Effect Of Dietary With Probioticson The Growth Rate, Disease Resistance And Intestinal Microflora Of Litopenaeus Vannamei

Part 1: In order to research the effect of Bacillus cereus on the growth rate and intestinal microflora of Litopenaeus vannamei, Bacillus cereus(number PC465) was added to basic feed which concentration of viable bacteria was 108CFU/g. Shrimps living in 8 pools with the similar light and position were divided into two groups, which the experimental group was fed of the immune feed everyday while the blank control group were fed of basic feed. Shrimps were fed with a complete breeding cycle(95days) in the farm. Sampled at Day 45, 52, 59, 66, 73, the method of high throughput sequencing of 16 S r DNA gene’s V4 region was used to determine diversity and composition of bacterial communities in each of these samples. Experiment showed:(1)The growth rate of the experimental group was average 15.2% higher than the blank control group.(2) The intestinal microflora of Litopenaeus vannamei were mainly with Proteobacteria and Bacteroidetes, while Firmicutes、Verrucomicrobia、Planctomycetes、Actinobacteria were at lower rate.(3) In intestinal microflora of the blank control group’ shrimps, the average proportion of Proteobacteria(68.30%) was higher than the experimental group(57.94%), while Bacteroidetes was lower than the control group. Proteobacteria was mainly with Vibrio, Anaerospora and Rhodovulum. The blank control group’ average proportion of Vibrio was 5.40%, while the experimental group was 1.94%. Bacteroidete was mainly with Lutimonas and Tenacibaculum. The blank control group’ average proportion of Lutimonas was 5.56%, while the experimental group was 8.12%. The results of the study suggest that dietary with Bacillus cereus can change the intestinal microflora of Litopenaeus vannamei and enhance the growth.Part2: In order to research the effect of Bacillus cereus biofilm on the growth rate,disease resistance and intestinal microflora of Litopenaeus vannamei, planktonic Bacillus cereus(number PC465) was added to basic feed which concentration of viable bacteria was 108CFU/g as the planktonic feed; Bacillus cereus biofilm was added to basic feed which concentration of viable bacteria was 108CFU/g as the biofilm feed. Shrimps living in 24 buckets with the similar light and position were divided into three groups, which the control group was fed of the basic feed everyday while the planktonicgroup were fed of planktonic feed and the biofilmgroup were fed of biofilm feed. Shrimps were challenged with white spot syndrome virus(WSSV) and Vibrio parahaemolyticus after 15 days of feeding experiment. The whole experiment was end after 40 days. Sampled at Day 1, 5, 10, 15, 20, 25, the method of high throughput sequencing of 16 S r DNA gene’s V3+V4 region was used to determine diversity and composition of bacterial communities in each of these samples. Experiment showed:(1)The growth rate of the biofilm group and the planktonicgroup were higher than the control group.(2) The intestinal microflora of Litopenaeus vannamei were mainly with Proteobacteria,while Bacteroidetes、Actinobacteria、Firmicutes、Verrucomicrobia、Cyanophyta were at lower rate,the Content of Proteobacteria was 94%.(3) The proportion of Firmicutes in the biofilm group(0.45%)and planktonicgroup(0.93%) were higher than the control group(0.02%).(4)Proteobacteria was mainly with Vibrio,Photobacterium, Pseudoalteromonas, etc.The proportion of Vibrio in the biofilm group、planktonicgroup and control group were 34.65%、39.27% and 58.00%.(5)Thecumulative mortality of the biofilm group、planktonicgroup and control group were 80%、77% and 92% in the challenge with WSSV; Thecumulative mortality of the biofilm group、planktonicgroup and control group were 61.3% 、 75% and 77.3% in the challenge with Vibrio parahaemolyticus.The results of the study suggest that dietary with Bacillus cereus biofilm and planktonic Bacillus cereus can change the intestinal microflora of Litopenaeus vannamei,improve the disease resistance and enhance the growth.Part 3:In order to research the effect of multiple bacteria biofilm on the growth rate,disease resistance and intestinal microflora of Litopenaeus vannamei, planktonic Bacillus cereus(number PC070465),Bacillus firmus(number 2011120102),Bacillus pumilus(number2012071703),Bacillus cereus(number2012070203),Bacillus baekryungensis(number201112010701),Bacillus megaterium(number 20120513-1-D-3),Bacillus subtilis(number 2012071701), Bacillus licheniformis(number 201112010602) was added to basic feed which concentration of viable bacteria was 106CFU/g as the planktonic feed;8Bacillus biofilm was added to basic feed which concentration of viable bacteria was 106CFU/g as the biofilm feed. Shrimps living in 24 buckets with the similar light and position were divided into three groups, which the control group was fed of the basic feed everyday while the planktonicgroup were fed of planktonic feed and the biofilmgroup were fed of biofilm feed. Shrimps were challenged with white spot syndrome virus(WSSV) and Vibrio parahaemolyticus after 15 days of feeding experiment. The whole experiment was end after 40 days. Sampled at Day 10, 15, 20, 25, the method of high throughput sequencing of 16 S r DNA gene’s V3+V4 region was used to determine diversity and composition of bacterial communities in each of these samples. Experiment showed:(1)The intestinal microfloraof Litopenaeusvannameiweremainlywith Proteobacteria,while Bacteroidetes,Actinobacteria,Firmicutes,Cyanobacteria,Verrucomicrobia, Crenarchaeota, Euryarchaeotawere at lower rate,the Content of Proteobacteria was 95.44%. Dietary with Bacillus cereus biofilm can make the intestinal microflora of Litopenaeus vannameimore stable.(2) Thecumulative mortality of the biofilm group 、planktonicgroup and control group were 40%, 60% and 76.67% in the challenge with WSSV; Thecumulative mortality of the biofilm group、planktonicgroup and control group were 41.67%, 53.33% and 56.67% in the challenge with Vibrio parahaemolyticus.The results of the study suggest that dietary with multiple Bacillus biofilm and planktonicmultiple Bacillus can change the intestinal microflora of Litopenaeus vannamei,improve the disease resistance.