Survival And Growth Responses Of Frys Of The African Catfish Hybrid (Clarias gariepinus X Heterobranchus bidorsalis) To Soluble Dietary Supplements Of Inorganic Phosphorus.

Abstract

Four (4) isonitrogenous experimental diets with 38.00% crude protein were formulated and replicated three times to include four supplemental inorganic phosphorus (H3PO4) levels of 0.20%, 0.80%, 1.00 and 1.20%. The control experiment (replicated three times) consisted of diets with non-inorganic phosphorus. The dietary treatments were fed to 4-weeks old hybrid of Clarias gariepinus × Heterobranchus bidorsalis (mean weight, 2.10 ± 0.14 g) at 5% body weight per day for 42 days. The soluble reactive concentration level of the inorganic phosphorus (SRP) in experimental water was investigated, the growth response and survival of the fish evaluated. The results indicated that the water treated with the control diet (0.03 mg/l) had a higher concentration of SRP than any of the H3PO4-supplemented diet. The range values of SRP in water with dietary 0.60% and 0.80% P-supplementation did not vary significantly (P > 0.05). There were significant differences (P < 0.05) in the range values of SRP of water treated with 1.00%, 1.20% and 0.00% P (control) diets, even though the values for the mean weight gain (MWG) and food conversion ratio (FCR) were not significantly different (P > 0.005). The phosphorus gain/loss (PGL) values of fish were only significantly different (P < 0.05) between the 0.80%, 1.20% and the control diets. The non-significant difference (P > 0.05) of the PGL of fish when 0.60% P and 1.00% diets were applied apparently corresponded with non-significant difference (P > 0.05) recorded for the SRP of water treated with 0.60% and 0.80% P diets.

Keywords:Inorganic phosphorus, soluble reactive concentration, supplemental diets.

Journal of Technology and Education in Nigeria Vol. 10 (1) 2005: pp. 11-19