Vitamin A supplements are very common in all animal foods. Most times it is added to the cat food or dog food outside of its existing content. As an example many of the high end food such as Innova Evo and Fromm’s Surf & Turf are expensive animal food and already contain Vitamin A in its ingredients but synthetic vitamins are added in the end to balance the food even more.
Effects: Its important for vision, appetite and for the maintenance of the skin and coat. The natural beta carotene (which the body converts to vitamin A based on its needs) has a well known antioxidant activity. Note that the synthetic form is identified only as “beta-carotene”.
Deficiency: What you will notice in animals are signs include decreased vision, skin lesions, and abnormal bone growth.
Toxicity: Signs include abnormal bone remodeling, lameness, and death.
Stability: Beta carotene (originates exclusively from plant sources but is readily converted by the dog’s metabolism) is one of the most stable and active vitamins in foods. The compound is sensitive to heat but significant losses only occur after long periods of boiling. Animal food sources contain active vitamin A.
Sources: Liver, fish liver oil, carrots, green leafy vegetables, egg yolks, yellow fruits. The more intense the color of a fruit or vegetable, the higher the beta-carotene content.