Melissa Merrill

The Animal Science Summer Undergraduate Research Experience (ASSURE) program is an experiential initiative that will provide Animal Science undergraduate students with hands-on research experiences, a detailed education on leadership and communication practices, and individualized mentorship and career guidance to strengthen US animal production. Our ASSURE program, which will target and recruit sophomore and junior baccalaureate students that are under-resourced (i.e., underrepresented, disabled, economically disadvantaged, rural and first generation college students), has three main objectives: (1) to create an intensive and extensive hands-on experience in applied and fundamental research, (2) to develop and refine essential workforce skills and enhance future employment, and (3) to strengthen and advance understanding of the opportunities available in food animal-related careers and graduate programs. Given that the theme of our ASSURE program is Research Advancing Sustainability in Animal Production, the cornerstone of this program is a 12-week Summer research experience that will include hands-on experience in applied and fundamental Animal Science research as well as Professional Development Fridays which will include instruction on leadership and communication practices, on-site tours of local animal agriculture industry facilities, and career guidance through mentoring meetings and career day panels from Animal Science experts in extension, industry, government, and academia professions. The intended impact of our ASSURE program is to educate and empower Animal Science undergraduates in order to enhance our ability to retain well qualified graduates in animal agriculture and strengthen the workforce in US food animal production.

The goal of our proposal is to recruit and train ethnic minority students in the Department of Animal Science at North Carolina State University (NCSU) for careers requiring advanced degrees in the agricultural sciences. Our goal is to recruit additional minority students into the Animal Science major who are potentially suitable for a graduate education in animal science or other related disciplines in the agricultural sciences. The proposed program will be distributed broadly through targeting recruitment efforts. Completion of the program will make the MSP Scholars highly competitive for graduate school and leadership positions related to the food and agricultural sciences.

Our goal is to improve productivity and profitability of cattle grazing E+. Our research approach is to feed diets that do not contain any fescue, and then add endophyte-infected (E+) or endophyte-free (E-) fescue seed to control the consumption of alkaloids by the cattle. We plan to conduct a study using steers. Environmental temperatures will be above the thermoneutral zone, so steers are under heat stress conditions. In response to thermal stress there are several ways that cattle dissipate heat. These include increasing blood flow to peripheral tissues, increasing skin temperature, increasing respiration rate, and increasing sweat rate. As ambient temperature increases, sweating increases in importance as a way to dissipate body heat. If an animal has a limited ability to sweat, then respiration rate might increase to a greater degree in order to dissipate body heat. We hypothesize that cattle consuming E+ fescue seed have limited ability to increase sweat rate and that this is a major contributor to heat stress in the cattle. Angus steers (n=20, approximately 600 lbs BW) of known genetic background will be used for the experiment. Thermal imaging measurements will be taken on the rib to measure changes in skin temperature. Physiology measurements (heat rate, blood pressure, respiration rate) will also be taken. Blood samples will be taken to measure prolactin concentration. These measurements will confirm that the steers have the physiological changes expected from ingestion of toxic fescue seed. Sweat rate will be measured. Hair coat scores will be assigned and hair density will be measured by clipping a measured area and weighing the hair after it is washed and dried on day 28. Biopsies will be taken on day 28 and sweat glands will be isolated to measure gene expression of receptors for hormones that regulate the function of sweat glands. This model of feeding a known amount of toxin will lead to a fuller understanding of the syndrome of fescue toxicity to enhance best management practices for use of E+ infected pastures.

Objective: To characterize the variation in efficiency of feed utilization of Angus females and to identify optimal methods of improving the biological efficiency of beef production using a multi-disciplinary approach. Rationale: Approximately 60% to 70% of overall energy costs for beef production go into the cow herd. Of that amount approximately 70% goes for maintenance energy (Ferrell and Jenkins, 1982). This is the energy that a cow needs to maintain her body weight and survive. It does not include energy for growth, lactation, or gestation. Thus, 46% of all energy required to produce a pound of beef is used to simply maintain the cow herd. It has been shown that variation does exist in maintenance energy requirements among cows, but maintenance requirements of cattle appear to have been largely unchanged during the past 100 years (Johnson et al. 2003). If methods of quantifying genetic variation in nutrient utilization of cows could be devised, efficiency of beef production could be improved through selection for reduced maintenance energy requirements. Collaboration: The objective will be accomplished through a collaborative agreement between North Carolina State University and the University of Illinois. All data will be put into a common database to which both universities will have full access. All data will be made available to the American Angus Association. What questions will this research project address? 1) How much variation is there in nutrient utilization among Angus cows? 2) Can we test replacement heifers in post-weaning heifer development programs and use the information to determine which ones will have the greatest biological efficiency as brood cows? 3) What are the phenotypic and genetic relationships among feed intake in developing heifers, measures of feed efficiency, and female productivity? How will the objective be achieved? It will be achieved via the following two aims: Aim 1: To estimate the relationship between measures of growth, feed intake, feed efficiency, ultrasound backfat, and ultrasound ribeye area in developing heifers and their subsequent performance in term of biological efficiency as cows. This will be accomplished by putting heifers on test during the post-weaning developmental period and recording individual feed intake and weight. The information will be used to calculate ADG, feed conversion rate, and residual feed intake. These measurements will then be correlated with the heifer?s subsequent performance as a brood cow. Brood cow performance will be measured as described in Aim 2. Aim 2: To estimate differences among cows for amount of energy (feed) consumed per unit of output. Aim 2 will be accomplished by collecting individual feed intake on lactating cows, calculating the Mcals of energy consumed and comparing that to the adjusted 205 day weight of their calves, calving intervals, milk production, and changes in body weight. Resources: North Carolina State University maintains approximately 150 registered Angus Cows descending from the Chinqua-Penn line which dates back to 1944 and has been designated as a Historic Angus Herd. University of Illinois maintains approximately 175 registered Angus cows and utilizes Angus bulls on 80 registered Simmental cows. Both universities have facilities for recording weights, measuring individual feed intake, and collecting lactation data. In addition, there are state of the art laboratories for measuring hormone concentrations and blood metabolites. Expected outcomes: The expected outcomes of this project are tools which American Angus may implement to improve the efficiency of nutrient utilization of Angus females. This will lead to a competitive advantage for the Angus breed and a reduction in the nutrient requirements to produce a pound of beef by their customers.

