Yucca saponins, and perhaps other components of yucca as well, have ammonia-binding activity. When added to the diet, yucca saponins pass through the digestive tract unabsorbed and are excreted in the feces. In the excreta, the yucca components bind to ammonia and certain other odiferous compounds and prevent them from being released into the air. In recent studies in England, feeding of yucca extract to dogs and cats was shown to reduce fecal odor and reduce emission of volatile compounds contributing to fecal odor. New applications for saponins in animal husbandry are being explored, especially the effect of saponins on protozoal diseases.
Saponins form strong insoluble complexes with cholesterol.
This has many important implications, including cholesterol-lowering activity in humans, discussed later in this article. Many protozoa enter the body via the digestive tract or cause their pathological effects in the gut. Saponins react with cholesterol in the protozoal cell membrane, causing the cell to rupture and lyse. Research currently in progress at Agriculture Canada in Lethbridge, Alberta, has shown yucca extract to be very effective in killing Giardia trophozoites, which are the infective stages released in the gut when the oocytes, or eggs, sporulate, although no studies with humans have yet been done. Other important protozoal diseases of livestock, including coccidiosis and equine protozoal myoencephalitis, may be amenable to treatment with saponins.