Sutton A L, Kephart K B, Verstegen M W, Canh T T, Hobbs P J
Department of Animal Sciences, Purdue University, West Lafayette, IN 47907-1026, USA.
J Anim Sci. 1999 Feb;77(2):430-9. doi: 10.2527/1999.772430x.
Recent public concern about air pollution from pork production units has prompted more research to develop methods to reduce and control odors. Masking agents, enzymes and bacterial preparations, feed additives, chemicals, oxidation processes, air scrubbers, biofilters, and new ventilation systems have been studied. Research relating the effects of the swine diet on manure odors has been scarce. Introducing feed additives to bind ammonia, change digesta pH, affect specific enzyme activity, and mask odors has been either costly or not consistently successful. Recent research emphasis has focused on manipulating the diet 1) to increase the nutrient utilization of the diet to reduce excretion products, 2) to enhance microbial metabolism in the lower digestive tract to reduce excretion of odor-causing compounds, and 3) to change the physical characteristics of urine and feces to reduce odor emissions. Primary odor-causing compounds evolve from excess degradable proteins and lack of specific fermentable carbohydrates during microbial fermentation. Reductions in ammonia emissions by 28 to 79% through diet modifications have been reported. Limited research on reduction of other odorous volatile organic compounds through diet modifications is promising. Use of synthetic amino acids with reduced intact protein levels in diets significantly reduces nitrogen excretions and odor production. Addition of nonstarch polysaccharides and specific oligosaccharides further alters the pathway of nitrogen excretion and reduces odor emission. Continued nutritional and microbial research to incorporate protein degradation products, especially sulfur-containing organics, with fermentable carbohydrates in the lower gastrointestinal tract of pigs will further control odors from manure.
近期公众对猪肉生产单位空气污染的担忧促使人们开展更多研究，以开发减少和控制气味的方法。人们对掩蔽剂、酶和细菌制剂、饲料添加剂、化学品、氧化工艺、空气洗涤器、生物过滤器及新型通风系统进行了研究。关于猪日粮对粪便气味影响的研究较少。引入饲料添加剂来结合氨气、改变消化物pH值、影响特定酶活性及掩盖气味，要么成本高昂，要么效果并不稳定。近期的研究重点集中在调整日粮，一是提高日粮养分利用率以减少排泄产物，二是增强下消化道的微生物代谢以减少致臭化合物的排泄，三是改变尿液和粪便的物理特性以减少气味排放。主要的致臭化合物是在微生物发酵过程中由过量的可降解蛋白质和缺乏特定的可发酵碳水化合物产生的。据报道，通过调整日粮可使氨气排放量减少28%至79%。通过调整日粮减少其他有气味的挥发性有机化合物的研究虽然有限，但前景乐观。在日粮中使用完整蛋白质水平较低的合成氨基酸可显著减少氮排泄和气味产生。添加非淀粉多糖和特定的低聚糖可进一步改变氮排泄途径并减少气味排放。持续开展营养和微生物研究，将蛋白质降解产物，尤其是含硫有机物，与猪下消化道中的可发酵碳水化合物结合起来，将进一步控制粪便气味。
