Effects of Lactococcus lactis MG1363 producing fusion proteins of bovine lactoferricin–lactoferrampin on growth, intestinal morphology and immune function in weaned piglet

Aims We developed a strategy for localized delivery of the LFCA (lactoferricinlactoferrampin), which is actively synthesized in situ by Lactococcus lactis (pAMJ399‐LFCA/LLMG1363), and explored the possibility of using pAMJ399‐LFCA/LLMG1363 as an alternative additive diet to antibiotics. Methods and Results The antimicrobial activities of the LFCA derived from pAMJ399‐LFCA/LLMG1363 were tested in vitro . The results showed that LFCA had an inhibitory effect on Staphylococcus aureus , Escherichia coli and Salmonella enteritidis . Then, the pAMJ399‐LFCA/LLMG1363 was used as an additive diet for piglets. Our data demonstrated that oral administration of pAMJ399‐LFCA/LLMG1363 significantly improved the average daily gain, feed‐to‐gain ratio, intestinal mucosal integrity and decreased the serum endotoxin and d ‐lactic acid levels. The mRNA expression levels of intestinal tight junction proteins (including occludin, Claudin‐1 and ZO‐1) were significantly upregulated by pAMJ399‐LFCA/LLMG1363 administration. The serum immunoglobulin G (IgG) levels, intestinal secretory immunoglobulin A (sIgA) levels, IL‐2, IL‐10 and TGF‐β levels were significantly increased by pAMJ399‐LFCA/LLMG1363. Furthermore, our data revealed that oral administration of pAMJ399‐LFCA/LLMG1363 significantly increased the number of general Lactobacillus , and decreased the total viable E. coli counts in the ileum and cecum contents. Conclusions We developed a novel pAMJ399‐LFCA/LLMG1363 secreting LFCA, which had probiotic effects on the growth performance, intestinal morphology, intestinal barrier function and immunological indices of weaned piglets. Significance and Impact of the Study pAMJ399‐LFCA/LLMG1363, with probiotic effects on the health of weaned piglets, may be a promising feed additive for weaned piglets.