RAPD-DNA technique using thirteen arbitrary random primers (OPA –1, OPA –3, OPA –6, OPA –7, OPA –10, OPA –11, OPA –12, OPA –13, OPA –14, OPA –15, OPA –16, OPA –17 and OPA –18) were tested to descriminate five carp species namely; Bighead, Black, Common, Grass and Silver carp. Genetic similarity estimation revealed that Common carp and Grass carp were close and showed high similarity (0.66), followed by between Common carp and Silver carp (0.56). At the same time, the similarity coefficient between Bighead carp and Silver carp was 0.50, while the lowest value (0.48) showed between Black carp and Silver carp. Only five primers OPA –1, OPA –3, OPA –7, OPA –15 and OPA –17) showed a closer relationship between Common carp and Grass carp, while another five primers (OPA –11, OPA –12, OPA –13, OPA –17, OPA –18) showed a closer relationship between Bighead and Grass carp or Bighead and Silver carp or Grass carp and Silver carp. The phylogenetic tree resulted from cluster analysis possessed Common and Grass carp in one main group, while Bighead, Black and Silver carp were separated to three different sub groups.

Genetics similarity and diversity of five cultured carp fishes collected from Abbassa area (CLAR) in Sharkia, Egypt were examined. SDS-PAGE for muscle protein and native-PAGE for some isozymes, such as esterase and malate dehydrogenase were studied on ten individuals fish of each species. To discriminate isozymes variation among carp species, different synthetic Est substrates; α, β-N acetate and α-N propionate were tested. The results indicated that the soluble muscle protein patterns it may be conducted that each population had a unique banding pattern. Close relationship was noticed between bighead and black carp with similarity coefficient value of (94%). Silver carp had a different banding pattern and branched out as subgroup from each of bighead and black. The results of α, β naphthyl esterase showed perfect similarity within silver individuals. The average similarity values among the five carp species resulted from cluster analysis of α, β esterase isozymes data showed a close relationship between grass and silver carp (95%). High similarity in black, mirror carp, and grass carp while bighead and silver carp showed rear polymorphism with propionate esterase. Also the result showed that the variation in Mdh was limited and restricted on silver and mirror carp, while bighead, black and grass carp showed no variation within their populations. The final data of this work showed close relationship between bighead and black carp (85%). Moreover, quite close relationship was also noticed between each of black and Silver carp followed by bighead and silver carp.

Four groups of tilapia fish belong to three species; Oreochromis niloticus, O. aureus, and Tilapia zillii, were collected from three different locations in Egypt, (Abbassa, Maryout and Manzala). Tilapia fingerlings were reared in two saline waters, 10, 17 ppt under controlled laboratory conditions for eight weeks. SDS-PAGE for eye protein and native-PAGE for some isozymes, such as esterase, alcohol dehydrogenase, lactate dehydrogenase and malate dehydrogenase were applied. The results showed decreased in band intensity due to the saline treatment in both O. aureus and T. zillii. However, loss of bands under saline was more noticed at 10 ppt than 17ppt salinity in both O. niloticus (Mr) and O. niloticus (Mz). Also, esterase and lactate dehydrogenase systems were more sensitive to saline than the others. The regulation of gene expression is affected by salinity. This affect is different from one species to another due to its tolerance to salinity concentrations

Four local populations of Nile tilapia (Oreochromis niloticus) were collected from different locations in Egypt namely, Abbassa, Maryout, Manzala and Aswan. Protein banding patterns (SDS-PAGE) for all populations were performed using soluble fraction of muscle extract. The variation among and between populations were estimated and compared. The intra-specific variation for SDS-PAGE was low for both Abbassa and Manzala and high for Maryout and Aswan. The results generated from protein analysis were pooled for drawing the genetic relationships among the four examined populations. The phylogenetic tree indicated that Maryout and Manzala form one group that branched to the subgroup of Abbassa, which branched in turn to another subgroup of Aswan population. The four populations of Nile tilapia, Oreochromis niloticus were evaluated under polyculture system (120 days) in earthen ponds. The growth performance and survival rate were determined. The result indicates highly final weight (188g); total yield (371.23 * 9.59 kg / feddan) and daily weight gain (1.28* 0.017 g/fish/day) in Maryout population followed by Manzala (1.261*0.01 g/fish/day), then Abbassa (1.22* 0.01 g/fish/day). While, the lowest final weight (165 g); total yield (301.69*24.127 kg / feddan) and daily weight gain (1.16*0.095 g/fish/day) on Aswan population. These differences in average individual daily weight gain may be due to genotype. On the other hand, we showed that increased survival rate on Maryout population (94 * 1.28 %) and decreased in Manzala population (83.4 * 1.92 %). We may conclude that the Maryout population is expected to perform better under polyculture system in earthen ponds.

