淡水养殖罗非鱼中病原菌和腐败菌的分离与鉴定初探

Isolation and Identification of Pathogens and Spoilage Bacteria on Cultured Hybrid Tilapia

本实验分析了刚捕获淡水养殖罗非鱼的体表黏液、腮、肠道、腐败肉和养殖池水的细菌菌相,结果表明,以上样品的菌落总数分别为1.0×103CFU/cm2、2.2×103CFU/g、1.4×105CFU/g、5.4×107CFU/g和2.6×104CFU/ml;共分离出353株菌,以革兰氏阴性菌为主。池水和新鲜鱼体的优势菌为芽孢杆菌、肠杆菌科、弧菌科,其主导地位随样品不同而有所差异,还有少量假单胞菌属、肠球菌属、葡萄球菌属等。腐败肉中的菌相较单一,优势菌为洋葱假单胞菌、嗜水气单胞菌和短芽孢杆菌,迟钝爱德华菌和克吕沃尔菌属少量。同时参照GB和SN标准对刚捕获罗非鱼的体表黏液、腮、肠道中病原菌进行分析,结果表明,在鱼体中检出大肠埃希氏菌、粪链球菌和铜绿假单胞菌,未检出单核增生李斯特氏菌、沙门氏菌、金黄色葡萄球菌、副溶血弧菌和溶血性链球菌等病原菌。

The bacterial flora occurring in pond water, surface mucus, gills, intestine and putrid meat of healthy tilapia cultured in freshwater, were estimated both quantitatively and qualitatively. The results showed that total viable count of bacteria in above samples respectively were 2.6 × 10^4 CFU/ml, 1.0 × 10^3 CFU/cm^2, 2.2 ×10^3 CFU/g, 1.4 × 10^4 CFU/g and 5.4 ×10^7 CFU/g. Total 353 isolates were dominated bv Gram-neeative bacteria. Bacillus st）.. Enterobacteriaceae st）. and Vibrionaceae so. were predominant in pond water and fresh fish, with a small number of Pseudomonas sp, Enterococcus sp., Staphylococcus sp. and so on; but the dominant position were changed with different samples. The bacterial flora were simple in putrid meat, Pseudomonas cepacie, Aeromonas hydrophila and Bacillus brevis were dominant spoilage organism, with a small number of Edwardsiella tarda and Kluyvera spp. In addition, GB and SN standard methods were used in detecting the pathogens on surface mucus, gills and intestine of newly-harvested tilapia, Escherichia coli, Pseudomonas aeruginosa and Streptococcusfaecalis were detected, but Listeria monocytogenes, Salmonella sp., Staphylococcus aureus, Vibrio parahaemolyticus and hemolytic streptococcus were not detected.