Effect of dietary L-ascorbyl-2-phosphate magnesium on gonadal maturation of Penaeus japonicus

Penaeus japonicus were fed semi-purified diets containing either 0, 500, 1000, or 1500 mg L-ascorbyl-2-phosphate magnesium (APM) as an ascorbic acid (AsA) source per kg dry diet for 170 days to investigate their effects on growth, survival, and gonadosomatic index (GSI). Female prawns were unilaterally eyestalk-ablated on the 126th day of the experiment. The female prawns fed with an APM deficient diet had reduced resistance to change which incurred through eyestalk ablation. Before eyestalk ablation, the survival of females fed with an APM deficient diet was 100%; however, after ablation, high mortalities were observed. The GSI of ablated females receiving 500 or 1000 mg APM/kg diet were significantly higher than those fed with 1500 mg. A level of 500 mg APM/kg diet was sufficient to promote good growth and survival in male prawns.