Protein quality of two varieties of high-lysine maize fed alone and with black beans or milk to normal and depleted weanling rats.
Opaque-2 corn, modified high-lysine corn with vitreous endosperm, and common corn were compared in rat growth studies. Corn alone supplied 8.6% protein; and at both 8.6 and 11.4% protein, corn furnished 60% of the protein and either milk or black beans supplied 40%. The modified corn, which also was high in both lysine and tryptophan, did not differ significantly from Opaque-2 corn in its ability to stimulate growth and nitrogen deposition in both well-nourished and partially protein-depleted rats; and both were significantly superior to common corn when fed alone. Milk was a more effective supplement for corn than black beans, especially when high-lysine varieties were fed, whereas beans exerted a similar effect on all varieties of corn. The depleted rats deposited more nitrogen as a result of eating most diets than did well nourished rats. Implications of these findings for preschool children are discussed.
D000601:Amino Acids, Essential / Q000032:analysis; D000603:Amino Acids, Sulfur / Q000032:analysis; D000818:Animals; D001823:Body Composition; D001835:Body Weight; D002364:Caseins; D055598:Chemical Phenomena; D002621:Chemistry; D004044:Dietary Proteins / Q000032:analysis / Q000378:metabolism; D008239:Lysine / Q000032:analysis; D008892:Milk / Q000032:analysis; D009584:Nitrogen / Q000378:metabolism; D014674:Plant Proteins, Dietary / Q000378:metabolism; D051381:Rats; D013045:Species Specificity; D003313:Zea mays / Q000032:analysis
D000601:Amino Acids, Essential; D000603:Amino Acids, Sulfur; D002364:Caseins; D004044:Dietary Proteins; D014674:Plant Proteins, Dietary; D008239:Lysine; D009584:Nitrogen