitochondrial membrane potential, apoptosis, protamine deficiency, reproductive hormone levels, testicular histological parameters, and transcriptomic profiles were assessed. The results demonstrated that the beneficial effects of Pediococcus acidilactici supplementation on rooster semen quality progressively increased with prolonged feeding duration. Notably, in the final week, compared with the control group, the P2 and P3 groups exhibited significantly improved sperm parameters (P < 0.01), motility (P < 0.05), viability, and mitochondrial function (P < 0.01), while apoptosis (P < 0.05) and protamine deficiency (P < 0.01) were significantly reduced. Additionally, reproductive hormone levels, testicular histology, and testicular antioxidant capacity were also significantly improved in the P2 and P3 groups (P < 0.05). Finally, transcriptomic analysis identified five key genes (RAF1, PIK3R1, ATRX, ARID4A, and SOX9) and four signaling pathways involved in testicular development. These findings suggest that supplementation with an appropriate level of Pediococcus acidilactici, particularly at 1 × 10⁹ CFU/mL, probably can enhance the reproductive capacity of roosters by improving sperm quality and testicular development.