| Popis: |
The absorption of food iron can be greatly influenced by other constituents in the diet such as ascorbic acid (Vitamin C) and phenolics. Ascorbic acid increases the bioavailability of iron by converting Fe3+ to Fe2+, while phenolics can reduce the bioavailability of iron by binding to it. Phenolics (e.g., tannins), however, are often not included in diets of captive animals because they 1) can act as digestibility reducers by binding to dietary protein, and 2) require the feeding of fresh leaf material which can be hard to obtain on a regular basis. Conversely, ascorbic acid levels can be excessive from fresh fruit (e.g., oranges) and green vegetables that are often fed. Captive folivorous and frugivorous animals, in particular, can be affected by excessive uptake of dietary iron leading to clinical/pathological iron storage disease; excess ascorbic acid and/or a lack of dietary tannins have both been suggested as contributing to the incidence of these health conditions. Experiments reported here... |
