Fermented bamboo powder enhances testicular function and reproductive performance by modulating spermatogenesis, hormonal profiles, and autophagy in yellow-feathered roosters

Objective: To investigate the effects of Fermented Bamboo Powder (FBP) supplementation on testicular development and reproductive performance in yellow-feathered roosters. Methods: A total of 300 roosters were randomly assigned to two groups ( n =150 per group) and subjected to a 77-day feeding trial. The control group received a standard basal diet, while the experimental group was fed the same basal diet supplemented with FBP in a stepwise dosing regimen: 1.0 g/kg during Phase I (days 1–22), 2.0 g/kg during Phase II (days 23–45), 4.0 g/kg during Phase III (days 46–60), and 6.0 g/kg during Phase IV (days 61–77). Testicular morphology and spermatogenesis were evaluated using hematoxylin and eosin staining and gonadosomatic index. Serum lipids and reproductive hormones were measured with assay kits and enzyme linked immunosorbent assay. Autophagy-related proteins were analyzed via Western blot, and spermatogenesis-related genes were quantified by quantitative real-time polymerase chain reaction. Results: FBP supplementation improved left testis width, length, and thickness, as well as right testis width ( P <0.05). Both individual and total testis weights were markedly higher in the FBP group. Histological analysis revealed notable improvements in testicular architecture, including increased seminiferous tubule diameter, epithelial height, luminal area, and Johnsen’s score. At the molecular level, FBP upregulated mRNA expression of spermatogenesis- related genes such as CREM, PCK2, DDX4, GDNF, SPAG6, SPAG16 , and SPAG17 ( P <0.05). There was a significant increase in total protein and a reduction in triglyceride concentrations. Hormonal evaluations indicated significantly elevated serum testosterone and FSH levels in the FBP group. Importantly, FBP enhanced the expression of autophagy-related proteins beclin-1 and ATG5, suggesting increased autophagic activity. Additionally, phosphorylated mTOR levels were significantly increased. Conclusions: FBP supplementation positively affects testicular morphometry, endocrine profiles, and molecular pathways involved in spermatogenesis and autophagy, supporting its potential role in improving male reproductive performance in poultry.