Abstract:

Due to intensification of aquaculture systems, diseases caused by microbes have surfaced significantly in farms. Fish are protected by using several drugs, synthetic chemicals and vaccination. However, partial success has been achieved. An alternative approach has been the application of various compounds to boost or stimulate the immune system of fishes.Such compounds are known as the immunostimulants. It has been established that the beneficial role of these compounds for disease management in aquaculture systems. The use of immune stimulants in fish could improve fish resistance against unfavorable environmental conditions and pathogenic agents compared with other treatment methods. Chitosan is produced commercially by deacetylation of chitin,the exoskeleton of crustaceans (i.e. crabs and shrimps) and cell walls of fungi. In this research, effects of chitosan on non-specific defence mechanism were investigated.The current study was used 50 mg/L, 100mg/L, 150 mg/L chitosan. Blood samples were collected at 1, 3, 7, 14 and 21 days. The current study was determined leucocrit, NBT and phagocytic activity. The current study showed that at day 3 among the doses, all chitosan groups of leucocrit valuses were increased. At day 7 and 21, the groups whic were 50 mg/L were increased in leucocrit values. The chitosan groups which were 100 mg/L were increased in leucocrit values in all days except at day 7 (p<0.05). The dose of 150 mg/L of chitosan were increased in all leucocrit values in all days except at day 3 (p<0.05). At day 1,3, 7, 14 and 21, among the doses, first and second doses were significant differences in NBT positive cell activation values when to compare the control groups (p<0.05). At day 21, the values of phagocytic activity were significant differences (p<0.05). Between at day 1 and 14, at 150 mg/L, the values of phagocytic activity were significant differences when to compare the control groups (p<0.05).

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