关键词：
乌鳢;蛋白质源;产蛋白酶好氧菌;产蛋白酶能力;益生菌
摘 要：
本试验通过对乌鳢肠道内产蛋白酶好氧菌株进行分离和培养,并测定其产蛋白酶能力,来评价豆粕替代鱼粉对乌鳢肠道好氧菌组成及产蛋白酶能力的影响。首先配制以脱脂鱼粉为主要蛋白质源的对照组(D1组)饲料,饲料中鱼粉添加量为55%;然后用豆粕替代对照组饲料中不同比例的鱼粉,配制2种试验组饲料,饲料中豆粕添加量分别为35%(D2组)和75%(D3组)。上述3种试验饲料分别投喂平均体重为(10.50±0.84)g的乌鳢幼鱼8周,每种试验饲料投喂3个重复,每个重复28尾鱼,试验在室内养殖系统中进行。结果显示:随着豆粕替代鱼粉比例的增加,乌鳢的终末体重、增重率和特定生长率显著降低(P<0.05)。从3组乌鳢肠道内共分离出21株产蛋白酶好氧菌,其中,D1组为16株,D2组为19株,D3组为20株。以水解圈直径与菌株直径之比值(R/r值)表示产蛋白酶能力,豆粕替代鱼粉显著降低了菌株P1004和P1018的R/r值(P<0.05),但显著增加了菌株P1009和P1012的R/r值(P<0.05)。随着豆粕替代鱼粉比例的增加,菌株P1018的R/r值显著下降(P<0.05)。对产蛋白酶能力最大的菌株P1009进行生理生化特征鉴定和16S r DNA序列分析,得出菌株P1009为铜绿假单胞菌(Pseudomonas aeruginosa)。本试验结果表明,乌鳢肠道内存在着丰富的产蛋白酶好氧菌,豆粕替代鱼粉对乌鳢肠道内产蛋白酶好氧菌数量和产蛋白酶能力产生了一定影响,乌鳢肠道内产蛋白酶能力最强的菌株P1009是铜绿假单胞菌,可以考虑将其作为益生菌开发的潜在菌种。
译 名：
Effects of Replacement of Fish Meal by Soybean Meal on Composition and Protease-Producing Activity of Protease-Producing Aerobic Bacteria in Intestinal Tract of Channa argus
作 者：
MIAO Shuyan;ZHU Jinyu;ZHAO Chenze;DONG Xiaojing;SUN Longsheng;College of Animal Science and Technology,Yangzhou University;
单 位：
College of Animal Science and Technology,Yangzhou University
关键词：
Channa argus;;protein source;;protease-producing aerobic bacteria;;protease-producing activity;;probiotics
摘 要：
In order to investigate the effects of replacement of fish meal by soybean meal on composition and protease-producing activity of protease-producing aerobic bacteria in intestinal tract of Channa argus,the protease producing bacteria in intestinal tract of Channa argus w ere isolated and cultured. The selected strains w ere further quantitatively assayed for the protease-producing activity. One control group( D1 group) diet w as formulated w ith defatted fish meal as the main protein source,and the defatted fish meal addition in this diet w as55%. Next then,tw o experimental group diets w ere formulated using soybean meal to replace different ratio of fish meal in control group diet,and the soybean meal in those tw o diets w as 35%( D2 group) and 75%( D3 group),respectively. Each diet w as assigned to three replicates of 28 Channa argus w ith the average body w eight of( 10.50 ± 0.84) g for 8 w eeks in a re-circulated w ater system indoor. The results show ed as follow s:The final w eight,w eight gain rate and specific grow th rate w as significantly decreased w ith the replacement ratio of fish meal by soybean meal increasing( P< 0.05). A total of 21 protease-producing aerobic bacteria w ere isolated from the intestine of Channa argus,w hich w as 16 from D1 group,19 from D2 group and 20 from D3 group. The replacement of fish meal by soybean meal significantly decreased the hydrolysis spot diameter( R)/strain diameter( r) value of strains P1004 and P1018( P< 0.05),w hich w as used to express the protease-producing activity,but significantly increased the R/r value of strains P1009 and P1012( P< 0.05). With the replacement ratio of fish meal by soybean meal increasing,the R/r value of strain P1018 w as significantly decreased( P< 0.05). Physiological and biochemical characteristics identification and 16 S r DNA sequence analysis revealed that the strain P1009,w hose protease-producing activity w as the highest in the present study,w as Pseudomonas aeruginosa. In summary,the results indicate that there exist a great variety of protease-producing aerobic bacteria in intestinal tract of Channa argus,and the replacement of fish meal by soybean meal can affect both the quantity and protease-producing activity of protease-producing bacteria. Strain P1009 w hich from the intestinal tract of Channa argus has the highest protease-producing activity,and it can be as a potential source of probiotics.
