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 What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Simple processing technique could cut cost of organic PV and wearable electronics

06.12.2016 | Materials Sciences

3-D printed kidney phantoms aid nuclear medicine dosing calibration

06.12.2016 | Medical Engineering

Robot on demand: Mobile machining of aircraft components with high precision

06.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>