WHERE DOES A DEFICIENCY COME FROM?
A nutritional deficiency occurs when the food does not contain enough of an indispensable nutrient. Now that most petfood manufacturers apply AAFCO* recommandations, this kind of absolute deficiency is now unlikely, except of course in home-made diets.
But there are other situations where secondary deficiencies can occur.
Presence of anti-nutritional factors
There are food that contain substances that can inhibit the absorption of a nutrient. These anti-nutritional factors are well-known, and the induced disorders are now observed only exceptionnally. Ex:
origin of the problem consequences anti-nutritional factor
Raw white-egg representing more than 20 % of the diet biotine deficiency avidine
consumption of raw fish vitamin B1 deficiency thiaminase
consumption of raw soya maldigestion of proteins antitrypsin
long-term antibiotic treatment biotine, folic acid (…) deficiencies disturbed intestinal flora
Alteration of the food
When fat preservation is not done properly, fatty acids are submitted to peroxidation, inducing essential fatty acids and liposoluble vitamins deficiencies.
Complexation between different elements
An excess of calcium can prevent from normal absorption of iron, zinc, copper, iodine (…). Using chelated trace-elements prevents from this complexation risk.
Too low digestibility of the food
Here, this is the example of the “ Generic Dogfood Disease ” that emerged in the USA during the eighties. In dogs fed with economical dryfood, some facial cutaneous lesions were regularly observed. These lesions responded favorably to zinc administration. However, these dryfood did respect the NRC** 85 recommandation.
The problem was issued from the fact that these food were basically formulated with the association corn + soya, that provided a lot of vegetable fibers, calcium and phytates. All these elements had a depressive effect on digestibility, and prevented from a right zinc absorption.
Since, NRC 85 recommandations have been judged too strict (they were obtained by using hyperdigestible purified ingredients). They have been re-evaluated by AAFCO, in order to provide more reliable guidelines to petfood manufacturers. But animal tests (AAFCO protocoles or tests with breeders), are the only means that can really guarantee the right adequation between a food and its indication.
The consumption of an acidified food makes the elimination of potassium increase. So, a lack of potassium in an acidified diet can induce a potassium secondary deficiency.
Individual or racial problem
Some dogs from nordic breeds are known to be able to develop a zinc deficiency, whereas other breeds perform perfectly well with the same zinc intake.
Because of the ageing process, some enzymes become less efficient. Ex: the transformation of linoleic acid into gamma-linolenic acid is altered in older animals, especially in case of hepatic disorders, diabetes or hypothyroidism. This is why borage oil is interesting: it provides what should be synthetized by the body.
Any disease that leads to an alteration of digestive absorption induces secondary deficiencies. Ex:
- chronic intestinal parasitism: the dog loses weight, its hair becomes dull
- chronic pancreatic deficiency: altered fat digestion is also responsible for weight loss, but also for an essential fatty acids deficiency that has got some negative consequences on the hair aspect.
When one observes disorders that can be linked to a lack of such or such nutrient, it is necessary to search for information about how the animal lives, what complements it gets, pathological predispositions related to the breed, and its general health status.
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