Field Studies Encysted Metacercariae infested Natural Male Tilapias and Monosex Tilapias in Kafr El-Sheikh Governorate Fish Farms

The present study was carried out on 1800 specimens of Tilapia fishes Oreochromis niloticus (O. niloticus) (phenotypic, hybrids and monosex O.niloticus of different size and body weight. They were randomly collected at different seasons from Kafr El-Sheikh Governorate cultured fish farms. The clinical signs of most examined fishes revealed no pathognomonic abnormalities on the external body surface except black spots were detected on skin and fins. Tilapia fishes were shown emaciation. The postmortem findings the black spots were detected on skin and fins. Encysted metacercariae including Euclinostomum heterostomum, Posthodiplostomum cuticola, Heterophidae and Haplorochoidae were investigated and recorded. The highest prevalence possessed in hybrids while monosex O. niloticus occupied the last position. The histopathological examination in different organs of infested fish revealed pathological changes in gills and musculatures. [Eissa, I. A.M.; Gado, M. S.; laila, A.M.; Mona S. Zaki and Noor El-Deen,A. E. Field Studies Encysted Metacercariae infested Natural Male Tilapias and Monosex Tilapias in Kafr El-Sheikh Governorate Fish Farms. Life Science Journal. 2011;8(2):7-12] (ISSN: 1097-8135). http://www.lifesciencesite.com.