Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Abundance of myostatin in infected swine may result in reduced muscle mass

18.11.2004


A study looking at chronic infectious respiratory diseases that affect most swine during their critical growing stage has shed new light on the reasons for restricted weight gain and reduced muscle mass.



In the November issue of the Journal of Nutrition, scientists at the University of Illinois at Urbana-Champaign report that the production of inflammatory cytokines by immune cells appears to be responsible for declines of both protein accretion and weight gain in swine infected with Porcine Reproductive and Respiratory Syndrome Virus (PRRSV).

The study also suggests that myostatin, a protein that limits muscle growth, is overproduced during infection, thereby reducing the growth of skeletal muscle, said Rodney W. Johnson, a professor in the department of animal sciences and the interdisciplinary Division of Nutritional Sciences.


Johnson and colleagues isolated pigs in disease-containment chambers and exposed different experimental groups to the bacterium Mycoplasma hyopneumoniae and/or PRRSV.

Almost all U.S. swine are exposed to the bacterium in production facilities, while about 60 percent are exposed to PRRSV. These pathogens open the way for other infectious agents. During the pivotal growing stage, pigs are at the most risk and suffer from cough, fevers and depressed appetite. Reduced market weight or increased time for pigs to reach a desired market weight can be a substantial cost to producers.

Infection from the bacterium alone did not reduce weight gain compared with the control group during the four-week-long experiment, but it did lead to the development of lesions that affected 8 percent of the total lung area in infected pigs. The finding was similar to earlier work in Johnson’s laboratory. However, the introduction of PRRSV caused damage to the lungs from the bacterium to jump to 40 percent. "One thing the virus does is suppress the immune system," Johnson said. "When PRRSV and mycoplasma are together, the PRRSV-induced immunosuppression allows the mycoplasma to spread unchecked. It really takes over the lungs."

PRRSV infection alone resulted in a daily weight gain of just 50 percent of that of the control animals (300 grams per day compared with 600 grams per day) and substantially less protein accretion. The drop in growth began three days after exposure to PRRSV and continued for the remaining two weeks of the trial.

PRRSV infects macrophages, a type of white blood cell that attacks pathogens. The virus is spread from the lungs as the macrophages migrate to other tissues. Before infected macrophages die from the virus, they produce inflammatory cytokines, hormone-like molecules that enable the immune system to influence other parts of the body. One part affected is the brain, which is why animals have reduced appetite when they are sick. "The cytokine molecules are the key, because they are the messengers used by the immune system to alter other systems that are relevant to growth," Johnson said.

At the suggestion of co-author Jeffery Escobar, a former doctoral student now with the USDA/ARS Children’s Research Center at the Baylor College of Medicine in Houston, the researchers examined myostatin gene expression in the infected pigs. Myostatin’s role in muscle development is becoming clear, Johnson said. Mice with the myostatin gene deleted become muscle-bound, and a defective myostatin gene has been linked to double muscling in cattle and to abnormally large muscles in a German child.

Johnson’s team found a substantial increase in the amount of myostatin mRNA in the muscles of infected pigs. "We have shown, using an infectious disease model where animals grow slowly, that there is an increase in muscle myostatin mRNA."

Jim Barlow | EurekAlert!
Further information:
http://www.uiuc.edu

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>