Corn is the main source of energy feeds for pigs. In recent years, both the increasingly rising price and also the tense supply of corn have influenced the development for the pig industry very severely. In order to accommodate with the states, people have been looking for alternative energy feeds actively, and have also conducted much extensive research. Among them, the possibility and prospect of using glycerol (a by-product of biodiesel production) as a source of energy feedstuff proposed by some countries have brought attention from the world.
According to statistics, the capacity of biodiesel under construction in China is up to 3 million t/ year. This means that large amounts of glycerol by-products will be produced worldwide. With the increase of biodiesel production, the quantity of its by-product glycerol also have increased accordingly, providing sufficient material base for the exploitation of glycerol.
Glycerol, a small molecule by-products, is a colorless, odorless, clear liquid, released during the process of biodiesel production. For livestock, fat intake from the fodder will be digested into glycerol and fatty acids in the digestive tract, which will be obtained and finally stored in the adipocytel as the most economical storage form in the body of livestock. And this could convert into heat energy when needed. Therefore, glycerol is one substance of the animal physiological system. Using glycerol as energy feed for livestock has become one of the hot research topics in this way for many countries.
Due to its small molecular weight and molecules, glycerol is easily absorbed by the intestinal tract of livestock via simple diffusion. In the metabolic pathway, glycerol is used for energy production.
The latest study shows that the metabolizable energy (ME) of glycerol is close to its total energy (GE). This indicates that glycerol has a higher digestibility. With proper content, glycerol could improve the quality of pelleted feed, reduce both the energy costs in the pelletizing process, and also the powder in fodder and additives.
Some researchers have pointed out that because glycerol is sweet, it can improve the palatability of fodder.
Iowa State University conducted a series of animal experiments on using glycerol as an energy feed instead of corn. And its results shows that effect of glycerol is comparable to that of corn, with a promising prospect. Dutch Dr. Jannes Doppenberg thought glycerin would be a popular nutritive material as it’s going to be a common ingredient, while other bio-fuel byproducts such as DDGS and rapeseed meal/press cake are low-energy and starch-deficient raw materials. William Dozier, an animal scientist at the USDA’s agricultural research service (USDA-ARS), has pointed out that glycerol can be used as an alternative source of energy in fodder to reduce fodder costs, from a nutritional standpoint. A series of experiments confirmed that glycerol had the same energy value as corn.
Although using glycerol as an energy feed for pigs still with many problems that need to be further studied has not been commercialized on a large scale, the current researches and future development trend indicates that using glycerol as a source of energy for pig fodder has a great foreground.
