Low-Protein Swine Diets

Researchers at Iowa State University conducted two swine feeding studies to compare the effects of supplementing low protein corn-soybean meal diets supplemented with amino acids and/or a yucca extract on nitrogen losses in feces and urine. The three treatments were: 1) 17.4% crude protein corn-soybean meal control diet; 2) 17.0% crude protein supplemented with lysine; and 3) 14.5% crude protein diet supplemented with lysine, methionine, threonine and tryptophan. The low protein diet supplemented with amino acids reduced (P>0.05) average daily gain and feed efficiency compared to the control diet. Lowering the protein content of the diet also reduced nitrogen in the feces and ammonia emissions. Yucca had no effect on rage daily gains, feed utilization or nitrogen in manure or ammonia emissions. The authors caution nutritionists when using strategies to reduce ammonia emissions to make sure animal performance is maintained. Little is gained when ammonia emissions are reduced at the expense of reduced pig performance and profits.

Panetta, D.M. and co-workers. 2006. Nitrogen excretion and ammonia emissions from pigs fed modified diets. J. Environmental Quality 35(4): 1297-1308.