Effect of feeding a reduced protein, amino acid-supplemented diet on the excretion of urine and nitrogen, and the ammonia emission from slurry in growing pigs

An experiment was conducted to determine the effect of feeding reduced CP, amino acid-supplemented diet on the excretion of urine and nitrogen, and the ammonia emitted from urine and feces in growing pigs. Twelve pigs (35kgBW) were fed corn-soybean meal diets containing either 16.4% CP (standard CP diet) or 10.9% CP supplemented with amino acids (low CP diet) for 28 d. After 8 d of feeding of the diets, a 4-d nitrogen balance trial was conducted. Ammonia emitted from urine, feces and the mixture, in which feces were mixed with urine (ratio of 1 : 2, wt/wt) to form a slurry, was determined by an in vitro system on the feces and urine excreted, on the 28th d. Body weight gain, feed intake and feed efficiency were similar between the pigs fed the standard CP diet and pigs fed the low CP diet. Water intake and excretion of urine tended to be lowered by feeding the low CP diet. Feeding the low CP diet reduced the excretion of fecal nitrogen (P