Acute stress deteriorates breast meat quality of Ross 308 broiler chickens by inducing redox imbalance and mitochondrial dysfunction

Abstract

This study investigated the effects of acute stress on breast meat quality, redox status and mitochondrial function in pectoralis major (PM) muscle of broilers. A total of 168 broiler chickens (42-day-old, Ross 308) were randomly divided into control (CON) and pre-slaughter transport (T) treatments. A broiler was an experimental unit. Each treatment consisted of 84 broilers, and they were put in 12 crates with 7 broilers each. Broilers in the T group were transported according to a designed protocol, and the CON broilers were kept in crates under normal living conditions before slaughtering. Based on the meat quality traits assessed at postmortem 24 h, all PM muscles of the transported broilers were further classified into normal (T-NOR) and pale, soft and exudative (PSE)-like (T-PSE) groups for the determination of redox status in PM muscle and isolated mitochondria, energy metabolites, mitochondrial electron transport chain complexes activities, as well as mitochondrial function-modulating genes expression. Compared with CON, the extent of lipid peroxidation as well as protein oxidation were significantly increased in both PM muscles and mitochondria in T-PSE (P < 0.05), whereas not in T-NOR. Higher activities of glutathione peroxidase, total superoxide dismutase and Cu-Zn superoxide dismutase were observed in PM muscle of T-NOR broilers as compared with CON (P < 0.05). Pre-slaughter transport increased the generation of reactive oxygen species, as well as enhanced antioxidant capacity in PM mitochondria of broilers (P < 0.05). Compared with CON, the ATP content, activities of complex I and III, as well as relative mitochondrial membrane potential and swelling were significantly decreased in T-PSE (P < 0.05), whereas no significant changes in either ATP content or complex I activity were observed in T-NOR. Pre-slaughter transport enhanced the mRNA expression of regulators involved in the glutathione system, thioredoxin 2 system and mitochondrial biosynthesis in PM muscle of broilers (P < 0.05). Moreover, we noticed a more evident enhancement effect in T-NOR than in T-PSE (P < 0.05). Overall, this work indicates that acute stress-induced redox imbalance and mitochondrial dysfunction have significant implications for the development of PSE-like meat.

Overexpression of Heat Shock Protein 70 Ameliorates Meat Quality of Broilers Subjected to Pre-Slaughter Transport at High Ambient Temperatures by Improving Energy Status of Pectoralis Major Muscle and Antioxidant Capacity

“…Herein, we observed that pre-slaughter transport at high ambient temperature disturbed redox homeostasis and induced oxidative stress in the PM muscles of broilers by increasing ROS generation, lipid peroxidation, and protein oxidation. In addition, the adaptive responses of broilers to pre-slaughter transport stress were insufficient, as the activities of antioxidant enzymes, including T-AOC, T-SOD, and GSH-Px, remained unchanged, which is in accordance with the findings obtained by Liao et al [ 40 ]. HSP70 exerts its cytoprotective effect by facilitating the degradation of damaged oxidized proteins via the ubiquitin-proteasome system, as well as by inducing the expression of key antioxidant enzymes and adjusting their activities under oxidative stress [ 41 ].…”

Intracellular Calcium Overload and Activation of CaMKK/AMPK Signaling Are Related to the Acceleration of Muscle Glycolysis of Broiler Chickens Subjected to Acute Stress

“…These results suggested that acute stress might change the expression of calcium channels on the cell membrane, leading to the continuous entry of extracellular Ca 2+ and the abnormal outflow of Ca 2+ in the cytoplasm, thereby triggering cytoplasmic calcium overload. We recently demonstrated that the impact of acute stress on the mitochondria mainly occurred in the imbalance of the redox state and mitochondrial dysfunction . Herein, no significant effect of acute stress on mitochondrial Ca 2+ concentration and MCU mRNA expression and protein content was observed.…”

“…We recently demonstrated that the impact of acute stress on the mitochondria mainly occurred in the imbalance of the redox state and mitochondrial dysfunction. 19 Herein, no significant effect of acute stress on mitochondrial Ca 2+ concentration and MCU mRNA expression and protein content was observed. Although acute stress induced the increase of the cytoplasmic Ca 2+ concentration, mitochondrial MCU did not perceive this change as the threshold for its opening was about 1 μM.…”

“…Meat cylinders perpendicular to the direction of muscle fiber (diameter = 20 mm, height = 20 mm) were obtained for texture profile measurement using a texture analyzer (TMS-Pro, FTC, Sterling, VA). The test settings of the texture analyzer were set as previously reported …”

“…The test settings of the texture analyzer were set as previously reported. 19 Plasma Stress Index Measurements. The activity of creatine kinase (CK) and the content of corticosterone (CORT) in plasma were examined using commercial assay kits (Nanjing Jiancheng Bioengineering Institute, Nanjing, China).…”