齐鲁医学碳水化合物的消化CHO-dig

1、2021/9/301Large IntestineCarbohydrate Digestion in RuminantSmall IntestinePancreasRumen-Reticulum2021/9/302FermentationMammalian digestionStarchSalivary AmylaseStarch + large dextrinsMaltotriose and alpha limit dextrinsMaltoseMaltasePancreatic amylaseGlucose+LactoseSucroseLactaseSucraseGlucoseFructo

2、seGalactoseFIBERFiberUndigested starch and dextrinsVolatile fatty acids非反刍动物的碳水化合物消化乳糖蔗糖纤维淀粉2021/9/303Large IntestineCarbohydrate Digestion in RuminantSmall IntestinePancreasRumen-ReticulumStarchAcetic acid Propionic acidButyric acidEnergy, Synthesis of Fatty acidEnergy,Synthesis of GlucoseEnergyCel

3、luloseHemicellulosePectinLignin GlucoseFermentationMammalian digestionFermentationFermentation2021/9/304What are the primary molecules pigs use for energy when fed a grain based dietVFAGlucose2021/9/305What are the primary molecules cattle, sheep and goats use for energy when fed a high grain dietVF

4、AGlucose2021/9/306What are the primary molecules cattle, sheep and goats use for energy when fed a all forage dietVFAGlucose2021/9/307What are the primary molecules horses use for energy when fed a all forage dietVFAGlucose2021/9/308What are the primary molecules horses use for energy when fed a die

5、t consisting of 50% grain and 50% forage?VFAGlucose2021/9/309Sites of Carbohydrate Digestion碳水化合物消化位置MouthSalivary amylase begins digestion of starch唾液淀粉酶开始淀粉消化True StomachHCl ruptures starch granules胃酸破裂淀粉细粒2021/9/3010Sites of Carbohydrate Digestion碳水化合物消化位置Small Intestine小肠Amylase淀粉酶From the pancr

6、eas; primary enzyme digesting starch胰腺分泌淀粉酶，是基本的淀粉消化酶。Maltase麦芽糖酶(brush border enzyme)刷状缘酶Sucrase甘蔗糖(brush border enzyme)刷状缘酶(not found in ruminants)反刍动物未发现甘蔗糖酶Lactase乳糖酶(brush border enzyme)刷状缘酶2021/9/3011Carbohydrate Digestion By Mammalian Enzymes哺乳动物碳水化合物消化酶Substrate物质Enzyme酶Product产物Starch淀粉Amyl

7、ase淀粉酶Dextrins糊精Dextrins糊精Amylase淀粉酶 maltose + maltotriose + -limit dextrins麦芽糖+麦芽三糖+-有限糊精Maltose麦芽糖Maltase淀粉酶glucose + glucose葡萄糖+葡萄糖Lactose乳糖Lactase乳糖酶glucose + galactose葡萄糖+半乳糖Sucrose蔗糖Sucrase蔗糖酶glucose + fructose葡萄糖+果糖2021/9/3012Sites of Carbohydrate Digestion碳水化合物消化位置Rumen-Reticulum/Large Intes

8、tine瘤胃-网胃/大肠Bacteria and protozoa ferment carbohydrates and produce the VFA细胞和原虫发酵碳水化合物生成挥发性脂肪酸For Example: Substrate物质Enzyme酶Product产物Cellulose纤维素Cellulase纤维素酶 cellobiose (2 glucose linked by 1-4 bonds)纤维二糖Cellobiose纤维二糖Cellulase纤维素酶 Glucose葡萄糖Glucose葡萄糖lots VFA 挥发性脂肪酸2021/9/3013Absorption of Monos

9、accharides单糖吸收Absorbed only in the small intestine 单糖只在小肠吸收Absorption requires carrier molecules and energy, so it is termed active transport 单糖吸收需要载体和能量，所以属于主动转运。2021/9/3014Volatile Fatty Acid Formation from Glucose葡萄糖形成挥发性脂肪酸Acetic acidGlucoseC6H12O62 acetate + CO2 + CH4 + Heat(2) C2H4O2Propionic

