Dietary phosphorus requirement of juvenile milkfish, Chanos chanos (Forsskal)

Seven isocaloric and isonitrogenous diets with graded levels of monopotassium phosphate to yield total phosphorus levels of 0.28 (no P supplementation), 0.43, 0.58, 0.73, 0.88, 1.03 and 1.18% were prepared and fed to five replicate groups of 10 juvenile milkfish (initial weight = 2.5 g). After 16 weeks of feeding, significant differences in growth (300-570%). survival rates (70-100%), and bone and scale mineralization were found among treatment groups. Weight gains of milkfish increased linearly up to the 0.88% dietary phosphorus concentration and levelled off beyond this dietary level. Bone and scale ash, calcium and phosphorus concentrations showed similar patterns as weight gain in response to dietary phosphor-Lis concentration. Broken-line regression analyses of these data indicated that the dietary phosphorus level required for optimal growth and mineralization of juvenile milkfish is approximate to0.85% of dry diet.