This page has been archived and is being provided for reference purposes only. The page is no longer being updated, and therefore, links on the page may be invalid.
New Transgenic Pigs with Lean Pork PotentialBy Tara WeaverFebruary 18, 1998 Pigs genetically engineered with a growth factor gene may give consumers leaner pork in the future, Agricultural Research Service scientists say. The new transgenic pigs carry a gene for insulin-like growth factor-I (IGF-I). The pigs were produced by ARS researchers in collaboration with GeneMedicine, Inc., of The Woodlands, Texas. The IGF-I transgenic pigs have some of the same positive carcass composition characteristics as transgenic pigs previously injected with a growth hormone (GH) transgene. However, none of these IGF-I transgenic pigs have developed the health problems encountered earlier in the GH transgenic pigs. IGF-I is a growth factor normally present in small amounts in most mammalian cells. It stimulates development of bone, muscle, nerve and organ tissues. IGF-I produced in muscle increases significantly without affecting the amount in the other tissues, making the IGF-I transgenic pigs unique. The scientists injected the IGF-I gene into pig embryos soon after fertilization. They mated several IGF-I transgenic pigs to non-transgenic pigs to produce a second generation in which half the offspring inherited the transgene and half did not. ARS scientists compared pigs with and without the transgene to see how IGF-I affected their growth rate, feed efficiency, carcass composition and general health. They compared those results with the results obtained earlier with the GH transgenic and non-transgenic pigs. The researchers found the IGF-I transgene helped reduce carcass fat and boost lean body mass, making those hogs worth $6 more at market than control pigs without the IGF-I transgene. The study also confirmed that the IGF-I pigs didn't suffer from severe health problems associated with the GH transgene. ARS scientists say this preliminary work is a first step to producing leaner pigs, but it will have to be tested on market-grade animals. Their next step will be to cross IGF-I transgenic pigs with market-line hogs to see if increased levels of the hormone enhance muscle development in already lean, heavy-muscled crossbred market hogs. Scientific contact: Vernon G. Pursel, Gene Evaluation and Mapping Laboratory, Beltsville, Md., phone (301) 504-8342, fax (301) 504-8414, vpursel@ggpl.arsusda.gov
|
