ABSTRACT The Enviropig is a transgenic pig that synthesizes phytase in the salivary glands and secretes active enzyme in the saliva. This capability enables pigs to utilize practically all the P in cereal grains and soybean meal and to excrete fecal material usually containing 60% less P than nontransgenic pigs fed the same conventional diet lacking supplemental phosphate. By computer simulation, it was determined that 33% less land would be required to spread manure from transgenic phytase pigs, and if the diet was modified to decrease crude protein, even less land would be required. Introduction of Enviropig genetics may be perceived as leading to an expansion of the pork industry, but perhaps a more realistic view is that introduction of the transgenic phytase pig would enhance sustainability of the industry in a world with increasingly stringent soil nutrient management legislation. The transgenic phytase pig is probably on the leading edge of the production of various types of genetically modified animals that will reduce the environmental footprint of animal agriculture through enhanced metabolic capabilities. These pigs, and other transgenic animals under development elsewhere, will require safety and quality testing in the country of origin and in countries to which the product is exported to ensure that they do not have a deleterious effect on human health and the environment. Consumer surveys suggest that transgenic technology directed to issues involving environmental sustainability and food safety will receive the greatest support.
Implications
Transgenic technology has the potential to enhance the role that the animal industries have in world food production system. This paper describes the science, thought process, reasoning, and outcomes that evolved during the development of the Enviropig. The importance society places on solving the environmental, food safety, and food quality challenges supports the contention that this particular transgenic technology should be directed first and foremost to these issues rather than the customary economically based production area. This paper emphasizes the general understanding and value of transgenic animal technology in helping to ameliorate the environmental impact of animal production.
Key Words: Environment, Phosphorus, Phytase, Pigs, Poultry
© 2003, by the American Society of Animal Science. All rights reserved.
J. Anim. Sci. 2003. 81(E. Suppl. 2):E68-E77
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