Major Strategies of Reducing Phosphorus (P) Levels in Animal Manure

Abstract

Animal production, including swine production, had been projected to be on the increase. However, the high levels of P released via pig manure into the environment are a major concern as it is associated with environmental deterioration and degradation leading to eutrophication. Nevertheless, the potential exists for the reduction of P levels in the pig manure as to reduce the damage done to the environment. This had led to the search for strategies to better manage the nutrition of P for swine as to reduce P levels release into the environment. The strategies are also required not to compromise animal performance and welfare. Additionally, they should not significantly alter the normal processes of nutrient metabolism and absorption. Furthermore, they should not significantly increase the total cost of production and be suitable for adoption via the available technology in the environment. More importantly, the strategies should trigger mineral synergies and homeostasis, including other nutrients thereby significantly reduce the formations of the insoluble-phytate-mineral-complexes that impede mineral solubility for absorption. This paper highlights the strategies that have been developed in dealing with P levels in the pig manure. These strategies are categorized into: the use of microbial phytase to release phytate-P, use of low-phytate crop varieties or cultivars, commercialization of the phytase enviropig^TM and improving diets based on the use of true digestible calcium to true digestible P ratio.