饲料分类英文课件Chapter 6 Energy feeds.ppt

Chapter 6　 High-Energy Feeds（能量饲料） Introduction Definition of high-energy feeds - High-energy feeds are feeds used primarily for their energy content. - Contain less than 20% protein and 18%CF. - Many protein supplements can also be classified as high-energy feeds. Introduction Classification Cereal grains Grain milling and milling by-products Fats and oils Molasses Roots and tubers 6.1 Cereal grains Source Grains are seeds from cereal plants. Corns, oats, barley and sorghums are the primary grains, which are known as feed grains(饲料谷物). 6.1 Cereal grains Functions They are widely used as sources of energy in animal feeding. They also provide substantial portions of protein. The energy comes from their starch content, the protein and EE together supplying about 1/3 as much energy as the starch. 3. Structure of Grain 3. Structure of Grain Aleurone(糊粉层） The aleurone surrounds the starchy endosperm of grain. The cells of the aleurone are thick-walled and rich in oil, niacin（烟酸）, and mineral. Phytic acid（植酸） is also produced in rather large quantities in this region. 3. Structure of Grain Starchy endosperm（淀粉胚乳） Endosperm contains most of the starch and cells fill with starch granules. Starch granules(淀粉粒） are enveloped in a protein matrix which impedes digestion of starch and the digestion of starch can increase if granule are broken open. About 60% of the entire wheat grain and 70% of its endosperm are starch. 3. Structure of Grain ③Germ（胚） Wheat and corn germ have a rather large lipid fraction, containing 10-35% lipid. 4. Nutrient Composition of Grains 4.1 Carbohydrates About 83% of the DM of grains consists of carbohydrates. Corn contains about 70% soluble carbohydrate, over 90% of which is highly digestible starch. The carbohydrate fraction of grain is composed primarily of pentosans（戊聚糖), starch, dextrins(糊精）, sugars, cellulose and hemicellulose（半纤维素）. 4. Nutrient Composition of Grain 4.1 Carbohydrates Grains are generally conside