Also called · essential amino acids · leucine · arginine · lysine
What it is
Protein quality is decided by amino acid composition, not by percentage. If even one required amino acid falls short, the rest are only used up to that level, however much of them there is — Liebig’s barrel.
The number of essential amino acids differs by species: 9 for humans, 10 for dogs, 11 for cats.
What it does
Why egg is the benchmark
In chick trials, a grain-and-fishmeal feed needed 20% protein, while egg protein was sufficient at 14%. The same "x% protein" is not the same thing.
Requirements run higher than in dogs
As obligate carnivores, cats keep protein-metabolising enzymes permanently elevated. Feed them dog food and it is a low-protein diet by definition.
How to feed it
Higher than dogs. Follow the standards for complete and balanced cat food.
The principle is meeting the requirement through the main diet; supplements are supporting cast.
What to watch for
There is actual published work on whether a high-protein diet makes dogs more reactive. The explanation runs through tryptophan competing for entry to the brain.
Disease states may require protein restriction or adjustment. Follow veterinary judgement without exception.
Common questions
No. Collagen is digested into amino acids like any other protein — it does not travel to the skin in the form you fed it.
Concerns this ingredient relates to
General nutrition information. It does not replace a diagnosis or a prescription. If your animal has a medical condition or is on medication, talk to your veterinarian first.