OPEN ACCESS International Journal of Aquatic Science ISSN: 2008-8019 Vol. 9, No. 2, 99-105, 2018 () floraolaifa@yahoo.com Response of Clarias gariepinus juveniles to varying concentrations of copper in water containing Pteridium aquilinium (Bracken Fern) and Poultry manure Flora Eyibio Olaifa Department of Aquaculture and Fisheries Management, University of Ibadan, Ibadan, Nigeria Received: June-07-2017 Accepted: December-19-2017 Published: April-02-2018 Abstract: 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. Keywords: Uptake, copper, Clarias gariepinus, Haematology, histopathology Introduction Fish in polluted waters accumulate heavy metals in their tissues with higher concentrations in water producing greater levels in tissues (Jezierska and Witeska, 2006). Natural hyper accumulators are plants that can tolerate and incorporate high levels of toxic metals in their tissues with no signs of toxicity (Bennett et al., 2003; Mokhtar et al., 2011). For phytoremediation to succeed, the plants must extract large concentrations of heavy metals from the soil or water into their roots, translocate the heavy metal into the surface biomass, and produce a large quantity of plant biomass. The accumulation of some heavy metals and trace elements by some plants has been demonstrated (Ma et al., 2001; Choo et al., 2006, Olaifa and Omekam, 2014). Copper is essential as a trace element for several metabolic activities of fish and plays important roles in many enzymatic activities. It also serves as an herbicide, fungicide and an algaecide (Wani et al., 2011). Clarias gariepinus is a commonly cultured fish species which is hardy and can withstand many adverse environmental conditions. Manure is regarded as a complete fertilizer with organic and inorganic components which can be used without other chemicals (FAO, 2003). The compositions of different poultry manures including heavy metal contents from different locations have been reported (Nnaji et al., 2011). Pteridium aquilinum (bracken fern) is a vascular wetland plant found in Nigeria which was employed in this study to extract copper present in water at varying concentrations and to test the efficacy of the remediation using C.gariepinus juveniles in a 96-hour bioassay. Poultry manure was used to stimulate the growth of P. aquilinum in water. Materials and Methods Pteridium aquilinum plants (whole rhizomes) were obtained from within the University of Ibadan Campus and acclimatized for one week. Four fully formed fronds and 3-4 young shoots were later taken out and grown in experimental tanks containing 20 L water and varying concentrations of copper (1.8mg/l, 3.2mg/l, 5.6mg/l and 10.0mg/l/) as hydrated copper chloride (Reish and Oshida, 1987) and 10 mg/L poultry manure (Ndimele, 2009) for one more week. The compositions of poultry manure used were given as calcium (10.39), magnesium (1.46), potassium