Protein and Amino Acid Evaluation of Commercially Grown Opaque-2 Corn

Abstract

The protein content of 18 samples of commercially grown opaque-2 corn obtained from various areas in Illinois was 8.9 ± .17% and the lysine content was .33 ± .01% (mean ± SEM and based on 90% dry matter). For 30 samples of commercially grown opaque-2 corn obtained from various areas in Virginia in 1973, the protein content was 8.37 ± .07% and the lysine content was .37 ± .01%. For 26 samples of opaque-2 corn obtained in Virginia in 1974, the protein content was 8.61 ± .17% and the lysine content was .36 ± .01%. The protein content of 10 samples of normal corn obtained in Virginia in 1973 was 8.72 ± .24% and the lysine content was .25 ± .01%. The protein content of 18 samples of normal corn obtained in Virginia in 1974 was 8.52 ± .22% and the lysine content was .27 ± .01%. There was a positive linear relationship between protein (X) and lysine (Y) content of opaque-2 corn: Y = .037X + .002 (r = .62; P<.01) for Illinois; Y = .044X − .002 (r = .59; P<.01) for Virginia in 1973; and Y = .032X + .084 (r = .80; P<.005) for Virginia in 1974. There was no relationship between protein and lysine content of normal corn in 1973 with only a weak relationship (P<.05) in 1974. Results of three feeding trials using opaque-2 corn grown commercially in Virginia indicate that the lysine in opaque-2 corn is as available for growing pigs as the lysine in normal corn and that feedlot performance is directly related to the lysine content of the corn.