Tibetan Pig-Derived Probiotic Lactobacillus amylovorus SLZX20-1 Improved Intestinal Function via Producing Enzymes and Regulating Intestinal Microflora

Abstract

The interaction between exogenous microorganisms and the host has received great attention, and finding new probiotics is always the way to improve the health of humans and animals. <i>Lactobacillus amylovorus</i> (<i>L. amylovorus</i>) is a kind of <i>Lactobacillus</i> that can efficiently utilize starch, as a food and feed additive, it has been widely used for mildew prevention and antibacterial, bacteriostasis, and enzyme production. Herein, a strain of <i>L. amylovorus</i> was isolated from the feces of Tibetan weaned piglets, named <i>L. amylovorus</i> SLZX20-1. Physiological and biochemical experiments <i>in vitro</i> confirmed that it had a fast growth rate and could produce a variety of enzymes, including α-galactosidase, β-galactosidase, α-glucosidase, β-glucosidase, and ferulic acid esterase. In addition, <i>L. amylovorus</i> SLZX20-1 exerted antibiotic effects on the growth of <i>Salmonella typhimurium</i> (<i>S. typhimurium</i>) SL1344, <i>Citrobacter rodentium</i> (<i>C. rodentium</i>) DBS100, <i>Salmonella pullorum</i> (<i>S. pullorum</i>) CVCC1791, <i>Staphylococcus aureus</i> (<i>S. aureus</i>) CVCC1882, <i>Escherichia coli</i> (<i>E. coli</i>) O157, <i>E. coli</i> K88, <i>E. coli</i> K99, and <i>E. coli</i> 987P, which are closely related to acid productivity, such as lactic acid and acetic acid. <i>In vitro</i> co-culture, <i>L. amylovorus</i> SLZX20-1 has shown the strong adhesion ability to intestinal porcine epithelial cells (IPEC-J2 cells) and activated IPEC-J2 cells with high expression of host defense peptides (HDPs), such as <i>NK-Lysin, PEP2C</i>, and <i>PBD-1</i>. <i>In vivo</i> experiment, <i>via</i> intragastric administration, <i>L. amylovorus</i> SLZX20-1 significantly improved the feed intake of mice, declined the crypt depth of jejunum and ileum, <i>L. amylovorus</i> SLZX20-1 changed the composition of intestinal microbes, especially at the level of colonic genus, the dominant genus was changed from <i>Lactobacillus</i> to <i>S24-7</i>, which indicated the change of intestinal carbohydrate nutrition. In conclusion, <i>L. amylovorus</i> SLZX20-1 showed strong probiotic characteristics, which met with the standard of probiotics and is worth further exploring its impacts on host health and its potential as a candidate strain of probiotics.