Growth comparison of Nile tilapia (Oreochromis niloticus) and Blue tilapia, (Oreochromis aureus) as affected by classical and modern breeding methods

This study was conducted to compare and evaluate the productive performance characteristics of the base generation (F0) of Nile tilapia, Oreochromis niloticus and Blue tilapia, Oreochromis aureus under the effect of interspecific hybridization and genetically modified breeding by introducing a fragmented purified DNA isolated from O. aureus or O. niloticus into the gonads of O. niloticus or O. aureus parent, respectively. The results showed that the growth performance, body composition and feed utilization parameters of genetically modified O. aureus or O. niloticus treated with O. niloticus or O. aureus DNA, respectively were improved significantly (P0.05) as compared to both purebred and interspecific hybridization (♀ O. aureus x ♂ O. niloticus and ♀O. niloticus x ♂ O. aureus). RAPD analysis was used for constructing parsimony tree depicting relationships among the different genotypes studied. The hierarchical cluster analysis based on RAPD fingerprinting, grouped the six genotypes of fish into two major category groups. Within these major grouping, purebred of O. niloticus, O. aureus and their reciprocal hybrid grouped close together. Also, the dendrogram showed that the hybrid of ♀ O. aureus x ♂ O. niloticus appear to be more genetically similar to that of the hybrid ♀O. niloticus x ♂ O. aureus than that of the purebred of either O. niloticus or O. aureus. The other major group showed that O. aureus injected with O. niloticus DNA appear to be more genetic dissimilarity to that of O. niloticus injected with O. aureus DNA. The results of this study suggested that genetically modified O. niloticus and O. aureus with higher growth rate can be produced using a feasible and fast methodology compared as to interspecific hybridization.Key words: Productive performance, Oreochromis niloticus, Oreochromis aureus, inter-specific hybridization, genetically modified

Phenotype and genotype differentiation between flathead grey mullet [Mugil cephalus] and thinlip grey mullet [

This study aimed to study the phenotype and genotype differentiation and to compare the amount of differences in phenotype based on morphometric character indices and meristic counts with the amount of differences in genotype based on random amplified polymorphic DNA (RAPD) fingerprinting between two Mugilidae, Flathead grey mullet (Mugil cephalus) and Thinlip grey mullet (Liza ramada). The results showed that there were significant differences in most of the morphometric character indices but no significant differences were detected in most of the meristic counts between M. cephalus and L. ramada. In addition, the euclidean distance between M. cephalus and L. ramada using hierarchical cluster analysis of quantitative phenotype based on morphometric character indices and meristic counts and condition factor was (0.421). Genotype analysis based on RAPD fingerprint showed highly genetic dissimilarity (0.437) between M. cephalus and L. ramada. These results confirmed that the amount of differences in genotype reflected the same amount of differences in phenotype between M. cephalus and L. ramada. Therefore, either phenotype analysis can be use based on a large number of morphometric character indices and meristic counts or genotype analysis based on RAPD fingerprinting to discriminate M. cephalus and L. ramada with the same results.Key words: Phenotype, genotype, Mugil cephalus, Liza ramada

Evaluation of the productive performance characteristics of red tilapia (Oreochromis sp.) injected with shark DNA into skeletal muscles and maintained diets containing different levels of probiotic and amino yeast

This work aimed to study the effect of direct injection of shark (Squalus acanthias L.) DNA into skeletal muscles of red tilapia (Oreochromis sp.) fed at different additive levels (two probiotic levels; 0.3 and 0.5%, two amino yeast levels; 0.5 and 1.0% and a mixed of 0.3% probiotic and 0.5% amino yeast), on the productive performance. The results show that red tilapia injected with DNA had significant (P≤0.05) superiority of growth performance and feed utilization; besides the body composition was improved. In addition, the different levels of probiotic and amino yeast were more effective in stimulating most of the productive performance traits compared to the control group and the mixed of probiotic and amino yeast. The result indicates a possible easy and rapid way for improving red tilapia characteristics.Key words: red tilapia, shark DNA, direct injection, productive performance, probiotic, amino yeast

Production of salinity tolerant Nile tilapia, Oreochromis niloticus through traditional and modern breeding methods: II. Application of genetically modified breeding by introducing foreign DNA into fish gonads

This study was conducted to produce a salinity tolerant Nile tilapia, Oreochromis niloticus through genetically modified breeding by introducing a fragmented purified DNA isolated from sea bream, Sparus aurata or Artemia, Artemia salina into the gonads. The results showed a significantimprovement (P . 0.05) in most of the growth performance and feed utilization parameters of genetically modified O. niloticus treated with sea bream-DNA and reared at different salinity levels up to 16 ppt compared to both genetically modified O. niloticus treated with Artemia-DNA and the control fish reared at the same salinity levels. Genetically modified O. niloticus treated with Artemia-DNA reared at 32 ppt, had displayed better traits results (P. 0.05) compared to the other fish within the same salinity level. Furthermore, genetically modified O. niloticus treated with sea bream-DNA showed a silver color covering all the body and no dark vertical bands. The results of the random amplified polymorphic DNA (RAPD) fingerprinting showed highly genetic polymorphic percentage (35.95%) among fish receiving foreign DNA and their control using different random primers. The results of the present work suggested that, hyper-saline genetically modified O. niloticus with higher growth rate can be producedusing a feasible and fast methodology.Key words: Salinity tolerance, Oreochromis niloticus, productive performance, genetically modified, DNA transfer