课件：DigestiveSystems消化系统.ppt

水分,无氮浸出物,图 概略养分与饲料组成之间的关系,饲料,干物质,无机物（粗灰分或矿物质）,有机物,含氮化合物（粗蛋白质）,无氮化合物,乙醚浸出物（粗脂肪）,碳水化合物,粗纤维,四、养分含量的表示方法,某饲料新鲜基础含CP5%，水分75%，求饲料风干基础（含水10%）下含蛋白质多少？,四、养分含量的表示方法,某饲料新鲜基础含CP5%，水分75%，求饲料风干基础（含水10%）下含蛋白质多少？,设为x，则,x90%=5%25%,x=（5%90%）25%=18%,DIGESTION消化,Anatomy and Function of the Gastrointestinal Tract胃肠道解剖和功能,Key concepts about the digestive system and digestion,Large complex molecules, like proteins, polysaccharides, and triglycerides must be broken down into their simplest part before they are absorbed into the blood or lymph. This is the job of the digestive system 大复杂分子如蛋白质、多糖和甘油三酯在吸收入血或淋巴之前必须分解成最简单成分。这是消化系统的工作。 Digestion requires enzymes that break specific types of chemical bonds. If an enzyme is not present, digestion of that molecule does not occur 消化需要酶。 There are two sources of digestive enzymes: those made by the animal (digest soluble CHO, protein and lipids) and those made by microbes during fermentation (digest soluble CHO, protein and lipids and fiber). 消化酶有两个来源： 一是来自动物本身（消化可溶性碳水化合物、蛋白质和脂类）； 二是来自于微生物（消化可溶性碳水化合物、蛋白质和脂类及纤维）,Key concepts about the digestive system and digestion,For optimum utilization, digestion or fermentation needs to occur either in front of, or inside the part of digestive system that absorbs the final products produced by digestion 为优化利用，消化或发酵需要发生在消化系统吸收消化产物之前或当中。 Fermentation improves overall utilization of feeds for all animals 发酵改善所有动物饲料充分利用。 Differences in size of some parts of the digestive system and location of fermentation within the digestive system dictate the types of feeds animals can utilize and the proper means of feeding. 由于消化系统尺寸大小不同或发酵位置不同决定动物能利用饲料的类型及适宜的饲喂方法。,为什么胃没有被消化了！,Gastrointestinal Tract,Complex physiologically and anatomically Extends from mouth to anus Functions Digestion Absorption Protect body from: Remove undigested material and wastes Immunological function Metabolism Endocrine functions (Hormones) Site of fermentation (symbiosis),咽,盲肠,十二指肠,肝脏,胆囊,唾液腺,舌,牙齿,幽门括约肌,胃,食道,唾液腺,肛门,阑尾,会厌,胰腺,大肠,小肠,直肠,RuminantCattle, Sheep, Goats 反刍动物-牛，绵羊，山羊,Nonruminants 非反刍动物,网胃,小结肠,盲肠,小肠,牙齿,食道,胃,大结肠,食道,瘤胃,皱胃,小肠,直肠,胃,小肠,小肠,食道,肝脏,盲肠,结肠,瓣胃,Simplified Digestive Systems,Mouth and Saliva嘴和唾液,Function of the mouth 嘴的功能 Take in food 采食 Prehensile structure Horses-lips 马-唇 Cattle-tongue 牛-牙齿 Pigs-lips 猪-唇 Sheep-lips 绵羊-唇 Taste accept or reject food 品尝 Chewing 嚼 Reduces particle size which improves digestibility Stimulates saliva flow Mix digesta with saliva 混合,Pig猪,Horse马,Sheep绵羊,Cattle牛,臼齿,切割和犬齿,牙床,Grinding grain to reduce particle size,锤片转子,出料口,磨的档板,Mouth and Saliva,Function of saliva唾液的功能 Lubricate food to allow swallowing and mixing of food in stomach of nonruminants 润滑食物便于吞咽和食物在反刍动物胃里混合 Initiate enzymatic digestion (amylase) of starch开始淀粉酶解（淀粉酶） Produce buffer to counteract acid in stomach产生缓冲液中和胃酸,Mouth and Saliva,Composition of saliva 唾液成分 Water水 Inorganic components无机成分 Used to supply minerals to digesta and buffers to regulate pH Organic components有机成分 Needed for digestive functions Urea Enzymes Mucoproteins黏蛋白,Esophagus食道,Muscular tube肌管 Extends from pharynx to cardia of stomach 咽至贲门 Striated muscle 纹状肌which changes to smooth muscle平滑肌 Esophagus of dogs and ruminants have striated muscle throughout,Esophagus,Extended by reticular groove (esophageal groove) in young ruminants Allows passage of milk from esophagus directly into omasum during nursing奶至皱胃 This prevents milk from entering the rumen, where it would be fermented resulting in a loss of nutrients 防止奶流入瘤胃,Stomach胃,(Glandular or True) Stomach腺胃或真胃 Functions of true stomach真胃的功能 Mixing of food 混合 Hold food for gradual release into small intestine食物进入小肠 Production of HCl and pepsinogen盐酸和胃蛋白酶原 Absorption of alcohol, aspirin, volatile fatty acids (ruminants), and various other compounds. 