Vitamin E is the most commonly used antioxidant, essentially acting as the body's own preservative. It is not a vitamin whose benefits should be visibly apparent in a dog, but…
Vitamin B12 is obtained only from a meat-based diet. A dog may not necessarily need it every day, but vitamin B12 is practically always obtained.
Cobalamin is the most complex vitamin and the only one that dogs can obtain solely from meat products. Every plant-based form of vitamin B12 is an antagonist of cobalamin, meaning it acts as an inhibitor or counteragent. These are also known as pseudo-vitamin B12.
Vitamin Bs are a loosely related group of vitamins with similar functions. Chemically, they have nothing in common except being water-soluble. They all participate in the body’s enzyme functions as coenzymes, essential precursors for enzymes. B vitamins are especially involved in energy production because, without B vitamins, the metabolism of fats, carbohydrates, and proteins suffers, particularly in energy metabolism. B vitamins are also involved in the functioning of the nervous system.
Vitamins are organic compounds that must be obtained from food and are not used for any specific purpose. Therefore, fats or proteins are not considered vitamins. Vitamins have been misidentified in the past and have since lost their “vitamin status.” This is why there are gaps in the numbering of B vitamins. Some compounds have also been intentionally misnamed as vitamins.
Vitamin A, or retinol, is a collective term for naturally occurring retinoids and those carotenoids that have retinol activity, such as beta-carotene. Retinol, the pure form of vitamin A, is only found in animal products, especially liver and eggs. In vegetables, vitamin A only appears in its precursors, usually as beta-carotene. Breast milk contains a lot of vitamin A and is the most important source for a puppy. This should be considered for bottle-fed puppies.