نوع مقاله : مقاله کامل علمی - پژوهشی
1 1دانشآموخته شیلات، دانشکده علوم دامی و شیلات، دانشگاه علوم کشاورزی و منابع طبیعی ساری
2 گروه شیلات، دانشکده علوم دامی و شیلات، دانشگاه علوم کشاورزی و منابع طبیعی ساری
3 مربی گروه شیلات، دانشکده علوم دامی و شیلات، دانشگاه علوم کشاورزی و منابع طبیعی ساری
عنوان مقاله [English]
The effect of different water hardness levels on growth indices, survival rate, hematological parameters, and water quality of Caspian Kutum (Rutilus kutum) fingerlings was investigated in a completely randomized design with six water hardness treatments (350, 600, 650, 700, 800, and 900 mg of calcium carbonate (CaCO3) each with three replications containing 13 pieces of fish (n = 300 in total) with an average weight of 2 g for 56 days. The highest final weight, body weight gain, and daily growth rate were estimated in the treatment with a hardness of 650 mg/L CaCO3 (P < 0.05); the same treatment represented the minimum feed conversion ratio and the lowest daily food intake (P < 0.05). The highest values of hardness and alkalinity of water were measured in the treatment with a hardness of 900 mg/L CaCO3 (P < 0.05). The highest levels of red blood cells were counted in well water treatment (600 mg/L CaCO3) + distilled water with a hardness of 350 mg/L CaCO3 (P < 0.05). The highest and lowest hemoglobin levels were estimated in treatments containing 700 and 900 mg/L CaCO3, respectively (P < 0.05). The highest levels of cortisol and glucose with significant differences between treatments were recorded in the treatment containing 15 g of CaCO3 with a hardness of 900 mg/L (P < 0.05). The highest amounts of sodium and calcium in fish meat were obtained in the treatment with a hardness of 650 mg CaCO3 (P < 0.05). Therefore, water hardness of 650 mg/L CaCO3 led to the highest values of final weight, body weight gain, and daily growth rate in R. kutum fingerlings in the laboratory (P < 0.05), which can be used for the culture of this valuable fish species.