Effect of dietary catechin and Spirulina on vitamin C metabolism in red sea bream [Pagrus major]

The zero‐year red sea bream Pagrus major were fed for 41 days on dry pellets containing 1% Teaflan (60% catechin) or Spirulina supplement. The effects of catechin and Spirulina on ascorbate absorption, lipid metabolism, and collagen synthesis were compared in relation to vitamin C nutrition. Total ascorbate concentrations in the serum and liver were increased significantly in the catechin‐fed groups relative to the control, but Spirulina increased in value only in liver. Feeding with catechin and Spirulina depressed non‐esterified fatty acid and total lipid in serum, respectively. Liver lipid was depressed by feeding catechin and Spirulina. Hepatic free carnitine and long‐chain acylcarnitine contents were markedly higher in both catechin‐ and Spirulina‐fed groups than in the controls. Hepatic carnitine palmitoyltransferase activity was markedly elevated in the Spirulina‐fed group. In contrast, glucose‐6‐phosphate dehydrogenase and fatty acid synthase activities were not different among the groups. The collagen fraction soluble at 20°C was lower and the insoluble collagen fraction (not soluble at 70°C) was higher in catechin‐ and Spirulina‐fed groups. These results suggest that dietary supplementation with catechin, as well as Spirulina, improved vitamin C metabolism in young red sea bream.