College of Agriculture, Food and Environment

Research Annual Report

2012 Kentucky Agricultural Experiment Station

The Whole is Greater

Agricultural experiment stations, created as part of the U.S. Department of Agriculture system, use the best science to solve problems, with a view to the practical application down the road. And when experiment station researchers work closely with able-minded partners, it can often spawn new ideas and strengthen their work.

With federal, state, industry, and other universities as partners, UKAg faculty conducted 147 projects and brought in more than $23 million in external funds in fiscal year 2012. And partnerships don’t just come from outside the university. At UK, in a setting typical of the modern land-grant university, College of Agriculture, Food and Environment researchers are part of an integrated program that often includes experts from the research, teaching, or extension fields. Kentuckians can be rightfully proud of this core of dedicated people.

We, in the Kentucky Agricultural Experiment Station, are proud of those of us who work to improve animals, plants, and the lives of humans. You might be familiar with the concept of the “microbiome,” the pervasive collection of bacteria that influence virtually all body functions. A USDA research arm, the Agricultural Research Service Forage-Animal Production Unit, has been in the College since 2003. Having ARS-FAPRU scientists Michael Flythe and Isabelle Kagan collaborate with UKAg equine researcher Laurie Lawrence has created a powerful team to study the microbiome in horses. The power of this partnership lies in the fact that each individual comes from a different scientific background, yet they share their unique skills to work on a very important aspect of a horse’s health and well-being.

Bacteria are also prominent in the study of insect control. How nice it would be to harness known enemies of insect pests so they could be targeted specifically rather than to use broad-spectrum chemical insecticides. Jen White received a competitive grant from the USDA National Institute of Food and Agriculture to learn how to control the cowpea aphid by studying its bacteria in relation to one of its predators, a wasp. She used her grant-funded research to educate a graduate student in the analysis of bacteria and wasp DNA. The outcome is both good science and a capable student prepared for a research career.

There’s a new area of emphasis for the College—behavioral effects on eating and weight loss. We are proud of Kelly Webber, whose research support includes a new grant from another federal partner, the National Institutes of Health. Kelly has worked hard to establish yet another set of partners, clinical researchers from the UK College of Medicine. Kelly’s unique knowledge of eating and dieting behavior provides the clinical researchers with more tools to improve human health.

The researchers featured in this issue represent our entire dedicated faculty as they conduct creative research to serve agriculture and society. They demonstrate the fact that the whole is more than the sum of its parts, or in this case, its partners!

Nancy M. Cox
Associate Dean for Research
Director, Kentucky Agricultural Experiment Station
S-129 Agricultural Science Center
University of Kentucky
Lexington, KY 40546-0091



Online Weight Loss

Kelly Webber can often be found where weight management intersects cyberspace. The Dietetics and Human Nutrition assistant professor, whose focus for the last eight years has been on adult weight management, has been conducting studies to improve Internet-based weight programs.

“Internet-based programs improve accessibility, especially for people with low access to health care; however, these online programs historically have not been as effective as face-to-face programs—probably because of the lack of accountability,” Webber said.

Healthcare professionals and the media have focused a great deal on the so-called obesity epidemic over the past decade, but Webber said overall projections show the problem is not reversing itself, but will continue to increase. Data does show that in some male populations the rise in obesity numbers is slowing, a trend that can be looked on as slightly encouraging. That does not change the fact, however, that obesity continues to be a major health problem. Kentucky is among 13 states where 30 percent or more of the population is considered obese.

Image of iPad

For her studies, Webber created an Internet weight loss program based on the Diabetes Prevention Program created by the National Institutes of Health. The program focused on behavioral weight loss, better eating, more exercise, and self-monitoring. Because online, self-directed programs often need some enhancement to reach the success rates of face-to-face programs, Webber added motivational components to one study, such as journaling and motivational interviewing. In a separate study, half of the participants received portion-controlled meals in addition to the online program.

“In the motivational study, we found that people who come into the study with external motivation—that is, they felt guilty, their doctor said they had to, or they were trying to lose weight for a class reunion—really benefited from the extra motivational intervention that we gave them,” Webber said. “We found that people who came in already internally motivated did well no matter which program they were in. The key really is internal motivation when trying to make long lasting change.”

Webber is beginning a new study this fall looking at stress eating. Researchers at the University of California, San Francisco have developed a program that basically “rewires” the brain’s response to stress. The theory is if you can successfully rewire the brain, you can keep people from stress eating. She is going to compare the UCSF stress management program to a mindfulness-based weight loss program to see which has a higher success rate in improving weight loss.

