Some studies on clostridia infection in fresh water fishes with special reference to treatment with antibiotics

A total number 1873 fish were used in our study, from which 1493 fish of different fish species as Tilapia species (o.spp.), Commoncarp spp.(Ccarpio) and Nile catfish (Cgariepinus)and of different lifestages, where they were collected from different sources at variouslocalities as from El-Abbassa fish farms and from Muweis Canal atZagazig city at Sharkia govemorate and in different seasons of year.They were subjected to clinical and bacteriological examination todetermine prevalance of Clostridium species infection. Typing ofC.perfringens isolates were done by using guinea pigs and PCR.Besides, 80 apparently healthy 0. niloticus were used for studying thepathogencity and degree of virulence of Cperfringens type A &Disolates. Another 300 fish were used for trails for treatement ofexperimentally infected fish by using antibiotics according to theresults of sensitivity test against Cperfringens type A &D isolates andalso , used to determine the effect of these antibiotics on some serumbiochemical parameters (AST , AL T and Creatinine) and onhistopathological findings of treated 0. niloticus.The results of this study revealed that:1. Out of 1493 examined fishes ,only 532 were clinically infected with Cperfringens at the rate of (35.63%), Nile catfish (Cgariepinus) possessed the highest infection percentage at the rate of (43.69%) followed by Tilapia spp.(o.spp.) and Common carp spp) The highest infection percentage was recorded during Summer atthe rate of (41.97%)followed by Spring (38.28%), Autumn (34.77%) and finally Winter (26.45%).