Isolation,Identification and Biological Characteristics of Probiotic Strains Derived from Intestine of Rockfish Sebastes schlegelii
In order to isolate potential probiotics from the intestinal tract of rockfish Sebastes schlegelii for application in its aquaculture production,two strains of Bacillus were isolated from the intestinal tract of wild rockfish with body weight of 62.96 g caught in the sea,and identified by morphological observation,biochemical identification,16S rDNA gene sequencing and phylogenetic tree.The growth curves,growth characteristics,enzyme production,self-agglutination ability and hydrophobicity of two strains of Bacillus were investigated,and the drug sensitivity test and hemolysis test of two strains were carried out.The two strains of Bacillus were identified as B.licheniformis A1M1 and B.subtilis A3M3,respectively,and Gram-positive and rod-shaped,with logarithmic growth stage in 3 h of culture,and stable growth stage in 21 h and 24 h of culture,respectively.The most suitable cultivation conditions were shown to be tempera-ture of 30 ℃,pH 7,salinity about 5-24 for strains A1M1 and A3M3.B.licheniformis A1M1 and B.subtilis A3M3 had the ability to produce amylase,cellulase,lipase and protease,and showed strong auto-agglutination at 24 h(52.78％and 77.29％,respectively).The hydrophobicity of the both strains to differ-ent solvents was found to be significantly different,with the best to xylene(81.04％and 84.92％,respec-tively).B.subtilis A3M3 was sensitive to penicillin,ampicillin,ceftriaxone,gentamicin,tetracycline,e-rythromycin,ciprofloxacin,cotrimoxazole and lincomycin.B.licheniformis A1M1 had different degree of resistance to 9 kinds of antibiotics.The hemolytic test showed that the two strains had no hemolytic abili-ty,and were featured by wide temperature and salinity,and acid and alkali resistance,fast growth rate,good enzyme production performance,strong self-agglutination ability and good hydrophobicity,indicating that they can be used as a probiotic candidate for the development of aquaculture and probiotics prepara-tions of S.schlegelii.The findings provide data support for their application in aquaculture,especially in aquaculture of S.schlegelii.
万方数据
维普
