Abstract
The present study was aimed at evaluating Bacillus subtilis subsp. inaquosorum strain IS02 (B.s.i. IS02; GenBank accession number: JN856456.1) to determine the growth kinetics of antimicrobial metabolite production in different ranges of environmental factors, such as salinity (15-55‰), pH (5-9), and temperature (30-40°C); to evaluate the lifespan of antimicrobial metabolites in different ranges of salinity (0-57‰), pH (2-12), and temperature (35-121°C); and to investigate the effect of B.s.i. IS02 as an additive to functional feed on the digestive activity of Litopenaeus vannamei under high-salinity conditions. Based on the present findings, the bacterium maintained its antimicrobial properties up to 45‰ salinity ( 10729.93 ± 23.93 A U m l − 1 ). There was no significant difference in the antimicrobial activity of metabolites at 35°C and 40°C ( p > .05 ). In the experimental trials, the shrimp postlarvae were fed different concentrations of B.s.i. IS02 (106, 107, and 108 CFU kg-1 diets) under high-salinity (>55‰) conditions. The activity of digestive enzymes, amylase, lipase, and protease in the probiotic-fed shrimp postlarvae was significantly higher than that of the control group ( p < .05 ). The present findings revealed that B.s.i. IS02 maintained the antimicrobial metabolite production, retained the antibacterial lifespan in high-salinity waters, and improved the growth and digestive enzyme activities of shrimps.
Highlights
The shrimp industry is one of the leading aquaculture industries around the world, which is ranked among the top sources of national revenue for some countries
Antimicrobial metabolite activity at 30°C (9890:4 ± 294:95 AU ml-1) was significantly higher than those obtained at 35°C and 40°C (p < :05) (Figure 1(b) and the same trend was observed for bacterial growth
Growth had been seen in all tested acidity ranges (Figure 1(c)) but the growth rate at pH 9 was significantly lower than other pH ranges (p < :05)
Summary
The shrimp industry is one of the leading aquaculture industries around the world, which is ranked among the top sources of national revenue for some countries. Supplementary feeds account for 40-70% of the total cost of shrimp farming [3]; following diseases, they are the second most important challenge facing shrimp farming around the world. Some preventive measures, such as the use of antibiotics, antimicrobial disinfectants, and chemical additives, are being taken to improve shrimp farming [4], resulting in the increased emergence of multidrug-resistant strains of bacteria in shrimp and the possible exposure of human consumers to antibiotic residues [5]. Comprehensive research is needed to discover new antimicrobials with high capacity and minimal residual accumulation in the shrimp tissue as environment-friendly alternatives to common antibiotics for the management of shrimp diseases. Application of various bacterial strains as probiotics in shrimp farms, Litopenaeus vannamei, which is one of the most important shrimp species, has a high economic value.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
