Increased resistance to abiotic stress in Penaeus vannamei postlarvae following chronic treatment with phloroglucinol

In this study we investigated if the exposure to phloroglucinol increases P. vannamei postlarvae resistance against abiotic stressors. FG showed toxicity from 10 μM after 24 hours exposure but when exposure duration was reduced to 2 hours no mortality was detected in concentrations up to 300 μM. FG administered acutely, in a single dose, appears to be ineffective to protect postlarvae against ammonia. On the contrary, when PG was administered chronically as seven sublethal treatments spaced in time, increased resistance to abiotic stressors was detected. However, after 10 days of recovery animals were still stressed and weight and ammonia resistance was lower in PG-treated animals (p salinity stress test (SST) was higher compared to control. After 20 days PG-treated animals had similar weight compared to control. Resistance to ammonia and SST was also higher in treated animals.