Effect of Different Top-Coating Materials on Minimizing Drug Leaching From Medicated Feed in Shrimp Aquaculture

Drug leaching from medicated feeds into water reduces the available drug for absorption in the gut and causes negative effects in environments. The objectives of this study were to evaluate various top-coating materials in reducing the leaching of florfenicol (FF) from shrimp medicated feed and to determine the drug concentrations in the body of Pacific white shrimp (Litopenaeus vannamei) fed medicated feed top-coated with tuna oil, chitosan, pectin, hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose sodium (CMC), and ethylcellulose (EC). FF concentrations that leached from the medicated feeds into water were analyzed using the HPLC method. Drug concentrations in the hemolymph and muscle of shrimp following oral administration were also analyzed. The results revealed that chitosan was the most effective material in reducing drug leaching, with only 27.8% leaching rate at 120 min. Tuna oil had the highest leaching rate (71.6%). Shrimp fed chitosan-coated medicated feed had significantly higher FF levels in hemolymph (2.04 μg/mL) and muscle (0.92 μg/g) than the other coating material groups. The tuna oil group had the lowest drug levels (0.20 μg/mL and 0.34 μg/g, respectively). These findings indicate that chitosan is the most effective in minimizing drug leaching and also exhibits the highest drug absorption in shrimp.