Growth in Arctic charr and rainbow trout fed temporally concentrated or spaced daily meals

The effect on growth of distributing feed over a few hours compared to more frequent meals was tested on 1+ Arctic charr (Salvelinus alpinus L.) and 1+ rainbow trout (Oncorhynchus mykiss Walbaum). Triplicate hatchery groups for each treatment were fed at a ration level of 1%/day either with few meals (8 times per day divided into morning and evening) or with frequent meals (32 meals equally distributed during the day). We found an opposite effect of meal frequency on growth in the two species. Low feeding intensity (8 meals per day) had a significantly positive effect on growth in rainbow trout but a significantly negative effect on growth in Arctic charr when compared to feeding the fish frequent meals. The opposite response to meal frequency is likely to be an effect of the differences in activity during feeding. Rainbow trout feed much more aggressively than charr which can result in feeding being a more stressful event. In this experiment, the specific growth rate was lower and the feed conversion ratio higher for Arctic charr compared to rainbow trout.