Nutritional strategies to reduce phosphorus excretion in swine

Environmental concerns associated with excreted nutrients in animal waste from swine production are continually present. Therefore, we initially determined the available phosphorus requirements for pigs to maximize body weight gain were 0.29, 0.275, 0.18, and 0.15% available phosphorus from 9 to 22, 24 to 50, 50 to 90, and 90 to 120 kilograms body weight, respectively. It was also determined that the requirements to maximize bone mineralization from 9 to 22 and 24 to 50 kilograms body weight were 0.41 and 0.32%, respectively. In a large scale study targeted at evaluating pig growth performance and nutrient excretion from 12 to 125 kilograms body weight was also conducted. By feeding pigs to meet their dietary phosphorus requirement versus a 25% oversupplementation, phosphorus excretion was reduced by 11%. Supplementation of an E. coli phytase to the diet further reduced phosphorus excretion by 25% and resulted in maintained growth performance. Removing all of the supplemental inorganic phosphorus from the pig's diet after 90 kilograms body weight resulted in reduced growth performance, bone ash content, and bone strength. Evaluation of the bioavailability of phosphorus in distiller's dried grains with solubles was also determined to be 85% with the remainder of the phosphorus liberated by supplemental phytase. Utilizing the proper nutritional strategies can result in maintained pig growth performance while reducing phosphorus excretion.