Effect of Dietary Keto Acids on Intermediary Metabolism of Nutrients in Atlantic Salmon (Salmo salar) during 17-β-Estradiol-Induced Vitellogenin Synthesis

Abstract Presmolt Atlantic salmon (Salmo salar), 16–17 months old and weighing 65 ± 5 g, were fed either a control diet or a diet containing equal portions of pyruvate and α-ketoglutarate replacing 10% of the total feed dry weight. In a pilot experiment the keto acid diet had been fed to 5-month-old salmon during 5 weeks without adverse effects on growth and the body amino acid content. Nitrogen excretion was markedly diminished. In the major experiment the 16–17-month-old presmolt salmon were divided into four groups. After one week on the diets one control and one keto acid group were continuously exposed to 17-β-estradiol by implanting a capsule containing the hormone. After further 4 weeks the fish were killed. The vitellogenin concentration in the plasma was 50.5 ± 5.1 mg and 56.7 ± 5.2 mg/ml for the hormone treated fish fed the control and the keto acid diet, respectively. Liver glycogen content decreased during hormone treatment, but the fish fed on the keto acids were less affected. Upon exposure ...