Feeding Frequency Differently Affects Post Prandial Patterns of Plasma Glucose, Insulin and Insulin-like Growth Factor I in European Sea Bass (Dicentrarchus labrax)

The aim of this study was to investigate the effects of feeding frequency on post-prandial pattern of circulating glucose, insulin and IGF-I (insulin-like growth factor-I) in European sea bass (D. labrax). Fish (average body weight 72.1 +/- 2 g) were randomly allocated in 12 tanks, reared in a closed thermo regulated recirculating system and fed a commercial diet at a fixed ration (1.5% body weight) for 7 weeks. Six fish groups were fed the ration in one meal a day (08:(30) am), while six fish groups were offered the same ration in two daily meals (08:(30) am and 04:(30) pm) according to a complete random design. Plasma insulin mean level was affected by the splitting up of the ration (14.4 vs 15.2 ng/ml, P<0.05, one meal and two meals/day, respectively) and showed a bimodal profile depending on the meal administration. The level of circulating glucose was slightly affected by feeding pattern with an increase of glycaemia after each meal. The daily pattern of plasma IGF-I did not appear related to meal administration. Results show that post prandial plasma glucose, insulin and IGF-I are differently affected by the meal administration pattern in sea bass due to their physiological role in maintaining the internal homeostasis.