Cellulose, a mandatory mention on the label
The percentage of crude cellulose is one of the mandatory information that must appear on the labels of pet food such as kibble or dog food. It is more precisely the European regulation n° 767/2009 which imposes it by fixing the analytical constituents to be registered on each label. Thus, we find the percentage of crude cellulose alongside those of crude protein, crude fat, crude ash and moisture (for foods whose water content exceeds 14%).Consult for example the products offered on the Maxizoo online store and you will see that all the labels mention the same information.
This forensic pet food analysis is based on Weende's method of acid hydrolysis followed by base hydrolysis. This method of analysis is recommended by AFNOR.
What is cellulose?
Cellulose is the main constituent of plant cell walls. Biochemically, it consists of a long chain of interconnected glucose molecules.
In kibble or dog food, cellulose is therefore provided by all ingredients of plant origin such as cereals, legumes as well as fruits and vegetables.
Crude fiber=fibre?
We often tend to equate crude cellulose with the fibers found in dog food.In reality, if cellulose is indeed part of the fiber family, it does not represent all the fibers present in its ration. Crude cellulose as it appears in the table of analytical constituents of kibble only doses part of the insoluble fiber and no soluble fiber. Thus, it does not take into account soluble fibers and badly hemicellulose and lignin, two other "families" of insoluble fibers. In other words, it is only an imperfect reflection of the insoluble fiber content of the food.
What is cellulose for dogs?
Cellulose is part of the family of complex carbohydrates not assimilated by dogs and more precisely of the class of insoluble dietary fibers. In other words, this means that the dog is not able to digest or assimilate the cellulose and that the latter does not pass through its digestive system, without providing calories to the dog.
We thus find the cellulose ingested by the dog as it is in its stools.
But make no mistake! Just because cellulose doesn't undergo transformation during the dog's digestive process doesn't mean it's useless. On the contrary, it plays an important role in the digestive comfort of the animal by stimulating it and promoting intestinal hygiene by participating in the renewal of the digestive mucosa.
How much crude fiber is recommended in kibble?
In terms of crude cellulose, there is not really any recommendation. The average levels found in dog food are generally between 6 and 9% and do not seem to pose any particular problem for most dogs. Nevertheless, there are individual sensitivities and it is for this reason that it is always necessary to test the tolerance of a new food by observing, in particular, the frequency and the aspect of the stools.The goal is to ensure that excess insoluble fiber does not cause inflammation of the dog's digestive system or diarrhea.
The foods richest in crude fiber are generally kibbles for sterilized or overweight dogs for which manufacturers seek to reduce the energy density. Due to their high crude fiber content, these foods may cause an increased frequency of bowel movements.