Exposure of male rabbits to heat stress during summer adversely affects their fertility leading to major production losses. A total number of 24 male rabbits were randomly divided into four experimental groups exposed to temperatures ranging from a high of 32 degrees C to a low of 23 degrees C. Animals of the 2nd, 3rd and 4th group were individually orally given 200, 400, or 800 mg royal jelly (RJ)/kg body weight once a week to evaluate the ability of RJ feeding to counteract "summer infertility" in bucks and enhance their physiological status. Royal jelly treatments significantly boosted testosterone level to 133, 143 and 124% of basal, increased ejaculated volume by 36, 31 and 18%, increased seminal plasma fructose to 122, 124, and 111%, improved sperm motility by 15, 18 and 5%, increase sperm total output by 65, 63 and 35%, reduced abnormal sperm by 24, 24 and 15% and dead sperm by 27, 25 and 17% compared to the heat stressed control animals. Serum total protein, albumin and globulin increased while serum total lipids, cholesterol and triglycerides decreased with RJ treatments. Creatinine was reduced by 5, 13 and 8% and uric acid by 4, 7 and 4%, respectively for the three doses of RJ compared to control. Alkaline phosphatase has significantly increased to reach 114, 118, and 108% of heat stressed level with the three doses of RJ, indicating the occurrence of active bone deposition. Glucose level increased significantly to reach 105, 112, and 116% of heat stressed control and both calcium and phosphorus increased significantly with RJ treatments. It was concluded that royal jelly administration to heat stressed male rabbits can counteract their "summer infertility" and improve their physiological status.
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