Nutritional Evaluation of Rice Mill Waste Fermented with Pap Water for rabbit production

Abstract

 The rising cost and increasing scarcity of conventional feed ingredients have become major constraints to sustainable livestockproduction, particularly in developing countries, which led to search for alternative, low-cost, and locally available feed resources,including agro-industrial by-products. Rice mill waste (RMW) is abundantly produced in rice-processing regions and has potential asa livestock feed ingredient; however, its utilization is limited by low crude protein content and high fibre levels, which reduce digestibility and animal performance. This study therefore evaluated the effects of fermentation using water and pap water on the physico-chemical characteristics, proximate composition and acceptability of RMW for rabbit production. Rice mill waste was subjected to water or pap water fermentation under controlled conditions. Physico-chemical parameters, including temperature and pH, were monitored before and after fermentation, analyses were evaluated using standard analytical procedures. A preference test was conducted to assess the acceptability of the products by rabbits. Data obtained were subjected to appropriate statistical analysis to determine significant differences between treatments. Results showed that the temperature of the fermentation substrate remained constant at 28 °C before and after fermentation for both treatments, indicating stable fermentation conditions. The pH values varied between the treatments, with pap water-fermented RMW recording a lower pH (5.0) compared to water-fermented RMW (7.0), suggesting enhanced microbial activity in the pap water medium. Proximate analysis revealed that the crude protein content of pap water-fermented RMW (5.7%) was slightly higher than that of water-fermented RMW (5.6%), although the difference was not statistically significant. A notable reduction in crude fibre content was observed in pap water-fermented RMW (43.5%) compared to water-fermented RMW (45.6%). The coefficient of preference was highest for diets containing pap water-fermented RMW, indicating improved palatability and acceptability by rabbits. In conclusion, fermentation of rice mill waste using pap water improved its nutritional quality by slightly increasing crude protein content, reducing fibre levels, and enhancing acceptability. Pap water therefore shows considerable potential as a low-cost fermentation medium for upgrading agro-industrial by-products for sustainable rabbit nutrition.