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story to find out more. Scientists
Study Early Warning Stress Indicator in AnimalsBy Sharon Durham January 15, 2002Although an animal's life
processes--such as giving birth and weaning--are natural, they can be
stressful, and that stress can impair the animals normal biological
functions. But how do you know how stressed an animal is?
Agricultural Research Service scientist
Ted H. Elsasser is close to answering that question. Elsasser, based at the ARS
Growth Biology Laboratory in Beltsville, Md., is investigating nitrated
protein measurement as a biomarker of stress. Nitrated proteins, naturally
present in the body, may serve as an early warning system for identifying an
animal that may need help recovering from an illness, or that could yield
unsafe meat or milk. In response to high levels of infectious stress or injury, or when immune
system hormones are secreted inside the animal, certain protein components,
called tyrosines, can alter the function--and the shape--of the proteins. When
this happens, the protein is said to be nitrated. Proteins are like
jigsaw puzzle pieces that are designed to fit together to perform a specific
function. When proteins are altered, they no longer fit and become ineffective.
Stress causes several undesirable effects, including slow animal growth and
lowered immune response. Currently, farmers often use antibiotics to avert
these effects. But sustained doses of antibiotics can accelerate the
development of antibiotic-resistant bacteria that may later infect humans. To slow the formation of nitrated--and thus ineffective--proteins, Elsasser
is investigating vitamin E, a standard antioxidant supplement. Using vitamin E
as a preconditioner allowed researchers to maintain animal growth rates better
under stress and perhaps prevent the occurrence of secondary infections. Being
able to prevent infections due to stress could lead to lower disease-management
costs, less antibiotic use, and healthier animals. A more detailed story appears in the January issue of Agricultural
Research magazine. ARS is the chief scientific research agency of the
U.S. Department of Agriculture. Story contacts Growth Biology Laboratory Sharon A Durham U.S. Department of Agriculture |