Characterization of a Bacillus sp. KRF-7 isolated from the intestine of rockfish and effects of dietary supplementation with mannan oligosaccharide in rockfish aquaculture. Issue 119 (December 2021)

• Record Type: Journal Article
• Authors: Jang, Won Je; Lee, Su-Jeong; Jeon, Mi-Hyeon; Kim, Tae-Yong; Lee, Jong Min; Hasan, Md Tawheed; Lee, Hyun-Tai; Park, Jung-Ha; Lee, Bong-Joo; Hur, Sang Woo; Lee, Seunghan; Kim, Kang Woong; Lee, Eun-Woo
• Is Part Of: Fish & shellfish immunology. Issue 119(2021)
• Page Start: 182
• Page End: 192
• Publication Date: 2021-12
• Subjects: Rockfish -- Probiotics -- Growth performance -- Innate immunity -- Microbiota; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2021.09.039
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: The purpose of this study was to characterize the bacteria isolated from rockfish intestines and to investigate the effects of feed supplementation in rockfish aquaculture. Bacillus sp. KRF-7 isolated from the intestine of rockfish ( Sebastes schlegelii ) was demonstrated to be safe based on in vitro tests confirming the absence of hemolysis, cytotoxicity, and genes with toxigenic potential. In a feeding trial, providing a supplemental diet of 1 × 10 8 CFU g −1 Bacillus sp. KRF-7 was observed to positively alter the weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio of juvenile rockfish. KRF-7 supplementation showed positive regulation of nonspecific immune parameters, such as superoxide dismutase, lysozyme activity, and myeloperoxidase activity. This analysis also revealed a change in the composition of the intestinal microbiota at the phylum level from Proteobacteria to Firmicutes. In both the kidney and spleen, the expression levels of IL-10, NF-κB, and B cell activating factors in the KRF-7-supplemented group were significantly increased compared to those in the control group. Therefore, this study verified the safety of KRF-7 isolated from the intestine of rockfish and suggests that dietary supplementation with KRF-7 enhances the growth performance of rockfish and has beneficial effects on the regulation of the intestinal microbiota and immune response. Highlights: The probiotic properties of Bacillus sp. KRF-7 were investigated. Dietary supplementation of KRF-7 upregulated the growth performance of rockfish. Supplementation with KRF-7 modulated gut microbial community of rockfish.