吸收乙醇、阿司匹林、挥发性脂肪酸和其它不同化合物。 There is no absorption of monosaccharides, amino acids, or long chain fatty acids in the stomach. 胃不吸收单糖、氨基酸或者长脂肪酸链。,Stomach,Secretions of true stomach真胃分泌作用 HCl Denatures protein-breaks intermolecular bonds Kills most bacteria present in foodstuffs Activates pepsinogen Ruptures starch granules破裂淀粉颗粒 Pepsinogen胃蛋白酶原 HCl converts pepsinogen to pepsin the active enzyme 胃蛋白酶原 胃蛋白酶 Pepsin begins digestion of proteins Clots milk 合牛奶牛凝结成块,Regions of true stomach真胃的区域,Esophageal region食道 Nonglandular 无腺体 Area most prone to ulcers溃疡 Cardiac region喷门 Produces mucus, which protects stomach lining产生黏液保护胃内层 Fundic region胃底 Produces mucus, enzyme, HCl Parietal cells-produce HCl Chief cells-produce pepsinogen Pyloric region幽门,贲门腺体区域,胃底腺体区域,憩室外部表面,幽门,食道腺体区域,胃切面边缘,憩室外部表面,幽门腺体区域,Normal Esophogeal Area of Pig Stomach 猪胃正常的食道,Stomach Ulcer in a Human 人的胃溃疡,Stomach,Secretions of true stomach真胃分泌作用 Rennin (abomasum)凝乳酶 Clots milk Mucus黏液 Protects lining of stomach from acid and pepsin,Ruminant Stomach 反刍动物的胃,网胃,瓣胃,食道,瘤胃,皱胃,小肠,瘤胃,皱胃,网胃,气体,液体,瓣胃,Ruminant Stomach,Rumen 瘤胃Development In newborn ruminants the abomasum is the only fully developed part of the stomach. 新生反刍动物皱胃充分发育 The rumen, reticulum and omasum are present, but they are very small and nonfunction. 其它胃小而无功能。,Ruminant Stomach,Consumption of forages and concentrates and inoculation with rumen bacteria from other ruminants begins fermentation in rumen which caused the rumen to develop. 粗饲料和精饲料消耗和接种瘤胃细菌开始在瘤胃中发酵，引起瘤胃发育。 On average, it takes about 2 3 months in calves and lambs for the rumen to develop. 犊牛和羔羊大约2-3个月瘤胃发育期。,Relative Size of Stomach Compartments胃分隔相对尺寸,Function and Gross Appearance of Stomach Compartments,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 610 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 valve which regulated flow of digesta into the large intestine,Small Intestine,Primary site for digestion of proteins, non-fibrous carbohydrates, and lipids. 蛋白质、非纤维型碳水化合物和脂类。 The only site for absorption of amino acids, monosaccharides and long chain fatty acids. 吸收氨基酸、单糖和长链脂肪酸的唯一位置。 All vitamins and minerals can be absorbed in the small intestine. 所有维生素和矿物质能被吸收到小肠中。,Small Intestine,Large amount of surface area in small intestine is due to folds in the wall, presence of villi, and especially microvilli 绒毛 The surface of the villi are covered with enterocyte cells which contain microvilli. Absorption occurs when compounds pass through the microvilli, enter the enterocyte, and are transferred to either the blood or lymph淋巴.,Villi,Microvilli (Brush border),Pancreas胰腺,Enzymes and buffer from the pancreas enter into the small intestine via the pancreatic duct. Cell Types: Acinar Cells Secrete enzymes Centroacinar Cells Secrete buffer (bicarbonate) Pancreas secrete 1.5 to 2.0 liters of fluid per day for an average human,Pancreas,Pancreatic enzymes digest starches, dextrins, fats and protein into monosaccharides, fatty acids and monoglyc