Maintaining healthy animals is critical to ensuring animal wellbeing, profitability, and global food security. Despite the critical role animal health plays in the sustainability of food production, our knowledge of drug metabolic pathways in livestock is very limited. Drug withdrawal times, as currently established by the FDA, were based on information from relatively few animals. Inter-individual genetic variation and its role in drug metabolism have not been thoroughly evaluated. This lack of knowledge may result in drug efficacy and animal welfare issues. We propose to estimate genetic variation in pharmacokinetic profiles and liver gene expression among pig breeds. First, we will determine if existing genetic variation affects drug metabolism. Then we will examine the pharmacogenetic effects on drug depletion in the presence of genetic variation. This will result in more precise standards for withdrawal time of drugs and lead to better understanding of the dosage of drugs targeted to different groups of individuals. Finally we propose to identify genetic variation in drug metabolism which will allow us to design safer and more effective drugs. It may also be possible to select against pigs whose rate of drug metabolism is unfavorable. This would make it possible to exploit existing genetic variation and create pigs useful as models in the discovery and testing of human drugs. We will accomplish these goals through the following objectives: 1) Identify genetic and gender differences among swine breeds explaining variation in pharmacokinetics of four drugs registered for use in pigs. We hypothesize different selection history will result in phenotypic differences in plasma pharmacokinetic parameters between individuals, influencing withdrawal times. 2) Identify pharmacogenomic and liver gene expression differences in pigs. We hypothesize pharmacogenomic differences between breeds in genes involved in Phase I and II drug metabolism reactions will affect drug disposition, influencing withdrawal times. 3) Identify relationships between pharmacokinetic and gene expression profiles in the presence of genetic differences. We hypothesize different principal components from combined kinetic parameters and gene expression analysis will be able to predict an individual?s unknown pharmacokinetic profile.

Agricultural productivity is a foundational component of the US economy. Advances in traditional animal breeding, nutrition, and immunology have made us a worldwide leader in animal agriculture; however with the threats of global warming, globalization, and competition from countries such as China and Brazil it is imperative that we aggressively develop new technologies if we are to ensure our position of leadership. With the completion of several food-animal genomes, attention must now be placed on how to translate genomic information into practical applications. To do this, a new generation of scientists must be trained. Herein, we propose an integrated program of graduate training, research, and industry outreach designed to meet the national need for animal/poultry scientists trained in the emerging functional genomics discipline. The objectives are to: 1) attract three exceptional pre-doctoral students in the targeted area of Agricultural Genomics and Bioinformatics, emphasizing Functional Genomics of animal agriculture; 2) provide students with inter-disciplinary training, merging Functional Genomics, Bioinformatics, and Animal/Poultry Sciences; 3) provide students with significant training in online learning. We will meet these objectives by taking advantage of existing curricula and resources at NCSU. The National Needs Fellows will be recruited into the Functional Genomics graduate program, with a concerted effort to recruit students from under-represented groups by partnering with other UNC system universities. The graduates of this program will be leaders in the emerging online learning environment, developing rational pedagogies and technologies for instructional and outreach activities. These Fellows will enhance the competitiveness and sustainability of US farm communities and strengthen our capacity for international trade.

The objective of this project is to develop critical knowledge necessary for the application of genomic tools for improving nutrient utilization in pig production. A population of 1000 Duroc boars will be genotyped using the porcineSNP60Chip and genome wide association analysis will be done to identify genomic regions affecting nutrient utilization, growth rate, and birth weight. Improving nutrient utilization and growth rate are critically important to the U.S. pig industry improving its global competitiveness. Birth weight is of interest because of its association with preweaning survival and the probability of a pig being ?full value? at slaughter. The expected outcomes of this research are methods for generating genomic enhanced EPD?s feed efficiency, growth rate, and survival. The data generated will also be used to explore the potential for developing a ?reduced? SNPChip which would significantly reduce the cost of genotyping while minimizing the loss of information. Final genomic regions associated with nutrient utilization, growth, and birth weight will be identified.

