Hi, everyone. Thank you for tuning into this podcast. My name is Molly McGhee and I am a first-year grad student in Dr. Stein's lab. The title of this podcast is “Apparent and standardized ileal digestibility of amino acids and starch in hybrid rye, barley, wheat, and corn fed to growing pigs.” So to begin with, I'd like to start with an outline. I will start off with an introduction and give you a bit of background about hybrid rye, and then I will move into talking about the nutritional characteristics of hybrid rye, followed by a discussion about a digestibility experiment that we conducted, and lastly I will conclude and leave you with some take-home messages. So to begin with, I'd like to discuss hybrid rye and why we're studying it in the first place. Hybrid rye has many agronomic advantages which makes it an ideal crop for farmers to grow. It's also used for multiple purposes and it's a high-fiber cereal for livestock diets. So focusing on the agronomic advantages specifically, hybrid rye has higher yields and lower inputs compared to other cereal grains. Hybrid rye, in some field tests for KWS, was yielding up to 200 bushels per acre on good quality soil and on lower quality soil was still yielding around 100 bushels per acre—and these are with lower inputs per unit of yield compared to other comparison crops like wheat. Furthermore, hybrid rye is very drought tolerant. It has deep roots, which makes it able to sequester more water from the soil. Hybrid rye also has several winter crop advantages, including its ability to disrupt the weed cycle in a traditional corn-soybean rotation as well as being hearty and able to withstand cold temperatures. And then lastly, the new hybrids of rye that are developed by KWS have a reduced ergot contamination risk. The way that KWS has been able to do this is by utilizing the RFP-1 gene which increases the efficiency of fertilization, which basically reduces the opportunity for ergot to infect the plant. So the next advantage of growing hybrid rye is that it can be used for multiple purposes including the biogas industry, in the human food sector as bread and also for distilling and then lastly as a livestock feed, which is what we're going to focus on today. So as a livestock feed, hybrid rye is a very high fiber cereal compared to some other grains such as corn. So, it is a cereal grain, so it's in the same category as barley, wheat, sorghum, and corn and it's very high-energy—it has a lot of starch. Furthermore, hybrid rye has a greater concentration of fiber than other cereal grains and its specific fiber composition translates to improved gut health. It has been shown that hybrid rye promotes the production of butyrate, which can be used as an energy source in the colon and overall improve the health of the gut in livestock animals. Lastly, we feel that hybrid rye is best suited to be used in sows and growing and finishing pigs. So now that we have a bit of a background about hybrid rye, I'd like to move into talking about the nutritional characteristics of hybrid rye. This photo is a photo of our University of Illinois feed mill, which is where all of our grains were ground. And so once we had all of the samples in the lab, we did a complete nutritional analysis, which I will give you an overview now. So to begin with, I'd like to look at crude protein. On the bottom I'd like to set up the slide. I have Bono, Daniello, and Brasetto, which are three hybrids of rye the first to Bono and Daniello were grown in Germany while Brasetto was grown in Canada. And then we compared these with three comparison cereal grains including barley, wheat, and corn, and these are all grown in the United States. So to begin with, you can see that all three of the hybrid ryes had a crude protein concentration of right around 9%, while barley and wheat had a greater concentration of crude protein at 10.5 and 11.4% respectively and corn had the lowest concentration of crude protein at 7.2%. When looking at the specific amino acids within the crude protein, you can see that lysine was exactly the same across the three hybrids of rye, which are shown in orange, and then barley and wheat had slightly greater concentrations of lysine while corn had the lowest concentration of lysine. And we see these general trends follow through other important amino acids including methionine, threonine, and tryptophan. You can see that there are very small differences between the three hybrids of rye while barley and wheat had greater concentrations of these three amino acids and then lastly corn was either very similar or lower than the hybrid rye. So next I'd like to discuss starch, which is the main energy component of these cereal grains. What we found is that the three hybrids of rye had around 55 to 56% starch while barley and wheat had around 60 percent, so a little bit greater, and then corn had the greatest concentration of starch at 63%. So starch, as we all know, is the digestible portion of the carbohydrate fraction. We also looked at the dietary fiber, so, the indigestible carbohydrate fraction of these grains. What we found is that Bono, Daniello, and Brasetto hybrid ryes had a greater concentration of IDF or insoluble dietary fiber as well as SDF or soluble dietary fiber compared to our comparison grains. These two fractions added together make up what we know as total dietary fiber or TDF. So as I mentioned, the three hybrids of rye had a greater concentration of TDF compared to barley, wheat, and corn. When we looked more specifically at the fiber components that made up TDF, what we found is that lignin and cellulose did not differ too much among all of the cereal grains. We expected this because both of these fiber components are associated with plant cell walls, so we would expect to find these in all of the cereals. The next fraction that we analyzed were arabinose and xylose which make up the fiber component known as arabinoxylans. What you can see here is that the three hybrids of rye had the greatest concentrations of arabinoxylans, followed by wheat and then barley, and corn had less arabinoxylans. The next component that we analyzed for were beta-glucans. What we expected to see is that barley would have the greatest concentration of mixed-linked beta-glucans and that's exactly what we found. However, we also saw that the three hybrids of rye also had a significant portion of beta-glucans, while wheat and corn had less. And then the last fraction that we looked at were fructans. And this is a very important fiber component