Renal L-gulono-1,4-lactone oxidase activity as affected by dietary ascorbic acid in lake sturgeon (Acipenser fulvescens)

Régis Moreau, Konrad Dabrowski, Paul H. Sato

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Sturgeon can synthesize L-ascorbic acid (vitamin C) as they possess in their kidney L-gulono-1,4-lactone oxidase, the enzyme catalyzing the last step of AA biosynthesis. The effect of increasing dietary ascorbic acid on gulonolactone oxidase activity was studied in lake sturgeon. Two-year-old lake sturgeon (body weight 253 ± 89 g) were fed in triplicate groups with casein-based semipurified diets supplemented with either 0, 50, 250 or 1250 mg ascorbic acid/kg in the form of ascorbyl-2-monophosphate Mg for 38 days at 19.8°C. At the end of the trial, there were no significant differences in growth rate and survival among groups. Tissue total ascorbic acid concentrations increased significantly with dietary ascorbic acid. Renal gulonolactone oxidase activity was inconsistently affected by dietary treatment. These results suggested that, in sturgeon kidney unlike in the livers of ascorbic acid-synthesizing mammals, dietary ascorbic acid did not exert a negative feedback control on gulonolactone oxidase activity and thus on ascorbic acid synthesized. Using in vitro kinetics data we estimated a theoretical biosynthetic rate of ascorbic acid of 17 μmol (or 3 mg) per kilogram body weight per day at 15°C in juvenile lake sturgeon.

Original languageEnglish (US)
Pages (from-to)359-372
Number of pages14
JournalAquaculture
Volume180
Issue number3-4
DOIs
StatePublished - Nov 3 1999

Keywords

  • Ascorbic acid biosynthesis
  • Fish kidney
  • Gulonolactone oxidase
  • Sturgeon
  • Vitamin C requirement

ASJC Scopus subject areas

  • Aquatic Science

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