Lactobacillus casei TH14 and additives could modulate the quality, gas kinetics and the in vitro digestibility of ensilaged rice straw

This study's objectives were to (a) consider the combined effects of Lactobacillus casei TH14 and additives on fermentation quality, nutritive value and microbial composition when ensiling rice straw and (b) evaluate the ensiled rice straw using the in vitro gas production technique. A 2 × 2 × 2 factorial arrangement in a completely randomized design (CRD) was used in a randomized complete design with three replications. The rice straw was treated with L. casei TH14 (T) at 0 and 10⁵ colony-forming unit (cfu)/kg fresh matter (FM), cellulase (C) at 0 and 10,000 unit/kg FM and molasses (M) at 0 and 50 g/kg FM. After 30 days, the dry matter content of the ensiled rice straw was a range between 261.77 and 287.01 g/kg while untreated rice straw was 934.00 g/kg. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents were decreased when treated with C (p < .01). Th e pH, ammonia-nitrogen, lactic acid, acetic acid and butyric acid values were affected by the interaction among the additives. In particular, pH was significantly (p < .01) lower in rice straw treated with T × C × M. Lactic acid bacterium (LAB) counts were highest when ensilage rice straw with T × C × M (p < .05), while untreated rice straw indicated highest amount for aerobic bacteria (p < .01) and yeast populations (p < .01). Interaction among additives had no effect (p > .05) on gas production rate constant for the insoluble fraction (c value), but combination between C × M with ensiled rice straw reduced the c value (p < .05). The in vitro dry matter digestibility at 48 hr after incubation increased when rice straw was treated with T × C (p < .01), T × M (p < .05) and C × M (p < .05). Total volatile fatty acids at 4 hr and the mean value were increased (p < .05) when ensiled rice straw with T × C or T × M. Propionic acid was improved by adding C or M (p < .05). T × M did not influence (p > .05) any ruminal microorganism counts except for bacterial counts at 4 hr (p < .01). Thus, ensiled rice straw with T × C × M could promote the quality of ensiled rice straw and improve gas kinetics, fibre digestion and ruminal characteristics.