Response of Clarias gariepinus juveniles to varying concentrations of copper in water containing Pteridium aquilinium (Bracken Fern) and Poultry manure

Document Type : Primary Research paper



Pteridium aquilinum  (four fully formed fronds and 3-4 young shoots) were acclimatized in tanks containing 20 litres of water and 10 mg/l poultry manure for one week before the addition of different concentrations of copper (0, 1.8, 3.2, 5.6 and 10.0 mg/l) as hydrated copper chloride for twenty four hours. At the end of this period, juvenile Clarias gariepinus (mean weight 40g, length 22cm) which had been acclimatized for two weeks were introduced into the tanks containing P. aquilinum, poultry manure and different concentrations of copper as copper chloride for 96 hours. Each concentration of copper and 10mg/l poultry manure served as a treatment. This study aimed at evaluating the response of C. gariepinus juveniles when grown in water containing P. aquilinum, poultry manure and varying concentrations of copper. Alkalinity, phosphate and nitrate increased in water while copper content decreased at the end of the experiment. Concentrations of copper in water and fish flesh were significantly lower (p< 0.05) than in P. aquilinum with the highest concentration of 2776 mg/kg copper in the ferns exposed to 10mg/l copper and poultry manure. No significant differences were observed in the haematogical indices of fish. Histopathology showed changes in the gills, liver and kidneys. The muscle tissues showed no visible lesion even at 10mg/l copper and poultry manure. It was concluded that the water, C.gariepinus juveniles contained less copper than P. aquilinum in the presence of poultry litter.