Nutrient digestibility, rumen fermentation and microbial nitrogen synthesis of swamp buffaloes fed urea-lime treated rice straw

Abstract

This study aimed to evaluate the effects of urea-lime treatment on rice straw regarding its influence on nutrient digestibility and rumen fermentation efficiency in swamp buffaloes. Eight rumen-fistulated swamp buffaloes (353 ± 11 kg) were used in a completely randomised design experiment. They received one of the two diets (untreated rice straw (RS) and 2% urea + 2% lime treated rice straw (ULTRS)) during the feeding trial. Offered and residual feed were weight and collected during the 21–day experimental period while faeces and urine were sampled on the final 7 days when the animals were housed in metabolism crates. Rumen fluid and blood samples were collected on the last day for chemical analyses. The results showed a significant improvement in dry matter intake and digestibility with the use of ULTRS. Feeding ULTRS improved rumen NH3-N concentration, whereas blood and urine nitrogen contents were similar. The acetic acid concentration and methane production decreased while propionic acid content increased. Consequently, the ratio of acetic acid to propionic acid was significantly reduced in buffaloes that were fed ULTRS. Total viable bacteria, amylolytic, and cellulolytic bacteria enhanced in the ULTRS treatment. The efficiency microbial nitrogen synthesis and the microbial protein synthesis were both elevated in the ULTRS group. The findings suggest that ULTRS can be used as a source of roughage to enhance nutrient digestibility, rumen fermentation efficiency, microbial nitrogen and protein synthesis efficiency and methane reduction in swamp buffaloes.