Individual rainbow trout can learn and anticipate multiple daily feeding times

Abstract

The present study was conducted to investigate whether individual rainbow trout Oncorhynchus mykiss can simultaneously anticipate two daily meals, and to evaluate the influence of time‐restricted feeding schedules and light‐dark (L:D) cycles on the timing of self‐feeding activity. Individual rainbow trout were capable of anticipating not only a single meal but also two daily meals scheduled at different times; the duration of anticipation was short and precise. This seems to be the first convincing evidence to show that a single fish can simultaneously anticipate two daily meals. Change in the onset and cessation of light did not affect the duration of food‐anticipatory activity, although it led to shift the phases of the light‐related self‐feeding activity. Moreover, under constant light and ad lib feeding conditions, only one band of rhythmic activity was observed in individual rainbow trout that had previously developed food‐anticipatory activity to each of the two daily meals.