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T his is the first trial so far in Egypt through upgrading the fish production by revealing specific ovarian myxozoan and fungal infections that affect their fecundity. Fecundity comparison was held between noninfected and infected Oreochromis niloticus and Cyprinus carpio with either Myxobolus spp. or Icthyophonus hoferi. The myxosporean parasite, Myxobolus spp. (with higher prevalence in both species) appeared as numerous white large rounded spores embedded in the ovarian tissue causing excessive fibrosis. The fungus /. hoferi inspite of its lower prevalence among the 2 species, the white capsulated cysts and separate colonies caused ovarian atresia and fibrosis with inflammatory oedema. Drop of fecundity was represented by significant decrease in relative and absolute fecundity, total protein, gonadosomatic and hepatosomatic indices ranging from highly with 0. niloticus to moderately with C carpio. In O. niloticus (more sensitive) /. hoferi reflected a positive correlation with ovarian weight and gonadosomatic index, while Myxobolus spp. recorded a negative correlation between ovarian weight and the body parameters (weight, length & depth). The results revealed that infection takes place among apparently healthy fish proving that gonadal periodical examination is the only way for detecting such infections.

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This research studied effect of water temperature increase on male O. niloticus experimentally and survey. One hundred male O. niloticus delivered from private farm fish divided into four groups: 1 st kept at room temperature (Control) and others at 30, 33 and 36 ºC for 2 weeks. Two Survey groups collected from El-monib at 27 ºC (Control) and at 36 ºC water temperatures. Experimental fish suffered from nervous manifestations, detached scales, ulcers, tail rot. Unsymmetrical testis which appeared thread like especially at 36 ºC and survey. Growth measurements revealed highly significant drop in B.W., WH and WG. In addition, relative fecundity F.B.W. and F.O.W (only at 33 ºC) registered highly significant decrease. Sperm density and sperm live % also showed highly significant drop. On the contrary, survey group B.W., WG, WH, and IG as well as parameters of relative fecundity (F.B.W. and F.O.W) showed highly significant increase. Oppositely, Sperm density and sperm live % copied highly significant decrease. At 30 ºC and 36 ºC water temperatures and survey total protein and globulin decreased highly significant. Estradiol hormone decreased highly significant at experimental and survey groups. Glucose and testosterone increased highly significant at experimental and survey groups. Malformation and distortion of seminiferous tubules with lesser number of sperms. Hepatic cells appeared swollen with vacuolar degeneration. Favorable water temperature for Oreochromis niloticus to achieve their maximum reproductive performance and their health is 27 ± 2ºC. 46Eissa et al.