Field trials of investigational new animal drugs.

Field trials provide an opportunity to determine the efficacy and safety of drug treatments in a variety of environments and fish stocks that would not be possible or practical in laboratory settings. The steps for executing good field trials are discussed. The University of Idaho coordinates numerous field trials at over 100 hatcheries throughout the Pacific northwest as part of an intensive and extensive program to register erythromycin injectable and feed additive to control bacterial kidney disease in salmonids. A standardized toxicity test conducted at 52 hatcheries following the completion of administration of erythromycin feed additive provided a way to compare responses by fish at different times of the year, locations, and among different sizes of fish. Some of these fish were used in an assay to quantify the content of erythromycin in kidney tissue post treatment.