The experiment will be conducted at the Butner Beef Cattle Field Lab. Steers will be fed a control diet for 21 days afterwhich they will be switched to one of five treatment diets for 56 days. Diets will include one with 20% endophyte free seed (low ergot alkaloid), one with 10% endophyte infected seed (intermediate alkaloid diet), one with 10% endophyte infected seed plus Novus additives (intermediate alkaloid diet with additives), one with 20% endophyte infected seed (high alkaloid diet), and one with 10% endophyte infected seed plus Novus additives (high alkaloid diet with additives). Digital Infrared Photography will be used to determine changes in hock and side temperature, prolactin will be measured to determine effects on the dopamine agonist system, and urine alkaloids will be used to monitor effects on absorption and secretion of ergot alkaloids. After 56 days of treatment, steers will be switched back to a control diet for 28 days to monitor recovery.

Cartilage degeneration following an injury is a poorly understood process and symptoms may take years to progress to a state where treatment is sought. While the final stages of the disease process are quite well documented, the early tissue changes that start the tissue down the degenerative pathway are poorly understood. We propose to use an in vitro porcine patellae impact injury model to document changes in chondrocyte gene expression and tissue damage that may initiate the degenerative processes. We will examine different types of injury (normal and shear) and the physical extent of over which damage occurs. We will examine three different loading cases; a normal impaction, a shear impaction, and a non impacted control. Each patella will be impacted twice, once on each facet and load cases will be paired on left and right patellae. Following impaction intact patellae will be maintained in organ culture for 0, 3, 7, or 14 days. After remove from culture full thick cartilage strips will be harvested from directly below the impaction, part of the tissue will be used for histological analysis and part will be used for gene expression analysis. For gene expression analysis total RNA will be extracted from the tissue and reverse transcribed for real-time PCR assay. We propose to examine eight genes related to chondrocyte apoptosis, extracellular matrix components, and matrix degenerative enzymes production using real-time PCR assays. Histological analysis will include staining for chondrocyte necrosis and apoptosis, aggrecan loss, and immunohistochemistry for damage to type II collagen. Knowing the damage that occurs and the changes in chondrocyte gene expression following an impact injury will provide insights into the progression of early degenerative changes in the cartilage tissue. Are chondrocytes capable of orchestrating a successful repair or are their efforts doomed to failure with the decrease in cell number due to necrosis and apoptosis, the production of increased degenerative enzymes, and damaged, defective, or insufficient replacement matrix products? If we can gain a better understanding of the early degenerative changes we will be better able to treat the disease and prevent the debilitating changes that occur further down the road. Controlling the early degenerative changes holds the most promise for preventing or mitigating the disease process.

The effect of diet on microbial populations in the gastrointestinal tract is a topic of much research. Interactions between microbes and the host organism are implicated in pathology and overall health, transcending species boundaries. Primates are of special interest because their relatedness to humans makes the data valuable from a comparative medical and evolutionary standpoint. Differences in bacterial counts, diversity, and activity may result from inherited traits, such as anatomy and physiology of the gastrointestinal tract, or from changes in diet due to seasons, habitat destruction in the wild, or merely transition to captivity (Benno et al, 1987; Costa et al 1989; Stevens and Hume 1998; McKenna et al, 2008; Kisidayova et al, 2009; Nakamura et al, 2009). Nutrition as a form of preventative medicine and a foundation for good health is especially relevant in zoo settings. Diets are formulated to provide balance and variety, but not all species have been studied enough that acceptable domestic substitutes can be provided for the animals? native fare. The resulting dietary discrepancy has had quantitative repercussions in microbial activity and diversity in primates. For example, in chimpanzees higher fiber diets (more true to the composition of that observed in the wild) resulted in lower production of methane and volatile fatty acids, and in higher ratios of anaerobic to aerobic populations, than were recorded from fecal samples with low-fiber substrates and more readily accessible carbohydrates (Kisidayova, 2009). Similar trends were seen when African green monkeys were fed dietary cellulose instead of more fermentable psyllium husks (Costa, 1989). Although there is evidence of changing microbial populations across individuals within a species, no research has been focused on investigating the effects of feeding strategies on microbial populations across species. Microbial populations play a key role in fermentation of digesta for nutrient release. Just as animal populations adapt to specific conditions and available resources within their environment, different microbial populations within the digestive tracts of animals may have varying characteristics dependent on what is ingested by the host. For example, animals who consume diets higher in structural carbohydrates would be expected to exhibit different fecal microbial profiles than animals that have more fruit-based feeding strategies. As such, the characteristics of microbiomes in exotic species, as they relate to the animal?s overall health and well-being, geographic distribution and anatomical and physiological adaptation to dietary niches, are of great interest. We propose to analyze fecal samples across exotic species of Primates and Carnivores housed at the North Carolina Zoo, Duke Primate Center (DPC), and Carolina Tiger Rescue (CTR) to assess the role of microbes in extracting nutrients from digesta.