罗非鱼溶菌酶活力的研究

Study on Lysozyme Activity of Tilapia mossambica

采用试管法 (测定溶菌酶活力 )研究pH和温度对罗非鱼血清、肝、鳃中溶菌酶活力的影响 ,以确定其最适pH和最适温度 ,同时研究了溶菌酶对温度的耐受性及其在体外的抑菌效果。结果表明 ,罗非鱼血清、肝溶菌酶的最适pH是 6 3 0 ,最适温度是 2 8℃ ;鳃中溶菌酶的最适pH是 6 1 0 ,最适温度是 3 4℃。各种酶在 5 0℃保温 40min以上将被灭活 ,在 3 7℃以下活性是稳定的 ;体外抑菌试验表明罗非鱼溶菌酶对革兰氏阳性菌具有较好的抑菌效果。

Influences of pH and temperature on lysozyme activity in the liver,gill,serum of Tilapia mossambica were examined using the turbidimetric assay system.The heat resistance of lysozymes and the bacteriostatic test in vitro were studied as well.The optimal pH and temperature on lysozyme activity in the liver and serum of Tilapia mossambica are 6.30 and 28 ℃ respectively.The optimal pH and temperature on lysozyme activity in the gill of Tilapia mossambica are 6 10 and 34 ℃ respectively.These enzymes are heat labile at temperatures higher than 50 ℃ for 40 min or more,and are stable at temperatures lower than 37 ℃. Results may be useful in establishing a simple assay system for lysozyme activities in order to evaluate bio defenselevel in fish.The lysozyme of Tilapia mossambica restrains Gram positive bacteria more efficiently than Gram negative bacteria.So the bacteriostatic test in vitro for Gram negative is nessessary to be improved.