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Hydroxy trace minerals


By Pauline Paap, Orffa Additives

Commercial diets are generally well balanced and meet the dietary requirements for trace elements. Still, optimisation of the diets remains useful to consider. Great differences exist between trace mineral sources in terms of food stability and availability for the animal. Each source has a distinct influence on stability of sensitive food ingredients (like vitamins and fats). Moreover, differences in bioavailability of the trace elements, as well as the availability of feed ingredients which interacts with trace minerals are of importance for animal health. With the development of new stable forms of trace mineral sources, nutritional solutions can be provided on premix, food and animal level.

Bioavailability and antagonism of trace elements Adequate levels of trace minerals in the diet will not always secure the optimal trace element supply to the animal. Bioavailability depends on a number of factors such as health condition, trace element status in the body, pregnancy stage, dietary trace element concentration and antagonists in the diet which inhibit absorption. In addition, the trace element uptake capacity of the intestine decreases with increasing age of the animals in general. Between animal species it is known that the bioavailability of trace elements is difficult to compare due to differences in anatomy of the digestive tract (Flachowsky, 2000). Deficiencies in trace element status also exist in pet animals and

Figure 1: Symptoms of zinc deficiency; two-year-old male Siberian Husky with zinc responsive dermatosis (Reprinted from White et al., 2001).


can be caused by different reasons. A number of reports describe natural zinc-deficiency in dogs, where the deficiency most commonly occurs as a detrimental skin condition which is called ‘Zinc-responsive dermatosis’ (White et al., 2001; figure 1). Two forms of zinc-responsive dermatosis are described in literature. Especially the northern-breed dogs (Siberian husky, Alaskan Malamute, Samoyed) are known to have a genetic defect resulting in reduced zinc absorption from the intestines. Affected dogs usually require additional zinc supplementation for life. The second form of zinc-responsive dermatosis which mainly occur in growing puppies, independent of breed, is a form of zinc deficiency related to the fed diet. Mainly cereal based diets or diets containing high levels of substances that bind zinc (like phytate and fibre) decrease the availability of zinc. Excessive amounts of dietary calcium in the diet or calcium supplemented by dog owners are well known to reduce zinc absorption since calcium and zinc together form insoluble complexes in the digestive tract (Lowe et al., 1994; Costa-Val et al., 2010). Additional supplementation of calcium by dog owners are seen in practice especially in large and giant breeds like Great Dane, German Shepherd, Labradors, Standard Poodles and Dobermans (Vitale, 2004). Direct improvement in the health status of the dogs suffering from the latest form of zinc-responsive dermatitis are seen after additional zinc supplementation, diets with reduced zinc-antagonistic components or a change to a diet with a higher bioavailable zinc source (White et al., 2001). From studies in all kind of animal species it is well known that

the copper bioavailability is influenced by other dietary components. Hendriks et al. (2001) suggested a zinc-induced copper deficiency in

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