Xylanase and lactic acid bacteria mediated bioconversion of rice straw co-ensiled with pea waste and wet brewers' grains as potential livestock feed.

Ensiling straw for livestock feeding is an emerging technique for addressing the fodder shortage in the country, as it optimizes nutrient storage and utilization. In this study, rice straw was mixed with pea waste (pods) and brewer's grains in the ratio of 35:50:15 respectively, and ensiled in triplicate, with mini-silos opened and sampled at intervals of 30, 40, and 50 days.. These ingredients were mixed with exogenous fibrolytic enzyme (EFE, xylanase; X derived from Trichoderma citrinoviride, 1500 IU/kg), coupled with either a solitary homofermentative inoculant (Pediococcus acidilactici NCDC 609; PA), heterofermentative inoculant (Leuconostoc mesenteroides NCDC 421; LM), or a combination of both. Ensiling of peapods, brewer's grain, and additives reduced (p<0.05) pH from 4.4 to 3.9 (control vs combination of xylanase with homo and heterofermentative bacteria (X+PA+LM group), ammonia-N from 0.20 to 0.18% of DM (control vs X+PA+LM group), butyric acid (0.0114 to 0.0110% of DM), and fiber content from 39.91 to 37.20% of DM (control vs X+PA+LM group) in the treatment groups in which ingredients were supplemented with a combination of homofermentative and heterofermentative bacteria with the exogenous enzyme at all time intervals, i.e., 30th, 40th, and 50th days. However, the best quality silage in terms of pH, lactic acid content, and NH₃-N was formed after 50 days of fermentation. The addition of enzymes solubilized the fiber-bound nitrogen fraction of ingredients and made it available to LAB, hence enhancing (p<0.05) its crude protein content. Therefore, it is advisable to ensile the rice straw with peapods and brewer's grain in the suggested ratio to meet the feed demands of livestock and address environmental issues. [ABSTRACT FROM AUTHOR]