Effects of dietary vitamin E on daily intake, serum testosterone and epididymal sperm quality in Sprague-Dawley rats subjected to heat stress

Abstract

This study examined the effects of vitamin E on daily intake, serum testosterone levels, and epididymal sperm 
quality in heat stressed male rats. Rats were heat stressed (HS; 35°C) or housed at room temperature (control; 24°C) 
for 20 days and offered one of the following dietary vitamin E concentrations: 42 (low), 242 (med- low), 2,042 (med
high), or 20,042 (high) IU/kg diet. On day 21, rats were euthanized. In rats offered a low vitamin E diet, serum 
testosterone was greater (P = 0.002) in controls than in HS rats on the same diet. However, serum testosterone did 
not differ (P > 0.201) between controls and HS rats offered other dietary vitamin E levels. Epididymal sperm motility 
was reduced (P = 0.002) in HS rats compared to controls independent of vitamin E level, while sperm cell 
concentration was reduced (P = 0.010) in HS rats offered med-high dietary vitamin E compared to controls of the 
same diet. Sperm cell morphology did not differ between HS and control rats (P = 0.183). No sperm trait mentioned 
above was affected by dietary vitamin E level (P > 0.170). Testicular weight (P = 0.005) was reduced in HS rats, but 
not affected (P > 0.190) by vitamin E. Data indicate testicular mass loss and mild adverse effects on some 
components of male fertility due to heat stress However, these effects were inconsistent and were not relieved by 
increased dietary vitamin E concentration. Interestingly, no organ lesions were observed in rats consuming extreme 
amounts of vitamin E and vitamin E concentration did not influence intake or weight gain.