Study On Shelf-Life Of Bdellovrio-and-Like Organisms(BALO) Strain BDS01and Its Effects On Intestinal Microflora Of Scophthatmus Maximus

Bdellovibrio-and-like organisms (BALO) are a group of Gram-negative bacteria thatprey on other bacteria and have great use of prospects in aquaculture. In this paper, six kindsof protectants, glycerol, sucrose, raffinose, glucose, sodium glutamate, meso-inositol wereapplied to study how they extend shelf-life of BALO strain BDS01. With Arrhenius equation,the shelf-life of BDS01microbial preparation is predicted when its concentration drop downby2log. And then following experiments are conducted to verify the predicting result.Scophthatmus maximus is one of the rarest fish and is one of a pillar industry in ourcountry’s aquaculture. Fish’s growth environment and nutrition factor have a lot to do withfish intestinal microbes. Probiotics can regulate fish intestinal microbes. This paper appliedBDS01or Bacillus subtilis during the growth of Scophthatmus maximus. And the bacterialconcentration and changes of bacteria group structure were discussed. The main results in thispaper are as follows:1. Three protectants, Glycerol, sucrose and glutamic acid Sodium were used to designfor orthogonal experiments. After testing,17%glycerol,5%sugar and7%Sodium wereoptimized by orthogonal experiments. Results of constant temperature verification experimentshowed that the real shelf-life of BDS01at25℃were constant with the prediction results, andthe real shelf-life at10℃and4℃were both slightly lowed than the prediction results whenBDS01reducing2orders of magnitude. And the real shelf-life of BDS01reducing2orders ofmagnitude at4℃were about13weeks. Prediction model established on the basis of theArrhenius equation can predict shelf-life of Bdellovibrio-and-like organisms effectively.2. With the passage of time, species and quantity of Scophthatmus maximus intestinalmicrobes increased in control. Concentration of some bacteria increased in group1, somebacteria disappeared and some increased, but the bacteria abundance remained stable as awhole. Change for microflora abundance in group2was not obvious. It indicated that BDS01had played an important role in control of gut bacterial microflora, and kept the microbialcommunity structure relatively stable in group2. 3. Result of two months intervals of all groups showed that both microflora richnessvalues and diversity index increased in the control group and group1. But microflora richnessvalues keep the same in group2, which showed gut microbial abundance was under control ingroup2. And adjustment effect in group1is not obvious. In this paper, the intestinal bacteriaare mainly Proteobacteria and Firmicutes bacteria. Sequencing results showed thatScophthatmus maximus intestinal bacteria were abundant.