Heat stress is one of many problems facing the modern rabbit production. This study was planned to ascertain the effect of ingestion of different sources of selenium on alleviation of heat stress in growing rabbits, productive Performance, mutagenicity in somatic cells and oxidative status in rabbits was used as indices for the study. A total number of 60 unsexed weaned New Zealand White (NZW) rabbits, aged 6 weeks and averaged 660±3 gm of body weight were randomly distributed into four experimental groups (15 rabbits of each). The first group was used as a control and received orally 2ml of saline solution every day, while the 2nd, 3rd and 4th groups were received orally selenium three sources of nano, organic and inorganic, respectively, at level of 0.3 mg/kg body weight every day using stomach tube. The experiment continued for 6 weeks. The sources of selenium were dissolved in 2ml of saline solution. Heat stress was induced by exposure of all rabbit groups to a temperature of 38 °C for 4 hours daily.
The results demonstrated that heat stress significantly depressed body weight gain, feed intake, feed conversion ratio, empty carcass (%), dressing % and abdominal fat weight, while feeding nano-Se or organic form clearly alleviated these negative effects of heat stress as compared to those fed inorganic Se form and control groups. Also, heat stress caused increase in chromosomal aberrations, as well as it decreased the total nucleic acids and protein contents. In addition, nano and organic selenium treatments caused to decrease in all studied parameters relative to heat stress compared to those of inorganic Se form and control groups. In addition, ingestion of nano and organic source of selenium by rabbits caused significant improvement in total antioxidant capacity in blood and alleviated the negative effects of heat stress via reducing the malondialdehyde content in blood.
In conclusion, feeding of nano and organic source of selenium enhance productive performance of rabbits by improving the antioxidative properties under heat stress. This effect could be due to their ability in decreasing frequencies of chromosomal aberrations and decreasing total nucleic acids and protein contents. The use of nano-Se or organic Se form appeared to be more significant than inorganic Se in alleviation the undesirable effects of heat stress.