Effect of vitamin C, vitamin E or betaine addition on alleviation of heat stress impacts on growing rabbits

الملخص EN

This study was conducted to evaluate the effects of vitamin C (VC), vitamin E (VE) or betaine (BET) dietary supplementation on growth performance, nutrients digestibility and antioxidant status of growing male rabbits under heat stress conditions.

A total of ٤٨ weaned New Zealand male rabbits with ٦٤١±١٥.٧٧ g average body weight and ٥ weeks of age was randomly divided to four experimental groups (١٢ rabbits per group), each was fed a basal diet without any supplementation (control group) or supplemented with ٥٠٠ mg VC (٢nd group), ٢٠٠ mg VE (٣rd group) or ١٠٠٠ mg BET (٤th group)/kg diet for ٨ weeks.

Throughout the experiment, the overall mean of temperature humidity index (THI) was ٨٤.٦٧± ٠.٣٥, reflecting a state of severe heat stress.

Results of growth performance showed that rabbits receiving VE, VC or BET had significantly higher live body weight (LBW), daily body weight gain (DBWG), and reduced water intake and feed conversion rate (FCR) as compared to the non-supplemented group.

In particular, BET supplemented growing rabbits showed significantly marked improvement of the digestibility of dry matter (DM), organic matter (OM), crude protein (CP) and nitrogen free extract (NFE) and nutritive values compared to the non-supplemented group.

All tested additives evoked significant improvement of antioxidant status, lipid peroxidation, white blood cells (WBCs) and lymphocyte count.

Conclusively, the results revealed that VE, VC and BET could be useful as an economic efficient and natural dietary additives protecting against the negative impacts of heat stress in growing rabbits to maintain performance and antioxidant status