Impairment in the haematological parameters of tench (Tinca tinca) infected by Saprolegnia spp.

Haematological parameters of tench (Tinca tinca) infected by Saprolegnia spp. were studied. All parameters, except mean corpuscular volume (MCV), decreased in response to infection. A significant (P < 0.05) decrease was observed in haemoglobin (Hb) (−26.85%), red blood cell count (RBCc) (−20.94%), leucocrit (Lct) (−24.14%), and mean corpuscular haemoglobin concentration (MCHC) (−9.06%). Haematocrit (Hct), white blood cell count (WBCc), and mean corpuscular haemoglobin (MCH) also decreased (−7.66%, −12.44%, and −6.19%, respectively); however, differences between the infected and control groups were not significant. Among the parameters, only MCV had a non-significant increase (+7.84%) in the infected fish. The study results show that saprolegniasis caused anaemia and immunosuppression, followed by mortality in tench. Mortality was attributed to haemodilution caused by haemorrhaging and the breakdown of osmotic balance due to tissue (skin and muscular layer) destruction via the penetration of the hyphae; however, lethargy was another mortality promoting factor. Mortality among the Saprolegnia-infected fish also depended upon the initial site of infection, type of tissue destroyed, growth rate of the fungus, and ability of individual fish to withstand the stress. The present study was conducted to investigate physiological impairment in Saprolegniainfected Tinca tinca under laboratory conditions; however, further studies at the population level in natural habitats and under similar stress conditions are needed.

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1. Grosch, U., Rennert, B., Hilge, V.: Development and use of surface waters and the fate of the related fisheries in the Berlin area of Germany. Fish. Manag. Ecol., 2000; 7: 179-188.
2. Noga, E.J.: Fish Disease: Diagnosis and Treatment.Mosby-Year Book, Inc., St. Louis, MO, 1996; pp: 367.
3. Pickering, A.D.: Factors which predispose salmonid fish to saprolegniosis. In:Mueller, G.J. Ed., Salmon and Saprolegniosis. U.S. Department of Energy, Bonneville Power Administration, Portland, Oregon, 1994; 67-84.
4. Stueland, S., Hatai, K., Skaar, I.: Morphological and physiological characteristics of Saprolegnia spp. strains pathogenic to Atlantic salmon, Salmo salar L. J. Fish Dis., 2005; 28: 445-453.
5. Willoughby, L.G.: Fungi and Fish Diseases. Pisces Press, Stirling, Scotland, 1994; pp: 57.
6. Pickering, A.D., Willoughby, L.G.: Saprolegnia infections of Salmonid fish. In: Roberts, R.J. Ed., Microbial diseases of fish. Academic Press, London, 1982; 271-297.
7. Bruno, D.W., Poppe, T.T.: A Colour Atlas of Salmonid Diseases. Academic Press, London, 1996; pp. 189.
8. Hatai, K., Hoshiai, G.I.: Pathogenicity of Saprolegnia parasitica Coker. In: Mueller, G.J., Ed. Salmon and Saprolegniosis. U.S. Department of Energy, Bonneville Power Administration, Portland, Oregon, 1994; 87-98.
9. Howe, G.E., Stehly, G.R.: Experimental infection of rainbow trout with Saprolegnia parasitica. J. Aquat. Anim. Health, 1998; 10: 397-404.
10. Shah, S.L., Altindag, A.: Haematological parameters of tench, (Tinca tinca L.) after acute and chronic exposure to lethal and sublethal mercury treatments. Bull. Environ. Contam. Toxicol., 2004; 73: 911-918.
11. Jones, S.R.M.: The occurrence and mechanisms of innate immunity against parasites in fish. Dev. Comp. Immunol., 2001; 25: 841-852.
12. Blaxhall, P.C., Daisley, K.W.: Routine haematological methods for use with fish blood. J. Fish Biol., 1973; 5: 771-781.
13. McLeay, D.J., Gordon, M.R.: Leucocrit: a simple haematological technique for measuring acute stress in salmonid fish, including stressful concentrations of pulp mill effluent. J. Fish. Res. Board Canada, 1977; 34: 2164-2175.
14. Gill, T.S., Pant, J.C.: Erythrocytic and leukocytic responses to cadmium poisoning in a freshwater fish Puntius conchonius Ham. Environ. Res., 1985; 36: 327-337.
15. Eddy, F.B.: Oxygen dissociation curves of the blood of the tench, Tinca tinca. J. Exp. Biol., 1973; 58: 281-293.
16. Collazos, M.E., Ortega, E., Barriga, C. Rodriguez, A.B.: Seasonal variation in haematological parameters in male and female Tinca tinca. Mol. Cell Biochem., 1998; 183: 165-168.
17. Jensen, F.B., Weber, R.E.: Respiratory properties of tench blood and haemoglobin adaptation to hypoxic-hypercapnic water. Mol. Physiol., 1982; 2: 235-250.
18. McLeay, D.J.: Effects of a 12-hr and 25-day exposure to kraft pulp mill effluent on the blood and tissues of juvenile coho salmon, Oncorhynchus kisutch. J. Fish. Res. Board Canada, 1973; 30: 395-400.
19. Wepener, V., Van Vuren, J.H.J., Du Preez, H.H.: Effect of manganese and iron at a neutral and acidic pH on the haematology of the banded tilapia (Tilapia sparrmanii). Bull. Environ. Contam. Toxicol., 1992; 49: 613-619.
20. Gill, T.S., Epple, A.: Stress-related changes in the haematological profile of the American eel (Anguilla rostrata). Ecotoxicol. Environ. Saf., 1993; 25: 227-235.
21. Tort, L., Torres, P., Flos, R.: Effects on dogfish haematology and liver composition after acute copper exposure. Comp. Biochem. Physiol. C, 1987; 87: 349-353.
22. Ackerman, P.A., Forsyth, R.B., Mazur, C.F., Iwama, G.K.: Stress hormones and the cellular stress response in salmonids. Fish Physiol. Biochem., 2000; 23: 327-336.
23. Alvarez, F., Razquin, B., Villena, A. López Fierro, P., Zapata, A.: Alterations in the peripheral lymphoid organs and differential leukocyte counts in Saprolegnia-infected brown trout, Salmo trutta fario. Vet. Immunol. Immunopath., 1988; 18: 181-193.