Tissue and organ distribution of C-14-activity in dextrin-adapted Atlantic salmon after oral administration of radiolabelled C-14(1)-glucose

Summary

Accumulation of C-14 in various tissues and organs was studied in three different groups of 0.8-kg Atlantic salmon Salmo salar force-fed with C-14(1)-glucose in order to evaluate if metabolism of glucose depended on adaptation to dietary carbohydrate level. The salmon had been fed diets supplemented with 0, 100 and 200 g maize dextrin kg(-1) for 10 months before the experiment. The fish were force-fed 6.65 x 10(4) Bq of C-14(1) glucose kg(-1) BW, in gelatin capsules. Fish for analysis were obtained 16 h later. C-14 was measured in blood plasma, gill, kidney, liver and white muscle, and in lipid extract of liver. The liver contained most C-14, followed by heart, blood plasma, gill and liver lipid extract, while kidney and muscle contained the least C-14 per gram or millilitre tissue. The muscle contained most radioactivity, on an estimated total tissue basis, followed by liver, blood plasma, gill, liver lipid extract, kidney and heart tissue. Thirty-eight per cent of the orally administered C-14 was recovered in the salmon adapted to the diet without dextrin after 16 h. This was significantly (P < 0.05) higher than the 30% and 32% recovered in the salmon adapted to diets with 10% and 20% dextrin. This effect on adaptation to dietary dextrin level in glucose uptake or metabolism was supported by a trend (P < 0.10) toward higher radioactivity per gram or millilitre of each individual tissue in the fish adapted to the diet without dextrin, when compared with the other two adaptation regimes.