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 Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>