ABSTRACT
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.1 Introduction This chapter will concentrate on the distribution of L-ascorbic acid (AA, vitamin C) biosynthesis capacity in vertebrates with an emphasis on fishes. Since a decade ago, research work in fish biology has shed a new light but also brought some controversy on the ability to synthesize AA in the animal kingdom, and the origin and phylogeny of AA. These new data have initiated this review in which earlier and present states of knowledge are presented. The methods frequently employed to measure L-gulono-1,4-lactone oxidase (GLO, EC 1.1.3.8) activity will be critically reviewed. Further research into the mechanism of AA biosynthesis in fish has been initiated and will be compared to the mammalian model. Studying the regulation of AA biosynthesis in fish will have implications in fish nutrition and aquaculture, possibly in determining the vitamin C requirement associated with specific physiological conditions, including reproduction, immune challenge, and stress.
