Effect of ethylcellulose coating of albendazolemedicated feed on the efficacy of acanthocephalosis treatment in naturally parasitized tambaqui (Colossoma macropomum)

Coating medicated fish feed with a polymer minimizes the chances of drug leaching into the water. Tambaqui (Colossoma macropomum) is an economically important Amazonian fish frequently parasitized by the acanthocephalan Neoechinorhynchus buttnerae. In this study, we compared the effect of ethylcellulose (EC 0.75%) coating of feed medicated with the antihelminthic albendazole (ABZ 10 mg kg bw-1) and uncoated feed on treatment efficacy and bioaccumulation of ABZ in naturally parasitized tambaqui during 35 days. Treatment efficacy was 34% and 66% in fish fed uncoated and coated feed, respectively, but did not vary significantly among treatments. Total ABZ residue reached concentrations from 122.0 to 151.7 ng g-1, and did not vary significantly among treatments. lhe biomagnification factor was low, ranging from 0.0003 to 0.0004. EC coating did not significantly affect the efficacy of ABZ treatment and did not interfere with ABZ bioaccumulation in the edible tissue of tambaqui.