بررسي ضايعات آبششي ناشي از آلودگي انگلي در ماهيان كپور علفخوار

study on the parasitic infection and lesions of gills in Grass carp (Ctenopharyngodon idella) in Azadegan fish farming site - Ahvaz

In this research, 120 fish of cultured grass carp, during two times, beginning of culturing period and at the time of harvesting, were studied. For this purpose, fish randomly were caught from three fish farms (Azadegan-Ahvaz). The average weight range of the studied fish in the two groups were 26.96±11.77 gr and 1660±215.91 gr respectively. After killing the fish by destroying the brain, samples were taken from the gill. 1*1x1 cm pieces were cut from each gill and placed in 10% formalin. The tissue samples were processed through historogical method and studied under light microscope. The parasites that were observed belonged to two following genera: Dactylogyrus sp and Trichodina sp. Results of histopathological studies (tissue damages and parasite analyzing) in fishes showed that in the beginning of culturing period hyperplasia rate was 1.06±0.08, necrosis rate was 0.26±0.14, hemorrhage rate was 1.33±.30, edema rate was 0.43±019, parasitic infection rate was 0.8±0.7 and telengectasis rate was 0.42±12. while at the end of culturing period hyperplasia rate was 1.80±0.16, necrosis rate was 0.10±0.1, hemorrhage rate was 1±0.22, edema rate was 0.90±0.25, parasitic infection rate was 2.43±0.19, telengectasis rate was 0.43±0.12. The average infestation rate in the most of studied parameters among the two studied groups showed significant difference (P<0.05). However the average rate of necrosis among two studied groups did not showed significant difference (P>0.05).