VMD 513: Pet animal Breeding, Management, Nutrition and Health Care (1+1)

PROTEIN REQUIREMENT IN CAT DIET

• Early studies of the cat’s nutrient requirements showed that it has a protein requirement substantially higher than that of other mammals, including the dog.When growing kittens were fed varying levels of dietary protein, supplied as minced herring and minced liver, growth was reported to be satisfactory only when protein exceeded 30% of the dry weight of the diet.
• In comparison, growing puppies fed mixed diets required only 20% protein for adequate growth and development. One of the first studies of the protein requirement of the adult cat reported that 21% dietary protein was necessary to maintain nitrogen balance when cats were fed a mixed diet containing liver and whitefish as the primary protein sources.
• Subsequent experimentation using crystalline amino acids and protein isolates allowed more precise definition of the minimum protein requirements of growing kittens and adult cats.
• One study reported a protein requirement of 18% to 20% (by weight) in growing kittens fed either crystalline amino acid diets or casein diets supplemented with methionine.
• Another study reported requirements as low as 16% of ME calories when growing kittens were fed a purified diet containing all of the essential amino acids in their assumed correct concentrations and ratios.
• Using a similar semipurified diet, the protein requirement of adult cats was determined to be 12.5% of ME.
• The profound effect that protein digestibility, amino acid balance, and amino acid availability have on determining an animal’s dietary protein requirement is illustrated by the substantially lower values that were obtained when semipurified and purified diets were used to determine requirements.
• However, the comparison of these figures with the ideal minimum protein requirements of other mammals still demonstrates that the cat, together with other obligate carnivores such as the fox and the mink, has a higher requirement for dietary protein.
• NRC recommended minimum requirement of protein for adult cats of 160 g crude protein/kg food in a diet containing 4 kcal/kg.
• The NRC’s minimum requirement for kittens after weaning is 180 g/kg, equivalent to 15.75% of ME 
• Once again, it is important to recognize that all of these values assume highly available and well balanced protein sources that contain all of the necessary amino acids.
• AAFCO Nutrient Profiles for cat foods, as with dog foods, suggest a higher level of protein for inclusion in commercially prepared foods.
• A level of 30% of the diet (dry matter [DM]) is suggested for growth and reproduction in foods containing 4 kcal of ME/g of food. This value is equivalent to 26.25% of ME calories. A level of 26% of the diet, equivalent to 22.75% ME, is suggested for adult maintenance.