Effects of Artemia enriched with L-ascorbyl dipotassium-2-sulfate dihydrate on stress tolerance and disease resistance of Penaeus monodon postlarvae

Abstract

Penaeus monodon postlarvae (stage 10) were reared with Artemia nauplii enriched with 50,100 and 150 mg/l (ppm) of L-ascorbyl-dipotassium-2- sulfate dihydrate for 5 days. Postlarvae in the control group were given non-enriched Artemia nauplii. Responses of postlarvae to toxic (ammonia and methyl parathion exposure) and stressful (salinity and dissolved oxygen stress) conditions, as well as their resistance to challenge with Vibrio harveyi, were compared. Acute toxicity tests using ammonia and methyl parathion revealed better tolerance of postlarvae given enriched Artemia at 100 and 150 ppm L-ascorbyl-dipotassium-2- sulfate dihydrate for 5 days. Transfer of postlarvae from 30 to 0 ppt water caused 100% mortality in all groups after 2 hr of transfer, but postlarvae that were transferred from 30 to 5 ppt showed significantly different mortality rates after 48 hr. Postlarvae that were given enriched Artemia had lower mortality compared with the control. In the oxygen depletion experiment, mortality rates were significantly different between enriched and non-enriched postlarvae. However, on the fourth day, all enriched and control shrimp died. Challenge with pathogenic Vibrio harveyi by bath challenge for 7 days showed significantly different mortality rates among postlarval groups. Postlarvae given 100 and 150 ppm L-ascorbyl-dipotassium-2- sulfate dihydrate for 5 days had lower mortality. Results from this study indicate the benefits of L-ascorbyl-dipotassium-2-sulfate dihydrate enrichment through Artemia in improving the survival of P. monodon postlarvae against some stressful conditions and bacterial challenge.