The symptoms of Arginine-free diet are hypersalivation and frothing from the mouth, depression with eye closed, nodding of the head, hyperaesthesia, sudden hyperactivity, moaning, ataxia, tetanic spasms with emprosthotonus. Even with low Arginine, the kittens had diarrhea and was vomiting. The cat is unable to make Ornithine, and unable to make Arginine even if Ornithine is provided. However, the required levels for Alginine for cat's growth was not more than any other animals. Therefore, the cat required a high protein diet because of an unusually high requirement for one or more of the essential amino acids is nullified.
Most mammals can adjust to various levels of protein intake.
If the animals are fed low protein, hepatic amino acid catabolic enzymes decrease so that a lower proportion of the amino acids from the diet are catabolized. This enable s the animals to conserve nitrogen. And when animals are fed high protein, the opposite will happen. They found little difference between enzymes activities of cats fed the low as compared to the high protein diet. This means enzyme activities in cat remains the same low or high protein diets.