PSLBII-23 Effects of alternative production systems on growth and circulating blood profiles in Berkshire grower pigs

Abstract In this study, we compared the growth performance and circulating blood profiles 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. Protein expression profiles associated with growth (FGF-19, PDGF-BB, IGF-1), feed intake (CCK), stress (cortisol) and the ability to handle oxidative stress (T-AOC) were analyzed in blood plasma obtained from 24 Berkshire nursery/grower pigs. Berkshire pigs (n = 12) were managed in a 12.19 m x 18.28 m hoop structure with the end walls removed for ventilation and a straw deep bedding system. Twelve additional Berkshire nursery/grower pigs were managed in a 0.08-ha dry-lot. These animals were provided with a canopy for shade and a wallowing area for evaporative cooling. All animals were provided with ad libitum ration and water. Individual body weights (BW) and 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. The data were analyzed using the two-way ANOVA feature of JMP 17.2.0 software (SAS Institute, Inc., Cary, NC) with production system and growth period considered fixed variables, while either growth rate or protein concentration were considered as the response variable. There were four significant treatment effects observed (P < 0.05). Significantly greater concentrations of IGF-1, CCK, and T-AOC were detected in the plasma collected from Berkshire pigs managed in the dry-lot. Whereas those managed in the hoop structure production system had heavier BW. The results show that exposing pigs to higher temperatures can reduce feed intake and growth rates. However, this same stress elicits the release of hormones that promote growth, while enhancing the total antioxidant capacity in these animals. The results support the adoption of the hoop structure production system over the dry-lot production system when managing swine in regions that experience higher temperatures.