草鱼和银鲫肠道产消化酶细菌的研究

检测了分别从草鱼(Ctenopharyngodon idellus)和银鲫(Carassius auratus gibelio)肠道中分离的180株细菌的蛋白酶、脂肪酶、淀粉酶和纤维素酶的产酶能力。结果显示,两种鱼肠道内可分泌胞外消化酶的细菌包括Aero-monas(气单胞菌属,Aer.)、Vibrio(弧菌属,Vib.)、Bacillus(芽孢杆菌属,Bac.)、Pseudomonas(假单胞菌属,Pse.)四个种属的细菌,Aer.在其中占主要优势,45.71%的Aer.可分泌胞外消化酶。草鱼可分泌上述四种胞外消化酶的菌株共有33株,占肠道菌总数的36.67%;银鲫43株,占47.78%。产酶菌的分布上,草鱼中肠内产消化酶细菌数量显著多于前肠和后肠(P<0.05),前、中、后肠分别是6株、20株和7株;银鲫中肠和后肠数量差异不显著,前肠分布最少。草鱼分泌蛋白酶、脂肪酶、淀粉酶和纤维素酶的菌株分别有21株(23.33%)、10株(11.11%)、30株(33.33%)和16株(17.78%)。银鲫肠道内未检测到可分泌纤维素酶的细菌,蛋白酶、脂肪酶和淀粉酶菌株的数量分别是21株、37株和17株。可见鱼类肠道细菌对食饵消化有重要作用。

Study on Digestive Enzyme-producing Bacteria from the Digestive Tract of Ctenopharyngodon idellus and Carassius auratus gibelio

180 strains of bacteria were isolated from the intestinal tract of Ctenopharyngodon idellus and Carassius auratus gibelio.The ability to produce four extracellular enzymes(protease,lipase,amylase and cellulase)of all strains was measured.The results indicated that the dominant group of the digestive enzymes-producing isolates in all parts of intestine were strains Aeromonas.45.71% of all strains Aer.can produce digestive enzyme.There were 33 strains could produce four extracellular enzymes,which account for 36.67% of the total bacterial populations in the gut of C.idellus.From the gut of C.auratus gibelio,43 digestive enzymes-producing strains were isolated,which accounted for 47.78% of the total bacterial populations.Extracellular enzymes active isolates comprised 20%,66.67% and 23.33% of all bacteria in foregut,midgut and hindgut of C.idellus,respectively.The largest number of four extracellular enzymes active strains was detected in the midgut of C.idellus.But in the gut of C.auratus gibelio,the difference of the number of digestive enzymes-producing strains between midgut and hindgut was not significant,while the strains in the foregut was lower compared to the midgut and hindgut isolates.There were no cellulase-producing strains in the gut of C.auratus gibelio.So that the intestinal bacteria of fish produce extracellular enzymes have a beneficial effect in the digestive processes of fish.