Slide 1 Hi. My name is Oscar Rojas, and I'm a master's student in Dr. Stein's Monogastric Nutrition Laboratory. And today, I will have the pleasure to talk about phosphorus and amino acid digestibility in fermented and conventional soybean meal fed to weanling pigs. Slide 2 For the outline of my presentation, I will start with an introduction, and then I will move on to the first and the second experiments, which are phosphorus digestibility and amino acid digestibility, and finally some conclusions, and the implications of this research. Slide 3 As part of my introduction, later on I will explain how phosphorus is present in conventional soybean meal, and how phytate concentration and microbial phytase have an effect on the digestibility of phosphorus. Fermentation of conventional soybean meal is an important process, and the main reason of this is because young pigs cannot tolerate conventional soybean meal due to the presence of anti-nutritional factors in conventional soybean meal, which have a negative effect in the digestion and absorption of nutrients. And that's why we use fish meal in weanling pig diets. However, fermentation of conventional soybean meal may remove these anti-nutritional factors. At this point, I would like to mention that fermented soybean meal is produced now in the U.S. and is also available in the market right now. Slide 4 Most of the phosphorus in conventional soybean meal is bound in the phytate molecule. The phytate-bound phosphorus is not available to the pigs because the pigs have limited endogenous phytase activity. And therefore phytate-bound phosphorus is excreted in the feces, which may contribute to environmental problems. However, when we add phytase enzyme, which is the one that hydrolyzes the phytate-bound phosphorus, digesting the phytate molecule, and the result of the addition of this phytase is going to be an increase in the digestibilty of phosphorus. So however, we don't know exactly what happens when conventional soybean meal is fermented. Perhaps we can say that fermentation of conventional soybean meal may result in hydrolysis of phytate and release the phosphorus. So our hypothesis here is that fermentation can break these phytate bonds and therefore increase the digestibility of phosphorus. Slide 5 In this slide, I am going to explain briefly how is the fermentation of conventional soybean meal. We start again with the conventional soybean meal that is the byproduct of the production of soybean oil. This conventional soybean meal is going to be soaked and then cooked and then inoculated with Aspergillus oryzae and Bacillus subtilis to produce fermented soybean meal. Slide 6 In this slide, I am going to show you what is the composition of fermented and conventional soybean meal. For crude protein, it's slightly higher in fermented soybean meal, which is 55.5%, than in conventional soybean meal, which is 47.2%. When we look at dry matter, it's slightly higher, too, in fermented soybean meal, 90.8% and in conventional soybean meal just 88%. When we look at ether extract, it's around the same value -- 1.4% in both sources. And ash and lysine is slightly higher in fermented soybean meal than in conventional soybean meal. Slide 7 So what is the distribution of phosphorus in fermented and conventional soybean meal? The total phosphorus in fermented soybean meal is 0.78 versus 0.66 in conventional soybean meal. Remember that I mentioned before that the two forms of phosphorus are phytate-bound phosphorus and non-phytate phosphorus. The phytate-bound phosphorus in fermented soybean meal is 0.39 and in conventional soybean meal is 0.43. When we look at non-phytate phosphorus, it's 0.39 in fermented soybean meal and 0.23 in conventional soybean meal. This means that 50% of the total phosphorus is phytate-bound phosphorus in fermented soybean meal, and the other 50% is non-phytate phosphorus in fermented soybean meal. In the case of conventional soybean meal, 64.5 is phytate-bound phosphorus, and 35.5% is non-phytate phosphorus. So maybe at this point, we can start thinking that fermentation can have an effect in the concentration of phytate-bound phosphorus in conventional soybean meal. Slide 8 So let's move on to the first experiment. Slide 9 The objective of this experiment was to test the hypothesis that the STTD of phosphorus in fermented soybean meal is greater than in conventional soybean meal. Slide 10 In this experiment, we used 30 barrows with initial body weight around 14 kg. They were put in metabolism cages, and they were allotted in a randomized complete block design with five diets. We used six pigs per treatment, and feces samples were collected after five days adaptation period. Slide 11 So how did we calculate the ATTD and STTD? ATTD is calculated by simply subtracting the output phosphorus from the intake phosphorus. And then divide it for the phosphorus intake. When we calculate STTD, it is basically just: correct ATTD values by the basal endogenous phosphorus losses. This means that we subtract the basal endogenous losses from the phosphorus output and then we subtract the phosphorus intake, and then divide it by the phosphorus intake. Slide 12 So what are the composition of the experimental diets? We formulated two fermented soybean meal diets -- one without phytase and the other one with phytase -- and we included fermented soybean meal at 47% in the first and the second diets. We also formulated two conventional soybean meal diets -- one without phytase and the other one with phytase -- and we included conventional soybean meal at 50% in the third and