Drug Research Information Bulletin - Efficacy of SLICE® Premix (0.2% emamectin benzoate) to Control Infestations of Salmincola spp. on Freshwater-reared Rainbow Trout

SLICE® (0.2% emamectin benzoate; EB) is approved for the control of sea lice (a parasitic marine copepod) in salmonids in the United Kingdom, Europe, Norway, Chile, and Canada. When SLICE® is fed to fish, EB is absorbed from the gut and distributed to a variety of tissues. When sea lice feed on the host fish, EB is taken into the tissues of the parasite, binds to ion channels of nerve cells and disrupts transmission of nerve impulses, resulting in paralysis and death. In addition, EB is metabolized and excreted slowly by the fish resulting in an extended period—up to 9 weeks—of protection from sea lice (Stone et al. 2000a). It has been reported that SLICE® may be similarly effective for the treatment of freshwater copepods. As such, we conducted a trial to evaluate the effectiveness of SLICE®-medicated feed to control infestations of S. californiensis on freshwater-reared rainbow trout O. mykiss.