Research News from the College of Veterinary Medicine
Excerpted from stories by Jim Barlow, UI News Bureau

Antibiotics boost swine profits
Antibiotics used on swine farms generate significant production efficiency and a 9 percent boost in pork producer profits, according to a study conducted by Dr. Gay Y. Miller, veterinary pathobiology, and colleagues.

The study, published in the December 2003 Journal of Agricultural and Applied Economics, provides an economically detailed look at the use of antibiotics for growth promotion following dramatic changes that have altered the face of the U.S. swine industry in the last three decades. It is based on industry statistics compiled in the 1990s.

Results indicate that for average modern-day swine facilities antibiotics boost daily growth and reduce swine death rates during the growth-finisher stage of production. Swine farmers operating a 1,020-head finishing barn realize a profit of 59 cents per pig in annual returns.

“Antibiotics used for growth promotion have a positive impact on production efficiency and producer profitability,” says Dr. Miller. “When production is more efficient, there are more products for consumers at lower prices. Improved efficiency also means that fewer numbers of animals are needed to provide the same amount of product. Using less resources takes fewer farms to produce the same amount of pork, less manure is generated and you see a reduction of other environmental concerns.”

A previous study by Iowa State University had found the benefit of antibiotic use in the swine industry to be almost five times higher than the findings of the new research. That study used European statistics, according to Dr. Miller, while her study looks solely at the U.S. industry, which has become concentrated, with large production facilities and advances in genetics and production approaches.

The study was funded in part by the Illinois Council on Food and Agricultural Research.

Read the full story here: http://www.news.uiuc.edu/scitips/03/1216pigs.html.

 

Fish toxins may impair motor skills
Pups of female rats exposed to a combin-ation of polychlorinated biphenyls (PCBs) and methylmercury (MeHg) slip and fall more often trying to maneuver on a rotating rod than do pups from non-exposed moms, reports Dr. Susan Schantz, veterinary bio sciences, in the February issue of Toxicological Sciences.

Dr. Schantz and fellow researchers studied the effects of combined exposure of the two commonly found environmental contaminants on motor function driven by the cerebellum.

“Because people are exposed to these toxicants by eating fish taken from ecosystems where these chemicals accumulate, our findings suggest that we should seriously consider the possible impact of their additive toxic effects on human health,” says Dr. Schantz.

Previous laboratory studies had suggested that the two chemicals act together to impair nervous system function. A study in February’s issue of the Journal of Pediatrics found that exposure to methylmercury causes heart damage and impairs brain growth.

The new study – pursued as part of a doctoral dissertation by Schantz’s graduate student Cindy S. Roegge – shows that motor skills were not significantly affected by methylmercury exposure alone, but when paired with PCBs the combined effect during development dramatically impacted the pups’ skills in one of three motor tests.

The research was done for the FRIENDS Children’s Environmental Health Center, a five-institution consortium based at the College of Veterinary Medicine. Dr. Schantz is director of FRIENDS (Fox River Environment and Diet Study), which studies the effects of exposure to toxicants in fish being eaten in large quantities by Laotian and Hmong refugees in Green Bay and Appleton, Wis.

Dr. Schantz says that the study showed that PCB exposure contributed more than did the methylmercury to the pups’ motor skill deficits, perhaps due to the low dosage of MeHg used in the study. It could be that the chemicals have independent mechanisms of toxicity or they each act by means of the same mechanism but with greater impact together.

In addition to Dr. Schantz and Roegge, the other contributors were Illinois doctoral students Victor C. Wang and Brian E. Powers; Sherilyn Villareal, a visiting research specialist in veterinary biosciences; William T. Greenough, a professor at the Beckman Institute for Advanced Science and Technology at Illinois; and Anna Y. Klintsova, currently a psychology professor at Binghamton University in New York.

The U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences funded the study and also fund the FRIENDS Children’s Environmental Health Center.

Read the full story at http://www.news.uiuc.edu/news/04/0301fishtoxin.html.

 

Ecosystem problems impact amphibian populations
During the last decade, Dr. Val Beasley, veterinary biosciences, has led a team wanting to know why the world’s amphibian populations have been dwindling or riddled with limb deformities.

Evidence points to increasing numbers of common parasites as an important cause. However, the problems facing amphibian habitats really pose a poignant example of ecosystems out of balance because of human activity, according to Dr. Beasley, who is also executive director of the Envirovet Program.

Dr. Beasley’s main collaborators on this work have been postdoctoral researcher Anna M. Schotthoefer and Rebecca A. Cole, an adjunct professor of veterinary pathobiology at Illinois and scientist with the National Wildlife Health Center in Madison, Wis.

Their research dramatically refines the data on parasitic activity and argues that physically and chemically induced changes of aquatic habitats are taking a toll.

Dr. Schotthoefer conducted research that provided the first stage-specific data involving two types of trematode parasites common to frogs. In work reported in the Canadian Journal of Zoology and funded by the U.S. Geological Survey’s Amphibian Monitoring and Research Initiative, she showed that about 16 percent of northern leopard frog tadpoles infected with Ribeiroia during the limb-bud stage had major deformities. However, when infected earlier, in the pre-limb stage (two weeks of age), tadpoles suffered massive tissue destruction that resulted in almost 100 percent mortality.

Amphibians are clearly important players in ecosystem functioning. “The frogs that develop from tadpoles subsequently devour thousands of insects,” says Dr. Beasley. The frogs themselves are also important prey for reptiles, birds and mammals.

“We have to be asking what human activities are contributing to imbalances in these ecosystems to set the stage for more severe infections,” Dr. Beasley says. “It’s becoming a serious question of how we can better manage landscapes, streams, wetlands, ponds and lakes.”

Read the full story at http://www.news.uiuc.edu/news/04/0210frogs.html.