the fourth diets. In addition to these four diets, we formulated a phosphorus-free to measure the basal endogenous phosphorus loss. Slide 13 These data were analyzed as a 2x2 factorial, and we used the Proc Mixed procedure. The fixed effects were the sources of soybean meal, phytase, and the interaction between soybean meal and phytase, and the random effect was the replicate. Slide 14 So let's move on into the results. Slide 15 So just take a minute to set up this slide. In the Y-axis, we have the digestibility in percent, and in the X-axis, we have on the left the fermented soybean meal, and on the right the conventional soybean meal. The red bar represents without phytase, and the blue bar represents with phytase. The STTD of phosphorus was greater when phytase was used than if no phytase was included in the diets, regardless of the source of soybean meal. The increase in STTD when phytase was used was, however, greater for conventional soybean meal than for fermented soybean meal. The reason of this observation may be that the amount of phytate-bound phosphorus is greater in conventional soybean meal than in fermented soybean meal. And therefore, phytase hydrolyzed more phytate in conventional soybean meal than in fermented soybean meal, and increased the digestibility of phosphorus. The digestibility of phosphorus was greater in fermented soybean meal than in conventional soybean meal. And this observation is the result of the reduced concentration of phytate-bound phosphorus in fermented soybean meal compared with conventional soybean meal. So at this point, I would like to emphasize that fermenttaion did indeed reduce the amount of phytate-bound phosphorus, and indeed increase the digestibility of phosphorus. However, you could get the same increase in conventional soybean meal by adding phytase to the diet. Slide 16 The conclusions for this experiment are the STTD of phosphorus is greater in fermented soybean meal than in conventional soybean meal if microbial phytase is not added to the diet, and if phytase is used, there is no difference in STTD of phosphorus between fermented soybean meal and conventional soybean meal. Slide 17 Let's move on to the second experiment. Slide 18 The objective of this experiment was to determine the standardized ileal digestibility of amino acids in fermented soybean meal and to compare these values to the values obtained for conventional soybean meal and fish meal. Slide 19 In this experiment, we used eight barrows with initial body weight around 10.4 kg. We formulated four diets, and ileal digesta were collected for eight hours on days 6 and 7 of each period. The experimental design was a repeated 4x4 Latin square with four periods and four diets. Slide 20 What are the composition of the experimental diets? We formulated three cornstarch-based diets, and we included at the first diet fermented soybean meal at 30%. We included also conventional soybean meal in the second diet at 33%, and fish meal in the third diet at 25%. In addition of these three diets, we formulated a nitrogen-free diet to calculate the basal amino acid endogenous losses. Slide 21 These data were analyzed by Anova using the Proc Mixed proceudre. The fixed effect was the diet, and the random effects were the pigs and the replicate. Slide 22 So let's move on into the results. Slide 23 When we look at SID of lysine, we didn't observe any significant difference among treatments. Slide 24 However, when we look at SID of methionine, we observe that in fermented soybean meal, was greater than in conventional soybean meal and that in fish meal. Slide 25 When look at the SID of threonine, we didn't observe any significant difference among treatments. Slide 26 And when we look at the SID of tryptophan, we have the same pattern of lysine and threonine: no significant difference among treaments. Slide 27 In this slide, we are looking at digestible amino acids g/kg. You can obtain these values when you multiply the amino acid concentration in the ingredient by the SID coefficient. We observe here that fish meal has greater digestible lysine, methionine, and threonine than fermented soybean meal and conventional soybean meal. And the reason of this observation is that fish meal has more lysine, methionine, and threonine concentration than in fermented soybean meal and conventional soybean meal. However, when we look at digestible tryptophan, it's greater in fermented soybean meal and in conventional soybean meal than in fish meal. And once again, it's because fermented soybean meal and conventional soybean meal have greater tryptophan concentration than fish meal. Slide 28 So the conclusion for these experiments are: the fermentation of conventional soybean meal does not reduce the amino acid digestibility; and the SID of most amino acids is not different between fermented soybean meal and conventional soybean meal, but these values are greater than in fish meal. Slide 29 The implications of this reasearch are that fermented soybean meal contains more digestible phosphorus than conventional soybean meal, which reduces the need for inclusion of inorganic phosphorus in diets containing fermented soybean meal. And fermentation of conventional soybean meal does not affect the amino acid digestibility and therefore fermented soybean meal can be used for diets fed to weanling pigs. Slide 30 So I would like to thank you for your attention, and I hope this information was useful. And if you want to know more about phosphorus and amino acid digestibility, you are more than welcome to watch the other presentations in our web site.