Diel feeding activity and the effect of time-restricted self-feeding on growth and feed conversion in European sea bass

The feeding rhythm and growth performance of European sea bass Dicentrarchus labrax (initial weight 65 g) were studied under free and time-restricted access to self-feeders, Under free access to the feeders, significant feeding rhythms with a nocturnal acrophase were observed, although there was considerable variability between replicates, When access to the self-feeders was restricted to two periods of 4 h day(-1), the feed demand (FD) was reduced at the beginning of the experiment but not at the end, indicating that the period of adaptation, rather than appetite, was affected by such feeding practice. When access to the self-feeders was restricted to only one period of 4 h day(-1), two thirds of the replicates eventually displayed FD similar to the fish having free access to feed, indicating that the restricted temporal access to feed could be compensated for. There was no detectable effect of feeding protocol on feed conversion or body composition, but growth was closely related to the total FD. Thus, growth was influenced by the fact that fish subjected to a time-restricted access to feed needed time to adapt to the new feeding situation, The results indicate that sea bass are capable of operating self-feeders, and can easily modify their feeding, resulting in both good growth performance and good feed conversion.