Sustained swimming enhances white muscle capillarisation and growth by hyperplasia in gilthead sea bream (Sparus aurata) fingerlings

Abstract Exercise training in fish leads to enhanced growth, mostly in salmonids, but also in gilthead sea bream ( Sparus aurata ). Most of the published studies have involved juveniles or adult fish, but little is known about the effects of exercise on early stages of fish growth. Our study aimed to examine the effect of sustained swimming on the growth of gilthead sea bream fingerlings, by analysing white muscle cellularity and capillarisation. Two groups of fingerlings were compared: the exercise group (EX), forced to swim at five body lengths·s −1 , and the control group (CT), maintained under still water flow and showing only voluntary swimming. After 5 weeks the EX group had a significantly higher body weight (CT: 17.5 ± 0.46; EX: 20.3 ± 0.38 g, p p p 2 ) was significantly ( p p p