Effect of L-Ascorbyl-2-phosphate-Mg on the Yellowtail Seriola quinqueradiata as a Vitamin C Source.

Abstract

A stable form of vitamin C, L-ascorbyl-2-phosphate-Mg (APM), was tested for efficacy as a vitamin C source in the juvenile yellowtail Seriola quinqueradiata. The fish, weighing 2.67g, were fed 4 fish meal-based diets containing graded levels of supplemental APM (0, 3, 6, and 10mg/100g diet) for 83 days. The fish receiving the diet without supplemental APM showed deficiency sym-ptoms such as reduced growth rate, deformity (lordosis and scoliosis), distorted gill support car-tilage (degeneration of the ravine part of gill-cover), high mortality, and so on. The supplementa-tion of 3 to 10mg of APM/100g diet improved the growth and feed efficiency of the fish. The results of the feeding experiment indicated that a supplement of about 3 to 6mg APM/100g diet was sufficient to support good growth and survival and to prevent the gross vitamin C deficiency symptoms of the yellowtail. The supplementation of APM elevated the L-ascorbic acid (AsA) contents of serum and liver, serum alkaline phosphatase activity, and the ratio of hydroxyproline/proline in the bone. The results of the present study showed that APM can be effectively utilized by the yellowtail as a good replacement for AsA.