Stress, Nutrition, and Intestinal Immune Responses in Pigs — A Review

Lee, In Kyu; Kye, Yoon Chul; Kim, Girak; Kim, Han Wool; Gu, Min Jeong; Umboh, Johnny; Maaruf, Kartini; Kim, Sung Woo; Yun, Cheol-Heui

Various stressors are threatening the health and, at the same time, suppressing the growth performance in farm animals. The present paper focused on major stress factors, including thermal, nutritional and infectious, in relation to gut immunity in pigs. Numerous studies focusing on stresses in conjunction with porcine gut examined TJ proteins for the permeability, pro-inflammatory cytokines and/or gene profiles (Table 1 ). However, we do not know enough today to fully explain the precise mechanism of the gut immune system in pigs under stress conditions. In addition, the pig's immune system cannot be directly extrapolated from that of humans and mice, for instance, CD4 + CD8 + T cells in peripheral immune system (Cheon et al., 2014) . In the near future, studies are expected to define i) the identification and the function of immune cells like innate lymphoid cells in intestine, ii) the immunological interaction between immune cells and gut epithelial cells under major stresses, iii) the alteration of intestinal immune system by major stresses to systemic immune responses and iv) gut health leading host immune system under multistress condition in pigs.