Food intake regulation in the weanling rat: effects of the most limiting essential amino acids of gluten, casein, and zein on the self-selection of protein and energy.
The effects of altering the quality of the dietary protein source on the self-selection of protein and energy by the weanling rat simultaneously offered a choice of two diets differing only in protein concentration were tested. The protein-energy selected was measured when the first limiting amino acid lysine was added to gluten; when lysine, methionine, or the first four limiting amino acids were added to gluten or to casein; or when the nutritional quality of zein was altered by manipulation of the content of tryptophan, lysine, or the four most limiting amino acids. The additions of lysine to gluten caused a decrease in the protein-energy selected and an increase in growth rate of the weanling rat. However, improving the amino acid balance of casein or zein did not have this effect. It was concluded that the selection of protein and energy by weanling rats is not related to the nutritional quality of the protein fed.
D000601:Amino Acids, Essential / Q000008:administration & dosage*; D000818:Animals; D001069:Appetite Regulation; D001835:Body Weight; D002364:Caseins / Q000378:metabolism*; D004044:Dietary Proteins / Q000592:standards; D004734:Energy Metabolism; D005518:Food Preferences; D005527:Food, Fortified / Q000592:standards; D005983:Glutens / Q000378:metabolism*; D008239:Lysine / Q000008:administration & dosage; D008297:Male; D008715:Methionine / Q000008:administration & dosage; D051381:Rats; D015028:Zein / Q000378:metabolism*
D000601:Amino Acids, Essential; D002364:Caseins; D004044:Dietary Proteins; D005983:Glutens; D015028:Zein; D008715:Methionine; D008239:Lysine