Feeding rice fermented beer waste improves growth performance, nutrient digestibility and nitrogen utilization in growing rabbits.

This study was conducted to investigate the effects of dietary rice brewer waste (RBW) on growth performance, nutrient utilization and nitrogen balance in growing rabbits. Thirty growing rabbits (758 ± 25.7 g initial body weight) were randomly assigned to control and four treatment groups (containing RBW) in a completely randomized design with six rabbits per group. The study lasted 6 weeks for measurements of feed intake and growth performance followed by a five-day metabolic trial to determine nutrient digestibility and nitrogen balance. The five diets contained RBW at 0% RBW (control group), unsterilized RBW at 10% and 20% and sterilized RBW at 10% and 20% in the concentrates. The average daily body weight gain (ADG) in the 20% unsterilized RBW group was higher (p < 0.01) than the control group. No statistically significant difference (p = 0.089) of ADG was observed for the control vs. the sterilized groups, but the overall ADG was better (p = 0.044) in the unsterilized RBW groups than the sterilized RBW groups. The daily dry matter intake in unsterilized and sterilized RBW groups was higher (p < 0.01) than the control group. However, no difference (p = 0.22) was found between the unsterilized and sterilized RBW. The feed conversion ratio (FCR) was lower for the unsterilized RBW groups vs. the control group (p = 0.041), but there was no difference of FCR in the control vs. sterilized RBW groups (p = 0.37) and the unsterilized RBW groups vs. unsterilized RBW groups (p = 0.14). The digestibility of organic matter, crude protein and crude fibre was greater (p < 0.01) in the unsterilized and sterilized RBW groups than the control group. The nitrogen balance and efficiency of nitrogen utilization were also higher in the unsterilized and sterilized RBW groups than the control group (p < 0.01). The study showed that the dietary RBW could improve growth performance and nutrient utilization in growing rabbits with superior responses for the unsterilized RBW.