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INVESTIGATOR: Vizcarra, J.

PERFORMING INSTITUTION:
ALABAMA A&M UNIVERSITY
4900 MERIDIAN STREET
NORMAL, ALABAMA 35762

BUILDING CAPACITY IN POULTRY RESEARCH

NON-TECHNICAL SUMMARY: Poultry is a common domestic species that plays an important role in agriculture by generating over 35 billion dollars per year. However, rapid growth rate in broilers is known to be associated with pulmonary hypertension syndrome (ascites). Ascites causes substantial economic losses due to mortality and condemnation in poultry. Most economical feasible treatments used to reverse ascites are in direct conflict with normal management practices (i.e. feed restriction). Thus, there is a need to develop new methods to prevent ascites. In the absence of such methods, the developments of effective interventions strategies to address this health problem will likely remain problematic. The long-term goal in our research program is to develop and implement effective interventions that will improve the health of poultry, especially those that are susceptible to ascites. The overall objective of this particular application, which is the next step toward attainment of our long-term goal, is to determine the contribution of ghrelin in the development of ascites in broilers. Our central hypothesis is that ghrelin is a key hormone involved in feed intake, energy homeostasis, and cardiovascular function in birds. Using complementary experimental strategies that have been validated in our laboratories, we intend to down- and up-regulate the activity of ghrelin. We also propose to use non-invasive method, such as mild hypothermia, and feed restriction to modify the incidence of ascites in broilers. The expected outcome of this proposal is to improve the therapies that significantly impact animal health and the sustainability and competitiveness of U.S. agriculture.

OBJECTIVES: The long-term goal in our research program is to build capacity in poultry research, and to develop and implement effective interventions that will improve the health of poultry, especially those that are susceptible to PH. Thus, the goal is significant because it falls within the USDA/CBG Program Priority Areas of "Animal health," "Sustainable agriculture," and "Global Food security and agricultural biosecurity." The overall objective of this particular application, which is the next step toward attainment of our long-term goal, is to determine the contribution of ghrelin in the endocrine control of PH in broilers. Our central hypothesis is that ghrelin is a key hormone involved in feed intake, energy homeostasis, and cardiovascular function in birds. We also hypothesize that rapid growth in poultry is associated with changes in endogenous ghrelin concentrations that leads to PH. Our preliminary data and earlier published reports strongly suggest a link between ghrelin, feed intake, and energy homeostasis in birds. There is, therefore, a critical need to determine the underlying effect of ghrelin in the development of PH in chickens. For this study we will target broilers, a bird with known susceptibility to this significant health problem. This is a multi-institutional and multi-disciplinary project (Alabama A&M University, AAMU; Auburn University, AU; and Aviagen). Therefore, this proposal will establish the link between the Industry, Farmers (Alabama is the second state with the largest numbers of broilers in the US), and University institutions for continued support and partnership after the end of the current project. Using complementary experimental strategies that have been validated in our laboratories, we intend to down- and up-regulate the activity of ghrelin, and to use non-invasive method, such as mild hypothermia, to amplify the incidence of ascites in broilers. Thus, the overall objective of this project is to determine the role of ghrelin in the endocrine control of ascites in broilers.

APPROACH: A.1. Experiment 1: The effect of active immunization against ghrelin and mild hypothermia on the incidence of ascites in broilers.A.2. Approach to be used: One-day-old broiler males will be randomly assigned to four treatments in a 2 X 2 factorial arrangement (n = 25 broilers/trt). Treatments associated with the first factor include immunization against ghrelin conjugated to KHL or immunization against the carrier protein. Primary immunization will be provided at 1 week of age (WOA) and booster immunizations will be given at 2, 4 and 5 WOA. The second factor includes treatments used to amplify the incidence of PH. Immunized birds (50%) will be reared in a thermo-neutral environment (21±1C), while the rest will be exposed to cold conditions (16±1C) in controlled environmental chambers. Blood samples will be collected weekly, starting on wk 2, until the end of the experiment (6 WOA). We choose to end the experiment at 6 WOA because ascites develops at 4-6 WOA (mostly in males) and birds are typically processed by the industry at 6 WOA. Antibody titers and concentrations of glucose, insulin, corticosterone, ACTH, GH, IL-1, IL-6, and NO will be analyzed. Feed intake will be measured daily, and body weight will be recorded weekly. The basal diet throughout the experiment will consist of a corn-soybean meal-based broiler ration including: 22.7% CP, and 3,059 kcal ME/kg. At the end of the experiment, cardiovascular performance will be evaluated.B.1. Experiment 2: The effect of exogenous ghrelin and mild hypothermia on the incidence of ascites in broilersB.2. Approach to be used: Starting at 3 WOA broiler males will be confined to individual cages, fitted with a canvas saddle, and randomly assigned to four treatments in a 2 X 2 factorial arrangement (n= 25 broilers/trt). Treatments associated with the first factor include ghrelin or saline infusion. The second factor includes treatments used to amplify the incidence of PH (thermo-neutral environment or cold conditions; 21±1C or 16±1C, respectively). Blood samples will be collected daily (using the same infusion cannula) starting on wk 4, for a total of 2 wk. Concentrations of, glucose, insulin, corticosterone, ACTH, GH, IL-1, IL-6, and NO will be analyzed. Feed intake will be measured daily, starting 1 wk before treatments are applied, and body weight will be recorded weekly. At the end of the experiment, cardiovascular performance will be evaluated.C.1. Experiment 3: The effect of feed restriction and low temperatures on ghrelin concentrations and the incidence of ascites in broilers.C.2. Approach to be used: One-day-old broiler males will be randomly assigned to four treatments (n = 25 broilers/trt) in a 2 x 2 factorial arrangement. The first factor consists of two levels of feed intake. Starting at 1 WOA, birds in treatment group 1 will be allowed to unrestricted access to feed and water intake (FF). Birds in treatment group 2 will be placed in a restricted feeding regimen (RES) consisting of one-third of the quantity of feed per unit of BW given to birds in FF treatment and ad libitum water intake. We choose to use 33% of the intake of ad libitum to be consistent with normal management practices used in broiler breeders restriction programs. In both treatment groups, birds will be fed daily starting at 0900, using individual feeders. The second factor includes treatments used to amplify the incidence of PH. Feed restricted birds (50%) will be reared in a thermo-neutral environment (21±1C), while the rest will be exposed to cold conditions (16±1C) in controlled environmental chambers. Blood samples will be collected weekly, starting on wk 2, until the end of the experiment. Concentrations of ghrelin, glucose, insulin, corticosterone, ACTH, GH, IL-1, IL-6, and NO will be analyzed. Feed intake will be measured daily, and body weight will be recorded weekly. At the end of the experiment, cardiovascular performance will be evaluated.

