Effects of a low CP diet fed to barrows on N excretion and subsequent GHG emissions in feces and urine after composting
and wastewater treatment were assessed. Results reveal that under ad libitum feeding, a low CP amino acid supplemented
diet can reduce N excretion in manure with no impact on animal growth. Thus, the amount of N excreted in feces and urine
was reduced by 28.7% in the low CP group. The reduction of the manure’s GHG emissions was even higher, with a 39.1%
reduction of GHG from the low CP amino acid supplemented diet compared with manure from the high CP non-amino acid
supplemented diet.