Vitamins are necessary in small amounts for maintenance, growth, reproduction, and lactation. Vitamins A, D, E, and K are fat-soluble vitamins. They can be stored in the liver or in other organs. A reasonable daily intake is recommended, however.
Dehydrated alfalfa meal and fish meal are natural sources of vitamin K. Naturally occurring vitamin K is a mixture of derivatives of the chemical compound menadione. These derivatives can have rather different molecular weights, so many people express vitamin K activity in terms of the amount equivalent to menadione. TestDiet® products are supplemented by adding synthetic vitamin K as menadione dimethylpyrimidinol bisulfite and the reported value is in terms of the menadione equivalent.
The water-soluble vitamins, including the B-complex group and vitamin C, can be stored only in very limited quantities and, therefore, need to be a regular part of the daily diet. Monkeys, guinea pigs, and fish are three species of animals, besides human beings, that need regular doses of vitamin C.
In purified diets, some trace vitamins may be derived from some of the macronutrients (protein, carbohydrate, and fat). For the most part, however, each vitamin is obtained from a single source allowing very close control over total vitamin content. Because of trace amounts of vitamins from other ingredients, often it is quite difficult if not impossible for us to create a diet totally devoid of a specific vitamin. Even if the amounts of such vitamin may be below measurable levels, we would be reluctant to certify that it was absolutely free of that specific vitamin.
TestDiet® can customize the vitamin composition of any LabDiet® product. Diets can be formulated to omit a vitamin added to the standard diet or they can be reformulated to eliminate the ingredients that are naturally-occurring sources of the vitamin in question. Likewise, a diet can be formulated with additional quantities of any vitamin specified.