ABSTRACT
Mitochondria function and integrity may impact postmortem metabolism and meat quality development. Adaptations in heat tolerant Brahman may persist to limit cellular stress postmortem. Our objective was to evaluate glycolysis, pH decline, and mitochondria function in longissimus lumborum (LL) from Angus and Brahman steers (N = 28) early postmortem (1 to 6 h) and after rigor (24 h). We evaluated metabolites of anaerobic glycolysis, ATP, pH, and temperature, and determined mitochondria oxygen consumption rate (OCR) in permeabilized fibers. The main effects of breed (b) and time (t) and the interaction were tested. Brahman LL contained greater ATP during the first 6 h postmortem; Brahman also tended to exhibit a slower pH decline (b × t, P = 0.07) and more rapid temperature decline (b × t, P < 0.001), but metabolites of anaerobic glycolysis were not different. Mitochondria in Brahman and Angus LL were well-coupled and respired at 1 h postmortem. However, outer membrane integrity became increasingly compromised postmortem (t, P < 0.001). Brahman tended to exhibit greater electron transport system capacity (b, P < 0.1) and had greater capacity for oxidative phosphorylation (complex I and II substrates) at 6 h compared with Angus (P < 0.001). In totality, greater ATP, slower pH decline, and enhanced mitochondria capacity indicate that Brahman possess mitochondrial properties or cellular adaptations that help protect the cell during energy stress postmortem. Slower pH and more rapid temperature decline in LL from Brahman may also help preserve mitochondria function postmortem.
Subject(s)
Adenosine Triphosphate , Glycolysis , Muscle, Skeletal , Oxidative Phosphorylation , Postmortem Changes , Red Meat , Animals , Cattle , Male , Muscle, Skeletal/chemistry , Muscle, Skeletal/metabolism , Hydrogen-Ion Concentration , Adenosine Triphosphate/metabolism , Red Meat/analysis , Oxygen Consumption , Mitochondria/metabolism , Temperature , Mitochondria, Muscle/metabolismABSTRACT
Background: Studies in thoracic surgery have long raised concerns that intraoperative administration of intravenous fluids exacerbates or causes postoperative complications and hence advocate fluid restriction. Methods: This retrospective 3-year study investigated the role of intraoperative crystalloid administration rates on the duration of postoperative hospital length of stay (phLOS) and on the incidences of previously reported adverse events (AEs) in 222 consecutive patients following thoracic surgery. Results: Higher rates of intraoperative crystalloid administration were significantly associated with shorter phLOS (P=0.0006) and with less variance in phLOS. Dose-response curves showed progressive decreases in the postoperative incidences of surgical, cardiovascular, pulmonary, renal, other, and long-term AEs with higher intraoperative crystalloid administration rates. Conclusion: The rate of intravenous crystalloid administration during thoracic surgery was significantly associated with duration of and variance in phLOS, and dose-response curves showed progressive decreases in the incidences of AEs associated with this surgery. We cannot confirm that restrictive intraoperative crystalloid administration benefits patients undergoing thoracic surgery.
