Hello. My name is Laura Merriman and today I will be discussing some research that was conducted at the University of Illinois swine research farm. The title for todays presentation is the effect of fat sources on the apparent total tract digestibility of minerals. The outline for this presentation is as follows. I will start with an introduction on the use of fat supplements and past results with human and pig data. I will then state the objective of this experiment, provide you with the materials and methods, and then state the results for the digestibility of macrominerals, microminerals, and fat. I will then leave you with some conclusions and some take home messages. There are many reasons why fat may be included in diets fed to pigs. First, these ingredients are an excellent source of energy. Next, they reduce the dustiness of the diet. And lastly, they increase the palatability of the diet. The basis for the present experiment came from data reported with humans. In humans, it has been observed that an increase in dietary calcium results in an increase in fat excreted in the feces when saturated fats are included in the diet. In this experiment by Bendsen and others, a low calcium diet and a high calcium diet were provided to humans. Those individuals consuming the high calcium diet had 6% more fat being excreted in the feces. Simultaneously, greater concentrations of calcium were observed in the high calcium diet. It was hypothesized that complexes between calcium and fat were formed, and excreted in the feces. However, inconsistent results have been observed. Previous work with pigs has been reported evaluating calcium and phosphorus digestibility in the presence and absence of soybean oil. In this work by Gonzalez-Vega and others from 2015, she fed a fishmeal and corn basal diet. She also fed a diet containing 7% soybean oil at the expense of cornstarch. She observed no difference in the apparent total tract digestibility or standardized total tract digestibility of calcium, and no difference in the apparent total tract digestibility of phosphorus. However, in this experiment she used an unsaturated fat, soybean oil. In humans, it was suggested that the saturated fats were causing the formation of calcium-fat complexes. Here I have listed 5 fats often used in pig diets. These fat sources include tallow, choice white grease, palm oil, corn oil, and soybean oil. You can see that the fats on the left are more solid but the fats on the right are more liquid. The reason for this is the concentrations of saturated and unsaturated fatty acids. The concentrations of saturated fats are greater on the left side of the slide such as tallow. Alternatively you can see that the concentrations of unsaturated fats are greater in the ingredients to the right, such as corn oil and soybean oil. So, the objective of the current experiment was to determine the effect of supplementing diets fed to growing pigs with fat sources that differ in their concentrations of saturated and unsaturated fatty acids on the digestibility of minerals, those minerals being calcium, phosphorus, magnesium, zinc, manganese, sodium, and potassium. To answer our objective, we used 60 growing barrows with initial body weight of 16kg. In total, there were 6 experimental diets. The first diet was a basal diet containing 7% sucrose and no supplemental fat. Then, 5 diets were formulated to include 7% of tallow, choice white grease, palm oil, corn oil, or soybean oil, and those ingredients were included at the expense of sucrose. Each diet was fed to 10 replicate pigs, and diets were fed in 2 blocks of 30 pigs. The source of calcium for the experimental diets was calcium carbonate, and most of the phosphorus was provided by monosodium phospahte. Here I have provided the composition of the basal diet. The diet consisted mostly of corn and potato protein. The basal diet contained 7% sucrose, and individual test ingredient was included at the expense of this sucrose, such that the diets were identical except for this 7%. The calcium was provided by calcium carbonate and phosphorus was mostly provided by monosodium phosphate. All diets were formulated to contain 0.7% total calcium and 0.33% standardized digestible phosphorus. Pigs were individually housed in metabolism crates. Total feces were collected using the marker to marker approach. For this experiment, each period lasted a total of 12 days. The first 5 days served as the adaptation period to the diets and the environment. Then on day 6, the indigestible marker indigo carmine was included in the morning meal to indicate the beginning of collection, and on day 11, the indigestible marker ferric oxide was included to indicate the end of collection. The direct procedure was used for the determination of nutrient digestibility and the standard calculation for apparent total tract digestibility was used. Where the apparent total tract digestibility was computed using nutrient intake minus nutrient output, that divided by nutrient intake, and multiplied by 100%. For the statistical analyses, we used the Mixed procedure of SAS. The model contained a fixed effect of fat source and a random effect of block. The experimental unit was the pig. Significance was observed when P values were less than 0.05, and tendencies were observed when P values were greater than or equal to 0.05 but less than 0.1. As we move to the results, I will first set up the slide, and subsequent slides will follow the same format. Across the X axis, we have the experimental diets, the basal diet, the diet containing tallow, the diet containing choice white grease, the diet containing palm oil, corn oil, and soybean oil. Then, on the Y axis, we have the digestibility expressed as a percentage. First, I have there the apparent total tract digestibility of calcium. And the apparent total tract digestibility of calcium was greater by pigs fed diets containing tallow, palm oil, corn oil, and soybean oil, compared to that of the basal diet. However, the basal diet was not different from the diet containing choice white grease. The digestibility of calcium among these diets was between 50 and 70%. The apparent total tract digestibility of phosphorus was greater by pigs fed the diet containing soybean oil, palm oil, and tallow compared with the basal diet. The apparent total tract digestibility of phosphorus was not different between pigs fed the basal diet and pigs fed diets containing choice white grease or corn oil. Here, the apparent total tract digestibility of phosphorus was between 50 and 65%. There were no differences among diet treatments for the apparent total tract digestibility of magnesium; however, a tendency was observed. The values for the apparent total tract digestibility of magnesium were between 25 and 35%. There were no differences in the digestibility of sodium, and all values were close to 90%. Next, I’ve shown the digestibility of sulfur. The apparent total tract digestibility of sulfur was greater by pigs fed the diet containing soybean oil than the diet containing choice white grease, but all other diets were intermediate. The digestibility of sulfur was between 81 and 85% in all diets. There were no differences among dietary treatments for the apparent total tract digestibility of zinc, and those values were between 10 and 20%. There were also no differences among dietary treatments for the apparent total tract digestibility of manganese, and those values ranged from 15 to 25%. Lastly, there were no differences in the apparent total tract digestibility of potassium, with those values ranging between 70 and 80%. Next, I’ve displayed the concentration of fat, represented in g/d. Greater concentrations of fat were observed by pigs fed diets containing choice white grease and palm oil, compared with soybean oil. This resulted in greater digestibility of fat in palm oil, corn oil, and soybean oil compared with pigs fed the diets containing either 7% choice white grease or no supplemental fat. In conclusion, the digestibility among different minerals is quite variable. For instance, the digestibility is quite low in manganese, zinc, and magnesium but relatively high in sodium, potassium, and sulfur. Supplementation of choice white grease in diets fed to pigs does not change the digestibility of minerals from the basal diet. And also, tallow, palm oil, corn oil, and soybean oil may increase the digestibility of calcium and phosphorus, but not of other minerals. Furthermore, the results from the present experiment are consistent with human data in regards to the concentrations of fat being greater in diets containing more saturated fats. However, the digestibility of fat was similar across dietary treatments with the exception of choice white grease. Therefore, the take home message is that providing fat, with the exception of choice white grease, at 7% of the diet may increase the digestibility of calcium and phosphorus, but does not influence the digestibility of other minerals such as zinc, manganese, potassium, or sodium. I would like to thank AB Vista for supporting this project. If you have any questions about this work or other work conducted by our lab, please visit our website at nutrition.ansci.illinois.edu.