Potential probiotics from Indian major carp, Cirrhinus mrigala. Characterization, pathogen inhibitory activity, partial characterization of bacteriocin and production of exoenzymes.
The study explored antagonistic activity of the cellular components of potential probiotic bacteria from mrigal (Cirrhinus mrigala) against fish pathogens with a basic insight of the chemical nature of the antagonistic compound. Totally 208 autochthonous gut bacteria were isolated, of which 22 strains revealed antagonism towards ≥2 of the six common fish pathogens. Zones of inhibition (halo diameter) were presented as score and the four most promising strains were selected as putative probiotics based on the cumulative score assigned. Further, evaluation of different cellular components exhibited bactericidal activity against the fish pathogens. Verification of other probiotic properties revealed that each of the selected strains produced diverse extra-cellular enzymes. The selected strains grew better in intestinal mucus than skin mucus, were resistant to diluted bile juice (2-20%) and safe for the target fish. The extracellular product used as crude bacteriocin revealed thermostability (up to 90°C) and activity over wide pH range (4-9). Partial loss of activity through treatment with proteinase-K and trypsin indicated proteinaceous nature of the antibacterial compound produced by the probiotic strains. 16S rRNA partial gene sequencing revealed that the four strains CM1FG7, CM1HG5, CM3FG19 and CM3HG10 were similar to Bacillus stratosphericus (KM277362), Bacillus aerophilus (KM277363), Bacillus licheniformis (KM277364) and Solibacillus silvestris (KM277365), respectively.
Aquaculture Laboratory, Department of Zoology, The University of Burdwan, Burdwan 713104, West Bengal, India.
Anjan
A
Mukherjee
Aquaculture Laboratory, Department of Zoology, The University of Burdwan, Burdwan 713104, West Bengal, India.
Dipanjan
D
Dutta
Aquaculture Laboratory, Department of Zoology, The University of Burdwan, Burdwan 713104, West Bengal, India.
Sudeshna
S
Banerjee
Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, NO 9037, Tromsø, Norway.
Einar
E
Ringø
Department of Arctic and Marine Biology, Faculty of Bioscience, Fisheries and Economics, UiT The Arctic University of Norway, NO 9037, Breivika, Norway.
Eva Marie
EM
Breines
Department of Arctic and Marine Biology, Faculty of Bioscience, Fisheries and Economics, UiT The Arctic University of Norway, NO 9037, Breivika, Norway.
Ellinor
E
Hareide
Parasitology Laboratory, Department of Zoology, The University of Burdwan, Burdwan 713104, West Bengal, India.
Goutam
G
Chandra
Aquaculture Laboratory, Department of Zoology, The University of Burdwan, Burdwan 713104, West Bengal, India. Electronic address: kghoshbu@gmail.com.
Koushik
K
Ghosh
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000737:chemistry* / Q000187:drug effects* / Q000235:genetics; D001430:Bacteriocins / Q000494:pharmacology*; D002347:Carps / Q000382:microbiology*; D000069196:Gastrointestinal Microbiome; D019936:Probiotics / Q000494:pharmacology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA / Q000662:veterinary
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D012336:RNA, Ribosomal, 16S
Antagonism; Autochthonous gut bacteria; Bacilli; Bacteriocin; Indian major carp; Mucus