Title Studies on the Distribution and Physiological Function of Vitamin K in Fish
Authers Miho Udagawa
Keywords phylloquinone, menaquinone, tissue distribution, vitamin K deficiency
Citation Bull. Fish. Res. Agen. supplement No. 18,1-40, 2006
Basic information on the distribution and role of vitamin K in fish was studied in relation to dietary intake.
Chapter 1 describes the concentrations of phylloquinone (PK) and menaquinones (MKs) in various tissues of wild and cultured fishes as the results of analysis based on the HPLC method. The major vitamin K in wild pelagic fish was PK, and the stomach and intestinal contents of pelagic fish showed much higher levels of PK than MK-4. Demersal fish contained relatively large amounts of MK-4 and PK but only small amounts of long chained MKs. In demersal fish, the contents of the gastrointestinal tracts were rich in MK-long chains. However, a discrepancy between the composition pattern of vitamin K in the tissues and contents of the gastrointestinal tract was observed. Cultured fish fed a menadione (MD) supplemented feed were rich in MK-4, which indicates that MD was converted to MK-4 in the body. From these results, it was concluded that either PK or MK-4 deposited in the body originates from their food and stored mainly in the liver, and the different forms of vitamin K are absorbed and/or accumulated in the tissues based on different physiological pathways.
In Chapter 2, the contents of vitamin K in the plasma and tissues (kidney, liver and gonad) of fish fed diets supplemented with different vitamin K groups were determined. The PK rich diet raised the PK concentration in the plasma and the tissues much higher than the diets supplemented with short and/or long chain MKs. This indicates that PK is more easily accumulated into the body of fish than the MK homologues.
Chapter 3 describes the effect of different dosages of vitamin K, either as PK or menadione sodium bisulfite (MSB), on mortality and vertebral formation. Rearing during the spawning season with a vitamin K free diet for 11 weeks, led to most of the male fish dying. In the kidney tissue of the fish fed with a vitamin K free diet, a large number of immature erythrocytes was observed. This indicates that the female fish had been affected by hematoporia and/or hematopoiesis brought about by a deficiency in vitamin K. Diets without vitamin K caused a significantly higher incidence of bone deformity in larvae than diets supplemented with vitamin K. The maternal effect of PK deficiency on bone structures was examined in the larvae. The vitamin K deficient larvae had an abnormal vertebral formation, while PK rich larvae showed a low rate of abnormality. When fed the vitamin K deficient diet, larvae which had been fed the vitamin K rich and deficient diets had a both high rate of abnormality after 30 days, with only larvae which wrere hatched from vitamin K rich eggs and then fed on a vitamin K rich diet showed a low rate of abnormality. These results indicate that vitamin K deficiency affects bone structure both in early development and during growth.
In Chapter 4, the effect of PK on the bone structure in fish was observed histochemically. The bone structure of vitamin K deficiency larvae was thin and rough after the feeding experiment for 30 days. It seemed to be connected after fine fracture of a bone surface. In contrast, in larvae fed a PK rich diet this phenomenon was not observed. These results imply that vitamin K deficiency induced bone abnormality with thin and weak structure. A vitamin K rich diet increased the osteoblast-like cells. These results imply that PK is necessary to activate the osteoblasts. It is indicated that at least part of the effects of PK on bone resorption may regulate the osteoblasts activity through an unidentified mechanism.
In Chapter 5, a comprehensive discussion is given of the all results and conclusions so far described.
URI http://www.fra.affrc.go.jp/bulletin/bull/bull18/udagawa.pdf