Gut Associated Lactic Acid Bacteria Isolated from the Estuarine Fish Mugil cephalus: Molecular Diversity and Antibacterial Activities against Pathogens
A. Deborah Gnana Selvam1
K. M. Mujeeb Rahiman1
A. A. M. Hatha1
1. Dept. of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Fine arts Avenue, Cochin- 682016, India
2. Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, N-9037, Brevikia, Norway
International Journal of Aquaculture, 2014, Vol. 4, No. 1 doi: 10.5376/ija.2014.04.0001
Received: 11 Nov., 2013 Accepted: 18 Dec., 2013 Published: 22 Jan., 2014
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Preferred citation for this article:
Ghosh et al., 2014, Gut Associated Lactic Acid Bacteria Isolated from the Estuarine Fish Mugil cephalus: Molecular Diversity and Antibacterial Activities against Pathogens, International Journal of Aquaculture, Vol.4, No.01: 1-11 (doi: 10.5376/ija.2014.04.0001)
In the present study we address the issue on gut associated lactic acid bacteria (LAB) isolated from the intestine of estuarine fish Mugil cephalus using de Man Rogossa and Sharpe (MRS) agar. LAB isolates were identified biochemically and screened for their ability to inhibit in vitro growth of various fish, shrimp and human pathogens. Most of the LAB isolates displayed an improved antagonism against fish pathogens compared to shrimp and human pathogens. Selected representative strains displaying high antibacterial activity were identified using 16S rRNA gene sequence analysis. Of the selected strains Lactobacillus brevis was the most predominant. Four other species of Lactobacillus, Enterobacter hormaechei and Enterobacter ludwigii were also identified. It was also observed that even among same species, considerable diversity with respect to substrate utilization persisted. Considering the euryhaline nature of grey mullet (Mugil cephalus), the LAB isolated from the gut possessed good tolerance to varying salt concentrations. This finding merits further investigation to evaluate whether the isolated LAB could be used as probiotics in various fresh and sea water aquaculture.
Probiotics; Antibiotic resistance; Lactobacilli; Molecular diversity