AUTHOR=Li Yuanyuan , Li Xin , Nie Cunxi , Wu Yanyan , Luo Ruiqing , Chen Cheng , Niu Junli , Zhang Wenju 

TITLE=Effects of two strains of Lactobacillus isolated from the feces of calves after fecal microbiota transplantation on growth performance, immune capacity, and intestinal barrier function of weaned calves

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1249628

DOI=10.3389/fmicb.2023.1249628

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>Weaning stress seriously affects the welfare of calves and causes huge economic losses to the cattle breeding industry. Probiotics play an important role in improving animal growth performance, enhancing immune function, and improving gut microbiota. The newly isolated strains of <italic>Lactobacillus reuteri</italic> L81 and <italic>Lactobacillus johnsonii</italic> L29 have shown potential as probiotics. Here, we studied the probiotic properties of these two strains on weaned calves.</p></sec><sec><title>Methods</title><p>Forty calves were randomly assigned to four groups before weaning, with 10 calves in each group, control group (Ctrl group), <italic>L. reuteri</italic> L81 supplementation group (2 g per day per calf), <italic>L. johnsonii</italic> L29 supplementation group (2 g per day per calf), <italic>L. reuteri</italic> L81 and <italic>L. johnsonii</italic> L29 composite group (2 g per day per calf), and the effects of <italic>Lactobacillus reuteri</italic> L81 and <italic>Lactobacillus johnsonii</italic> L29 supplementation on growth performance, immune status, antioxidant capacity, and intestinal barrier function of weaned calves were evaluated.</p></sec><sec><title>Results</title><p>The results showed that probiotics supplementation increased the average daily weight gain of calves after weaning, reduced weaning diarrhea index (<italic>p</italic> &lt; 0.05), and increased serum IgA, IgM, and IgG levels (<italic>p</italic> &lt; 0.05). <italic>L. reuteri</italic> L81 supplementation significantly decreased IL-6, increased IL-10 and superoxide dismutase (SOD) levels at 21 d after weaning (<italic>p</italic> &lt; 0.05). Moreover, probiotics supplementation significantly decreased serum endotoxin (ET), diamine oxidase (DAO), and D-lactic acid (D-LA) levels at different time points (<italic>p</italic> &lt; 0.05). In addition, supplementation with <italic>L. reuteri</italic> L81 significantly reduced the crypt depth and increased the ratio of villus height to crypt depth (<italic>p</italic> &lt; 0.05) in the ileum, increased gene expression of tight junction protein <italic>ZO-1</italic>, <italic>Claudin-1</italic> and <italic>Occludin</italic> in jejunum and ileum mucosa, reduced the gene expression of <italic>INF- γ</italic> in ileum mucosa and <italic>IL-8</italic> in jejunum mucosa, and increased the abundance of beneficial bacteria, including <italic>Bifidobacterium</italic>, <italic>Lactobacillus</italic>, <italic>Oscillospira</italic>, etc.</p></sec><sec><title>Discussion</title><p>verall, these results showed that the two strains isolated from cattle feces after low concentration fecal microbiota transplantation improved the growth performance, immune performance, antioxidant capacity, and intestinal barrier function of weaned calves, indicating their potential as supplements to alleviate weaning diarrhea in calves.</p></sec>