Researchers Study Ways to
Protect Immune Systems of Young Pigs
A piglet today is commonly weaned from its
mother after 18 to 21 days, and sometimes as early as 10 days, because diets
now available are much better suited to the piglet's immature digestive system
and support a rate of growth desirable to producers in the United States.
However, the piglet's immune system may still be vulnerable at that age to
infection from pathogens.
During weaning, pigs eat less and gain
less weight, which leaves them vulnerable to disease. That's why producers
often rely on low-dosage, subtherapeutic treatments of antibiotics to increase
the animal's health and productivity. This usage has improved the
feed-to-weight gain ratio while also decreasing illness and morbidity. However,
the practice has also been implicated in the emergence of antibiotic-resistant
strains of common food-borne illnesses.
If natural, yet still affordable,
supplements could be found to increase the health and feed intake after
weaning, then the overall well-being and growth performance of pigs would be
improved. Also, pigs would reach market faster, which saves the producer feed,
as well as medication and facility costs.
When animal physiologist
Jeff
Carroll was with the Animal Physiology Research Unit in
Columbia,
Mo., he worked with
Gary Allee,
a swine nutritionist at the University of Missouri, to
investigate the benefit of adding various natural supplements to pig diets.
They found that fish oil in young weaned pigs' diets can help build up their
immune systems.
Carroll, currently the research leader at
the Livestock Issues
Research Unit located north of Lubbock, Texas, says it's been known that
fish oils containing long-chain omega-3 fatty acids can be nutritious additions
to a person's diet because they appear to lower the risk of cholesterol and
heart disease. However, the Columbia studies showed that compared to corn oil
and other supplements, different levels of menhaden fish oil
helped 18-day-old
pigs better prepare to fight off endotoxin challenges. The omega-3 fatty
acids are absorbed through the intestine and help the immune cells cope with
disease. U.S. producers could benefit from this finding because fish oil is
less expensive than antibiotics.
In addition to fish oil supplementation,
Carroll and Allee evaluated the use of the protein supplement spray-dried
plasma. They found that spray-dried plasma, like fish oil supplements, offers
immune protection to the pig. Growth and performance are enhanced because
nutrients from the pigs' feed are diverted to growth rather than utilized for
immune functions. Carroll says it has been estimated that 20 to 35 percent of
nutrients are at times diverted to the maintenance of the immune system and
fighting off pathogen challenges. Carroll says the spray-dried plasma offers
the piglets protection until their own immune systems take over when they are
about 35 days old.
The researchers found that both
supplements offer immune protection, but that they alter the immune system in
two different ways. Fish oil offers protection at the cellular level of the
immune system, while spray-dried plasma, which showed the most results of the
two supplements, appears to provide protection at the intestinal level.
In a related study, spray-dried plasma and
glutamine—an amino acid essential in some species' response to
inflammation following infection or injury—were examined to determine how
they would respond to challenges from Escherichia coli. Spray-dried
plasma had already been known to reduce the excretion of E. coli by
preventing intestinal pathogen invasion and the destruction of the intestinal
mucosal barrier in weaning pigs, so researchers wanted to study glutamine. They
found both were effective as supplements for preventing normal intestinal
integrity and function.
Carroll reports that his work with
nutritional supplements is continuing at his new location. He and his
collaborators are studying additional natural supplements and will soon be
transferring this line of research into studies with cattle.
For more information, contact the unit's
research leader:
Jeff
Carroll, Lubbock, Texas |
Research Briefs
ARS scientists found that feeding beef cattle
high-moisture corn
instead of dry-rolled corn significantly reduces manure odor.
Shawn L.
Archibeque
A new ARS
laboratory is dedicated to
egg safety, quality and
marketability.
Richard K.
Gast
ARS scientists are finding way to enrich the
lives of pregnant
sows.
Donald
C. Lay
An ARS-run database is being used to determine
the probability that bacterial resistance
will occur during different stages of food animal production if antibiotics are
used.
Paula
Fedorka-Cray
ARS scientists and collaborators invented a new
method for treating swine-production
wastewater.
Matias
B. Vanotti
Calves can fight infection from
Salmonella and other microbes better during transport when given an
ARS-developed anti-stress infant
formula.
Susan
D. Eicher
An ARS scientist has designed a system to
treat, filter and
conserve water in fresh-water fish tanks.
Brian L.
Brazil
Reduced forage quality as a result of continued
elevated carbon dioxide
concentrations in the atmosphere may lead to reduced weight gain among
livestock, according to ARS scientists and their collaborators.
Jack A.
Morgan
Awards
The following researchers who work in areas
related to animal health were among several agency employees honored during a
ceremony in Washington, D.C., Feb. 9 as
ARS' top researchers
for 2004.
- North Atlantic Area Senior Research
Scientist
Marvin
J. Grubman, Plum Island Animal Disease Center, Orient Point, N.Y., for
research on a novel vaccine strategy for prevention and control of
foot-and-mouth disease in livestock.
- Southern Plains Area Senior Research
Scientist
John E.
George, ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory,
Kerrville, Texas, for research and leadership in developing innovative methods
for controlling ticks that can spread cattle fever, including identifying the
means by which ticks can develop resistance to the chemicals used to combat
them.
- Mid-South Area Early Career Scientist of
the Year
Brian G.
Bosworth, ARS Catfish Genetics Research Unit, Stoneville, Miss., for
research to identify genetic factors controlling catfish fillet yield and
quality, and to develop improved catfish germplasm.
- Pacific West Area Early Career Scientist
of the Year
Kenneth
E. Overturf, ARS Small Grains and Potato Germplasm Research Unit, Hagerman,
Idaho, for development of innovative approaches to the genetic selection of
trout that can thrive on grain-based diets.
- South Atlantic Area Early Career Scientist
of the Year
Charlene
R. Jackson, ARS Southeast Poultry Research Laboratory, Athens, Ga., for
contributions to the study of antimicrobial resistance in Enterococci
bacteria.
Healthy
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