A gelatin-based feed for precise and non-invasive drug delivery to adult zebrafish.

Although the use of adult zebrafish as a model organism has increased in recent years, there is room to refine methods, like drug delivery, to make them less invasive and more precise. Here, we describe the development of a non-invasive gelatin-based feed method that is tailored to animals based on their weight. The feed was readily eaten by zebrafish (< 1 minute) with minimal leaching of compound when placed in water (< 5% in 5 minutes). As a proof-of-principle, we fed fish a NMDAR antagonist (MK-801, 4 mg/kg) prior to the novel tank test. We found that MK-801 caused a general decrease in predator-avoidance/anxiety-like behavior (bottom dwelling) and an increase in locomotion in male fish, but not females. Our simple, easy to prepare, and individually tailored gelatin-based feed enables precisely dosed, non-invasive drug delivery to adult stage zebrafish for the first time.