Hello everyone, my name is Su A Lee from University of Illinois. Today, we will discuss the effects of dietary calcium or phosphorus on body bone ash, and also demonstrate which bone most closely predict total body bone ash in pigs. Majority of calcium and phosphorus in the body are deposited in skeletal tissues and teeth, therefore, in many experiments, body bone ash, calcium, and phosphorus have been affected by dietary calcium and phosphorus in pigs. When these kinds of experiments are conducted, bones from legs or feet are usually used because it is easier if we take just one part of bones that represents the total body bone ash. In 2009, Crenshaw and his colleagues demonstrated that femur was a better indicator of total body minerals in 25 kilogram pigs compared with fibula, and since then a number of bone related experiment used femur from pigs. However, the previous experiment only compared the two bones and no data have demonstrated which bone among different bone parts most closely predict total body bone ash in pigs. Therefore, the objective of this experiment was to test the hypothesis that growth performance carcass weights, and total body bone ash are affected by dietary calcium and phosphorus and ultimately, to demonstrate which bone is most representative of total body bone. For this experiment, we utilized 20 pigs with an initial body weight of 40.8 kilograms. Because there were two diets, ten replicates per diet were used. First diet contained corn, soybean meal, calcium carbonate, and D-calcium phosphate DCP as calcium and phosphorus sources, and contained only 60% of requirements for calcium phosphorus. Second diet also contained corn, soybean meal, calcium carbonate, and DCP, but contains calcium and phosphorus at the requirement of pigs. It was a 28 day feeding trial. Body weight and feed intake were measured on day 1, 14 and 28. At the end of the trial, pigs were euthanized and weight of carcass was recorded. Total bones except head were collected and stored separately. The individual bones were third and fourth metacarpals, and metatarsals, femur, tibia, fibula, third and fourth ribs and 10th and 11th ribs. All other miscellaneous bones were also used. Total bone ash was calculated as the sum of the individual bones and miscellaneous bones. Let me briefly explain how body bones were processed. First photo shows frozen bones with soft tissues on. The frozen bones then were autoclaved for 55 minutes. As a result, the soft tissues were cooked and ready to be removed in the second photo. After autoclaved the soft tissues were removed, and the clean bones were soaked in petroleum ether for three days. After all fats on the bones were removed, the bones were dried. These dried bones without soft tissues or fat then were ashed overnight in the muffle furnace. For calculations, we weighed the dried bone as indicated here in A, we also weighed the ashed bone as indicated in B. To avoid any confusion, let me explain the difference between bone ash in gram and percent. First off, the weight of ashed bone itself was the bone ash in gram. Secondly, the concentration of ash in the dried and defatted bone was the bone ash in percent. Jumping to the results, data indicated that average daily gain and average daily feed intake were not affected by dietary calcium or phosphorus. However, pigs fed the diet containing 100% of the requirements for calcium and phosphorus, represented by blue bars, had greater gain to fed ratio compared with pigs fed the diet containing 60% of the requirements for calcium and phosphorus represented by orange bars. Weights of hot carcass, soft tissue, feet, skin, blood and viscera were not different between the two diets, but the weight of head was greater in pigs fed the diet with higher calcium and phosphorus. This may be because the big portion of the head is skull bones. We are looking at the weight of bone ash in gram, weight of total bone ash, and all other individual bone ash were greater in pigs fed the diet containing 100% of the requirements for calcium and phosphorus compared with the diet containing 60% of the requirements for calcium and phosphorus same was observed for weight of calcium and phosphorus in bones. Looking at the body bone ash in percent of the defatted dry bone, the ash concentrations in body bones ranged from approximately 54 to 62%. The concentrations of ash in total body bone, metacarpals, metatarsals, tibia and ribs were greater in pigs fed the diet containing 100% of the requirements for calcium and phosphorus than in pigs fed the died containing 60% of the requirements. This data only show the concentrations of calcium and phosphorus in total bone ash, and there was no effect of dietary calcium and phosphorus on the concentrations of calcium and phosphorus in bone ash. As you already noticed the difference between the two diets in the weights of ashed bone and bone calcium and phosphorus were greater than the difference in the ash, calcium and phosphorus percentage. This indicates that it was the size of bones that were more influenced by diets than concentrations of ash, calcium and phosphorus. Using the data from this experiment, correlation between individual bones and total body bone was analyzed. Because it looks complicated if all lines are lying in one graph, I will show you the correlation graph in three separate slides. The correlation coefficient, r, between weight of total body bone ash, in the vertical axis, and weight of individual bone ash, in horizontal axis, were 0.957 and 0.846, for tibia and femur respectively. As discussed before, femur has been frequently used when calcium and phosphorus related experiments are conducted. So keeping in mind that femur has a coefficient of 0.846 the correlation coefficients were 0.929, 0.956 and 0.971 respectively for fibula, metacarpals and metatarsals. Even though any statistical comparison was not possible, we can see that the correlation coefficient for these three bones were greater than that for femur. The coefficients were 0.876 and 0.817 respectively for 10 and 11 ribs and third and fourth ribs. The previous graphs showed that the correlation between weight of total bone ash and weight of individual bone ash in grams, ranged from 0.817 to 0.971. The correlation coefficients for bone ash in percent, however, were lower than those for the weight of bone ash and the coefficient ranged from 0.539 to 0.741. The correlation coefficients for calcium and phosphorus concentrations in bone ash were close to zero, and all of them were not significant. This again indicated that the composition of calcium and phosphorus are not likely changed much. In conclusion, pigs fed the diet containing 60% of the requirements for calcium and phosphorus showed the reduction in growth and total bone ash in both gram and percent. However, there was no effect of dietary calcium and phosphorus on the concentrations of calcium and phosphorus in bone ash. Based on the correlation coefficient metacarpals, metatarsals, and tibia were better correlated with the total body bone ash than other bones. I would like to acknowledge the sponsor of the study ABVista, and I'd also like to thank my fellow lab members without their help, this experiment would not have been possible. If you enjoyed my presentation, and you'd like to know more about pig nutrition visit our website. You can find the website by googling pig and Stein. Thank you for your attention.