Effect of Diets Containing Dried Taro (Colocasia esculanta) Waste and Dried Yeast (Saccharomyces cerevisiae) on Performance of Growing Rabbits

Abstract

A total of hundred and four New Zealand White (NZW) rabbits were chosen after weaned at 6 weeks of age and randomly divided into 8 equal groups (13 rabbits/ group) according to their initial live body weight (804.31±20g), to evaluate the utilization of dried taro waste (TW) without or with dried yeast (DY) in feeding growing rabbits and their response on growth performance, nutrients digestibility, carcass traits, some blood parameters, cecum activity as well as economic efficiency. Rabbits were fed ad-libitum on diets containing 0.0, 7.5, 15, 22.5% TW without supplement for groups G1, G3, G5 and G7, respectively and the other groups (G2, G4, G6 and G8) were fed the same levels of TW, with 0.5% DY. At the end of the experimental period (14 weeks of age), digestibility trials were carried out to determine the digestibility of feed nutrients and the feeding values of the experimental diets. In addition, four rabbits were slaughtered from each group to test the carcass traits, some blood parameters and cecum activity. The experimental diets were fed to growing rabbits for 8 weeks post-weaning period. Results revealed that the TW contained 2479 Kcal digestible energy/Kg, 16.41% crude protein, 14.30% crude fiber, 7.42% ether extract, 16.92% ash, 1.22% calcium 0.27% phosphorus on DM basis, and some anti-nutritional factor such as calcium oxalate (0.56%). Formulation of rabbit diets with different levels of TW (0.0, 7.5, 15 and 22.5%) without or with 0.5% DY showed no significant differences (P>0.05) among the dietary treatments in respect of live body weight and total weight gain at different ages (6-14 weeks). It was also clear that the insignificant highest weight gain was associated with rabbits fed diets containing DY (G2, G4 and G6) during 6-14 weeks of age than those fed the un-supplemented diets. Total feed intake of TW-diets was slightly decreased during the whole experimental period with G3 and G5, but significant decreased with G7 compared to that of control diet (G1). Supplemented DY with rabbit diets tended to improve total feed intake at 6-10 and 6-14 weeks of age comparing with the non-supplemented ones. Feed conversion and performance index didn’t affected significantly by dietary treatments. In comparison with control diet, most nutrient digestibilities of most tested diets did not affected significantly. Almostly carcass traits (empty carcass, edible giblets, non-edible parts and dressing percentage) did not affected significantly by most tested treatments compared with control diet. TW or DY had slightly changes on blood constituents of experimental rabbits. Insignificantly higher concentrations of TVFA´s and ammonia-N were observed in the cecum contents of rabbits fed on the different levels of TW without or with DY compared with the control group. Similarly each of cecum weight and pH of cecum content were not significant changed by all tested rations based on control one. Profitability and economic efficiency were markedly improved with TW-diets without or with DY compared with control diet.In conclusion dried taro waste could be used in feeding of growing rabbits up to 22.5% without or with dried yeast with no adverse effect on productive performance, carcass traits, physiological function and economical efficiency.