Divergent genetic selection for residual feed intake impacts mitochondria reactive oxygen species production in pigs1

Abstract

The objective of this study was to determine the extent to which genetic selection for residual feed intake (RFI) impacts electron leakage and reactive oxygen species (ROS) production in mitochondria from muscle and liver tissue. Understanding how genetic selection for RFI impacts animal physiology and growth efficiency is of the utmost importance as the world population increases. Production efficiency is tied directly to energy use. Mitochondria were used in this study because they produce 90% of the ATP in the body and use a large majority of dietary energy. Mitochondria were isolated from both muscle and liver tissue from pigs genetically selected for RFI (n = 8 per RFI line; 34 ± 4 kg). A 2,7-dichlorofluorscein diacetate assay was used to detect differences in hydrogen peroxide production between the more efficient low RFI line and the less efficient high RFI line. Our hypothesis was that greater efficiency would be linked to less ROS production from the mitochondria. There was less ROS production in mitochondria from the white portion of the semitendinosus in the low RFI line compared with the high RFI line, when both NADH and Flavin Adenine Dinucleotide (FADH2) energy substrates were used (glutamate and succinate, respectively). Additionally, mitochondria from the red portion of the semitendinosus in the low RFI line had less ROS production when succinate was used as an energy substrate (P < 0.05). A positive correlation was observed between RFI and ROS in mitochondria from the LM. These data indicate genetic selection for RFI may influence mitochondrial ROS production and efficiency of pork production. ABSTRACT: The objective of this study was to determine the extent to which genetic selection for residual feed intake (RFI) impacts electron leakage and reactive oxygen species (ROS) production in mitochondria from muscle and liver tissue. Understanding how genetic selection for RFI impacts animal physiology and growth effi ciency is of the utmost importance as the world population increases. Production effi ciency is tied directly to energy use. Mitochondria were used in this study because they produce 90% of the ATP in the body and use a large majority of dietary energy. Mitochondria were isolated from both muscle and liver tissue from pigs genetically selected for RFI (n = 8 per RFI line; 34 ± 4 kg). A 2,7-dichlorofl uorscein diacetate assay was used to detect differences in hydrogen peroxide production between the more effi cient low RFI line and the less effi cient high RFI line. Our hypothesis was that greater effi ciency would be linked to less ROS production from the mitochondria. There was less ROS production in mitochondria from the white portion of the semitendinosus in the low RFI line compared with the high RFI line, when both NADH and Flavin Adenine Dinucleotide (FADH2) energy substrates were used (glutamate and succinate, respectively). Additionally, mitochondria from the red portion of the semitendinosus in the low RFI line had less ROS production when succinate was used as an energ...

Evidence of decreased muscle protein turnover in gilts selected for low residual feed intake1

“…Breast muscle mitochondria as well as gut, leg, heart, liver, and lymphocyte homogenates from low FE birds consistently exhibit a greater pervasive total protein carbonyl content compared with high FE birds (Bottje and Carstens, 2009). This supports previous observations of greater mitochondrial ROS production in low FE broilers (Bottje et al, 2002;Iqbal et al, 2004;OjanoDirain et al, 2005OjanoDirain et al, , 2007Lassiter et al, 2006) and in our high RFI pig lines (Grubbs et al, 2013a). This is further supported by low FE steers having greater neck muscle mitochondria protein carbonyl content (Sandelin, 2005).…”

“…Improved FE and low RFI could be partially explained be a reduction in the amount of electron leakage from mitochondria isolated from muscle, liver, and intestines, reactive oxygen species (ROS) production, and oxidative stress (Bottje and Carstens, 2009;Grubbs et al, 2013a). Decreasing ROS production could lead to a decrease in oxidative damage to DNA, lipids, and proteins, leading to a decrease in mitophagy and protein turnover (Bottje and Carstens, 2009).…”

Liver and skeletal muscle mitochondria proteomes are altered in pigs divergently selected for residual feed intake1,2

“…Mitochondrial reactive oxygen species (RoS) production is closely associated with feed efficiency in pigs (Grubbs et al, 2013a) and poultry (Bottje et al, 2002). However, the cause of these differences has eluded researchers.…”

“…Finally, the explanation for differences in RFI phenotype may be independent of mitochondria proteome. In fact other factors including protein turnover (Cruzen et al, 2013), stress (Bottje et al, 2006;Bottje and Carstens, 2009;Grubbs et al, 2013a), and potentially other cellular organelles and the systemic physiological response to those factors likely will contribute to changes in the observed RFI phenotype. In contrast, 8 generations of selection for RFI may have resulted in a stable shift in mitochondria proteome.…”

“…All pigs were fed a standard cornsoybean-dried distillers grain solubles diet that met or exceeded NRC (1998) nutrient and energy requirements for this size pig. The diet and overall performance were reported previously (Grubbs et al, 2013a). Growth performance is reported in Table 1.…”