Reactive oxygen species production in mitochondria of pigs selected for residual feed intake

Abstract

Electron transport in the mitochondria is a primary source of reactive oxygen species (ROS). Excess production of ROS may lead to increased oxidative stress, decreasing nutrient utilization and efficiency. The purpose of this study was to compare mitochondrial ROS production in pigs (n = 7 per line) divergently selected for residual feed intake (RFI). Mitochondria were freshly isolated from liver by differential centrifugation. The production of H2O2 was determined by using 2, 7 ‐Dichlorofluorescein diacetate. Glutamate or succinate was provided as an energy source for complex I and II respectively. Rotenone inhibited electron backflow when using succinate. No differences in H2O2 production between the lines were observed when using glutamate as an energy substrate. When succinate was added, H2O2 production was decreased by 8% in low RFI pigs compared to their high RFI counterparts (46.7 vs. 34.3 nmol H2O2/mg protein/min ± 8.87). Other inhibitors of electron transport, 4,4,4‐trifluoro‐1‐ [2‐thienyl]‐1,3‐butanedione, malonate, or the combination of these, yielded similar results (P<0.05). Altogether, these data indicate that less efficient, high RFI, pigs are more prone to hepatic intracellular oxidative stress. This may explain why low RFI pigs are more efficient at utilizing and partitioning nutrients for growth and metabolism. This research was supported by USDA‐AFRI grant# 2010‐65206‐20670.