What is the protein-phosphoric ratio?
The protein-phosphorus ratio, often abbreviated RPP, is nothing other than the result of the division between the percentage of protein and the percentage of phosphorus in a dog food.
Why have fun doing this calculation? Quite simply because the value of this report can tell us about the quality of the ingredients - and in particular the meat ingredients - used in your dog's kibble recipe. It is an indicator available to everyone to choose the best food for their pet.
Why is it important to take an interest in the protein quality of kibbles?
If we are only interested in the percentage of protein displayed on the label of a packet of croquettes, we are only interested in the quantitative aspect of the thing but not in the quality of the proteins contained in the croquettes. However, when it comes to proteins, the quality of the latter is just as important as their quantity. If the protein in your kibble comes from a majority of plant-based ingredients or low-quality animal-based ingredients, it doesn't matter if they are present in large quantities. Your dog will not be able to digest or assimilate them properly, so he may nevertheless be deficient in protein even though his kibbles display a correct protein percentage.
Of course, you can also refer to the list of ingredients to get an idea of the origin and quality of the proteins contained in your dog's kibble.But here again, the exercise has its limits. An industrialist can display terms such as "animal by-products" , "poultry" , "chicken" or "beef" without really knowing what proportion of cartilage, bone or tendons has been introduced into recipe. It should be known that only the skeletal muscle, in other words the meat or the flesh of these animals, provides proteins that are digestible and usable by the body of the dog. However, to be completely clear, an industrialist never uses "real meat" to make kibble. It always uses animal by-products, a mixture of muscles and carcass fragments, with varying levels of good protein for the dog, which cannot be judged just by reading the list of ingredients.
Read also: What are animal by-products in kibble?To judge the quality of the proteins used in kibble, it is therefore possible to rely on the protein-phosphoric ratio.If the kibble contains too much phosphorus in relation to its amount of protein (and therefore a low RPP), it means that the raw materials are of poor quality. They are too rich in bones and cartilage whose proteins are not easily digestible and assimilated for the dog. Phosphorus is a mineral that is found in large quantities in the bones. The more there is in kibble, the more carcass has been used in its composition.
How to calculate and use the RPP?
The calculation
To calculate the protein to phosphorus ratio, simply divide the percentage of protein by the percentage of phosphorus. These percentages generally appear on the label of the kibble packet or on its technical data sheet.
- The kibble brand shown in the following example is a fictitious brand -
Let's take an example to understand:
The RPP of Carnicroc' kibble is 30/0.9=33.33
I can't find the phosphorus level
Unlike the percentage of protein, the phosphorus level is not a data that the manufacturer must display on the kibble label. If you cannot find it, you can request it from the manufacturer. If he refuses to give it to you, he may have something to hide
Interpretation
The result of this report division gives an idea, with the limits set out below, of the level of quality of the raw materials used in a kibble composition.
So an RPP:
- less than 30 indicates the presence of low quality raw materials,
- between 30 and 35 is acceptable,
- above 35 is excellent.
It is therefore recommended to choose foods with an RPP greater than 35 and whose phosphorus level does not exceed 1.1%.
In our previous example:
The RPP for Carnicroc' kibble is acceptable.
Keep a critical mind
A high RPP often means that the meat raw materials are of good quality or that the kibble proteins are provided by legumes (chickpeas, lentils, dried beans).
The latter have a relatively high level of vegetable protein and are naturally low in phosphorus, which can affect the RPP value. However, the vegetable proteins provided by these legumes are far from being the best for the dog.
When you calculate the RPP, also remember to cross-reference the value you will obtain with the list of ingredients in order to know where the proteins come from and to properly interpret your result!