ABSTRACT
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 8.2 Vitamin C deficiency symptom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 8.3 L-ascorbic acid requirement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 8.4 Instability of L-ascorbic acid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 8.5 Ascorbic acid derivatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
8.5.1 C2MP-Mg vs. C2S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 8.5.2 C2PP vs. C2S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 8.5.3 C2MP-Na vs. C2MP-Mg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
8.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Abstract Vitamin C is an essential nutrient for crustaceans. Traditionally, L-ascorbic acid (AA) was the only source of vitamin C used in shrimp feed. A dietary requirement of vitamin C (in the form of AA) has been quantified for several penaeid species. However, AA is unstable, and practical diets have been shown to lose AA during processing and storage. AA derivatives with sulfate and phosphate moieties at carbon C-2 position in the lactone ring of AA have been shown to be stable and effective in satisfying the requirement of penaeid
shrimp. Several derivatives, namely L-ascorbyl-2-sulfate (C2S), L-ascorbyl-2monophosphate-Mg (C2MP-Mg), L-ascorbyl-2-monophosphate-Na (C2MPNa) and L-ascrobyl-2-polyphosphate (C2PP), have been used to quantify the vitamin C requirements for penaeid shrimps. The requirement of these derivatives as vitamin C sources for penaeid shrimp was more markedly reduced than the value estimated earlier with AA. Caution needs to be taken, however, when comparing the requirements of each of these ascorbate derivatives from the published data.
