An experiment was conducted with 48 crossbred rabbits (49 days old) averaging 757.5 ± 0.50 g to assess haematological and serum biochemical response of growing rabbits exposed to varied levels ofdietary fumonisin of 0.1, 5.0, 7.5 and 10 mg fumonisin B1/kg diet containing in diets 1 (control) 2, 3 and 4 respectively, for a period of 12 weeks. Blood samples were collected from the animals through theear vein, after the feeding trial, for haematological studies and serum biochemistry. Results showed that packed cell volume, haemoglobin concentration and erythrocytes of rabbits fed diets containing7.5 and 10.0 mg fumonisin B1/kg were significantly (P 0.05) different amongdietary treatments. However, lymphocytes of animals fed control diet were significantly (P 0.05) different among the diets. Serum total protein, albumin and albumin-globulin ratio significantly (P < 0.05) decreasedwith increase in the dietary fumonisin levels. Serum total protein of rabbits fed diets 3 (5.20 g/dl) and 4 (5.03 g/dl) were identical but both were significantly (P < 0.05) lower than those fed diets 2 (5.60 g/dl)and the control (6.20 g/dl). Urea decreased while creatinine increased apparently with increase in the dietary fumonisin levels. Among the serum enzyme activities examined, AST and ALP were significantly (P < 0.05) elevated in the serum of animals fed diets 3 and 4 than those fed diets 2 and the control. ALT, AST and ALP were significantly (P < 0.05) highest (94.33, 70.00 and 17.37 i.u/l respectively) in animals fed diet 4 containing 10 mg fumonisin B1/Kg. These results suggest thatfumonisin B1 above 5.0 mg kg-1 in the diet of growing rabbits significantly altered haematological parameters and induced anaemic condition in the animals. It also depressed serum total protein andenhanced abnormal increase in serum enzyme activities, which is an indication of organ toxicity by cellular destruction induced by the toxin most especially when fed at 7.5 and 10.0 mg fumonisin B1/Kgdiet
