RESUMO
The physiological effects of dietary boron (B) supplementation for farm animals specifically goat on male fertility are still scarce and need deep investigation. Thus, the current study was designed to investigate how adding B to the diet of male goats affected their testicular and thyroid activity. For that purpose, twelve male goats were divided randomly into two groups (six animals each); control group that was fed the basal diet and B group that was fed the basal diet containing 70 mg B/kg diet for 6 months. Serum samples were collected at different intervals, while testicular biopsies were obtained at the end of the experiment. The results showed that 6 months of dietary B supplementation resulted in a significant increment in serum B concentration. The results of repeated measure analysis showed that there were significant GROUP and TIME × GROUP interactions effects on blood testosterone levels (F = 119.408, p = .000 and F = 6.794, p = .013, respectively), demonstrating that compared with control, B supplementation caused a significant rise in serum testosterone levels over time. However, the mean animal body weights and the serum levels of triiodothyronine (T3) and thyroxine (T4) were kept comparable with the control ones at the different time points. The most striking finding is that B supplementation increased significantly the mRNA expression of the CYP17A1 which is essential for steroidogenesis (p < .001). In addition, a histological examination of testicular tissue corroborated our findings and demonstrated that B supplementation had a positive effect. As a result, B might be considered an excellent food supplement that could be safely added to the male goats' diet at the current dose to improve their reproductive capacity.
