Amino Acid and Mineral Manipulation in Pig Diets to Reduce Nitrogen and Odors in Pig Manure
Purdue University 1998 Swine Research Report. Recent increased public concern, legislation and environmental regulations have focused on pollution and have created a major threat to the viability and growth of the pork industry. Even though water pollution control has been a major focus of regulations, recent public concerns and lawsuits have revolved around odors from pork operations. Most research has focused on measuring odor and gas intensity and occurrence with proposed attempts to reduce or mask odors (Miner, 1995). The first line of defense against any emitted aerial contaminant is source control. In the case of swine odor, the obvious source control technique is diet manipulation. Odorous compounds result from the anaerobic microbial degradation of proteins and carbohydrates (Drochner, 1987). Ammonia, short-chain volatile fatty acids, amines, skatole, indole, pcresol, H2S and other sulfur-containing compounds have been identified in air samples over manure pits (Hobbs et al., 1995). Significant levels of sulfide-containing compounds (dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, hydrogen sulfide, carbon disulfide, and dimethyl sulfoxide) were measured in previous studies (Sutton et al., 1995). Primary sulfur sources are derived from the amino acids methionine and cystine, and/or from trace minerals in the diet. The objectives of this research were to determine the effects of dietary methionine and cystine level and sulfur-containing mineral additions to the diet on the production of odorous sulfide compounds and other odorous compounds from cecal contents, fresh manure and stored manure.