study may lead to understanding human stress
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Anyone who has seen the Chinese Meishan
pigs at the University of Illinois knows the animals have definite
appearance differences with U.S.-bred swine. The differences are
more than skin deep, and researchers are trying to determine why the
Chinese swine deal better with physical and mental stress than do
the standard white crossbreds on American swine farms.
Romana Nowak, an associate professor in
the U of I Department of Animal Sciences, has undertaken a
two-pronged approach to answer that question. Funding for the
research comes from Cargill's Horizon Research Initiative.
"I'm trying to identify the genes that
give the Chinese pigs a better immune-system response," she
explained. "The first stage will be high tech; the second stage will
involve work with the animals."
The first step is the preparation of a
DNA microchip array. It will contain about 5,500 porcine genes and
will be used to compare differences in gene expression between the
Meishan and domestic white pigs.
"We'll be able to look at all the genes
at one time and should be able to determine which ones are expressed
Studies have shown that the Chinese
pigs tolerate stress better than the crossbred pigs, leading
researchers to suspect there may be a genetic difference involved.
Once the DNA microchip is completed, research will move to a field
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Animals will be injected with PRRS
virus that will make them ill for several days. The Chinese and
domestic pigs will be monitored for development of a fever, changes
in feed intake and general well-being. Animals will be euthanized
and several of their tissues will be harvested for analysis on the
"In Chinese pigs, we actually see an
improved response in terms of food intake and weight gain when the
animal is under stress. The U.S. pigs tend to eat less and lose more
weight when they are sick," she said.
Determining the reason for these breed
differences and their origin could help U.S. producers become more
productive. But the benefits would not stop on the farm.
we identify as playing a role in this might be good candidates for
examination in relation to the way humans react to stress and
illness," she said.
of Illinois news release]