EFFECT OF GRADED LEVELS OF HIGH GLUCOSINOLATE MUSTARD (BRASSICA JÚNCEA) MEAL INCLUSION ON NUTRIENT UTILIZATION, GROWTH PERFORMANCE,ORGAN WEIGHT, AND CARCASS COMPOSITION OF GROWING RABBITS

Abstract

Mustard (Brassica juncea) meal (MM) was incorporated at the levels of 80, 160 and 245 g/kg of rabbit diets in replacement of soybean meal (SBM) and compared with a SBM based diet. The three levels of incorporated MM contributed total glucosinolate (TGLS) 3.6, 8.0 and 11.5 g/kg DM respectively. Forty-four weaning rabbits (4 weeks old, 314 + 24 g live weight) of Soviet Chinchilla and White Giant breed comprising 24 males and 16 females were balanced for weight and sex, and randomly allocated to the four experimental diets. The feed intake and growth of the rabbits were monitored in an 8-week long growth study. The nutrient utilization was determined at the middle of the study. The MM used in the experimental diets contained 58 g TGLS/kg. MM incorporated diets had higher ME content ranging from 11.05 to 11.48 MJ/kg DM. The replacement of SBM protein at 33% amounting to incorporation of 8% MM in diet increased (P<0.05) the apparent digestibility of DM, OM, CP, ADF and GE. Quadratic increase was observed for nutrient digestibility except for GE, which showed both linear and quadratic increase. The MM incorporation in growing rabbit diets linearly reduced protein and increased fat content in muscle. The liver weight increased due to MM incorporation. Rabbits fed MM diets reduced feed intake whereas feed conversion efficiency was improved, which showed linear and quadratic effects. Average daily gain of rabbits reduced linearly (P<0.05) on MM diets. Further, rabbits in the present experiment tolerated up to 3.6 g TGLS/kg diet DM during active growth phase without any apparent effect on health and growth performance. It is concluded that MM cannot replace SBM in growing rabbit feeding due to growth and feed intake depression which could be attributed to the TGLS presence, depressing the liver function and affecting the muscle nutrient accretion pattern. However, partial replacement of SBM amounting to 80 g MM/kg diet could not have apparent adverse effects on growth and health of growing rabbits.