STUDIES ON SOME PROBLEMS FACING CULTURED AFRICAN CATFISH (CLARIAS GARIEPINUS) IN ABBASSA FISH FARMS
El- Bouhy, Z.M.1; R.M. El-Gamal2;
A.S. Diab3 and A.H. Fadel 4
1. Department of Fish Diseases and Management, Veterinary Medicine,
Zagazig University
2, 3 and 4. Department of Fish Diseases and Management, Central Laboratory For Aquaculture Research. Abbassa.Abo Hammad, Sharkia.
Received 30/ 5/ 2010 Accepted 24/ 6/ 2010
Abstract
A number of 440 diseased cultured African catfish Clarias gariepinus ranging from 50-250 g. were subjected to parasitological, bacteriological examination and correlation between some environmental factors and the incidence of C. gariepinus pathogens. Beside trials of treatment of naturally infected fish with monogenea. Aeromonas hydrophila and Edwardseilla tarda. The prevalence of obtained parasites reached up to 79%; monognetic trematode (Gyrodactylus sp.) was isolated with a prevalence of 25%, dignetic trematodes (Oreintochridum batrachoidus) 40%, cestodes (Monobothrium chalmersius) 32% and nematodes (Procamallanus laeviconchus) 33%. A. hydrophila was isolated from C. gariepinus with prevalence 6.5% and E. tarda 5.5%. The total mortality rates among injected C. gariepinus were 90%, 50%, 0 % and 0% respectively in A. hydrophila, E. tarda and control groups. The histopathological changes of parasitic diseases showed mucinous degeneration, desquamation and necrosis of intestinal epithelium and bacterial infection showed congestion and hemorrhages in kidney, liver and spleen. Enrofloxacin application according to antibiogram sensitivity test, showed good recovery of infected C. gariepinus with A. hydrophila and E. tarda. Monogenea were found dead in all treated C. gariepinus after two successive days with salt 0.5 %.There was a direct effect of low oxygen and high pH values as well as high ammonia levels on abundance of monogenea, digenea and incidence of A. hydrophila and E. tarda infection in cultured C. gariepinus at earthen ponds and in drainage canals.
