Effect of graded levels of raw bambara nut (Voandzeia subterranea L) waste on nutrient intake, digestibility and utilization by rabbits

Abstract

The effect of graded levels of raw bambara nut (Voandzeia subterranea L) waste on nutrient intake, digestibility and utilization by weaner rabbits was investigated. Four diets were formulated to contain 0, 10, 20 and 30% raw bambara nut waste (RBW). Twenty-four hybrid (Chinchilla x New Zealand white) weaner rabbits weighing 790-880g at six weeks were randomly divided into four groups of6 rabbits each. The groups were randomly assigned to the four diets in a completely randomized design (CRD) for 56 days. Each treatment was replicated 3 times with two rabbits per replicate. Results showed that significant differences (P<0.05) existed among treatments in final body weight (FBW), average daily weight gain (4DWG) and intake of dry matter (DM), crude protein (CP), gross energy (GE) and digestible energy (DE). There were also significant differences (P<0.05) among treatments in digestibility coefficients of DM, CP crude fibre (CF), ether extract (EE) and nitrogen free extract (NFE), Rabbits fed 20 and 30% RBW diets had significantly (P<0.05) lower FBW and ADGW, and lower (P<0.05) intake of DM, CP GE and DE than rabbits fed the control diet. Rabbits fed 20 and 30% RBW diets also had significantly (P<0.05) lower digestibility coefficients of DM, CP CF, EE and NFE Results showed that nutrient intake, weight gain and digestibility coefficients were depressed. Mortality was observed at 20 and 30% RBW levels. Although there were no significant differences (P>0.05) among treatments in relative organ weights and in carcass dressing percentage, the kidney of rabbits fed 30% RBW diets had mild degeneration necrosis and dilatation of the tubules. Bile duct dilatation, hyperplasia of the bile duct epithelia cells. fibrosis and thickening of the interlobular septa were observed in the liver of rabbits fed 30% RBW diets. The depression in nutrient intake, and weight gain, and the observed histopathological changes at 20 and 30% RBW levels could be due to ant nutritional factors present in the raw bambara nut waste or done to high fibre levels of RBW The results indicate that up to 10% RBH can be included in the diets of weaner rabbits without serious deleterious effects on rabbits