Chemical compounds known as vitamins are necessary in small amounts for maintenance, growth, reproduction and lactation. As components of certain enzymes, vitamins are essential to maintaining life processes. Vitamins A, D, E, and K are fat-soluble vitamins. They can be stored in the liver or in other organs to provide the needs of the animal. 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, the chemical species common to all vitamin K forms. LabDiet® products are supplemented by adding synthetic vitamin K as menadione dimethyl-pyrimidinol 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.
Niacin is one of the B vitamins and is added to LabDiet® products in the form of nicotinic acid. Natural ingredients can be a source of niacin, but much of the niacin from plant sources is bound and not biologically available. In previous editions of the Animal Diet Reference Guide, the reported value for niacin referred to "available niacin," whereas the chemical assay for niacin measures total niacin. Values for both available and total niacin are listed in the Chemical Composition section of the product fact sheets in this edition of the Animal Diet Reference Guide.