Sodium butyrate mitigates in vitro ammonia generation in cecal content of laying hens

One of the environmental challenges that modern poultry industry faced is odor pollution caused by ammonia emission. The objectives of the study were to determine the effect of sodium butyrate on the production of ammonia in the cecal contents of laying hens using in vitro gas production study and to elucidate the mechanism behind it. The study consisted of a control (without sodium butyrate), and three experimental groups added with 10, 15, and 20 mg of sodium butyrate, respectively. Results showed that ammonia production in headspace of the syringe decreased by 8.2, 23, and 23 %, respectively, while ammonium production from the fermentation broth decreased by 6.3, 14.4, and 13.7 %, respectively. Sodium butyrate had no significant effect on the contents of uric acid and urea, nitrate-N, or total N in all treatments. However, sodium butyrate decreased the urease and uricase activities (P < 0.05) in the fermentation broth. Sodium butyrate also altered volatile fatty acids profile of the fermentation broth by decreasing the production of isovalerate (P < 0.05) and increasing those of acetate, butyrate, and isobutyrate (P < 0.05). The MiSeq System Sequencing results showed that sodium butyrate increased the relative abundance of Bacteroides and Faecalibacterium (P < 0.05) and decreased the relative abundance of Desulfovibrio, Helicobacter, and Campylobacter (P < 0.05).Our results concluded that sodium butyrate changes the diversity and relative abundance of the microbes which altered the fermentation characteristics leading to reduction in ammonia production.