Evaluation and characterization of a novel probioticLactobacillus pentosusPL11 isolated from Japanese eel (Anguilla japonica) for its use in aquaculture

Abstract

In the present study, a potential Lactobacilli probiotics were isolated from Japanese eels (Anguilla japonica) and characterized and evaluated for their possible use in eel farming. Sixteen Lactobacilli were isolated from intestines of Japanese eels, using selective media. The lactobacilli strains (represented as PL1 to PL16) were screened by their ability to produce digestive enzyme. Among these, three strains (PL11, PL13 and PL16) producing four digestive enzymes (amylase, cellulase, protease and phytase) simultaneously were characterized further using API ZYM kit. From these, PL11 (Lactobacillu (L.) pentosus) was identified as potential probiotics candidate producing 15 enzymes among 20 tested. Further examination of biological activities of PL11 revealed tolerance against pH, artificial bile juice and antibacterial activity against several fish pathogenic bacteria. The in vitro competitive exclusion assay also revealed 88.4% reduction in adhesion of fish pathogen (Edwardsiella tarda) by PL11 to host intestinal mucus. In vitro incubation of Japanese eel foregut with Baclight‐labelled PL11 showed colonization of the enterocyte surface by confocal and scanning electron microscopy. In summary, PL11 isolated from eels could serve as a potential probiotics with acid and bile tolerance, production of digestive enzymes, antibacterial activity and inhibition of fish pathogen adhesion to intestinal mucus.

Revealing the compositions of the intestinal microbiota of three Anguillid eel species using 16S rDNA sequencing

“…Probiotics are beneficial microbes that could colonize in the intestine of the host and maintain normal function of gut, including promoting growth of the host, generating digestive enzymes and essential nutrients, withstanding the infection of pathogens and stimulating the innate immune system (Balcázar et al., ; Hai, ; Kesarcodi‐Watson et al., ; Martínez Cruz, Ibáñez, Monroy Hermosillo, & Ramírez Saad, ). Some studies further indicated that microbes isolated from the intestine of the studied fish may be potential probiotics for themselves (Buntin, Chanthachum, & Hongpattarakere, ; Ghosh, Sinha, & Sahu, ; Lee et al., ). Therefore, identifying the dominant intestinal bacteria of Anguillid eels would be helpful for the development of probiotics used in the eel farming.…”

“…The intestinal microbiota of Anguillid eels was seldom studied; to our knowledge, only one study investigated the intestinal microbiota of Japanese eel according to culture‐based techniques with selective or non‐selective isolation media (Lee et al., ). However, many microbes in the intestinal tract of fish could not be cultured and identified because the in vitro culturing conditions of these microbes were little known (Kim, Brunt, & Austin, ).…”

Culturable gut bacteria of Ikan Batak (Neolissochilus sumatranus Weber & de Beaufort, 1916) collected in Toba Samosir, Indonesia

“…Previously, L. pentosus PL11 has been isolated from gut of Japanese eels (Anguilla japonica). In addition, L. pentosus PL11 has been also characterized and evaluated for probiotic properties of production of digestive enzymes, bile and acid tolerance, adhesion to intestinal mucus, and antibacterial activity to inhibit fish pathogen (Lee et al 2015). Specifically, L. pentosus PL11 demonstrated the immunomodulation of the inflammatory responses in fish owing to infection by pathogenic Edwardsiella tarda (Birhanu et al 2016).…”

Oral pharmacokinetics of a novel Lactobacillus plantarum PSCPL13 in the intestines of experimental flounder

“…In ongoing screening and field studies of potential probiotic strains for use in aquatic and domestic animals, we isolated several lactic acid bacteria from the intestines and undertook morphological, biochemical and molecular characterization, as well as in vitro and in vivo testing of potential probiotic candidates (Kim, Kim, Rhee, Song, Lee, Kim, Lee, Lee & Park ; Lee, Cheng, Damte, Lee, Kim, Rhee, Suh & Park ; Lee et al . ; Park & Park ; Birhanu, Lee, Lee, Choi, Hossain, Park, Kim, Suh & Park ). The patented strain used in this study, Lactobacillus plantarum PSCPL13 (International depository authority, KCCM1168P), was previously isolated from fish intestines and characterized in vitro for its probiotic potential (Park & Park ).…”

“…The intestines were aseptically removed from the fish abdominal cavity after dissection, and the contents were squeezed out using sterile forceps into previously weighed dishes containing storage medium for isolating the bacteria and homogenized. L. plantarum PSCPL13 was isolated and identified as previously described (Lee, Damte, Lee, Hossain, Belew, Kim, Rhee, Kim & Park ), with some modifications. Briefly, one gram of intestinal contents was mixed with 9 mL physiological saline (0.9% NaCl) in PBS buffer.…”