Phosphorus Requirement and Optimum Level of Dietary Supplementation with Magnesium Hydrogen Phosphate (MgHPO₄) Recovered from Swine Manure for Juvenile Carp Cyprinus carpio

Abstract

A growth trial was conducted to determine the optimal supplement of dietary magnesium hydrogen phosphate (MHP, MgHPO 4 ) which was manufactured from swine manure and phosphorus (P) requirements of juvenile carp Cyprinus carpio. Graded MHP of 0.5, 1.0, 1.5 and 2.0%, each was added to the basal diet (control) in lieu of cellulose to become the range of available P from 0.4 to 0.7%. The lowest weight gain (WG) and highest feed conversion ratio (FCR) were found in the control group (P<0.05). The group fed a diet supplemented with 2.0% MHP showed the highest WG, which was not significantly different from those of fish groups that received 1.0% and 1.5% MHP (P>0.05). The lowest FCR was observed in fish groups fed 1.5% and 2.0% MHP. Plasma inorganic P was significantly higher (P<0.05) in all fish groups fed MHP-supplemented diets than in control group. A second-order regression analysis on WG revealed that the optimum dietary MHP level and the available P (AP) requirement were found to be 1.85 and 0.66%, respectively. Expressed in terms of 'g AP intake per kg BW 0.8 per day', the AP requirement was found to be approximately 0.032 g/kg BW 0.8 /d.