The effect of induced molting on the testicular physiological remodeling in no-semen roosters.

Background: The fertility of roosters significantly impacts the economic outcome of the poultry industry. However, it is common for some roosters to fail to produce semen during production, and the underlying reasons remain largely unclear.

Results: To investigate a solution to this problem, induced molting (IM) was performed on no-semen (NS) roosters. Remarkably, the NS roosters recovered and began producing semen on 30 d after recovery feeding (R30), with semen quality and ejaculation volume returning to normal levels by 39 days after recovery feeding (R39). The difference in testicular weight between the NS and healthy roosters was significant on one day before fasting (F0) (P < 0.05). Meanwhile, morphological analysis of NS roosters' testicular seminiferous tubules suggested that Sertoli cells (SCs), which form the scaffold in the testicular microenvironment, were severely damaged in NS roosters. Their spermatogenic cells were disordered and fewer, suggesting abnormal testicular function in NS roosters. Following induced molting, the epithelial structure of seminiferous tubules in the testes of NS roosters was restored, and follicle-stimulating hormone (FSH) levels in both serum and testicular were significantly higher (P < 0.05). To further elucidate the mechanisms, transcriptome analysis was conducted to uncover dynamic gene expression changes in testicular tissues at two time points: F0 and R39. Results indicated that ALDH1A1 levels in the testes of NS roosters were 16.0-fold lower than those in healthy roosters at F0 but significantly increased by R39, suggesting that the ALDH1A1 gene may be closely related to testicular failure in NS roosters. Pathway-enrichment analyses revealed that IM significantly activated the phagosome pathway in the testes of NS roosters, and the genes ATP6VOD2,ATP6V1A,Ighm and MHCY2B1 were involved in this pathway, associated with autophagy. We hypothesize that in response to nutrient deprivation, autophagy is initiated to degrade damaged components in the seminiferous tubules of NS roosters, leading to testicular physiological remodeling and resumption of semen production.

Conclusions: This report identifies critical pathway and molecular markers related to testicular failure and physiological remodeling in NS roosters caused by induced molting, offering an essential reference for accelerating genetic selection.