Slide 1 Hello. I am Caroline Gonzalez, and today I would like to discuss amino acid digestibility in heated soybean meal fed to growing pigs. This study was conducted by Gonzalez, Kim, and Stein in the University of Illinois. Slide 2 Contents: First, an introduction. Second, the objective. Third, the materials and methods. After that, the results and the discussion. And finally, the conclusion. Slide 3 Soybean meal has different antinutritional factors. Some of them are the trypsin inhibitors. These can reduce the performance in pigs. However, some studies show that heat treatment can reduce their concentration in soybean meal. But at the same time, the heat can affect the concentration and the digestibility of amino acids. The amino acid most affected is lysine, by Maillard reaction. However, development of Maillard reaction depends on the water activity, temperature, pH, time of heating, and the type and availability of the reactants. Therefore, amino acid digestibility can be impaired with the heat treatments. Slide 4 For this reason, the objective of this study is to measure the effects of heat treatment of soybean meal on apparent and standardized ileal digestibility of amino acids by growing pigs. Slide 5 The materials and methods that we used for this study were ten growing barrows with initial body weight 25.3 kg, with a standard deviation 2.15. The treatments were five different diets. Four of them were with soybean meal, and the same formulation. However, each soybean meal had different heat treatment. The first diet was a control which had no heat treatment. The other ones were heated at the same temperature: 125 degrees Celsius. However, two of them were autoclaved for different times. One was for 15 minutes, and the other one was 30 minutes. The other soybean meal diet was oven dried for 30 minutes. Autoclaving and oven drying are heat treatments, but they have different properties. Autoclaving involves moisture, pressure, and heat, and oven drying involves just thermal treatment whose function is to remove moisture by heating. The last diet was a nitrogen-free diet for estimating basal endogenous losses. The pigs were fed at three times the maintenance energy requirement, and the diets were changed according to the period. The pigs had free access to water. The sample collections were done each period. Each period was seven days long, and the collection was done on the sixth and seventh day for eight hours. Slide 6 This table shows the chemical composition of soybean meal after heat treatment. The content of crude protein were similar between diets; however, the concentration of the lysine and cysteine in autoclaved soybean meal were decreased. The content of the other amino acids was not affected. Slide 7 The ingredient composition of the four soybean meal diets had the same formulation. The soybean meal was included at 40% and was the only protein source. The nitrogen-free diet did not contain protein. Slide 8 The chemical composition of the experimental diets showed that the crude protein and amino acid content were similar between soybean meal diets; however, the lysine content was reduced in autoclaved soybean meal. Slide 9 Now, I would like to show you the results and the discussion present in this study. Slide 10 In this table, we can see the results in apparent ileal digestibility of crude protein and amino acids in soybean meal subjected to different thermal treatments. The crude protein and amino acid digestibility were linearly decreased as the time of autoclaving increased from 0 to 30 minutes. The greatest reductions were observed for lysine and aspartic acid. However, the apparent ileal digestibility for most amino acids were numerically reduced in oven dried soybean meal compared with the control, but was not significantly different. Slide 11 The standardized ileal digestibility of crude protein and amino acids showed a linear decrease in autoclaved soybean meal when the time was increased. The greatest reductions were found in lysine and aspartic acid. However, the standardized ileal digestibility in oven dried soybean meal was numerically decreased compared with the control diet, but it was not significantly different. Slide 12 The reduction of apparent ileal digestibility and standardized ileal digestibility of crude protein and amino acids observed in autoclaved soybean meal diets is in agreement with other studies realized by Moughan and Rutherford in 1996 and Martinez Amezcua 2007. The reduction of the amino acid digestibility may be due to cross-linkage established between lysine and other amino acids and polypeptide chains during advanced Maillard reaction, which reduce the efficiency of proteolytic enzymes. Slide 13 Most affected was lysine. Maillard reactions involving the amino group of lysine and the carbonyl group of reducing sugars caused a reduction in the digestibility of lysine. Slide 14 The color differences observed between the four soybean meal diets may be due to the melanoidins formed during Maillard reactions. Samples were darker the longer they were autoclaved. However, the oven dried soybean meal had no difference with the color of the control diet. This may be because the moisture content in oven dried soybean meal was too low for developing Mallard reaction. Slide 15 In conclusion, heat treatment with moisture and pressure impaired the apparent ileal digestibility and standardized ileal digestibility of amino acids in soybean meal. Furthermore, increasing the time of autoclaving decreased the digestibility of all amino acids. Slide 16 Thank you for your attention. If you would like more information about monogastric nutrition research, visit our website. Thank you again, and have a good day.