A complete food does not require any mineral supplement. An excess in mineral salts has an adverse effect on good digestibility and may even produce effects contrary to expectations.
When a food is burnt the ashes produced are the minerals that were in the food, which generally represent 5-8% of a dry food.
The minerals that are present in high quantities (calcium, phosphorus, potassium, sodium, magnesium) are called macro elements. Those present in very low quantities –trace elements– represent a few mg/kg (or ppm), but they are essential to the functioning of the body (e.g. iron, zinc, manganese, copper, iodine, selenium).
Minerals are provided by the different ingredients in the ration.They may also be included in the form of purified salts: iron sulphate, zinc oxide, manganese oxide, copper sulphate,sodium selenite,calcium iodate, etc.
Each mineral is involved in several different functions.To keep things simple, we limit ourselves to some of the main roles the most important minerals play in the body.