Daily feeding and protein metabolism rhythms in Senegalese sole post-larvae

Abstract

Fish hatcheries must adapt larval feeding protocols to the feeding behavior and metabolism pattern to obtain a more efficient feeds utilization. Fish larvae exhibit daily ingesting rhythms rather than ingesting food continuously throughout the day. The aim of this study was to determine the daily patterns of feed intake, protein digestibility, protein retention and catabolism in Senegalese sole post-larvae (Solea senegalensis; 33 days post-hatching) using 14C-labelled Artemia protein and incubation in metabolic chambers. Sole post-larvae fed at 09:00, 21:00, 03:00 and 09:00+1 day showed significantly higher feed intake than post-larvae fed at 15:00h (p=0.000). Digestibility and evacuation rate of ingested protein did not change during the whole cycle (p=0.114). However, post-larvae fed at 21:00 and 03:00h showed the significantly highest protein retention efficiency and lowest catabolism (p=0.002). Therefore, results confirm the existence of daily rhythmicity in feeding activity and in the utilization of the ingested nutrients in Senegalese sole post-larvae.