PROGRESS: 2019/03 TO 2020/03
Target Audience:Scientific community Changes/Problems:We don't foresee any obstacles to continue and finish with our research. What opportunities for training and professional development has the project provided?One PhD, and 3 undergraduate students were involved in this project. Students had the opportunity of being trained in cannulation techniques, blood sampling, recording of feed intake, as well as, general lab management How have the results been disseminated to communities of interest?Results have been disseminated using the traditional oral presentation in Scientific Meetings What do you plan to do during the next reporting period to accomplish the goals?We will continue our plan of action as described in the grant protocol.

IMPACT: 2019/03 TO 2020/03
What was accomplished under these goals? We were able to expose birds to mild hypothermia and measure pulmonary tension at Auburn University. Birds were successfully feed restricted, and we were able to obtain blood samples and measure feed intake. . Blood samples were obtained and feed intake was measured as indicated in the grant protocol.

PUBLICATIONS (not previously reported): 2019/03 TO 2020/03
Type: Conference Papers and Presentations Status: Accepted Year Published: 2020 Citation: 1. Taofeek, N., N. Chimbetete, N. Ceron-Romero, M. Verghese and J. Vizcarra. 2020. The effect of systemic infusion of active and non-active ghrelin on feed intake, weight gain, and corticosterone concentrations in male broiler chickens. International Poultry Scientific Forum. Atlanta, Georgia. 2. Ceron-Romero, N., N. Taofeek, A. Thomas, H. Chance, E. Vroonland, M. Verghese1, E. Heinen, and J.A. Vizcarra. 2020. The effect of a ghrelin receptor agonist (Capromorelin) on feed intake and body weight gain in broiler chickens (Gallus gallus domesticus). International Poultry Scientific Forum. Atlanta, Georgia.

PROGRESS: 2017/03/15 TO 2018/03/14
Target Audience:Scientific community Changes/Problems:We don't foresee any obstacles to continue with our research. No major changes will be incorporated. What opportunities for training and professional development has the project provided?One PhD, one MS student and 2 undergraduate students are involved in this project. Students had the opportunity of being trained in cannulation techniques, blood sampling, recording of feed intake, as well as, general lab management. The PI and graduate students also had the opportunity to participate in professional development activities by attending the International Poultry Scientific Forum (Atlanta, GA). How have the results been disseminated to communities of interest?Results have been disseminated using the traditional oral presentation in Scientific Meetings (International Poultry Scientific Forum). What do you plan to do during the next reporting period to accomplish the goals?We will continue our plan of action as described in the grant protocol.

IMPACT: 2017/03/15 TO 2018/03/14
What was accomplished under these goals? Birds were successfully feed restricted, and we were able to obtain blood samples and measure feed intake. In addition, we were able to cannulate 5 birds that were randomly distributed into different ghrelin treatments. Blood samples were obtained and feed intake was measured as indicated in the grant protocol.

PUBLICATIONS: 2017/03/15 TO 2018/03/14
Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: 1. Taofeek, N., F. Vizcarra, M. Verghese, and J.A. Vizcarra. 2018. The effect of Feed Restriction on ghrelin concentrations in male broiler chickens. International Poultry Scientific Forum. Atlanta, Georgia. (M3 p 1).