10、acidGlucose + electrons2 propionate + H2O(2) C3H6O2Butyrate + CO2 + CH4Butyric acidC6H12O6C6H12O6C4H8O2Glucose乙酸丙酸丁酸葡萄糖2021/9/3015Efficiencies of Volatile Fatty Acid Formation*挥发性脂肪酸合成效率2021/9/3016Acetate乙酸Absorbed and carried to the liver, but a small amount is converted to ketone bodies in the rum

11、en wall 吸收转运至肝脏，但小量在瘤胃壁内转化成酮体In the liver acetate is converted to acetyl CoA which can be:在肝，乙酸被转化成乙酰辅酶AOxidized via the TCA cycle to produce energy 通过三羧酸循环氧化产生能量Used to synthesize fatty acids用于合成脂肪酸Precursor of milk and body fatty acids; inadequate production of acetate by fermentation in lactating

12、 dairy cows will lower butter fat content乳和体内脂肪酸的前体，泌乳牛通过发酵产生的乙酸量不足时，体脂含量会降低。2021/9/3017Propionate丙酸Absorbed and carried to liver吸收转运至肝Converted to Succinyl CoA转化成辅酶ASuccinyl CoA can be used in TCA cycle to produce energy or it can be used for synthesis of glucose 辅酶A被用于三羧酸循环而产生能量，或者用于合成葡萄糖。Propioni

13、c acid is the main precursor for glucose synthesis in ruminants 反刍动物中，丙酸是合成葡萄糖的主要前体。2021/9/3018Butyrate丁酸Almost all is converted to 3-hydroxybutyrate (a ketone body) in rumen wall and used for energy production在瘤胃壁内转化成3-羟基丁酸（一种酮体），用于产生能量。2021/9/3019Importance of VFAs for Ruminants挥发性脂肪酸对反刍动物的重要性Prim

14、ary molecules used for energy at the tissue level 在组织水平是合成能量的基本分子Acetate is the most abundant VFA produced by fermentation; propionate = 2nd; butyrate = 3rd 乙酸是通过发酵产生的最多挥发性脂肪酸，是丙酸二倍，丁酸三倍。Exact ratios of acetate:propionate:butyrate vary with diet and feeding practices, but the ranking never changes 乙

15、酸:丙酸:丁酸的比例会随饲粮和饲养水平而变化，但排序不会变。2021/9/3020Effect of Forage:Concentrate Ratio on Proportion of Fatty Acids in the Rumen粗精比对瘤胃中脂肪酸含量的影响Molar Ratio摩尔比Forage:Concentrate粗精比Acetate乙酸Propionate丙酸Butyrate丁酸100:071.416.07.975:2568.218.18.050:5065.318.410.440:6059.825.910.220:8053.630.610.72021/9/3021Importan

16、ce of VFAs for Ruminants挥发性脂肪酸对反刍动物的重要性Feeding high starch diets (high in grain) increases the proportion of propionate and increases growth rate, feed efficiency and milk production compared to feeding high fiber diets. 与饲喂高纤维饲粮相比，饲喂高淀粉饲粮（谷物含量高）提高丙酸的比例，进而提高生长速度、饲料转化率和奶产量。Feeding high fiber diets (h

17、igh in roughages) increases the proportion of acetate and increases fat content of milk in cows. Growth rate, feed efficiency and milk production will be lower, compared to high grain diets. 与饲喂高谷物饲粮相比，饲喂高纤维饲粮（粗饲料含量高）提高乙酸的比例，进而增加奶牛中乳脂含量。但生长速度、饲料转化率和奶产量将下降。2021/9/3022Importance of VFAs for Ruminants挥

18、发性脂肪酸对反刍动物的重要性Grinding, pelleting, and some additives (e.g., monesin) increase production of propionate by altering the microbial population in the rumen 粉碎、制粒和一些饲料添加剂通过改变瘤胃中微生物数量提高丙酸产量2021/9/3023Importance of VFAs for Herbivores, Omnivores挥发性脂肪酸对草食性家畜的重要性In the cecum and colon, acetate is predominant product of fermentation followed by propionate and butyrate. 在盲肠和直肠，乙酸是由丙酸和丁酸发酵的前体物质。The VFA are the primary molecul