|Vitamin A content of
vegetables and greens.
Vitamin A plays an important role in vision, bone growth, reproduction, cell division and differentiation.
Vitamin A also helps regulate the immune system, which helps prevent or fight off infections by making white blood cells that destroy harmful bacteria and viruses . This is the reason many vets wish to give vitamin A shots to tortoises with respiratory infections. However vitamin A injections are very toxic to tortoises (http://www.turtlerescues.com/vitamin_a.htm).Vitamin A promotes healthy surface linings of the eyes and the respiratory, urinary, and intestinal tracts . When those linings break down, it becomes easier for bacteria to enter the body and cause infection. Vitamin A also helps the skin and mucous membranes function as a barrier to bacteria and viruses .
Vitamin A comes in 2 main forms depending on the source. Vitamin A from animals is in the form of retinols. This is the most active form of the vitamin.
The other vitamin A source is provitamin A carotenoids found in fruits and vegetables. Provitamin A carotenoids is converted in the body to retinol. The most usable form of provitamin A carotenoids is beta-carotene.
Beta-Carotene is found in large quantities in carrots and sweet potatoes (not recommended for Russian tortoises) and gives them their orange coloration. However most greens and weeds also contain considerable amounts. It would be extremely rare for a tortoise fed the diet recommend on this site to suffer from vitamin A deficiency.
|Vegetable||Vitamin A IU/100mg|
|carrots (only feed occasionally)||16,706|
|green leaf lettuce||7,405|
|red leaf lettuce||7,492|
recommended for Russian tortoises, included for
|violets (American )||15,000|