Dietary carbohydrate utilization in cod ( Gadus morhua). Hormonal response of insulin, glucagon and glucagon-like-peptide to diet and starvation

1. 1. Two groups of 60 cod each were fed for 8 weeks, followed by 3 weeks of starvation. The diets were equal in protein energy, while in one of the feeds 40% of the lipid energy was substituted by carbohydrate. 2. 2. Both groups showed the same weight increase. Feed consumption and feed conversion were, however, highest in the carbohydrate group reflecting equal intakes of protein energy. 3. 3. Plasma glucose, lactate, insulin and glucagon were substantially higher in fish fed dietary carbohydrate. Plasma values were significantly reduced after 3 weeks of starvation (glucagon was significantly reduced after 1 week). 4. 4. Liver glyeogen content was highest in the carbohydrate group after feeding. After starvation the liver glycogen content was equal in both groups.