Influence of light on feeding anticipatory activity in goldfish

Most animals when presented with food on a periodic basis develop feeding a nticipatory activity (FAA). The objective of the present study was to inves tigate the synchronization of activity rhythms to light and feeding in sing le goldfish given a single daily meal and exposed to different light regime s. In the Ist experiment, the group of fish fed at the end of the day showe d a longer FAA (228 +/- 27 min) than the group fed 1 h after lights-on (97 +/- 31 min). In the 2nd experiment, goldfish under conflicting zeitgebers, LD (T = 26) and feeding (T = 24) cycles, initially synchronized to the ligh t cycle although feeding time gradually assumed greater importance as the e xperiment progressed. In the 3rd experiment, after altering the feeding cyc les by advancing or delaying feeding time by 4 h in LD 0.25:23.75, most gol dfish resynchronized to the feeding stimulus and developed FAA. In conclusi on, the authors' results revealed that FAA in goldfish is driven by an endo genous timing system that is entrainable by periodic feeding and influenced by the light regime.