The digestion of yeast cell wall polysaccharides in veal calves.
1. The digestibility of the cell wall polysaccharides of an alkane-grown yeast in different parts of the digestive tract of two veal calves fitted with re-entrant cannulas at the end of the ileum was studied by replacing part of the skim-milk powder of their 'normal', milk-substitute (all-milk-protein) diet by yeast (yeast diet). 2. The lactose and glucose of both the all-milk-protein diet and the yeast diet were almost completely digested before the end of the ileum. During this digestion a small amount of oligosaccharides composed of galactose and glucose was synthesized. These oligosaccharides were digested again in the large intestine. 3. The constituent sugars of the water-soluble fraction of the yeast cell wall carbohydrates were glucose and mannose. The 0-5 M-sulphuric acid-hydrolysate of the water-insoluble fraction contained glucose and mannose and the 12 M-H2SO4-hydrolysate only glucose. 4. Digestibilities measured at the end of the ileum varied considerably between the two animals and averaged only about 0-40. 5. These findings suggest that the cell wall polysaccharides of yeast are digested very little by the normal digestive enzymes of the calf's small intestine, but are used as a substrate by the bacterial flora which are mainly concentrated in the large intestine.
D000821:Animal Feed; D000818:Animals; D002417:Cattle; D002473:Cell Wall / Q000378:metabolism*; D004040:Dietary Carbohydrates / Q000378:metabolism; D004063:Digestion; D005243:Feces / Q000032:analysis; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D007082:Ileum / Q000378:metabolism; D008358:Mannose / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism*; D015002:Yeast, Dried
D004040:Dietary Carbohydrates; D011134:Polysaccharides; D005947:Glucose; D009584:Nitrogen; D008358:Mannose; D005690:Galactose