Nutrient digestibilities, weight gain and plasma and liver levels of carbohydrate in Atlantic salmon (Salmo salar, L.) fed diets containing oats and maize

The aim of the study was evaluation of whole oat meal as an ingredient in salmon diets. Atlantic salmon (145 g) were fed diets with 0, 100, 150, 200, 250 or 300 g kg(1) of oats (oat series), or diets containing 300 g kg(-1) of mixes of oats and maize (oat maize series). The mixes of oat/maize were 0/300, 60/240, 120/180, 180/120, 240/60 and 300/0 g kg(-1). Net pens in sea water were used. The growth trial lasted 72 days and was followed by a digestibility trial. Oat starch, which had not been subjected to any form of heat treatment, was found to be well digested at low dietary incorporation levels. In the oat series, starch digestibility decreased with increasing starch level and lipid digestibility improved, whereas no changes were observed in protein digestibilities. The fish absorbed significantly more starch from the diet with oat/maize mix 180/120 g kg(-1) than from the diet with only oats or maize. A significant growth reduction was observed in the oat series as oat inclusion increased. Absorbed starch (calculated value) was not significantly correlated to plasma glucose or insulin level, but was found to be positively correlated to liver glycogen in the maize oat series.