Effect of feeding method and protein source on Sparus aurata feeding patterns

The influence of dietary protein source (fishmeal, soy-protein concentrate and soy-protein concentrate supplemented with methionine) on voluntary feed intake, daily feeding rhythm and nutritive utilisation of diet was studied in the gilthead sea bream (Sparus aurata) fed by hand or demand feeding. Fish weighing 21 g were maintained indoors under natural conditions of temperature and photoperiod (transparent ceiling) and allowed ad libitum or self-feeding of experimental diets for 26 days, with three replicates per treatment. In the first experiment, the influence of hand or demand feeding on growth rate and feed utilisation of a fishmeal-based control diet was studied. In a second trial, involving different protein sources, fish were maintained under the experimental conditions for 6 days after 20 days training. The general composition of the experimental diets was: 45% protein, 14% lipids and 20% carbohydrates. Results showed that: (1) gilthead sea bream preferentially feed in the afternoon and evening; (2) demand feeding improved both food conversion and protein efficiency; (3) the protein source appeared to induce changes in the timing of feeding; and (4) supplements of methionine advanced the time of feeding and lengthened ingestion phases. D 2003 Elsevier Science B.V. All rights reserved.