Accepted 12th July, 2016.
An eight-week study was conducted to determine the response of growing rabbits to varying dietary levels of vitamins C and E under a hot humid tropical environment. Thirty-six hybrid (Chinchilla × New Zealand white) growing rabbits of both sexes with initial average weight of 0.60-1.0kg were randomly divided into nine groups of four rabbits each and assigned to 9 diets a in a 3×3 factorial arrangement involving three vitamin C levels (0, 200 and 400mgkg-1 diet) and three vitamin E levels (0, 200 and 400mgkg-1 diet) in a completely randomized design. Each treatment was replicated 4 times with one rabbit constituting a replicate. Feed and water were supplied to the animals ad libitum. Data were collected on nutrient digestibility, haematology, carcass and organ weights of rabbits. Results showed that although dietary treatments had no significant effects on dry matter (DM) and crude protein (CP) intakes by rabbits, they had significant effects (p<0.05) on the intakes of crude fibre (CF), ether extract (EE) and nitrogen- free extract (NFE) by rabbits. The diet containing 200mg/kg of vitamin E(treatment 4) produced the highest dry matter (DM) digestibility coefficient which was similar (p> 0.05) to that of the control and the diet containing 400mg/kg vitamins C and E. Haemoglobin concentration (Hb), red blood cell count (RBC), white blood cell count (WBC), packed cell volume (PCV), mean cell haemoglobin (MCH) and differentials (neutrophils, lymphocytes, monocytes, eosinophils and basophils) were significantly (p<0.05) affected by dietary treatments, while mean cell haemoglobin concentration (MCHC) and mean cell volume (MCV) were not significantly (p>0.05) affected by the dietary treatments. The white blood cell count (WBC) of rabbits on treatments 5 and 7 increased significantly (p<0.05). Treatments had significant (p<0.05) effects on the carcass traits (live weight, carcass weight and dressing percentage) and organ characteristics (relative lungs and large intestine weights) of the rabbits. Rabbits on treatment 4 had significantly (p<0.05) higher live weight, dressed carcass weight and dressing % than the control group. It was concluded that a combination of 200mg of vitamin C per kg diet and 200mg of vitamin E per kg diet can be successfully added to the diet of growing rabbits in a hot humid tropical environment, without having any negative effect on carcass yield, relative organ weights and haematological parameters of rabbits.
Keywords: Rabbits, vitamins C and E, nutrient digestibility, haematology, carcass, organ weights