The present study was conducted to investigate the effects of dietary water hyacinth (Eichhornia crassipes) leaves powder (WLP) on growth performance, skin mucus and serum immune response, as well as antioxidant capacity of pikeperch (Sander lucioperca). During 7 weeks culture period, 120 fish (21.2 ± 0.55 g) were fed by experimental diets containing 0% (control), 0.5%, 1% and 1.5% WLP (four treatments in triplicate). At the end of the feeding trial, results revealed a significant increase in final weight (FW), weight gain (WG), daily weight gain (DWG) and specific growth rate (SGR) in fish fed with the highest value 1.5% WLP. Furthermore, increased skin mucus total immunoglobulin (Ig) level and lysozyme (LYZ) activity was noticed in 1 and 1.5% WLP groups, protease in 1.5% WLP group, and alkaline phosphatase (ALP) in 0.5 and 1% WLP groups. Haematological evaluation showed a significant rise in red blood cell (RBC) and haematocrit (HCT) at all WLP inclusion levels, while haemoglobin (Hb) value only increased in group fed by 0.5% dietary WLP. Also, remarkable increase in LYZ, protease and alternative complement (ACH50) activity were observed in WLP-treated groups. Moreover, higher catalase (CAT) activity was detected in WLP supplemented groups, while higher superoxide dismutase (SOD) activity was detected in 0.5 and 1.5% WLP groups. However, glutathione peroxidase (GPx) activity was higher only in 0.5% WLP group. In conclusion, the present findings showed beneficial effects of water hyacinth leaves powder as a plant-derived growth promotor and immunostimulant in the pikeperch.
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