Utilization of Environmentally Produced High Nitrogen Corn by Weanling Rats and Adult Humans

Experiments with rats and human subjects were carried out to study the utilization of nitrogen from high-nitrogen corn produced by natural or artificial defoliation of the corn plant at various stages of development. Weight gain, food intake and digestible nitrogen were significantly higher and food required per unit of gain was significantly lower for rats fed high-nitrogen corn. That the increased protein content of the damaged corn was not due to an increase in zein content, was demonstrated by feeding zein in combination with control corn. Nitrogen balances of human subjects were studied when control corn, corn defoliated at the milk stage, and corn defoliated at the blister stage were fed in isonitrogenous amounts. No significant differences were observed in response of subjects to the 3 types of diet; however, nitrogen balance tended to be higher and urinary nitrogen lower when the milk-stage corn was fed. Amino acid analyses indicated that the increase in essential amino acids in the high-nitrogen corn was proportional to the increase in nitrogen content.