Abstract
The study examines the effects of partially replacing well water with treated sewage water on water quality, growth performance, carcass composition, and blood parameters in common carp. Common carp (mean weight = 104.16 ± 0.83 g) were reared in 12 experimental tanks, which well water replaced by 0%, 25%, 50%, and 75% of treated sewage water. A result showed that final body weight (FBW) was significantly reduced in fish reared in tanks with 50% well water replaced with treated sewage water. No significant difference was found among treatments in the values of weight gain (WG), specific growth rate (SGR), and feed conversion ratio (FCR). The lowest level of survival was (83.33±3.33) recorded in fish reared in water with 75% well water replaced with sewage-treated water, which was significantly lower than the control and other groups of fish. Substituting well water with sewage-treated water resulted in higher levels of BOD, EC, NO₃⁻, COD, Mg, Cl, Na⁺, K⁺, TDS, TSS and salinity. However, ammonia levels decreased significantly as the replacement level increased. Biochemical tests in the serum showed a significant changes with the substitution of well water with sewage-treated water. The levels of AST, ALT, ALP, cholesterol, TG, HDL, VLDL, urea, uric acid, total protein, albumin, lipase, amylase, and glucose increased with the substitution of 75% of well water with sewage-treated water. The study concluded that substituting well water with sewage-treated water had a significant effect on water quality and serum biochemical testing, but no effects on growth performance and carcass composition.