乙醇合成饲料可降低淡水鱼生产成本

　美国农业研究局的科学家发现，乙醇合成饲料可以提供丰富的蛋白质和必需的氨基酸给鱼类，比普遍使用的大豆-玉米饲料营养丰富，而且节省成本。这项研究具有潜在的经济价值，可以帮助运营商找到更便宜的蛋白质来源，降低鱼饲料的成本，从而降低整个生产成本。（国际情报研究室译）

　　【原文】

　　Ethanol Co-Products Could Lower Cost of Freshwater Fish Production　

　　By Laura McGinnis

　　October 19, 2007　

　　Add this to the list of ethanol's potential benefits: lowering the cost of fish production.　

　　Fish feed is a major expense for many aquaculture operations. New research by Agricultural Research Service (ARS) scientists shows that ethanol co-products can provide protein for fish feeds at a lower cost than the soybean-corn combinations commonly used.　

　　The recent proliferation of ethanol processing facilities has led to a surplus of distiller's dried grains with solubles, or DDGS—a nutrient-rich processing co-product that is often used to feed livestock.　

　　DDGS is relatively protein-rich and lacks some of the undesirable characteristics that make many plant protein sources less suitable for use in fish feeds. In addition, DDGS is cheaper and more palatable to fish than soybean-corn combinations. However, it lacks some essential amino acids, such as lysine.　

　　In the ARS Aquatic Animal Health Research Unit at Auburn, Ala., nutrition scientist Chhorn Lim and his colleagues are evaluating how diets including DDGS influence growth performance and disease resistance in catfish and tilapia.　

　　The scientists gave the fish feeds that included 0, 10, 20, 30 or 40 percent DDGS. All five feeds had similar levels of energy, protein and fat. Results showed that tilapia thrive on feed with up to 20 percent DDGS. Adding supplemental lysine to the feed increased that percentage to 40 percent.　

　　The scientists found that catfish thrived on feed comprising up to 40 percent DDGS plus lysine. In addition, they observed that catfish raised on diets that included DDGS demonstrated greater resistance to at least one major disease: enteric septicemia of catfish. Catfish raised on DDGS-containing diets were more likely to resist infection.　

　　Surviving catfish raised on a diet without DDGS had fewer antibodies than those raised on the DDGS feed—particularly fish on the 20 percent DDGS diet, whose antibodies were significantly higher than those of the control fish.　

　　This work has potential economic benefits for both ethanol and aquaculture. Finding markets for DDGS is essential to economical ethanol production. And substituting soybean-corn combinations with a cheaper protein source could help reduce the cost of fish feed, thereby reducing overall production costs.