Different oxidative status and expression of calcium channel components in stress-induced dysfunctional chicken muscle

The objective of this study was to assess the effects of transport stress at high ambient temperatures on the oxidation status and the expression of essential elements responsible for the Ca2+ transport (sarco-(endo-) plasmic reticulum Ca(2+)ATPase (SERCA1) and the ryanodine receptor (RyR) in pectoralis major (PM) muscles of broilers. Briefly, Arbor Acres broiler chickens (n = 112) were randomly categorized into 2 treatments: unstressed control (C) and 0.5 h transport (T). Each treatment consisted of 8 replicates of 7 birds each. Birds were transported according to a designed protocol. PM muscle samples in T group were collected and classified as normal (T-NOR) or pale, soft, and exudative-like (T-PSE) using meat quality parameters. The results indicated that production of corticosterone (CORT) and reactive oxygen species (ROS) increased significantly after transportation (P < 0.05). Thiobarbituric acid reactive substance values and carbonyl contents increased significantly in the T group (P < 0.05). Moreover, the extent of lipid peroxidation and protein oxidation was more severe in the T-PSE group compared to the T-NOR group (P < 0.05). The mRNA and protein expression of SERCA1 and aRyR increased in the T-NOR group but decreased significantly in the T-PSE group compared to the CON group (P < 0.05). The mRNA expression of aRyR was found to be enhanced in the T-NOR group compared to the CON group, whereas there was no difference in the T-PSE group (P < 0.05). The results indicate that short-distance transport of broilers affects their physiological responses and biochemical changes which may lead to different oxidative states and, importantly, to different expressions of SERCA and RyR. These induced changes in abnormal sarcoplasmic Ca2+ homeostasis have significant implications for the development of PSE-like meat.