鲤科鱼肠道菌分布及共生关系研究

对草鱼、青鱼、白鲢、鳙鱼、团头鲂、三角鲂、鲤鱼和鲫鱼等4个亚科鱼肠道菌群中的好氧菌或兼性厌氧菌进行了分离鉴定，并对菌群种类和分布进行了X^2和相关分析，给出了一种测度菌群在寄主中广泛分布的广谱系数。结果发现同一亚科的鱼内菌群分布有极高的相似性。而不同亚科的鱼间菌群分布有较大的差异，但雅罗鱼亚科（Leuciscinae)和鳊亚科（Abramidnae)在菌群分布也有极显著的正相关性。哈夫尼亚菌属、致病杆菌属、气单胞菌属、柠檬酸菌属、假单胞菌属在这8种鱼中有较高的广谱系数（9．8937－19．0177）且其x^2测验不显著：而链球菌属、拉思氏菌属、芽孢杆菌属和葡萄球菌属的广谱系数很低。在0．54－2．3922之间各自只在1种或2种亚科中能检测到，因此是属于专一性共生菌。

Distributions of Intestinal Bacteria in Cyprinidate and Relationship of Symbiosis between Fishes and Intestinal Microorganisms

Intestinal microorganisms within intestines of 8 fish species,Ctenopharyngodom idellu and mylopharyngodon piceus of Leuciscinae,Hypophthalmich thys molitrix and Carassius auratus of Hypophthalmich thyase,Cyprinus carpio haematopterus and Carassius auratus of Cyprminae,and Megalobrama ambly cephala Yih and Megalopbrama termindis of Abramidnae,were identified and separated.Only 9 bacteria genera,Hafnia,Xenorhbadus,Ameromonas,Citrobate,Rahnella,Pseudomona,Bacillus,Strooptococus and Staphyolcoccus were discovered within intestines of these 8 fish species.Here we first established a broad-spectrum coefficient for measuring host range of an intestinal microorganism.We found through X2 and correlation analyses that distribution(species and amount) of intestinal microorganisms was very significantly similar between the fish species within subfamily but different between the fishes among subfamilies.However,Leuciscinae were also very significantly similar to Abramidnae in the distribution of intestinal microorganisms.Hafnia,Xenorhabdus,Ameromonas,Citrobater,Pseudomonas,and Strooptocous had much higher broad-spectrum coefficients(range of 9.8937-19.0177),whereas Rahnella,Staphyolcoccus,Bacillu,and Staphyolcoccus who were respectively identified only in one or two fish species had lower broad-spectrum coefficients(range of 0.54-2.3922).