Rabbit Vitamin
Why is it important to use natural vitamins for rabbits?
Although feeding carrots to rabbits isn't necessarily bad, vitamin A toxicity is possible when using some commercial rabbit food brands. Recent research has shown that rabbits are unique in that they convert all carotenoids (like beta carotene) into active vitamin A. This is important because rabbit food labels cite the amount of added synthetic vitamin A not accounting for the natural carotenoids already present in the feed. This makes it possible to have toxic levels of vitamin A in rabbit foods that, because of cost, don’t pay attention to the quality of ingredients they use (vitamin A and any of its forms costs hundreds of dollars each to test for).
In fact healthy rabbits are able to produce 10 to 60 times their daily need for vitamin A from beta-carotene. Even with extra high concentrations of dietary beta carotene (40 to 100 mg/kg live weight; easily 100x daily requirements) no trace of beta carotene can be detected in the blood, liver, or the ovaries of the rabbit, meaning the rabbit is able to efficiently convert beta-carotene into vitamin A. However, beta-carotene is better for rabbits than synthetic vitamin A because it is suspected to have a protective function against excesses in vitamin A (although the exact mechanisms have yet to be demonstrated). Considering this, research shows that adding vitamin A to a balanced commercial diet is “ nutritional nonsense “ and that “ it may induce toxicity problems”. Rabbits can store large quantities of vitamin A in the liver. Signs of toxicity begin to occur when it becomes overloaded and starts to release excesses into the blood. That is why problems can occur seemingly "spontaneously."
In the rabbit vitamin A and vitamin D3 interact with each other functioning like hormones because they regulate gene expression (growth and development). These vitamins are stored in the body and in excess they become toxic. They have been shown to disrupt development and growth patterns leading to deformities as well as long-term reproductive problems in breeding rabbits. The ratio between these two vitamins for rabbits is just as important as the amount because imbalances will lead to the same issues. Once again, carelessly adding a standardized vitamin/mineral mix can easily create these toxicities in rabbits when the quality (and the amount of pro-vitamin A) of ingredients in cheaper feeds can vary widely.
Vitamin D
- Rabbits are very sensitive to the active form of vitamin D (D3). For a rabbit vitamin D3 in excess will cause developmental deformities with higher levels being lethal.
- It is best to allow rabbits access to natural day light because the UV rays stimulate the formation of the natural vitamin D3 precursor (vitamin D2) in the skin. However, properly formulated rabbit food (higher quality ingredients) will have ample amounts of natural vitamin D2 that the rabbit can convert on an as needed basis to the active form (vitamin D3).
Vitamin A
Although feeding carrots to rabbits isn't necessarily bad, vitamin A toxicity is possible when using some commercial rabbit food brands. Recent research has shown that rabbits are unique in that they convert all carotenoids (like beta carotene) into active vitamin A. This is important because rabbit food labels cite the amount of added synthetic vitamin A not accounting for the natural carotenoids already present in the feed. This makes it possible to have toxic levels of vitamin A in rabbit foods that, because of cost, don’t pay attention to the quality of ingredients they use (vitamin A and any of its forms costs hundreds of dollars each to test for).In fact healthy rabbits are able to produce 10 to 60 times their daily need for vitamin A from beta-carotene. Even with extra high concentrations of dietary beta carotene (40 to 100 mg/kg live weight; easily 100x daily requirements) no trace of beta carotene can be detected in the blood, liver, or the ovaries of the rabbit, meaning the rabbit is able to efficiently convert beta-carotene into vitamin A. However, beta-carotene is better for rabbits than synthetic vitamin A because it is suspected to have a protective function against excesses in vitamin A (although the exact mechanisms have yet to be demonstrated). Considering this, research shows that adding vitamin A to a balanced commercial diet is “ nutritional nonsense “ and that “ it may induce toxicity problems”. Rabbits can store large quantities of vitamin A in the liver. Signs of toxicity begin to occur when it becomes overloaded and starts to release excesses into the blood. That is why problems can occur seemingly "spontaneously."
In the rabbit vitamin A and vitamin D3 interact with each other functioning like hormones because they regulate gene expression (growth and development). These vitamins are stored in the body and in excess they become toxic. They have been shown to disrupt development and growth patterns leading to deformities as well as long-term reproductive problems in breeding rabbits. The ratio between these two vitamins for rabbits is just as important as the amount because imbalances will lead to the same issues. Once again, carelessly adding a standardized vitamin/mineral mix can easily create these toxicities in rabbits when the quality (and the amount of pro-vitamin A) of ingredients in cheaper feeds can vary widely.
Vitamin E
- The manufacture of the synthetic vitamin E commonly added to rabbit food leads to the production of various “chiral stereoisomers,” or different forms of vitamin E. It has also been called "mixed tocopherols" which are used instead of chemical preservatives. These other forms of vitamin E may not be as bio-available to the rabbit and their presence dilutes the effective dosage the feed may claim to have (as low as only 12.5%).
- Rabbit vitamin E dosage recommendations have increased many fold over the years. Initially minimum values were presented that prevent nutritional muscular dystrophy, reproduction problems, and other health issues. Current research now touts many of the added benefits attributed to increasing the dietary dosage of vitamin E.
- Many commercial rabbit foods that add refined oils (lacking in vitamin E) to increase the energy content without increasing the carbohydrate load on the rabbit digestive system will unknowingly create a vitamin E deficiency. This is because the ratio of vitamin E to the amount of fat in the diet is important. Research shows that adding expensive whole oil seeds that contain vitamin E and essential fatty acids to rabbit food has measurable impacts on the health of rabbits. However the food must be processed properly and needs to be fresh, not stored for excessive amounts of time (unless whole oil seeds are added because they are loaded with anti-oxidants).
Other vitamins such as the B-vitamins, and Vitamin K, Choline, and Vitamin C
- Many of the B-vitamins for rabbits and are produced by the microorganisms in the caecum and a well balanced rabbit food will ensure adequate production. By supplementing this natural production with certain B-vitamins rabbits have been shown to respond with increased growth rates and better feed conversion ratios.
- Most of these B-vitamins as well as vitamin K can be added through natural sources by carefully chosen ingredients.
- Choline is an important part of cell membranes. Without it the cells of tissues rupture and die. A diet that is low in choline causes cirrhosis of the liver and poor health. Choline is also used to build acetylcholine, which is an important neurotransmitter needed for memory and to stimulate the muscles.
- Healthy rabbits make adequate amounts of vitamin C.
