Effect of Enterococcus faecium on intestinal metabolomics and inflammatory factors of Penaeus monodon

Abstract:

[Background] As a lactic acid-producing probiotic candidate, Enterococcus faecium is widely used in animal breeding owing to the satisfactory biological characteristics. However, a few studies of the influence of E. faecium on intestinal metabonomics are available. [Objective] To explore the effect of E. faecium on intestinal metabonomics and inflammatory factors of Penaeus monodon (giant tiger prawn) and thus to lay a theoretical basis for the application of E. faecium as a probiotic in prawn culture. [Methods] A total of 400 giant tiger prawns were randomly classified into four groups. For three groups (experimental groups) of them, E. faecium was added into the feed at 10⁷, 10⁸, and 10⁹ CFU/g, respectively. For the remainder, no E. faecium was added to the feed, and this group was regarded as control. The experiment lasted 28 days. Then, the content of immunoglobulin IgM, phenol oxidase (PO), interleukin-6 (IL-6), and complement fragment 3a (C3a) in P. monodon was measured, and the changes of intestinal metabolites were studied by LC-MS. On this basis, differential metabolites and related metabolic pathways were analyzed.[Results] The addition of E. faecium had positive effect on the inflammatory factors of P. monodon. It increased the content of IgM, PO, and C3a and reduced the content of IL-6 in P. monodon. A total of 165 differential metabolites between the control group and the experimental groups were identified, which were mainly lipids and lipid-like molecules, organic acids and derivatives, organic oxygen compounds, organic heterocyclic compounds, nucleosides, nucleotides and analogues, etc. The differential metabolites were involved in 37 metabolic pathways, including arachidonic acid metabolism, α-linolenic acid metabolism, choline metabolism, and pyrimidine metabolism (P<0.05), and arachidonic acid metabolism α-linolenic acid metabolism, choline metabolism, pyrimidine metabolism, and glycerophosphatide metabolism topped the pathways in the number of metabolites.[Conclusion] E. faecium has positive effect on lipid metabolism, amino acid metabolism, nucleotide metabolism, and inflammatory factors in the intestine of P. monodon, which lays a theoretical foundation for the application of E. faecium in shrimp culture, and has important significance and application prospects.