moxidectin and Fish-Diseases

Technical grade milbemycin (A3-A4 oxime) was formulated in propylene glycol to produce a stock concentration of 5.0 mg/ml. Groups of six pond-reared freshwater angelfish (Pterophyllum scalare) randomly housed in 32-L aquaria were exposed to milbemycin by prolonged bath at 63, 125, and 188 PPB or by its incorporation into their gelatinized food at 2.5 mg or 5.0 mg/100 g food, which they were fed ad lib. for 1 day. Control fish were exposed to a prolonged bath (24 hr without charcoal filtration) of 0.8 ml propylene glycol/32 L water, were given gelatinized food incorporating 1 ml propylene glycol/100 g food ad lib. for 1 day, or were untreated (no propylene glycol exposure). All fish treated at 188 PPB and the smallest individuals from the 63- and 125-PPB aquaria died. Other fish at 125 PPB exhibited transient lethargy and increased opercular movement but recovered within 24 hr. No deleterious effects were noted in the fish given milbemycin orally. Pretreatment parasitic nematode infection rate, evaluated by gut dissection of 16 randomly selected fish, was 68.75%. Identification of nematodes to species was not performed. No significant differences in infection rates between treated and untreated groups were detected.

Topics: Administration, Oral; Animals; Anthelmintics; Anti-Bacterial Agents; Fish Diseases; Fishes; Macrolides