Dissertation
Dissertation > Agricultural Sciences > Aquaculture, fisheries > Aquatic basic science > Aquatic Biology > Aquatic Zoology

Intestinal Flora Analysis of 4 Common Kinds of Freshwater Fish in Dongping Lake, Shandong Province

Author ZhouYuFa
Tutor CaiYuMei
School Shandong Agricultural University
Course Veterinary
Keywords Dongping Lake freshwater fish intestinal flora quantity of intestinal flora composition of intestinal flora ERIC-PCR
CLC S917.4
Type Master's thesis
Year 2011
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Fish intestinal flora, as a normal component, together hosts and aquatic environment, forms a mutually dependent and reliable micro-ecosystem, plays an important role in digestion,absorption, immune response, organ development and so on,and affects growth, development and physiology and pathology of fish. A micro-ecosystem study discovered that slight environment change might result in disorder of ecosystem. The destruction of the ecosystem could also cause endo-genous or exo-genous infections; metabolism and immunologic function disorder, even seriously affect health status and finally leading to high rates of a series of diseases. So it is crucial to study the composition diversity flora. In this study, a deep understanding of intestinal microorganisms of four common kinds of freshwater fishes in Shandong Dongping Lake can provide basic information for fish disease prevention, fish microbic feed additives and microflora breeding.In this study, four common kinds of experimented freshwater fishes in Dongping Lake, Ctenopharyngodomi dellus, Hypophthalmichths molitrix, Cyprinuscarpio haematopterus and Carassius auratus were all healthy, weighing about 0.5~0.6 kg, and ten fish of each kind was randomly selected. The bowel contents of these four kinds of freshwater fishes were sampled, and the bowel contents of each kind of fish were mixed, representing the bowel microbial population of one kind of fish. The mixed bowel contents of fish of each kind were taked into two parts, one for determining the dominant genus or species of each kind of freshwater fish through the enumeration、isolation and identification, and the other for further analysis through ERIC-PCR (enterobacterial repetitive intergenic consensus polymerase chain reaction) through extracting DNA of Intestinal contents.The results showed: there were eight main genuses, including Hafnia, Xenorhabdus, Ameromonas, Citrobater, Rahnella,Bacillus, Strooptococus and Staphyolcoccus. In the intestinal microbial flora of Ctenopharyngodomi dellus, the concentrations of Hafnia, Strooptococus and Staphyolcoccus were up to 107cfu/g, and others were 106cfu/g. There were Hafnia, Xenorhabdus, Ameromonas, Citrobater, Pseudomonas, Rahnella, Bacillus and Strooptococus in the intestinal microbial flora of Hypophthalmichths molitrix, among which the concentrations of Ameromonas were up to 107cfu/g, and others were 106cfu/g. There were Hafnia, Xenorhabdus, Ameromonas, Citrobater, Pseudomonas, Bacillus and Strooptococus in the intestinal microbial flora of Cyprinuscarpio haematopterus, among which the concentrations ranged from 106 to 107cfu/g. There were eight main genuses, including Hafnia, Xenorhabdus, Ameromonas, Citrobater, Pseudomonas, Bacillus, Strooptococus and Staphyolcoccus, in the intestinal microbial flora of Carassius auratus, among which the concentrations of Hafnia, Ameromonas and Citrobater were up to 106 cfu/g, and the other were 105cfu/g, and Rahnella was not detected.We obtained intestinal flora finger-printings of each fish through ERIC-PCR, and the cluster tree of these four kinds of fish was by NTSYS-pc software. The similarity index between Ctenopharyngodomi dellus and Hypophthalmichths molitrix was up to 0.64, indicating that those two kinds of fish have high intestinal flora similarity. Cyprinuscarpio haematopterus and Carassius auratus have less similarity and great difference with Ctenopharyngodomi dellus and Hypophthalmichths molitrix. This may be related to their feeding habits and the water in which they live.The overall conclusion of this study: with the study of the compositions of the intestinal flora of four common kinds of freshwater fishes in Dongping Lake (the second largest freshwater lake in Shandong Province) by conventional biochemical tests and ERIC-PCR technique, we confirmed the quantity and composition of the intestinal dominant microorganisms of four common kinds of freshwater fishes, established their ERIC-PCR fingerprinting and compared the similarity among them. Thus, the study can provide basic information for fish disease prevention, fish microbic feed additives and microflora breeding.

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