水产动物营养与饲料学－双语教学课件chapter 1-3-Carbohydrates.ppt

Chapter 1-3 Carbohydrates 1. General 2. Utilization of carbohydrate (CHO) 3. Digestibility and importance of crude fibre 1. General 1.1 Function of CHO (1) energy source (2) to assist the formation of the carbon skeleton for non-essential fatty acid （非必需脂肪酸的碳骨架） (3) for the synthesis of fats（合成脂肪） 1.2 The classes of carbohydrates（糖的分类） Monosaccharides（单糖） Di- and oligosaccharides（二糖和寡糖） Polysaccharides（多糖） Monosaccharides（单糖） hexoses (glucose, galactose, fructose) pentoses they are the building blocks for formation of di-, oligo- and polysaccharides Di- and oligosaccharides（二糖和寡糖） monosaccharide molecules are joined together by means of ether linkages （醚键） lactose, consist of α-glucose and β-glucose and is the sole disaccharide of animal origin sucrose, α-glucose and β-fructose maltose （麦芽糖）, two α-glucose cellobiose (纤维二糖), two β-glucose molecules Polysaccharides（多糖） macromolecules composed of large numbers of monosaccharides Starch in the cells of plants in the form of granules（颗粒） of various sizes (1-150 μm) each starch granule is composed of amylose (直链淀粉) (25%) ， 100-200 glucose molecules amylopectin (支链淀粉) (75%)，250-5000 glucose units Polysaccharides（多糖） Dextrin (糊精) a water soluble breakdown product of starch Glycogen (糖原) the animal starch, 5000-25000 glucose units, chiefly in the liver，some in the muscle. Polysaccharides（多糖） Cellulose （纤维素） the building material for plant cell walls, 2000-8000 β-glucose units. Cellulases（纤维素酶）, the enzymes for cellulose cleavage（分解）, only produced by micro-organisms Chitin （几丁质） forms the skeletal portions of crustaceans （甲壳类） insects， in the cell walls of yeasts（酵母）, Polysaccharides（多糖） Lignin（木质素） in the cell walls of woody plants together with cellulose, not a carbohydrate, but a derivative of benzene(