Vitamin C and vitamin E supplementation alleviates oxidative stress induced by dexamethasone and improves fertility of breeder roosters

This study was conducted to determine the effect of supplemental dietary vitamin C (VC) and vitamin E (VE) on improving semen quality and antioxidative status in breeder roosters challenged with dexamethasone (DEX). 120 45-week-old Lveyang black-boned breeder roosters were divided into 5 experimental treatments, including negative group, positive group, and three trial groups, which were fed basal diet supplemented with 300 mg/kg VC, 200 mg/kg VE, or 300 mg/kg VC and 200 mg/kg VE (VC + VE). At 49 weeks of age, the positive control and trial groups were subcutaneously injected 3 times every other day with DEX 4 mg/kg body weight, the negative control group was sham injected with saline. At 50 weeks of age, average daily feed intake of birds challenged with DEX significantly increased (P < 0.05), however, serum testosterone significantly decreased (P < 0.05). Dietary supplementation of VC + VE enhanced serum testosterone and sperm motility remarkably (P < 0.05). There were no differences in sperm viability between the DEX-treated groups. During the post-stress recovery period (52 weeks of age), dietary supplementation of VE and VC + VE significantly increased the body weight of birds under oxidative stress (P < 0.01). VC, VE, and VC + VE groups had greater sperm viability than control group (P < 0.01). Additionally, there was a decrease in the semen plasma malondialdehyde content (P < 0.05) of the VC and VC + VE groups, and in the testicular malondialdehyde content (P < 0.01) of the VE and VC + VE groups. In summary, VC, VE, especially their combination alleviate the oxidative stress induced by DEX and are favorable for the fertility of breeder roosters.