Sodium-EDTA effects on survival and metamorphosis of Penaeus monodon larvae

Abstract

The effects of Na-EDTA on growth and survival of Penaeus monodon larvae were determined for applications given daily or every 3 days. Application of 2.0, 5.0, and 10.0 ppm were given on day 1, day 4 and day 7 in Experiment 1, and 5.0 and 10.0 ppm were given daily for 8 days in Experiment 2. Larvae stocked at 100/liter were given a natural food diet of Chaetoceros calcitrans and Artemia salina nauplii. Chloramphenicol (2.0 ppm) and Treflan R (0.05–0.10 ppm) treatments were applied on the same days as Na-EDTA. Water change was 30% on day 4 and 50% daily thereafter.

Results showed that the application of Na-EDTA at 5.0 and 10.0 ppm on days 1, 4 and 7 greatly improved the survival of P. monodon larvae. With daily application, the larvae treated with 10.0 ppm showed the best survival rate during the 8-day culture period. Na-EDTA treatments at dosages above 2.0 ppm seem to prevent significant mortality. It is believed that Na-EDTA improved survival rates by chelating toxic elements in the culture medium. Growth (rate of metamorphosis) was not greatly improved except for anuplii to zoea where the highest percent molts were observed with the 10.0 ppm treatment in both experiments.