Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 7/15/2012
Publication Date: 9/11/2012
Citation: Shurson, J.C., Zijlstra, R.T., Kerr, B.J., Stein, H.H. 2012. Feeding biofuels co-products to pigs. In: Makkar, H.P.S., editor. Biofuel Co-products as Livestock Feed—Opportunities and Challenges. Rome, Italy: FAO Publishers. pp. 175-208. Interpretive Summary:
Technical Abstract: Distillers dried grains with solubles (DDGS) and other co-products from the fuel ethanol industry may be included in diets fed to pigs in all phases of production. The concentration of digestible energy (DE) and metabolizable energy (ME) in DDGS and corn germ is similar to corn, but high protein distillers dried grains (HP-DDG) contains more energy than corn. In contrast, if the oil is removed from DDGS, the co-product will have a lower energy concentration than corn or conventional DDGS. Glycerin is a co-product from the biodiesel industry and also contains more energy than corn. Phosphorus in DDGS and HP-DDG is highly digestible to pigs, and apparent total tract digestibility (ATTD) values of approximately 60 percent have been reported for these ingredients. In contrast, the digestibility of phosphorus in corn germ is much lower and similar to corn. The concentration of starch in DDGS is low (i.e., between 3 to 11 percent on an as-fed basis), but the concentration of fat in DDGS is approximately 10 percent and the concentration of acid detergent fiber (ADF), neutral detergent fiber (NDF), and total dietary fiber in DDGS is approximately three times greater than in corn (9.9, 25.3, and 42.1 percent, respectively). The ATTD of dietary fiber is less than 50 percent, which results in low digestibility values for dry matter (DM) and energy in DDGS. The concentration of most amino acids in DDGS is approximately three times greater than in corn, but the standardized ileal digestibility of most amino acids average approximately 10 percentage units less than in corn. The same is the case for corn germ and HP-DDG. Nursery pigs, beginning at two to three weeks post-weaning, and growing-finishing pigs may be fed diets containing up to 30 percent DDGS without any negative impact on pig growth performance, if they are formulated on a SID amino acid basis using crystalline amino acids to insure that all digestible amino acid requirements are met. However, carcass fat in pigs fed DDGS-containing diets has a higher iodine value (unsaturated to saturated fatty acid ratio) than in pigs fed no DDGS. As a result, it may be necessary to withdraw DDGS from the diet of finishing pigs during the final three to four weeks prior to harvest to achieve desired pork fat quality. High protein DDGS may be used in diets fed to growing-finishing pigs in quantities sufficient to replace all of the soybean meal, and at least 10 percent of corn germ. Up to 30 percent de-oiled DDGS can be included in diets fed to weanling pigs, but only 10 percent should be used in diets fed to growing-finishing pigs. Crude glycerin can be included in diets fed to weanling and growing-finishing pigs in quantities of up to 6 and 15 percent, respectively, and lactating sows fed diets containing up to nine percent crude glycerol perform similarly to sows fed a standard corn-soybean meal diet. Lactating sows can be fed diets containing up to 30 percent DDGS, and DDGS can replace all of the soybean meal in diets fed to gestating sows without negatively impacting sow or litter performance. Inclusion of DDGS in diets fed to pigs may improve intestinal health and the immune system activation, but more research is needed to elucidate the mechanism responsible for these effects. Manure volume will increase if DDGS is included in the diet because of the reduced dry matter digestibility. Nitrogen excretion may also increase, but this can be prevented by the use of crystalline amino acids in diets containing DDGS. In contrast, P excretion can be reduced in diets containing DDGS if the total dietary concentration of P is reduced to compensate for the greater digestibility of P in DDGS.