INFLUENCE OF PARTIAL AND TOTAL SUBSTITUTION YELLOW CORN GRAINS WITH SUGAR BEET PULP ON GROWING RABBITS PERFORMANCE

This work was carried out to study the effect of substitution yellow corn grains with sugar beet pulp on growing rabbits performance, carcass traits, digestability of nutrients, feeding values and economical efficiency. Eighty unsexed New-Zealand White (NZW) growing rabbits of 5 weeks of age were allotted randomly into 5 equal groups (16 rabbits each, with 8 replicates each of two rabbits) to study the effect of substituting yellow corn grain (YCG) by suger beet pulp (SBP) at different rates on growing rabbits performance. Five diets were fed to NZW rabbits from 5-13 weeks of age. The first group was fed the basal diet as a control, while the other four groups were fed diets contaning 9, 18, 27 and 36% SBP, respectivaly which represents replacment rate of 25, 50, 75 and 100% of YCG in the control diet. Results showed that live body weight (LBW) was significantly increased while body weight gain (BWG) insignificantly increased with increasing SBP in the diets up to 75% (27% SBP) substitution for YCG during the most ages of the experimental periods. Rabbits fed on 100% SBP replacement of YCG recorded the lowest value of viability while rabbits fed 75% SBP instead of YCG recorded the highest one of viability. Daily feed intake (FI) was insignificantly decreased with increasing the level of corn grain substitution with SBP up to 100% during the periods of 7-9, 9-11 and 5-13 weeks of age. The level of SBP substituted YCG in the control diet (25, 50 and 75%) resulted in a significantly better feed conversion (FC) values of growing rabbits during the periods of  5-7, 11-13 and 5-13 weeks of age than the other levels. Inclusion of SBP replacement of YCG up to 75% had a significantly (P<0.05 or 0.01) positive effect on the digestibility coefficients of DM, CP and NFE. Digestibility coefficients of OM were gradually increased (P<0.01) while digestibility coefficients of CF were decreased gradually (P<0.01) with increasing the level of SBP up to 100% substitution of YCG. Total digestible nutrient (TDN) and digestible energy (DE) gradually increased (P<0.01) when 25, 50 and 75% SBP replaced YCG as compared in the control diet. All carcass characteristics studied, length of each part of the gastrointestinal tract and pH of digestive tract were not significantly affected by feeding the SBP diets. The best efficiency value was recorded by the rabbits fed 75% SBP substitution of YCG, followed by 100, 50 and 25% SBP replacement for YCG. The obtained results seemed to justly the following conclusion: From the nutritional and economical point of view, using SBP up to 75% substitution for YCG (27% of the growing rabbit diet) in growing NZW rabbit diets had no adverse effect on growth performance, viability rate, digestion coefficients, carcass characteristics and digestive tract measurements.