Characteristics of Achly bisexualis Isolated from Eggs of Nile Tilapia (Oreochromis niloticus Linn.)

Abstract

Fungal infected eggs of Nile tilapia (Oreochromis niloticus Linn.) were collected from fish hatcheries in Kalasin, Khon Kaen and Sakon Nakhon provinces. The sample collections were conducted in three periods, June-July, October-November 2005 and March-April 2006. Effects of temperature, pH and sodium chloride (NaCl) on mycelial growth were studied. Several fungal species have been isolated and identified from the infected eggs. Among fungal isolates, a species that occurred frequently is Achlya bisexualis. Examination of the biological characteristics of the fungal species showed that the optimum temperature and pH for mycelial growth were 15-35 o C and 4-11, respectively. The vegetative growth of A. bisexualis was able to tolerate up to 15 ppt NaCl