Dynamics of appetite in three fish species (Gasterosteus aculeatus, Phoxinus phoxinus and Carassius auratus gibelio) after feed deprivation

The temporal dynamics of appetite (weight of food consumed per day) were an alysed for fish fed to satiation after a 1 or 2-week period of feed depriva tion. Three species were compared: two omnivores (minnow, Phoxinus phoxinus and gibel carp, Carassius auratus gibelio) and a carnivore (three-spined s tickleback, Gasterosteus aculeatus). All species showed compensatory change s in appetite and growth during the re-feeding period but in the sticklebac k, there was a lag of a week before the compensatory response was detected. The temporal dynamics of appetite differed between the three species but n ot within a species. Appetite of the minnow declined towards control levels from the onset of re-feeding. In gibel carp, appetite increased to a peak and then declined to control levels. In the stickleback, appetite was initi ally below control levels, increased to a maximum, then declined towards co ntrol levels. The differences between the species might have been artefacts of the experimental protocols used but could also reflect underlying diffe rences in the control of appetite in these species of fish.