Physiological response of rabbit bucks to prolonged feeding of cotton seed cake-based diets supplemented with vitamin E
Sixty-four (64) weanling rabbit bucks, 5 to 6 weeks old, were involved in a 2 x 4 factorial experiment to evaluate the effects of prolonged feeding of cottonseed cake (CSC) – based diets with or without vitamin E supplementation on the physiological response of the bucks. There were eight treatment combinations comprising four CSC (0, 5, 10 and 15%) levels and two vitamin E supplementation levels (0 and 30 mg/kg diet). Bucks were fed treatment diets for a period of twenty weeks after which blood was collected for haematological and serum analyses. The haematological parameters assessed include: Packed cell volume (PCV), red blood cell (RBC), haemoglobin concentration (Hb), white blood cell (WBC) and the differential counts. The serum parameters include the serum glucose, urea, creatinine, alanine transaminase (ALT), aspartate transaminase (AST), total protein, albumin, globulin and total cholesterol. The PCV, RBC and neutrophils declined (P < 0.05) with increase in CSC level; while the WBC and lymphocytes increased (P < 0.05) with increasing level of CSC. Other haematological parameters were not significantly (P > 0.05) affected by CSC level. Bucks that were fed 0, 5, 10 and 15% CSC supplemented with vitamin E recorded higher values for PCV, RBC and Hb than those that were not supplemented. At 15% CSC level, supplementing the diet with vitamin E significantly (P < 0.05) reduced WBC and lymphocyte counts. Serum urea, total protein and albumin were significantly (P < 0.05) lowered by the increasing level of CSC. Significant (P < 0.05) increase was observed in ALT and AST with increase in CSC level. Glucose and total cholesterol were not affected by CSC level. Supplementing the diet with vitamin E at all CSC levels reduced creatinine, ALT and AST levels significantly (P < 0.05). It was concluded that prolonged feeding of CSC – based diets to rabbit bucks had adverse effects on blood constituents of the bucks. However, supplementing such diets with 30 mg/kg diet of vitamin E ameliorated the adverse effects.
Key words: Rabbit bucks, haematology, serum chemistry, cottonseed cake, vitamin E.