Subletal amonyak konsantrasyonlarının Tilapia (Oreochromis niloticus)ve sazan (Cyprinus carpio) balıklarında büyüme ve kan parametreleri ile dokulara etkisi
Özet
In this study, the effects of sublethal ammonia concentrations on Nile tilapia (Oreochromis niloticus) and mirror carp (Cyprinus carpio) were determined in 20oC and 25oC water temperatures. The experiments were conducted under four different ammonia concentrations established; as control, 1, 2, 5,10 mg/L TA-N for Nile tilapia and control, 0.5, 1, 2, 5 TA-N mg/L for carp, respectively. After six weeks trials, in Nile tilapia average weight gain, absolute growth and condition factor were reduced (p<0.05),whereas feed conversion ratio increased (p<0.05). Reduction in specific growth rate is not significant statistically (p>0.05), however in mirror carp average weight gain, absolute growth and specific growth were reduced (p<0.05), feed conversion ratio increased (p<0.05), condition factor was not changed significantly (p>0.05). In both species survival rate were determined 100%. It eas observed that the feed intake decreased both Nile tilapia and carp after exposed to ammonia concentrations during the experiment. In both trials blood parameters effected differently from water temperature, sampling time and ammonia concentrations. In Nile tilapia, total plasma protein, magnesium (Mg++), sodium (Na+) decreased at the end of six weeks of experiment (p<0.05), hence, plasma glucose and ammonia levels increased linearly with water ammonia levels (p<0.05) where, plasma chloride (Cl-), potassium (K+) and hematocrit fluctuated unsteadily and calcium (Ca++) levels were remained same. In mirror carp, plasma potassium (K+), glucose and ammonia levels linearly increased with water ammonia levels (p<0.05), meanwhile total plasma protein, plasma magnesium (Mg++), sodium (Na+), chloride (Cl-) and calcium (Ca++) decreased comparing to control group at the end of six weeks experiment (p<0.05), hematocrit levels were fluctuated unsteadily by ammonia concentrations. In both Nile tilapia and carp fish exposed to different ammonia concentrations, revealed histopatologic findings in the gills, liver and kidney. In both species in gill tissues hyperemia, chloride cell proliferation, fusion in secondary lamella, telangiectasis; in liver passive hyperemia, albumin and hydropic degeneration; in kidney hyperemia, hemorrhage, glomerulonephritis were determined. In carp kidney, disturbances reaching up to necrosis in some kidney tubule epithelium were recorded.