Oxidative stress and plasma vitamin E variation and its relationship to sow productivity

Vitamin E (VE) status and oxidative stress (OS) in females in commercial sow farms are not well characterized. The goal of this study was to assess OS and VE status in breeding females over two parities and determine its relationship to reproductive performance. Blood samples were collected from 318 gilts to assess reactive oxygen species (ROS), antioxidant capacity (SAC), the ratio of ROS to SAC (oxidative stress index, OSi) and VE in an effort to depict an overall stress level. Baseline (BL) samples were collected at 23 weeks of age, day 40 gestation (d40G), day110 gestation (d110G), day 5 lactation (d5L), and day 5 postweaning (d5PW) over parity 1 (P1) and parity 2 (P2). There were significant interactions between parity and time of sampling for ROS, SAC, OSi, and VE (P < 0.01). The interaction between parity and time of sampling for ROS was due to ROS being lower at d110G compared to d40G from both P1 and P2 females, which did not change after d110G in P1 gilts but increased from d110G to d5L and d5PW in P2 sows. The interaction between parity and time of sampling for SAC was due to an increase in SAC occurring on d5L and d5PW compared to d40G and d110G, with the increase being greater in P2 than in P1. Overall, OSi was greatest at BL and P1 compared to P2, indicating OS is increased in younger breeding females. There was an interaction between parity and time of sampling for VE (P < 0.01) where the increase in plasma VE from P1 to P2 differed depending on the time of sampling, with the increase in VE of from P1 to P2 being 0.5, 0.3, and 0.2 for d40G, d5L, and d5PW, respectively. Few correlations between reproductive performance and OS or VE measures were observed, of which they were of low correlation and inconsistent across parities suggesting that the relationship between OS and VE with reproductive performance is influenced by numerous factors beyond those measured. While these data suggest that OS of breeding females in the commercial US swine herd may be elevated, and VE status reduced, to a level which may negatively impact productivity, greater characterization of farm conditions and experimentally relevant variables in a commercial setting are needed to help define and potentially mitigate factors that reduce reproductive productivity under commercial conditions.