Food deprivation and refeeding in Atlantic salmon,Salmo salar: effects on brain and liver carbohydrate and ketone bodies metabolism.

The capacity of carbohydrate and ketone bodies metabolism in brain and liver was evaluated in fed and food-deprived Atlantic salmon (Salmo salar) in a time period covering from 1 to 7 days (Experiment I), and in Atlantic salmon food deprived for 6 weeks, and food deprived for 4 weeks and refed for 2 weeks (Experiment II). The results obtained demonstrate for the first time in a teleost the existence of changes in brain metabolism due to food deprivation. Thus, decreased glucose levels in plasma are reflected in the brain by an increased mobilization of glycogen reserves, and by a decreased glycolytic capacity. Also, ketone bodies appear to increase their importance as a metabolic fuel from day 7 of food deprivation onwards. A possible increase in the gluconeogenic potential in brain simultaneously is not discarded. All these metabolic changes are reversed under refeeding conditions.