A cat’s diet should contain 30 to 45% protein on a dry matter basis (DMB) and it should be of high biological value which means that it should be meat proteins as opposed to plant proteins.
The phrase “biological value” means a measure of the proportion of absorbed protein from a food which becomes part of the protein of the animal’s body. It measures how easily the protein can be used in protein synthesis in the cells of the cat.
We all know by now that cats have an absolute requirement for protein. And higher protein diets are often more palatable to most domestic cats.
Plant proteins do not have a high biological value as I understand it.
A live mouse (a perfect diet except for the worms in the mouse!) eaten by a cat is 40% protein. If you want to read a discussion about “dry matter basis” then please click on this link. It is a link which discusses how to read domestic cat food labels.
P.S. We know that cats have a higher dietary requirement for protein than dogs or humans. There is an essential demand for protein to be used for gluconeogenesis regardless of the amount of carbohydrate in the diet.
The dietary requirement for protein varies with the age of the cat but for an adult cat in America it is set at 26% by the Association of American Feed Control Officials (AAFCO). The figure of 26% is interesting considering that experts state, as mentioned above, that the figure should be 30 to 40%. Can someone clarify this?
Source: Myself and K Sturgess and KJ Hurley in The Welfare of Cats.