A New Isolate of Pediococcus pentosaceus (SL001) With Antibacterial Activity Against Fish Pathogens and Potency in Facilitating the Immunity and Growth Performance of Grass Carps

Abstract

Probiotic-feeding continues to be a promising strategy to control the bacterial pathogens in aquaculture. A new Pediococcus pentosaceus strain (SL001) was isolated from 1000s of soil samples, which exhibited wide antimicrobial spectrum of against fish pathogens, involving Aeromonas hydrophila , Aeromonas veronii , Aeromonas sobria , Edwardsiella tarda , Lactococcus garvieae , and Plesiomonas shigelloide . The challenge test against A. hydrophila showed that the survival rate of SL001-supplemented group was significantly higher than that of control group ( P < 0.05). Moreover, SL001 could stably colonize in gut of grass carp and increased mucus-secreting goblet cells and extended intestinal villi could be observed in SL001-supplemented group ( P < 0.05). Feeding with SL001 supplemented diet could significantly enhance the growth rate ( P < 0.05) and markedly affect gut microbiota structure of grass carps, resulting in reduced potential pathogens and increased potential probiotics. Furthermore, feeding grass carps with SL001 caused the up-regulated expression of insulin-like growth factor (IGF-1 and IGF-2) and down-regulated expression of myostatin (MSTN-1 and MSTN-2) ( P < 0.05), which probably also account for the increased growth rate of SL001-fed group. Meanwhile, relative mRNA expression levels of immune-related genes in liver, spleen, and head kidney were analyzed in grass carps after feeding for 30 days with SL001 supplemented diets. In all three immune organs, the expression levels of immunoglobulin M (IgM) and complement 3 (C3) were significantly increased ( P < 0.05), whereas the interleukin-8 (IL-8) was down-regulated ( P < 0.05). Besides, whole genome sequencing revealed several probiotics properties of SL001, including organic acid synthesis, bacteriocin synthesis (coagulin), superoxide dismutase, and digestive enzymes. In conclusion, P. pentosaceus SL001 which could enhance immunity and promoter growth rate of grass carps, is prospective to be used as a dietary probiotic in freshwater fish aquaculture.

Pediococcus pentosaceus, a future additive or probiotic candidate

“…P. pentosaceus SL001, isolated from many soil samples, not only greatly increased the expression of complement 3 and immunoglobin M but also ameliorated damage to the intestinal villi and goblet cells, indicating promotion of the immune system of grass carp. Its broad-spectrum antibacterial properties also provided an opportunity for probiotic use in freshwater fish [ 19 ]. P. pentosaceus was found to be beneficial to mud crabs because of its bacteriostatic, immune-enhancing and growth-promoting virtues [ 68 ].…”

“…Promoting biological growth and storage [16][17][18][19][20] Inhibit bacteria and fungi without bacteriocins or BLISs P. pentosaceus T1, P. pentosaceus Z13P, P. Surviving manmade vaginal gel and producing antibacterial bacteriocin [58,59] system of grass carp. Its broad-spectrum antibacterial properties also provided an opportunity for probiotic use in freshwater fish [19]. P. pentosaceus was found to be beneficial to mud crabs because of its bacteriostatic, immune-enhancing and growth-promoting virtues [68].…”

Bacteriocins from Lactic Acid Bacteria. A Powerful Alternative as Antimicrobials, Probiotics, and Immunomodulators in Veterinary Medicine

“…A supplemented diet with P. pentosaceus enhanced the immunity of grass carp, increasing IgM and C3 (complement 3), whereas IL-8 was downregulated. Moreover, P. pentosaceus contributed to the elimination of pathogens and promoted grass carp growth rate [ 160 ].…”

Bacteriocins: An Overview of Antimicrobial, Toxicity, and Biosafety Assessment by in vivo Models

“…The effect of Pediococcus pentosaceus strain (SL001) in growth-related and immune-related genes was evaluated in grass carps. Results showed that the strain was able to enhance immunity and promoter growth of grass carps ( Gong et al, 2019 ). A recent study evaluated the effect of probiotic Chromobacterium aquaticum on zebrafish model.…”