Role of feed ingredients in the bromophenol content of cultured prawns

Commercial and experimental pelleted feeds were fed to prawns ( Penaeus monodon) in aquaculture ponds and laboratory tanks to assess the effect of different ingredients on the bromophenol content of cultivated animals. Ingredients with bromophenols typically used in commercial feeds were fish, shrimp head, krill and squid meals and those additionally used in experimental feeds were dried marine algae, dried polychaetes, free bromophenols and bromophenol sulphate esters. After harvest, prawns and feed were analysed by GC/MS for 2- and 4- bromophenol, 2,4- and 2,6-dibromophenol and 2,4,6-tribromophenol. The total bromophenol content of commercial feeds ranged from 1.4 to 153 ng/g and those of experimental feeds from 2.9 ng to 18.9 μg/g. Retention of bromophenols by prawns was low for all ingredients; prawns fed commercial feeds ranged from 0.3 to 9.7 ng/g and those fed experimental feeds ranged from trace to 22.2 ng/g. Sensory analysis showed that the flavour of most prawns was bland and lacked the characteristic ocean flavour of wild crustaceans. Possible reasons for the low retention of bromophenols in prawns fed pelleted feeds are discussed.