ABSTRACT
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 10.2 Vitamin C deficiency symptoms and established minimum
requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 10.2.1 Vitamin C sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 10.2.2 Changes in AA requirement in life cycle . . . . . . . . . . . . . . . 111
10.3 Micronutrient interactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 10.3.1 Interactions with vitamin E . . . . . . . . . . . . . . . . . . . . . . . . . . 112 10.3.2 Retinoids and carotenoids . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 10.3.3 Other vitamins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 10.3.4 AA interactions with minerals . . . . . . . . . . . . . . . . . . . . . . . . 118 10.3.5 Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 10.3.6 Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 10.3.7 Other minerals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
10.4 Perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Abstract Teleost fish lack the enzymes for endogenous ascorbic acid (AA) synthesis and therefore have a qualitative requirement for AA. The minimum dietary requirement for AA in most fish species has been estimated in the range of 10 to 60 mg kg1 dry diet when free AA was used. Below this level of supplementation the fish show dramatic deficiency symptoms such as reduced growth, vertebrae deformity, anemia, increased mortality, and reduced resistance to infections. Most ingredients used in feed for fish and crustaceans do not contain AA, due to type and pretreatment (heat) of the raw materials. Consequently, AA must be supplemented in the feeds to cover requirements for growth, health, and reproduction. By using mono-and polyphosphate derivatives of AA with high stability during processing and storage of feeds and high bioavailability, the requirement for AA has been determined to be around 20 mg kg1 in several fish, and between 40 and 210 mg kg1 in shrimp species.
