PSLBII-24 Effects of maintaining Berkshire grower pigs in alternative production systems on circulating cytokine profiles

In this study, we compared the cytokine profiles in the blood plasma of Berkshire grower pigs maintained in two different alternative swine production systems, the dry-lot production system and the hoop structure production system. This study was conducted during a 75-d period spanning from May to July at the North Carolina Agricultural and Technical State University Swine Facility in Greensboro, N.C. Cytokine profiles associated with the pro-inflammatory immune response [interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF) -α] and the anti-inflammatory immune response (IL-4, IL-10) were analyzed in blood plasma obtained from Berkshire grower pigs (n = 24). Berkshire pigs (n = 12) were managed in a 12.19 m x 18.28 m hoop structure with the end walls raised for ventilation and a straw deep bedding system. Twelve additional Berkshire pigs were managed in a 0.08-ha dry-lot. These animals were provided with a canopy for shading and a wallowing area for evaporative cooling. All animals were provided with ad libitum ration and water. Blood samples were collected at 25-d intervals throughout the 75-d trial, culminating in three different time points. Plasma was isolated from the blood samples and used for ELISA and colorimetric assays. The BioTek 800 TS absorbance reader and Gen5 Microplate Reader and Imager software (Agilent Technologies, Inc., Santa Clara, CA) were used to obtain and calculate the optical densities of the plasma samples, respectively. In turn, the standard curve was used to obtain the correlated protein concentrations. The data were analyzed using the two-way ANOVA feature of the JMP 17.2.0 statistical software (SAS Institute, Inc., Cary, NC) with production system and growth period considered as fixed variables, while protein concentration was considered the response variable. There were four significant treatment effects observed (P < 0.05). Significantly greater concentrations of IL-1β and IL-10 protein were detected in the plasma collected from Berkshire pigs managed in the dry-lot. Averaged across both production systems, there were greater concentrations of IL-1β and IL-10 protein detected in the blood plasma collected in growth period 1 compared with samples collected in growth periods 1 and 2. The results suggest that exposing Berkshire grower pigs to elevated temperatures during the summer elicits a dynamic immune response that favors an inflammatory response designed to destroy damaged tissues, followed by an anti-inflammatory response designed to promote tissue repair.