Abstract
The effect of six different feeding times was tested on feed intake, growth performance, proximate body composition and nutrient retention in the rainbow trout Oncorhynchus mykiss . Using a non‐linear regression model, a significant rhythmic pattern over a 24 h period was observed for feed gain ratio and nutrient retention responses to feeding time. Specific growth rate and protein growth rate responses were also rhythmic but the trends were not significant. There was no clear effect of feeding time on feed intake and proximate body composition. The study suggested that feed intake, at least under the experimental conditions encountered, was synchronized to feeding time while some physiological rhythms involved in nutrient metabolism were probably synchronized to photoperiod.