Author
Carroll, Jeffery - Jeff Carroll | |
Sanchez, Nicole | |
WELSH JR, THOMAS - Texas A&M University | |
RANDEL, RONALD - Texas A&M University |
Submitted to: Meeting Proceedings
Publication Type: Proceedings Publication Acceptance Date: 3/11/2011 Publication Date: 3/12/2011 Citation: Carroll, J.A., Sanchez, N.C., Welsh Jr, T.H., Randel, R.D. 2011. Relationships between Stress and Immunity. Proceedings of the Prince AgriProducts' Dairy Cow Academy, April 12-15, 2011, Ames, Iowa. Interpretive Summary: A series of collaborative studies was conducted involving scientists from the Livestock Issues Research Unit, Texas AgriLife Research and Extension Center-Overton, and Texas AgriLife Research-College Station to elucidate the relationships between stress and immunity in cattle, and how these biological processes are influenced by factors such as animal temperament, sex, and nutritional supplements. Utilzing our bovine endotoxemia model generated by administering an E. coli-derived lipopolysaccharide (LPS) to cattle, we have discerned individual variations in the stress and innate immune responses in different breeds of Bos taurus cattle that are considered to be either heat-tolerant or heat-sensitive. We have also demonstrated natural variations in the stress and innate immune responses of Bos indicus cattle, revealing sexually dimorphic variations following exposure to LPS, as well as variations associated with animal temperament. Additionally, we have utilized this model to demonstrate that nutritional supplements can be an effective management tool for altering the innate immune response following exposure to LPS. Understanding the relationships that exist between stress and immune responses, and elucidating potential variations associated with various environmental conditions, the genetic makeup of the animal, and the impact of nutrition are essential steps toward developing new management strategies that will improve the overall health, productivity, and well-being of livestock. Therefore, this information will be of interest to both scientists and producers working in the area of beef cattle production with specific focus on the regulation of stress and immune responses. Technical Abstract: Stress, as it relates to bodily functions, has been defined as the sum of all biologic reactions to physical, emotional, or mental stimuli that disturb an individual’s homeostasis. Therefore, a stressor can be defined as any internal or external stimuli or threat that disrupts homeostasis of the body and elicits a coordinated physiological response within the body in an attempt to reestablish homeostasis. Maintaining a state of homeostasis requires proper functioning of all physiological processes within the body, including the stress and immune systems which are influenced by numerous factors including environmental conditions, pathogen exposure, genetic makeup, animal temperament, and nutrient availability or lack thereof. Research related to stress in domestic animals has continued to evolve and expand, and multidisciplinary efforts have emerged leading to a greater understanding of homeostatic regulation. Of particular interest are animals that demonstrate differential stress and immunological responses due to previous exposure to various managerial, environmental, nutritional, or pathogenic stressors. To fully understand the relationships between stress and immunity, it is important to understand the various components of the immune system and their involvement in providing protection for the animal. Given the importance of the innate immune response with regard to the overall health and survival of domestic livestock, the primary immunological focus of this manuscript will be on variations that exist within the innate immune system and efforts to selectively and precisely modulate this system in a manner that is beneficial not only for survival, but also for enhancing productivity in domestic livestock. For more than a decade, our laboratory has utilized a reliable endotoxemia model generated by administering an E. coli-derived lipopolysaccharide (LPS) to livestock as a means to discern individual variations that exist in the innate immune response that can have significant impact on the overall health and productivity of an animal. Utilizing this model, we have characterized variations in the stress and innate immune responses following exposure to LPS in different breeds of Bos taurus cattle that are considered to be either heat-tolerant or heat-sensitive. We have also demonstrated natural variations in the stress and innate immune responses of Bos indicus cattle, revealing sexually dimorphic variations following exposure to LPS, as well as variations associated with animal temperament. Additionally, we have utilized this model to demonstrate that nutritional supplements can be an effective management tool for altering the innate immune response following exposure to LPS. Understanding the relationships that exist between stress and immune responses, and elucidating potential variations associated with various environmental conditions, the genetic makeup of the animal, and the impact of nutrition are essential steps toward developing new management strategies that will improve the overall health, productivity, and well-being of livestock. |