When hydrolysed and novel protein diets may not be hypoallergenic

Diagnosing food allergies

When it comes to adverse food reactions with dermatological or gastrointestinal manifestation in pets, the elimination and provocation protocol is the gold standard in diagnosis. Hydrolysed and novel protein diets are often used in both the diagnosis and treatment, but are not necessarily a straightforward choice. Certain considerations are worth highlighting.

Do we need to avoid grains?

The novel protein diet would ideally contain a limited number of allergen-containing ingredients that are simultaneously novel. That means excluding commonly used protein sources such as poultry and beef, and replacing them with horse, veal, or rabbit protein.

An additional step most manufacturers make is to replace commonly used carbohydrate sources such as rice and corn with potato and legumes starch. But, as rice and corn allergy are rarely seen in pets, this is not always necessary. Especially when it is at the cost of digestibility of the diet.

What about gluten?

A considerable number of commercial dog foods also make a gluten-free claim to help the dog owner make a safe choice. Gluten is a protein found in grains like wheat, barley, rye, oats and other related plants. Allergy to gluten has been identified in certain dog breeds like the Irish Setter and Border Terrier, but its prevalence in the general pet population is low. Keep in mind also that gluten-free does not always have to be grain-free. Both corn and rice are grains as well, but their gluten are not in the same category as other gluten-containing grains.

Hydrolysation pitfalls

Hydrolysed diets use a hydrolysed form of the protein that could be a potential allergen. Hydrolysation breaks down the protein into small molecules undetectable to the immune system. While convenient, even hydrolysed diets may contain hidden allergens further down the ingredients list, however. These could include protein particles in animal fat of unknown origin, protein cleated trace minerals or incompletely hydrolysed proteins.

Cross-contamination risks

As most manufacturers use the same manufacturing facility or even the same production line for all extruded diets, cross-contamination tends to be a challenge. Moreover, feed materials arriving from different suppliers should also all apply the same rule of purity, ideally checked using the identification of species-specific allergens by PCR analysis. This is a demanding good practice procedure and requires vigilance and impeccable quality control. The integration of cross-contamination risk assessment management into production processes at different levels is therefore essential.