Trace minerals – zinc, copper, manganese, selenium, cobalt, iron, iodine etc. – are essential nutrients for all animals. They have a wide range of activities and functions within the body, being involved individually or collectively in general metabolism, reproduction, the immune system, growth, development and repair of various tissues and so on.
But, as the name suggests, trace minerals are required in very small amounts in the diet and their uptake from the digestive tract can be impaired by other dietary components or the presence of ‘antagonists’. For example, the availability of copper for absorption is heavily influenced by molybdenum, sulphur and iron.
Natural feedstuffs such as corn, wheat, soybean meal, etc. contain essential trace elements, which are required by animals. However, these trace elements are often in a form which renders them unavailable to the animal. Also, even if the elements were totally available, in many cases, they would not be in adequate concentrations to meet the animal’s requirement.
Therefore, when deficiencies of one or more of the trace mineral elements exist in a diet, they are usually provided to the animal in an inorganic or organic supplemental form. It is advantageous for nutritionists to know the bioavailability of any element in the natural feed ingredient or mineral source used as a dietary supplement. With this knowledge the proper amount of the trace element can be supplied to the animal.