Interspecific crossing was carried out among and between two strains of Clarias gariepinus with mouth malformation and crooked-back traits to determine the source（s） of their deformities and the effects of these mor...Interspecific crossing was carried out among and between two strains of Clarias gariepinus with mouth malformation and crooked-back traits to determine the source（s） of their deformities and the effects of these morphological deformities on their growth and survival. Synthetic ovaprim hormone was used for their inducement at 0.5 mL/kg of the brood stock body weight at FEDAK integrated farm, Ado-Ekiti, Nigeria. Under indoor management, highest mean survival rate was 73% recorded in the hybrid of female mouth malformed C. gariepinus x male crooked back C. gariepinus and the least mean survival rate was 70% recorded in the mouth malformed C. gariepinus parental. Under outdoor rearing crooked back C. gariepinus parental had the highest mean growth rate （11.20 grammes） while the hybrid of the cross between female crooked back C. gariepinus and male with mouth malformed C. gariepinus had the least mean growth rate （8.63 grammes）. High frequency of occurrence of various morphological aberrations （0.92%） was recorded in the mouth malformed C. gariepinus parental and low frequency of occurrence （0.57%） of morphological aberrations recorded in hybrid of female crooked back C. gariepinus x male mouth malformed C. gariepinus. The reoccurrence of some of these morphological deformities in Clarias is a mystery based on their consistent occurrence even under a very good hatchery management. More research works still need to be done in this area of study of Clarias to unravel the mystery behind this morphological imbalance, because the deformities play special roles in discouraging both the farmers and the consumers of this fish.展开更多
文摘Interspecific crossing was carried out among and between two strains of Clarias gariepinus with mouth malformation and crooked-back traits to determine the source（s） of their deformities and the effects of these morphological deformities on their growth and survival. Synthetic ovaprim hormone was used for their inducement at 0.5 mL/kg of the brood stock body weight at FEDAK integrated farm, Ado-Ekiti, Nigeria. Under indoor management, highest mean survival rate was 73% recorded in the hybrid of female mouth malformed C. gariepinus x male crooked back C. gariepinus and the least mean survival rate was 70% recorded in the mouth malformed C. gariepinus parental. Under outdoor rearing crooked back C. gariepinus parental had the highest mean growth rate （11.20 grammes） while the hybrid of the cross between female crooked back C. gariepinus and male with mouth malformed C. gariepinus had the least mean growth rate （8.63 grammes）. High frequency of occurrence of various morphological aberrations （0.92%） was recorded in the mouth malformed C. gariepinus parental and low frequency of occurrence （0.57%） of morphological aberrations recorded in hybrid of female crooked back C. gariepinus x male mouth malformed C. gariepinus. The reoccurrence of some of these morphological deformities in Clarias is a mystery based on their consistent occurrence even under a very good hatchery management. More research works still need to be done in this area of study of Clarias to unravel the mystery behind this morphological imbalance, because the deformities play special roles in discouraging both the farmers and the consumers of this fish.
