The Effects Of Active Substances From Abalone Viscera On Intestinal Microflora Of Experimental Animals

Abalone is a marine shellfish which has high economic value,and it is at the top of four Chinese traditional seafood.It is delicious,nutritious,and it also has medicinal value.The breeding,processing and consumption of abalone is widespread in the world.When prosessing and consumption of abalone,the viscera of abalone are often abandoned,this is not only a great waste,but also caused pollution to the environment.Previous studies indicated that abalone viscera contains rich proteins,amino acids,fats and various bioactive substances.Intestinal microorganisms are known as "external organs" of the host,they are directly involved in the host’s nutrition,immunity,metabolism and so on.They play important roles in maintaining the health of the host.A few studies have reported the in vitro and in vivo antioxidant activity of abalone polysaccharide and polypeptide,however,the effects of abalone polysaccharide and polypeptide on the intestinal microorganism has not been reported before.In this study,the experimental animals（mices and tilapias）were fed via intragastric administration or diet with polysaccharide and polypeptide extracted from abalone viscera,and the intestinal microbiota and its changes were analyzed by DGGE and Illumina Miseq sequencing.The study would provide vaulable information for the development and utilization of marine active products and prebiotics.In addition,the study is of great significance in recycling abalone viscera and reducing the environmental pollution.The results of the study are as follows:（1）The effects of abalone polysaccharide and polypeptide on the diversity of intestinal microbiota of experimental animals: the microbial diversity in mice feces was increased after intragastric administration of abalone polysaccharide and polypeptide,and the diversity of intestinal microflora in tilapia was also increased by feeding the abalone polysaccharide.The difference between the treatment group and control group of mice did not reach a significant level,while the difference in tilapia reached a significant level.（2）The effects of abalone polysaccharide and polypeptide on the cluster of different treatments of experimental animals: the intestinal microbiota of mice was significantly effected by the intragastric administration of abalone polysaccharide and polypeptide.The samples of the control group and treatment group were clustered respectively,however,there was no significant difference between the polysaccharide treatments and the polypeptide treatments.The intestinal microbiota of tilapia was also obviously effected by feeding abalone polysaccharide,and the intestinal microbiota was different at different sampling time.（3）The influence of abalone polysaccharide and polypeptide on the composition of intestinal microbiota of mice were studied by DGGE and Illumina Miseq sequencing.The dominant bacterial phyla in intestine of mice were Bacteroides and Firmicutes.On the genus level,the most dominant group was norank_fBacteroidales_S24-7_group,followed by Bacteroides and Alloprevotella.After the intragastric administration of abalone polysaccharide and polypeptide,eight bacterial genus were up-regulated: Prevotellaceae_UCG-001,Marvinbryantia,Ruminococcaceae_UCG₀09,[Eubacterium]_coprostanoligenes_group,Desulfovibrio,Prevortellaceae_NK3B31_group,Ruminiclostridium₉,Parabcteroides;and two genus,Anaeropllasma and Helicobacter,were down-regulated.The differences of Parabcteroides and Marvinbryantia between treatments and controls reached significant levels.（4）The effects of abalone polysaccharide and polypeptide on the intestinal microbiota of tilapias were studied by Illumina Miseq sequencing.On the phylum level,the dominant bacterial phylum in tilapia intestine was Fusobacteria,accounting for 74.4% of the total sequence,followed by Chlamydiae and Chlamydiae.On genus level,the dominant group was Cetobacterium,followed by Bacteroides and Alloprevotella.After feeding with abalone polysaccharide,two bacterial genus up-regulated: Plesiomonas and Neochlamydia;and seven genus down-regulated: Aquicella,Escherichia-Shigell,Methylobacterium,Mycobacterium,Alsobacter,Cetobacterium and Cupriavidus.The difference of Cetobacterium,Mycobacterium,Plesiomonas and Neochlamydia between treatments and controls reached significant levels.