Utilization of dietary starch by juvenile white sea bream<i>Diplodus sargus</i>at different feeding frequencies

Abstract

To assess the effect of feeding frequency on the utilization of dietary starch by white sea bream juveniles, triplicate groups of fish were fed an experimental diet (400 g kg−1 protein, 140 g kg−1 lipids and 350 g kg−1 pregelatinized maize starch) to apparent visual satiation 2, 3 or 4 times a day for 63 days. Growth performance, feed utilization efficiency, glycaemia, cholesterolaemia, plasma triacylglycerides, liver lipids and glycogen content were unaffected by feeding frequency. α-Amylase activity increased from the pyloric caeca to the posterior intestine and was higher in fish fed twice a day than in fish fed 3 or 4 times a day. Hepatic glucokinase (GK) activity decreased with the increase in feeding frequencies, whereas fructose-1,6-bisphosphatase (FBPase) activity increased. Hepatic glucose-6-phosphate dehydrogenase and glutamate dehydrogenase activities were unaffected by feeding frequency. Overall, feeding frequency did not improve white sea bream dietary starch utilization. α-Amylase, GK and FBPase activities responded to dietary starch consumed at each meal, denoting a good metabolic adaptation of the fish to the feeding conditions.