Lactobacillus plantarum and Lactobacillus brevis alleviate Enterotoxigenic Escherichia coli-induced intestinal inflammation and stabilize intestinal microorganisms and serum metabolites in piglets

Enterotoxigenic Escherichia coli (ETEC) is a major pathogen causing diarrhea in weaned piglets, and oral administration of probiotics has become an important strategy for preventing and treating ETEC-induced diarrhea. The aim of this study was to investigate the protective effect of two probiotics, Lactobacillus plantarum and Lactobacillus brevis, on ETEC-induced injury in piglets. Twenty-four piglets were randomly divided into control (CON) group (fed with basal diet and treated with sterile saline), ETEC group (fed with basal diet and treated with ETEC), LP-ETEC group (fed with basal diet and treated with ETEC and L. plantarum) and LB-ETEC group (fed with basal diet and treated with ETEC and L. brevis), with 6 piglets in each group. The experiment lasted for 21 days. The results indicated that both probiotics were able to inhibit the ETEC-induced reduction in daily weight gain of piglets and prevent the damage to jejunum. Serum metabolomic analysis showed that both probiotics significantly increased some beneficial metabolites including phosphatidylethanolamine, monoacylglyceride, cholic acid and rhodoxanthin (P < 0.05). Transcriptome sequencing indicated that L. plantarum and L. brevis may alleviate piglet diarrhea by regulating genes including LBH and RNASE1. According to 16s rRNA sequencing, both probiotics were able to maintain the normal microbial community of the gut. In summary, L. plantarum and L. brevis can protect piglets from ETEC-induced damage and promote healthy growth of piglets by regulating metabolites and gene expression.