title: Enhancement of the immune response and protection against Vibrio parahaemolyticus by indigenous probiotic Bacillus strains in mud crab (Scylla paramamosain).
abstract: In a previous study, bacterial communities of the intestine in three populations of crabs (wild crabs, pond-raised healthy crabs and diseased crabs) were probed by culture-independent methods. In this study, we examined the intestinal communities of the crabs by bacterial cultivation with a variety of media. A total of 135 bacterial strains were isolated from three populations of mud crabs. The strains were screened for antagonistic activity against Vibrio parahaemolyticus using an agar spot assay. Antagonistic strains were then identified by 16S rRNA gene sequence analysis. Three strains (Bacillus subtilis DCU, Bacillus pumilus BP, Bacillus cereus HL7) with the strongest antagonistic activity were further evaluated for their probiotic characteristics. The results showed that two (BP and DCU) of them were able to survive low pH and high bile concentrations, showed good adherence characteristics and a broad spectrum of antibiotic resistance. The probiotic effects were then tested by feeding juvenile mud crabs (Scylla paramamosain) with foods supplemented with 10(5) CFU/g of BP or DCU for 30 days before being subjected to an immersion challenge with V. parahaemolyticus for 48 h. The treated crabs showed significantly higher expression levels of immune related genes (CAT, proPO and SOD) and activities of respiratory burst than that in controlled groups. Crabs treated with BP and DCU supplemented diets exhibited survival rates of 76.67% and 78.33%, respectively, whereas survival rate was 54.88% in crabs not treated with the probiotics. The data showed that indigenous mud-associated microbiota, such as DCU and BP, have potential application in controlling pathogenic Vibriosis in mud crab aquaculture.
authors.affiliation: Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China.
authors.forename: Hui-Juan
authors.initials: HJ
authors.lastname: Wu
authors.affiliation: Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China.
authors.forename: Ling-Bin
authors.initials: LB
authors.lastname: Sun
authors.affiliation: Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China.
authors.forename: Chuan-Biao
authors.initials: CB
authors.lastname: Li
authors.affiliation: Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China.
authors.forename: Zhong-Zhen
authors.initials: ZZ
authors.lastname: Li
authors.affiliation: Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China.
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Wen
authors.affiliation: Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China.
authors.forename: Yue-Ling
authors.initials: YL
authors.lastname: Zhang
authors.affiliation: Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China. Electronic address: lisk@stu.edu.cn.
authors.forename: Sheng-Kang
authors.initials: SK
authors.lastname: Li
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001407:Bacillus / Q000276:immunology / Q000378:metabolism*; D001646:Bile; D003386:Brachyura / Q000276:immunology* / Q000382:microbiology*; D003470:Culture Media / Q000737:chemistry; D017931:DNA Primers / Q000235:genetics; D041981:Gastrointestinal Tract / Q000382:microbiology*; D005838:Genotype; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D064307:Microbiota; D019936:Probiotics / Q000378:metabolism*; D016897:Respiratory Burst / Q000502:physiology; D014736:Vibrio parahaemolyticus / Q000276:immunology*
chemical_list: D003470:Culture Media; D017931:DNA Primers
keywords: Mud crab; Probiotic strains; Vibrio parahaemolyticus