Survey on alimentary tract parasites in cultured fish in Khouzestan province

Abstract

In this study which was carried out in khoozestan province, 1100 pieces of common carp (Cyprinus carpio), silver carp (Hypophthalmichthys molitrix), Grass carp (Ctenopharyngodon idella) and Big head (Arysthychthys nobilis) from different parts of the province were examined. From each part, 10% of the fish farms were sampled according to the fish density at each farm. parasitic infection of gastrointestinal tract were studied on 600 pieces of silver carp (60% ) , 244 pieces of common carp (25%) , 51 pieces of Big head (5%) . only Grass carp was infested to protozoan and metazoan parasites . thirty percent of examined Grass carp of 2-730 gr weight were infested to Hexamita but infestation was more severe in Grass carp with 20-40 gr weight . macroscopic manifestation included : dysphagia , weakness , circulating movements, paling of gills , stomach inflammation , intestinal inflammation , ascitis and yellowish gut contents . in severe and intestinal necrosis along with hyperemia was apparent . the cestoda , bothriocephalus opsariichthydis ( Rudolphi , 1808 ) with an infestation rate of 35 % were only observed in Grass carp in 2-40 gr . Grass carp that showed severe infestation, intestinal blockade was observed with more than 100 parasites. The length of adult cestoda was 450-530 mm and its width was 5mm. in severe infestations, macroscopic manifestations included: ascitis, abdominal inflammation, swimming on water surface and emaciation . Histologic studies showed necrosis of intestinal wall, hemorrhage and localized necrosis . In fishes with severe infestations, inflammation was observed . Infestation with the nematode, capilaria was observed in 10% of 20-750 gr Grass carp . No macroscopic symptoms were identified in the samples , but microscopic examination showed acute necrosis along with hyperamia and submocusal hemorrhage . lymphocytes were also observed . Adult nematode had a width of 0.075 and a length of 7.5-8.5 mm.