Effect of protein level in purified diet and of density, ammonia and O 2 level on growth of juvenile European eels ( Anguilla anguilla L.)

Abstract

The influence of protein level in a purified diet and of density on the growth of Anguilla anguilla in indoor and outdoor containers was examined. The average weight increase of eels that were fed on a diet of pellets containing 35%, 45%, or 55% protein was significantly higher than the mean weight increase of eels fed on pellets containing 25% protein. The production per m 3 was higher in the groups fed 45% or 55% protein level in the diet than in the groups fed 25% or 35% protein. Dissolved oxygen in the water of the growing tanks was 7–9 ppm in all groups. Ammonia production was lower in the group fed on pellets containing 25% protein and higher in the groups receiving higher protein diets. Eel growth at low density (4 kg/m 3) was almost the same as at high density (30 kg/m 3) for both slowly growing and moderately growing eels. Production was higher in the groups stocked at high density and lower in those stocked at low densities. The production of slowly growing eels was lower than that of moderately growing eels.