— Carol Lea Spence


Microflora with Macro Impacts

(l-r) Laurie Lawrence, Michael Flythe and Isabelle Kagan

The partnership between the UK College of Agriculture, Food and Environment and the U.S. Department of Agriculture-Agricultural Research Service Forage-Animal Production Research Unit continues to pay dividends. Michael Flythe, a microbiologist, and Isabelle Kagan, a plant physiologist in the unit, are looking at gastrointestinal microflora with UK equine nutritionist Laurie Lawrence from Animal and Food Sciences. The microflora include bacteria in an animal’s digestive system that break down high fiber feeds, like grasses.

“People think cows eat grass,” said Flythe. “Cows eat bacteria, and the bacteria eat the grass. Similarly, horses can’t digest fiber without the bacteria that live in the hindgut.”

The hindgut is composed of the cecum and colon of the large intestine.

Flythe, Kagan, and Lawrence study the intersection of plants, animals, and microbes.

“Largely, we are interested in disturbances, things that upset that relationship,” said Flythe. “Something that happens in the diet or something that happens to the animal upsets their microflora and causes a variety of problems.”

They are also interested in the beneficial things that plants do for the animal’s diet, such as whether a horse’s performance or health can be improved by supplementing them with something already found in forage, rather than giving them a man-made medicine. Over the next five years, the researchers plan to look at microbes involved in pasture-related laminitis. High levels of carbohydrates present in lush pastures are a risk factor for laminitis, which can cause serious lameness. The researchers want to find out what is going on microbiologically when the horses graze lush pasture and if there is a natural product for intervention.

Equine nutrition and the nutrition of mares and foals is the focus of Lawrence’s work. She said since the ARS unit came on campus in the early 2000s, it provided an opportunity to go in a whole new direction.
“We have been able to do several experiments looking at development in the foal, and we have been able to look at the microbiology of the digestive tract,” she said.

The big picture focus of the research is on the factors that affect the microflora of the horse’s gastrointestinal tract, such as diet, antibiotics, probiotics, and secondary plant metabolites, which are compounds produced by plants that may affect their susceptibility to insects or disease. Flythe and Kagan bring a new tool set that allows Lawrence's team to look at a part of equine nutrition they weren’t previously able to study.
“The best part is, we all have a different perspective,” Lawrence said. “We all look at it differently and ask different questions. They can help us find the answers, and I can help frame the right question and give them the right context. It has been a really great collaboration.”

— Jeff Franklin


Deciphering a Bacterial Shield

Worldwide, the cowpea aphid attacks more than 200 plants and 50 crops. The little pest prefers the taste of legumes, particularly alfalfa. Since the 1990s, cowpea aphid populations have caused enough damage in the United States to warrant insecticidal sprays.

An aphidiid wasp, Lysiphlebus testaceipes, helps keep aphid populations under control, but is not effective against the cowpea aphid in alfalfa. Researchers suspect this natural biological control agent may have failed with the cowpea aphid because of the type of bacteria the aphid possesses.

Jennifer White, UK assistant professor of insect ecology in the Department of Entomology, and graduate student Cristina Brady screened 46 cowpea aphid populations from around the world for bacterial symbionts as part of a grant from the U.S. Department of Agriculture'sNational Institute of Food and Agriculture.

Bacterial symbionts, such as Hamiltonella and Arsenophonus, live inside aphids and other insects. Insect mothers transfer the symbionts to their offspring. White said it appears that Hamiltonella helps the aphids protect themselves from the wasp.

“We found all six of the bacteria we were looking for in some aphid populations,” White said. “It became interesting when the type of bacteria a particular aphid possessed depended upon the host plant from which the aphid was collected. Hamiltonella was pretty uncommon, but when we did find it, it was virtually always in aphid populations that came from alfalfa, all over the world.”

Fortunately, researchers did not find Hamiltonella in the aphids they collected from Kentucky locust trees, which are native to the state but invasive in other parts of the world.

White and Brady conducted a second, localized study. Of the aphids they collected from locust trees, 92 percent were infected with Arsenophonus. Of the aphids they collected from alfalfa, 89 percent had Hamiltonella and none had Arsenophonus.

“Sometimes we collected locust aphids from trees right next to alfalfa fields with their own aphids,” she said. “Even though they look like the same aphid, their biological properties are very different and their ecology—how they’re going to interact with the other members of the community—is very different.”
She added that while these aphids can both eat some of the same plants, the ones feeding on locust trees didn’t do well on alfalfa, and the ones on alfalfa didn’t perform as well on locust.

White and Brady took their research a step further by using DNA analysis to study the success rate of the parasitoid wasp.

“We found more of the wasp’s DNA in the aphids coming from the locust trees than in the ones coming from alfalfa,” she said.

White’s research will continue with the goal of determining what causes certain bacteria to appear in some aphids but not in others and to understand the interaction between the symbionts and the host plants.

“This basic research will help scientists understand the basic biology of pest organisms, make the best biological control decisions possible and be aware of possible pitfalls certain biological control measures could have,” White said.

— Aimee Nielson