Mitigate Heat Stress Impacts on Semen Quality and Antioxidants Status of Male Rabbits Using Some Natural Antioxidants

Abstract

he present study was conducted to investigate the effects of feeding corn silk, orange peel, and pomegranate peel extracts on semen quality, blood biochemical constituents, antioxidants capacity of male New Zealand White rabbits under heat stress conditions. In an experiment that lasted 8 weeks, thirty male rabbits aged twenty-four weeks with an average body weight of 2.85±0.1kg were randomly distributed into five equal groups (6 rabbits/ group). Each rabbit was kept in an individual cage. The first group (control) was fed a basal diet. The second group (positive control) was fed the basal diet supplemented with vit E. at a level of 250 ppm. The third, fourth, and fifth groups were fed the basal diet supplemented with corn silk, orange peel, and pomegranate peel extracts at a level of 150 ppm, respectively. Experimental diets were offered ad-libitum and clean drinking water was freely available. The overall average of ambient temperatures and relative humidity were 31.1°C and 62.5%, respectively. Overall temperature-humidity index (THI) through the experimental period was 29.14 indicating severe heat stress conditions. According to the results of the HPLC screening for the different extracts: ferulic acid, cinnamic acid and coumaric acid were the most abundant polyphenols in orange peel extract, while gallic acid was the most abundant polyphenol in pomegranate peel extract. Semen quality parameters improved in rabbits of orange peel and corn silk groups, opposite to rabbits fed pomegranate peel extract. The activity of seminal catalase and glutathione peroxidase increased in rabbits fed orange peel and corn silk extracts. Blood total proteins, albumin, globulins and creatinine were not affected by different antioxidants supplements. Serum total antioxidants capacity, catalase and superoxide dismutase were significantly increased in all experimental groups compared with the control. In conclusion, the current results showed that using orange peel or corn silk extracts as feed supplements at a level of 150ppm could improve semen quality as well as antioxidants capacity of male rabbits reared under heat stress conditions.