Effect of Supplementing Zinc Nanoparticle on Testicular Blood Flow, Testicular Morphometry, Reproductive Hormone Profiles and NO Level in Native Goats

This study aimed to investigate the effect of oral supplementation of zinc nanoparticles (ZnONPs) on bucks reared under heat stress on testicular dimensions and hemodynamics, luteinizing hormone (LH), testosterone, estradiol, zinc, and nitric oxide (no). Ten native goat bucks were divided into two equal groups. Control bucks received their basal diet daily for 49 days. Treated group (ZnONPs) received their basal diet plus 50.0 mg ZnONPs orally for 50 days. Testicular dimensions and hemodynamics were performed biweekly associated with collecting blood samples. Results showed no association between the right and left testicles in their dimensions, blood flow parameters or indices with increased left testicle height (P= 0.029), right and left testes volume (P< 0.001) and mean velocity (P= 0.001). Compared to controls, LH (P= 0.002) estradiol (P= 0.005), testosterone (P< 0.0001), nitric oxide (P< 0.01), right testes volume (P= 0.047), right and left PCV (P< 0.01), left EDV (P= 0.031), right and left TAMV (P< 0.01), left testicular artery diameter (P= 0.018), right PI (p>0.05), and both right and left BFV (P< 0.01) decreased in week 4 after supplementation but serum zinc increased (P< 0.0001) from week 2 till week 7 of supplementation. In conclusion, ZnONPs modulated the responses of bucks to heat stress to reduce the testicular thermal load during heat stress via decreasing testosterone, NO, and estradiol within the normal minimum concentrations to decrease the testicular blood flow and testicular size to preserve the animal capacity to survive throughout the heat stress conditions. This study recommends supplementing goat bucks with 50 mg ZnONPs throughout heat stress conditions.