《第二章-DigestiveSystems消化系统》.ppt

Function and Gross Appearance of Stomach Compartments Primary Function Distinctive Internal Structure Rumen 瘤胃 Fermentation; absorption of VFA, NH3, water Papillae; 乳头 looks like shag carpet粗毛毯 Reticulum网胃 Fermentation发酵 Honeycomb appearance蜂巢 Omasum、瓣胃 Reduce particle size, absorb H2O “Leaves” or many piles – looks like a book on edge Abomasum 皱胃 Functions of “true” stomach None – shiny with mucus Papillae of the Rumen Reticulum (Honeycomb)网胃 Omasum (Butchers Bible)瓣胃 Fermentation in Rumen and Reticulum瘤胃和网胃中发酵 The rumen contains: 25 – 50 x 109 bacteria/ml细菌 25 – 50 x 104 protozoa/ml 原生动物 Yeast and fungi also present but in much lower concentrations酵母和真菌 淀粉颗粒 细菌 原虫 细菌 Fermentation in Rumen and Reticulum瘤胃和网胃中发酵 Anaerobic microbial digestion of feedstuffs into volatile fatty acids, methane, carbon dioxide, and heat.饲料厌氧微生物发酵生成挥发性脂肪酸、甲烷、二氧化碳和热量。 Microbes synthesize all amino acids, all B vitamins and vitamin K.微生物合成所有氨基酸和所有B族维生素和维生素K。 Most unsaturated fatty acids entering the rumen are saturated by the microbes. 绝大多数不饱和脂肪酸生成饱和。 Rumination (Chewing the Cud)反刍 Process by which ruminants rechew the coarse fibrous part of the diet.饲粮中粗纤维部分 Parts of rumination are: Regurgitation ? Remastication ? Reensalivation ? Reswallowing Rumination (Chewing the Cud) Rechewing reduces particle size and stimulates saliva flow 反复嚼咀降低颗粒尺寸和刺激唾液流动。 Diets low in forage result in reduced rumination which causes reduced saliva flow and less buffer entering the rumen 低粗饲料 Ruminants spend 6–10 hours/day ruminating Bloat膨胀 Accumulation of fermentation gas in rumen that is not belched. 发酵气体积聚，没有排出去 Bloat Eructation Expelling of gas produced from microbial fermentation During peak fermentation 12-30 liters of gas are produced each hour Small Intestine小肠 Divided into three segments: Duodenum十二指肠 Attached to true stomach, pancreatic and bile ducts enter near the beginning of the duodenum Jejunum空肠 Middle segment Ileum回肠 Last segment, ends in ileo-cecal val