Screening of pigmented Bacillus aquimaris SH6 from the intestinal tracts of shrimp to develop a novel feed supplement for shrimp

• Published in: Journal of applied microbiology Vol. 121; no. 5; pp. 1357 - 1372
• Main Authors: Ngo, H.T., Nguyen, T.T.N., Nguyen, Q.M., Tran, A.V., Do, H.T.V., Nguyen, A.H., Phan, T.‐N., Nguyen, A.T.V.
• Format: Journal Article
• Language: English
• Published: England 01-11-2016
• Subjects: Animal Feed; Animals; Bacillus; Bacillus - isolation & purification; Bacillus - metabolism; carotenoid; Carotenoids - biosynthesis; Decapoda; gastrointestinal tract; Gastrointestinal Tract - microbiology; Penaeidae - growth & development; Penaeidae - metabolism; Penaeidae - microbiology; pigmented; shrimp; supplement; Xanthophylls - metabolism; pigmented; gastrointestinal tract; shrimp; carotenoid; supplement; Bacillus
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/jam.13274

Aims
To develop a novel feed supplement for shrimp using pigmented spore‐forming bacterial strains isolated from their gastrointestinal tracts.
Methods and Results
Eight pigmented Bacillus strains were selected from the isolates based on high production of heat‐stable spores, typical UV‐Vis spectra of produced carotenoids (400–550 nm), and free radical scavenging activity of their extracts. Of the eight strains, the red‐orange pigmented Bacillus aquimaris SH6 was selected because it showed the highest abundance in shrimp guts (70% population). Whiteleg shrimp (n = 30 per group) fed with SH6 spores, at >3 × 106 CFU g−1 pellet for 4 weeks had redder colour (score of 21–23 vs 20–22), 2·7‐fold higher astaxanthin level (0·69 vs 0·25 μg g−1 shrimp), 34% higher weight gain (7·18 vs 5·32 g shrimp−1), and 85% higher phenoloxidase activity (OD490 = 0·265 vs 0·143) than shrimp in the control group.
Conclusions
The result supports the potential use of B. aquimaris SH6 as a feed supplement for promoting the colourization and weight gain, and for enhancing innate immunity of whiteleg shrimp.
Significance and Impact of the Study
This study demonstrates that carotenoids produced by B. aquimaris SH6 can be successfully absorbed and converted to astaxanthin in whiteleg shrimp.