AN EXAMINATION OF DIETARY AMENDMENTS TO AFFECT PHOSPHORUS UTILIZATION IN GROWING PIGS

For economical and ecological reasons, efficiency and profitability of swine production relies heavily on the way pigs utilize key nutrients such as P, which is considered a potential pollutant of water ecosystems. Although cereal grains and oilseed meals contain enough P to fulfill the biological needs of pigs, most of this P is tightly bound as phytate. As pigs do not have enough phytase (PHY) to cleave P from phytate, it is excreted in the feces. To prevent a deficiency, diets have traditionally been supplemented with highly available inorganic sources of P. Today, an environmentally-friendly alternative is to supplement diets with PHY. Growth promoting antibiotics are also used to enhance the utilization of dietary components such as energy and N. It has been suggested that the antibiotic virginiamycin (VIR) could also improve phytate-P utilization by pigs. Eight experiments evaluated the effects of VIR and/or PHY amendment