Chronic immune stimulation in adipose tissue and its consequences for health and performance in the pig

The pig has been domesticated for about 13,000 years in multiple centers in Europe, Eurasia and China. Chronic inflammation in pigs is a major mitigating factor against optimal health and growth performance. Therefore, strategies for improving health status of pigs must involve downregulation of inflammation. The recent revelation that the adipose tissue is an endocrine organ with immune function introduces an exciting possibility that pig adipose tissue is also involved in the regulation of immune response. The adipose tissue expresses innate pattern recognition receptors through which the tissue is able to recognize conserved pathogen structures, leading to an orchestration of immune response. Experimental evidence indicates that preadipocytes possess phagocytic properties that may contribute to the clearance of pathogens from circulation. A complication factor, however, is that activation of innate immune response pathways in adipocytes is often associated with onset of chronic inflammation. Because chronic inflammation is linked to impairment of animal health and optimal growth efficiency, strategies are needed to minimize exposure to factors that may activate immune response in pigs.