Abstract
Pathogenic Vibrio species is one of the major factors affecting the development of aquaculture and the safety of seafood. Using the antagonistic activity of probiotics against pathogens offers a promising alternative to fish and shrimp aquaculture. In the present study, nine strains of bacteria were isolated from the shrimp culture ponds and screened for their directly antimicrobial activity against pathogenic Vibrio parahaemolyticus Vp1. Strain G, showing significant antimicrobial and non-hemolytic activity, was selected for further assays. The results of biochemical and 16S rRNA sequence analysis indicated that strain G highly related to Bacillus licheniformis. The present study also evaluated the in vitro and in vivo antagonistic effect of strain G against the Vibrios. Strain G exhibited significant inhibitory activity of Vibrio fluvialis FX-2, Vibrio parahaemolyticus K, and V. parahaemolyticus Vp1 in vitro. The inhibition diameter of strain G against Vibrio spp. ranged from 16 to 20 mm on Nutrient Agar. Under in vivo conditions, strain G was non-toxic to zebrafish and effectively protected zebrafish against V. parahaemolyticus Vp1. The non-toxicity of strain G showed final survival rate of 100% in zebrafish at inoculation densities up to 5.6×1010 CFU/ml at 96 h postchallenge. A significant reduction in mortality (P<0.001) was found by addition of 1.5×108 CFU/ml or 1.5×107 CFU/ml strain G in zebrafish against V. parahaemolyticus Vp1. In conclusion, the present study result reveals that strain G is a promising probiotic candidate and has potential applications for controlling pathogenic Vibrios in aquaculture practices.
Highlights
With the increase in seafood consumption around the world, the occurrence of seafood safety issues presents a rising trend in recent years [1, 2]
In this paper we describe characters, phylogenetic analysis based on 16S rDNA sequence, and antagonistic activity of strain G against V. parahaemolyticus Vp1 of pathogenic Vibrio species
Besides of the morphological and physiological characters, the homology search based on 16s rDNA sequence showed that strain G was the number of Bacillus spp. and highly related to Bacillus licheniformis with 99% sequence similarity
Summary
With the increase in seafood consumption around the world, the occurrence of seafood safety issues presents a rising trend in recent years [1, 2]. Human pathogen Vibrio parahaemolyticusis is widely distributed in the marine environments and frequently isolated from a variety of raw seafood, shellfish. It is recognized as a main causative agent of human gastroenteritis associated with seafood consumption in many coastal countries, including China, Japan, India, and the United States [3,4,5,6,7]. The V. parahaemolyticus infected animals, including farmed aquatic animals, are the principal vehicle in the transmission of the pathogenic bacteria to human [5]. The use of various antibiotics to control vibriosis in farmed aquatic animals has a serious negative impact on environment caused by rapid increase of antibiotic resistance in pathogenic bacteria. Many pathogenic Vibrio strains isolated from fish show resistance to a variety of antibiotics [8].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