In this work, four tilapia groups that belong to three species; Oreochromis niloticus {from Maryuot (MR) & Manzala (MZ)}, O. aureus and Tilapia zillii {from Abbassa (AB)}, are examined under different saline water under controlled laboratory conditions through eight weeks. Specific growth rate, condition factor and weight and length parameters were studied. Two saline water, 10, 17 ppt and control, 0ppt were used. The average initial weight and length for the studied fish were approximately 8.68 ± 0.38g, and 7.84 ± 0.18cm, respectively. The LC50 at 72 hours was determined for all fishes before the rearing experiment. All fish (Oreochromis and Tilapia) had 100% survival up to 16 ppt. In contrast, T. zillii showed 100% survival up to 25 ppt. Through the experimental period, no significant differences were observed between the control group and fish reaered in 10 ppt, and a decrease of the body weight at 17 ppt with significant differences. The specific growth rate (SGR) of O. niloticus (MR) was very close at control and 10 ppt salinity (0.60 vs 0.61 ). In O. niloticus (MZ), the SGR showed the highest value at 10 ppt (0.64 %). This value was significantly different from both control and 17 ppt concentrations. For O. niloticus (MR) and T. zillii, SGR% showed no significant differences among the two saline levels. The specific growth rate (SGR) of O. niloticus (MR and MZ) was very close under 17 ppt. O. aureus, SGR showed significant differences under the three different saline conditions. O. aureus in control showed the highest SGR. The results showed that SGR of T. zillii increased as saline increased up to corresponding level (17ppt) with no significant differences. The condition factor (K) for all groups reared under different saline conditions was higher than one.

Four local populations of Nile tilapia (Oreochromis niloticus) were collected from different locations in Egypt namely, Abbassa, Maryout, Manzala and Aswan. protein banding patterns (SDS-PAGE) for all populations were performed using soluble fraction of muscle extract. Furthermore, isozymes banding patterns for each population was performed using eye extract. Total band numbers detected in each individual population sample were scored, compared, analyzed and assessed for the four-izosyme system ; Esterase (Est), Malate dehydrogenase (Mdh), Alcohol dehydrogenase (Adh), Lactate dehydrogenase (Ldh). The DNA markers were concluded applying RAPD-PCR technique. Two arbitrary random primers were tested. All primers (OPA-05 and B-19) amplified genomic DNA and produced distinct bands. The variation among and between populations were estimated and compared with that of both isozymes and proteins. The data concluded from each genetic criterion was pooled to draw the genetic relations among and between populations. The intra-specific variation for SDS-PAGE was low for both Abbassa and Manzala and high for Maryout and Aswan. Abbassa resembled Manzala and Maryout population showed more polymorphism. The esterase izosyme of Maryout and Manzala populations showed high similarity. The Adh of Manzala and Aswan populations showed high similarity. The Ldh showed inter-specific variation in both Maryout and Manzala, and no variation in both Abbassa and Aswan. The primer OPB-19 displayed high variation in RAPD fragment among four applied populations. Both Abbassa and Manzala populations had the highest value of similarity coefficient, followed by Maryout /Aswan. Also, the results indicated no similarity between Abbassa/Maryout and between Maryout/Manzala.
The results generated from the RAPD, isozyme, and protein analysis were pooled for drawing the genetic relationships among the four examined populations. The results revealed that the highest similarity coefficient value (0.83) was observed between Manzala and Maryout followed by that Abbassa and Aswan (0.79). The similarity coefficient value between Aswan and each of Maryout and Manzala showed the lowest value (0.65 and 0.69), respectively. The phylogenetic tree indicated that Maryout and Manzala form one group that branched to the subgroup of Abbassa, which branched in turn to another subgroup of Aswan population.

Pollution of surface water has increased due to the industrial effluents, waste municipal and agricultural drainage water that discharged directly into it. The present study measured the concentrations of some heavy metals (Fe, Cu, Zn, Pb and Cd) in water, sediment and fish collected from certain Egyptian lakes (Maryut, Manzala, El-Burullus, Edku and Qarun), a polluted site of the river Nile (Shubra El-Khiema, Cairo sector), in addition to Ismalia canal (El-Abbassa region). The results revealed that fish collected from the polluted site of the river Nile and the studied lakes (Maryut, Manzala, El-Burullus and Edku) showed the lowest growth factor, hepatosomatic index, meat quality and disturbances in the studied physiological state as indicated by the increase in serum glucose, total protein, AST, ALT, alkaline phosphstase, creatinine, uric acid and a decrease in serum total lipids. In comparison, fish collected from lake Qarun exhibited levels of meat quality and growth indices higher than those collected from the other studied sites and showed normal levels in the different studied biochemical parameters as those of the control group collected from Ismalia canal. Chemical analyses of water samples suggested that high salinity, total alkalinity and total hardness in lake Qarun might have inhibited the bioaccumulation of any of the studied heavy metals (Fe++, Cu++, Zn++, Pb++ and Cd++) in the different studied organs of Oreochromis niloticus to be within permissible levels as those of fish collected from Ismailyia canal (Abbassa region). However, fish collected from the other studied lakes and the polluted site of the river Nile accumulated spatially the heavy metals in the different studied fish organs.