Author/Authors :
Nouh، Wael G نويسنده Department of Pathology, Faculty of Vet Medicine, Zagazig University, Zagazig, Egypt/Department of Medical Laboratories, Faculty of Community in El-Na , , Selim، Ahmed G نويسنده Vet. Clinic, Faculty of Veterinary Medicine, Zagazig University, Egypt. ,
Abstract :
The effect of specific/therapeutic dose of disinfectants (formalin and copper sulphate) was studied on
180 apparently healthy Nile tilapia through hematological, biochemical, histopathological and electron
microscopic examinations.
Tilapia exposed to formalin (25mg/l, gp 2), clinically, no mortality was detected throughout the period of
the treatment. During the first three days post treatment, the exposed Tilapia nilotica showed accelerated
opercular beats while grossly, a copious mucus secretion covering the skin and gills with congested liver,
kidneys and spleen were seen.
Histopathologically, one days post-treatment, congestion was evident in all examined organs. Five and
ten days post-treatment, degeneration, leukocytic infiltration and focal depletion in the lymphoid tissue
were noticed.
Tilapia exposed to copper sulfate (2mg/l, gp 3), clinically, the mortality rate was 5% throughout the
period of treatment and the exposed Tilapia nilotica showed unbalanced fast movement and gasping
during the first three days post treatment. Grossly, the exposed tilapia showed numerous hemorrhagic
areas on the body along the period.
Histopathologically, one and five days post-treatment, the gills showed telangiectasis and focal
hyperplasia in the secondary gill lamellae and the other organs were congested and suffered muscular
hyaline degeneration, vacuolar degeneration in the hepatocytes, tubular nephrosis and proliferation of
splenic MMC.Ten days post-treatment, the gills exhibited hyperplasia in the secondary lamellae, the
muscles and liver showed degeneration and proliferation of melanomacrophages while the kidney
showed vacuolation in the renal epithelium with focal depletion of hematopoietic tissue.
The ultrastuructural changes in the hepatocytes and renal epithelium of tilapia exposed to formalin and
copper sulphate were mentioned and fully discussed.
It could be concluded that, although therapeutic dose of disinfections is efficient against many fish
infection, their use should be done under strict regulation to avoid its pathological side effect
