Regional and processor variation in the ileal digestible amino acid content of soybean meal measured in growing swine.

To determine whether quality differences existed in soybean meal, a major research effort was designed to measure the variation in nutritional value of soybean meal that was processed in a single plant over a 45-day period and to evaluate the amount of variation that exists between soybean meal processors. Researchers in Illinois, Kansas, North Carolina, Ohio and the Netherlands obtained four soybean meal samples processed locally 15-days apart. The meal samples were assayed for ileal digestibility in pigs. A common soybean meal, a soy protein concentrate and a low-protein casein diet were included for assessing variability between laboratories. Standard ileal digestibility procedures were used to determine amino acid digestibility of the various meal sources. Results indicated that the four soybean meal samples collected in the United States varied little in nutrient content and digestibility. The meal samples obtained in the Netherlands were more variable, had lower lysine and methionine levels and lower nutritional values compared to meals of U.S. origin. The soybean meals tested in this experiment were approximately four percent higher in total amino acid content compared to the values reported in the 1998 NRC tables. However, the differences in true digestibility values that were standardized were minor. Of interest to the nutritionist was the observation that digestible amino acids levels in soybean meal can be calculated from total amino acid levels; the total amino acid content of the meals explained 89 to 98 percent of the variation in digestible amino acid content. (These results have a lot of practical value: They indicate that soybean meal collected in four regions in the U.S. varied little in nutrient content or amino acid digestibility. Quality differences attributed to soybean processing were minor. Nutritionists interested in monitoring the quality of the meal being incorporated in feed formulations can rely on total amino acid determinations since total amino acid values are closely related to digestible amino acids and meal quality. These results again demonstrates soybean meal’s amino acid profile, high digestibility and competitive price make it a logical protein source for feeding swine and poultry).

Van Kempen, T. and co-workers. 2002. Regional and processor variation in th ileal digestible amino acid content of soybean meal measured in growing swine. J. Animal Sci. 80(2):429-439