These little piggies are a scientific marvel
Canadian scientists' 'Enviropigs' cause less pollution
In a feat of genetic engineering, scientists at the
University of Guelph have made a pig that should produce
environmentally friendly manure.
The end product will still stink, but it should contain very little
phosphorus, a water pollutant that promotes the growth of algae in
rivers, lakes and streams, ultimately robbing water and fish of
oxygen. "The smell is going to be there, regrettably," said Cecil
Forsberg, a microbiologist who helped create the transgenic pig that
will go by the trade name Enviropig. "That's task No. 2."
Although scientists have been genetically modifying plants and animals
for decades, this is believed to be one of the first animals
engineered to solve an environmental problem.
Even so, this transgenic piggy -- a term that indicates its cells
contain DNA from another plant, animal or bacteria -- will not be
ready to go to market for at least three years.
After they get a handle on phosphorus, the scientists want to take a
look at nitrogen, the other major pollutant found in pig manure and
the one associated with its rank odour.
For now, Dr. Forsberg and his colleagues, molecular biologist John
Phillips and doctoral student Serguei Golovan, are monitoring the
progress of three transgenic pigs born to surrogate sows in the past
Although outwardly they look like any other pigs of the Yorkshire
breed, inside the nucleus of each cell of an Enviropig is a piece of
DNA that contains a snippet of mouse and a bit of bacteria.
In the lab, the scientists took an E. coli gene that makes an enzyme
called phytase and spliced it with a fragment of a mouse gene that
controls the production of a protein secreted in the salivary glands.
The composite gene was inserted into the nucleus of a one-celled pig
embryo with a microscopic needle.
The transgene will allow the Enviropig to make phytase in the salivary
gland and secrete it into the saliva, where it is swallowed with the
food. The phytase releases organic phosphorus in the animal's gut so
it can be absorbed by the bloodstream.
The embryos were surgically implanted in a foster mother. On April 14,
Wayne was born. Two months later, Jacques and Gordie were born. And
yes, staff members who care for the pigs at the Arkell research
station near Guelph named them after Canadian hockey players.
Dr. Phillips, acting the proud papa, said his transgenic progeny don't
look like just any old Yorkshire pig.
"Do your kids look like just [any] kids?" he asked. "They do look like
pigs, but Wayne is a handsome dude. He's a good-looking pig."
The scientists report the pigs are growing at a normal rate, and are
acting like any other porcine youngsters: saucy, assertive and usually hungry.
A large part of the funding for the research comes from Ontario pork
producers themselves, who have contributed $270,000 over the past five
years through service fees to the Ontario Pork Marketing Board.
They are the ones who will benefit, ultimately, from the Enviropig.
Swine cannot digest the phosphorus found naturally in their feed, even
though they need it to produce energy and provide cell structure. So
farmers end up giving them a phosphorus supplement they can digest,
while all the organic phosphorus found in their food goes in one end
and out the other.
That creates an environmental problem for the farmer who wants to use
pig manure as fertilizer on crops -- the phosphorus content is very high.
The amount of phosphorus in Enviropig manure will decrease by an
estimated 20 to 50 per cent, but the scientists won't know how
successful the gene manipulation has been until they measure "what
goes in and what comes out."
Ontario Pork chairman Will Nap, a hog farmer from Thornton, said the
Enviropig will save pork producers as much as $1.70 per pig because
they will no longer need phosphorus supplements. Although a pig
fetches about $110, feed costs eat up almost half that.
Although the University of Guelph owns the Enviropig, Ontario Pork has
the exclusive licence to distribute the pig to breeders and producers worldwide.
"Once the research discovers how this is passed on to the piglets or
if it's indeed passed on . . . we'll then develop a business plan as
to how to market it through our breeders in Ontario first, then in
Canada, and finally throughout the world," said Mr. Nap.
Although pork producers support the research at this early stage, it
is unclear whether they will ultimately welcome the genetically
modified pig in their barns. That will likely depend on consumer reaction.
"So far it's all research, it's certainly not ready to be
commercialized," Mr. Nap said. "That will tell the story as to the
actual demand, I guess."
As the researchers are quick to point out, any genetically modified
bacon will have to meet federal regulations for novel food under the
Food and Drugs Act.
In fact, they suggest that some consumers might be willing to pay a
premium for the meat -- much as they do for organic products --
because of its environmental benefit to the farm.
The scientists rely on recently bred young females (called gilts) for
the fertilized eggs, which they collect at the campus slaughterhouse
after an animal has been killed. They have about 48 hours after the
time of breeding to gather the one-celled eggs before they undergo
their first cellular division.
"Their carcasses go on to make pork chops and bacon and we just keep
their embryos," Dr. Phillips said.