Complete genome sequence and antimicrobial activity of JT3-1, a microbial germicide isolated from yak feces.

JT3-1 was isolated from feces of the domestic yak () in Gansu province of China. Aim to know whether JT3-1 has the potency to be developed as a probiotic bacterium, works on the complete genome sequence, antimicrobial activity, growth performance in calves, and treatment effect on calf diarrhea of JT3-1 were carried out. The results showed that the complete genome of JT3-1 contains one gapless circular chromosome which is 3,929,799 bp, and has 3761 protein-encoding genes with an average GC content of 46.50%. From the antimicrobial activity results, JT3-1 has shown strong antagonistic activities against , , , , , , and . Compared with the control group, the average weight of the experiment animals from Bv1 group and Bv2 group which were supplemented with JT3-1 was significantly increased ( < 0.05). Meanwhile, the Bv1 and Bv2 supplement significantly improved the level of IgA, IgG, IgM, and IFN-γ in calves as compared with the controls (P < 0.05), but the IL-2 level was not obviously changed between the three groups. In addition, JT3-1 showed a good effect against diarrhea, as the cure rate reached 95.0% (171/180) in newborn calves (Angus cattle) in Xinjiang, and 100.0% (149/149) in yak calves in Qinghai, respectively. Our study will lay a good foundation for the elucidation of the molecular mechanisms of its antimicrobial activity, and supports the hypothesis that JT3-1 has the potential to be developed as a probiotic bacterium in cattle.