RECENT TECHNIQUE TO DETERMINE VIABILITY OF YXOSPOREAN SPORES

Document Type : Original Article

Author

Fish Diseases Department, Animal Health Research Institute, Dokki, Giza, Egypt.

Abstract

A vital staining technique with fluorescein diacetate (FDA) and propidium iodide (PI) was used for determining the viability of myxosporcan stage spores of Myxobolus species. Examined spores were collected in different ways from live infected tilapia fish, either naturally released from infected fish or collected from pseudocyst of infected fish. Separated spores from infected fish meal were collected and examined. In vitro survivability tests namely drying, aging, freezing and heating were done on collected spores and their viability under fluorescent microscopy was evaluated, viable spores stained green with FDA while non-viable stained red with Pl. Sporicidal testing of some chemicals revealed that calcium hydroxide was the most effective among other sporicidal treatments. Formalin and sodium chloride had a moderate effect on discharged spore viability and isolated spores were relatively sensitive. Vital Staining by FDA-PI can examine efficiency of manufacturing processes of infected fish meal. The results proved that pasteurization of fish meal is the only accurate preventive method.

Main Subjects