甘油在反刍动物生产中的应用

Application of Glycerol in Ruminant Production

随着大量生物燃料副产品的问世,人们对生产生物柴油作为生物可再生燃料的兴趣与日俱增。甘油是生产生物柴油过程中产生的副产物,又名丙三醇,是一种无色无味的糖醇,但口感甜美,在水中的溶解度指数高。此外,它也是肝脏和脂肪组织合成甘油三酯和磷脂的重要底物,还能够参与糖异生和糖酵解途径进行糖代谢,从而提高血液中葡萄糖含量并减少酮体含量。近几年大量的试验支持用低水平的甘油改善围产期奶牛能量平衡和肝脏糖原合成,以缓解酮病发生,但甘油的水平过高,会增加瘤胃中丙酸和丁酸的含量,从而造成反刍动物瘤胃代谢性酸中毒。本文基于近几年甘油对肉牛和奶牛生长性能和代谢、瘤胃内发酵和屠宰性状等方面的影响,客观论证甘油作为一种糖异生的前体物质取代传统饲粮中的部分能量饲料原料的可行性。

With the advent of a large number of biofuel by⁃products,people are increasingly interested in pro⁃ducing biodiesel as a bio⁃renewable fuel.Glycerin,also known as glycerol,is a by⁃product produced in the process of biodiesel.It is a colorless and flavorless syrup⁃like liquid,but it tastes sweet and has a high solubility index in water.In addition,glycerol is an important substrate for the synthesis of triglycerides and phospholipids in liver and adipose tissue,and also can participate in gluconeogenesis and glycolysis pathway for glucose metabolism,thus increasing blood glucose content and reducing ketone body content.In recent years,a large number of experiments used low level of glycerol as a supplement to improve energy balance and hepatic glyco⁃genesis for dairy cows in transient period in order to alleviate ketosis.However,when the level of glycerol sup⁃plement is too high,the ruminal contents of propionic acid and butyric acid would be increased,which could cause rumen metabolic acidosis.This review summarized the feasibility of glycerin as a precursor of gluconeo⁃genesis to replace some portions of energy source in diets according to the effect of glycerin in feed on growth performance,nutrient metabolism,rumen fermentation and carcass traits of ruminants.