Screening and Evaluation of In Vitro Probiotic Properties of Escherichia coli K88-inhibiting Microorganisms Isolated from Min Pigs Feces

摘要

In order to obtain probiotics that can adapt to the intestinal environment of pigs and inhibit Escherichia coli(E. coli) K88, microorganisms were screened from the feces of Min pigs, and their antibacterial and biological characteristics were studied. Using E. coli K88 as the indicator bacterium, the supernatant of the isolated strain from Min pigs was co-cultured with the indicator bacteria for the antibacterial test. The Bacillus velezensis(B. velezensis) strain MZ-78 showed stronger antimicrobial activity against E. coli K88 than other isolates, and its supernatant inhibited the growth of other pathogens including Salmonella typhimurium(S. typhimurium), E. coli, Staphylococcus aureus(S. aureus), and Pseudomonas aeruginosa(P. aeruginosa). Further studies showed that the selected strain MZ-78 exhibited a certain tolerance to sodium chloride conditions. The B. velezensis strain MZ-78 exhibited no hemolytic activity and was not susceptible to antibiotics. Additionally, during metabolism, it generated a certain quantity of short-chain fatty acids, including isobutyric acid and isovaleric acid. Furthermore, this strain demonstrated the capability to counteract the adhesion of E. coli K88 to porcine small intestinal epithelial cells(IPEC-J2), while also promoting their growth and proliferation. The B. velezensis strain MZ-78 isolated from Min pigs feces showed a series of probiotic characteristics and the potential to survive in the digestive tract of animals, which indicated its potential commercial application value as a probiotic alternative to antibiotics in animal husbandry.

关键词

Min pig / Bacillus velezensis / anti-bacterial activity / fatty acid / hemolytic activity