to look at because it's known to have prebiotic effects and can promote gut health. What we found is that the three hybrids of rye had the greatest concentration of fructans. So now that we've talked a bit about the nutritional characteristics overall of the cereal grains, I'd like to move into talking about the ileal digestibility experiment that we conducted at the Swine Research Center here at the U of I, which is shown in this photo. The objective of this experiment that we conducted is to determine the amino acid and starch digestibility of hybrid rye. And we did this by calculating the apparent and standardized ileal digestibility. And then we wanted to compare those values to other cereal grains. So as you may have guessed, we wanted to compare that to barley, wheat, and corn. To conduct this experiment, we had a Latin Square design with seven treatments and seven periods. And the experimental unit were seven cannulated barrows with an initial body weight of around 26 kilograms. For sample collection we had a seven-day period with five days of adaptation and then two days of collection for eight hours each. Collecting the samples is very straightforward—we simply take off the cap of the cannula, as you can see in the photo on the bottom left, and then put a bag on the cannula and then the ileal digesta flows through. And then we're able to collect that and analyze it for nutrients. So once we had all of our analysis complete and we had our data we analyzed it in SAS with the mixed procedure. We had treatment as the main effect and pig and period as the random effect. So before I move into discussing the results I just like to quickly go over the experimental diets that we used. You can see that treatment 1 through 6 had around 94% of the cereal grain as the main ingredient. And the reason we did this is so that the cereal grain was the sole contributor of amino acids and starch. We also included around 3 to 4% of soybean oil in all the diets to reduce dust, and then we used chromic oxide as an indigestible marker so that we can make those digestibility calculations. And then our seventh diet was a nitrogen-free diet, and it was primarily made up of corn starch and sucrose, which means that it was devoid of amino acids so that we can use it to calculate standardized ileal digestibility by calculating the basal endogenous losses. So moving into the results, again on the bottom we have our three hybrids of rye and then barley, wheat, and corn. The first slide that I'd like to discuss is the apparent ileal digestibility of starch. What we found is that there were no differences among the digestibility of starch in the three hybrids of rye and barley; however, the digestibility was greater in wheat and corn. Despite the differences that we picked up statistically I'd also like to point out that all of these digestibility values were over 95%, which was very high. This high digestibility of starch and all the cereal grains means that the pigs were obtaining about as much energy as they can from that starch fraction. When we looked at crude protein digestibility, we found that there were no differences among Bono, Daniello, and Brasetto. However, barley, wheat, and corn had a greater standardized ileal digestibility of crude protein than our hybrid ryes. When we looked at the digestibility of amino acids—specifically lysine, methionine, threonine, and tryptophan—we saw the same trends as the digestibility of crude protein. So you can see here when we look at the standardized ileal digestibility of lysine, that there are small differences among the hybrids; Daniello had a greater digestibility than Brasetto, however, there's no difference when comparing to Bono. However, barley, wheat, and corn had a greater digestibility of lysine than the three hybrids of rye. We see the same trends continue with methionine. Wheat and corn had the greatest digestibility of methionine followed by barley and then again the small differences among the hybrids of rye but significantly lower than the three comparison grains. And then again with threonine and tryptophan we see the same trends: there are no differences among the three comparison grains, but the hybrids of rye, there were small differences between them but all significantly lower than the other comparison grains. However, although the digestibility of amino acids were lower in the hybrids of rye compared to the other cereal grains, when we calculate the concentration of digestible amino acids on a g/kg basis by multiplying the digestibility coefficients by the amino acid concentrations in the grains, we found that there are very small differences between hybrid rye and corn. This is important because in the United States, if hybrid rye is included in a in a diet formulation it will be added at the expense of corn. So as you can see when we look at these nutrients—including crude protein, lysine, methionine, threonine, tryptophan, and valine—that there are small differences indicating that the provision of amino acids if we replace corn with hybrid rye is going to be roughly the same. So with all of that in mind I'd like to leave you with some conclusions. The digestibility of amino acids and starch is lower in hybrid rye than other cereals. However, when we looked at the concentration of digestible amino acids we found that the standardized ileal digestible crude protein and amino acid content in hybrid rye is not different from corn. I'd also like to come back and remind you of the agronomic advantages that we can achieve with hybrid rye. We can get higher yields than barley and wheat and we also have those winter crop advantages of growing hybrid rye which could be beneficial to adding hybrid rye to a corn-soybean rotation. And then lastly, I’d like to leave you with the take home thought that the feeding value of hybrid ryes may be greater than what is represented in these data because the greater concentration of fiber will contribute to hindgut fermentation, which may increase the overall feeding value as a whole. This is something that we will be looking at in a future experiment where we will look at the fermentation and digestibility of fiber. So with that, I'd like to acknowledge KWS cereals division for project funding and support and everybody in Dr. Stein's Monogastric Nutrition group. Thanks again for listening. If you have any other questions or you'd like other information about the work that we're doing in our group, feel free to reach out and visit our website at nutrition.ansci.illinois.edu.