A Comparison of the Nutritive Value of Opaque-2, Floury-2 and Normal Corn for the Chick

THE opaque-2 and floury-2 mutant genes of corn cause a marked alteration in the amino acid pattern of corn protein, including an increase in the lysine content of opaque-2 corn (Mertz, 1963; Mertz et al., 1964; Nelson et al., 1965) and an increase in the lysine and methionine content of floury-2 corn (Nelson et al., 1965). These differences have been partially attributed to a reduction in the zein to glutelin ratio (Mertz, 1963; Mertz et al., 1964; Mosse, 1966; Jimenez, 1966). Recent studies have suggested that the mode of action of the opaque-2 gene may be mediated through an increase in ribonuclease activity, particularly during the stage of greatest zein synthesis (Dalby and Davies, 1967; Wilson and Alexander, 1967). Nutritional studies with opaque-2 corn have shown it to be superior to normal corn for the rat (Mertz et al., 1965; Nelson, 1966), the pig (Beeson et al., 1966; Pickett, 1966; . . .