Flora Characteristics In The Gut Of Snakehead In Different Environments And Study On The Effect Of Lactic Acid Bacteria In Feed

Fish intestinal microorganisms play an important role in fish nutrition and health.Intestinal microorganisms can not only promote the normal digestion and absorption of fish intestines,but also inhibit the invasion of harmful bacteria,improve the activity of macrophages,and enhance immunity Features.This paper studies the structural characteristics of the intestinal microbial community of farmed and wild crucian carp in different environments,and the effects of the addition of lactic acid bacteria on the intestinal microorganisms and growth of crucian carp.It provides a basis for the healthy breeding of crucian carp and the promotion of good breeding methods for all male hybrid crucian carp.1. Community structure of gut microbes in salamander in different environments. Illumina hiseq 2500 was used to sequence and analyze the microbes in intestinal contents of adult healthy snakehead in different culture environments in this paper.The results showed that there were some differences in the number of OTUs among the intestinal contents of snakehead in different environments?four locations in Doumen,Zhuhai,Nanhai,Foshan,Xingtan,Shunde,and Yangjiang?,and the total number reached 585,it shows that the dominant microflora is rich in the contents of the intestinal tract in different environments.The dominant flora in the research samples are:Rhodococcus,Clostridium,Microbacterium,Vibrio,Aeromonas,Plesiomonas,Clostridium and Rhodococcus are present in all samples,but the proportions are different in different environments,Heatmap analysis found it also contained Proteus,Enterococcus,Lactobacillus,Lactobacillus,Bacteroides,etc.But the abundance is not high.PCA analysis found the intestinal microbial community structure of the artificially-bred Hybrid Snakehead is similar,it is different from the community structure of wild snakehead,the characteristics of microbial community in intestinal contents of snakehead in the same culture environment were similar,and the composition and diversity of intestinal microflora in different environments were quite different2. Effects of Lactic Acid Bacteria on Intestinal Microbial Community Structure in hybrids snakehead. High-throughput sequencing was used to detect the structure and changes of the microbial community in the intestinal tract of all male crossbreeds.The results show that:OTU analysis and Venn plots show that after feeding with lactic acid bacteria,OTUs of all-male hybrids snakehead and common hybrids snakehead increase slightly,idicatingat the microbial diversity has changed.In addition,Chao and Ace values during the period Both increased,Simpson decreased,and Shannon increased,indicating that feeding with lactic acid bacteria can indeed increase microbial richness and diversity.The histogram of species distribution shows that the dominant flora of the common hybrids snakehead pupae is Plesiomonas,Cetobacterium,Citrobacter,Lactobacillus,Lysinibacillus,Exiguobacterium,Klebsiella,Acinetobacter,Bacillus,and the dominant bacteria in the intestinal tract of all-male hybrids snakehead are Plesiomonas,Cetobacterium,Citrobacter,Lactobacillus,Klebsiella,Acinetobacter,Bacillus,Clostridium,Aeromonas,and the addition of lactic acid bacteria,the abundance of some dominant flora changed,and the abundance of Plesiomonas decreased significantly,It is shown that the addition of lactic acid bacteria can not only affect the diversity of intestinal microorganisms,but also change the structure of their microbial communities.3. Effects of Lactic Acid Bacteria on the Growth of all-male hybrids snakehead and Comparison of Growth between All-male and Common hybrids snakehead. This test lasted 73 days,and the data of length and weight was measured at 1d,25d,59d,73d separately.90 samples every time,360 samples in four collections together.And regression analysis using spss software to get the statistical analysis of equation of regression curve of all-male and common hybrids snakehead.Regression curve of carcass length and weight of all-male hybrids snakehead fed without lactic acid bacteria: curve of carcass length and weight of all-male hybrids snakehead fed with lactic acid bacteria:W=0.006L^3.165?R=0.9391?,body length growth curve,L=27.667(1-e^-3.165.Regression curve of carcass length and weight of common hybrid carcass fed with lactic acid bacteria,W=0.01L^2.919?R=0.942?,body length growth curve,L=19.435 ^{0.184*?t+7.39?}))^2.919.By comparing average daily weight gain,relative growth rate of body length,relative weight gain rate and bait coefficient of all-male hybrids snakehead?LAB?and all-male hybrids snakehead,the all-male hybrids snakehead?LAB?is better than all-male hybrids snakehead in the feed utilization,and the growth rate is 12%±2.3%higher?F>F crit,P<0.05?.Comparing the survival rate,it was found that lactic acid bacteria can also enhance the disease resistance of the fish,reduce the incidence and increase the survival.By comparing average daily weight gain,relative growth rate of body length,relative weight gain rate and bait coefficient of all-male hybrids snakehead?LAB?and common hybrids snakehead?LAB?,the all-male hybrids snakehead?LAB?is better than common hybrids snakehead in the feed utilization,And the growth rate is 15%±2.4%higher?F>F crit,P<0.05?.