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Summary: This study was aimed to evaluate the effects of pre‐slaughter low‐current/high‐frequency (LH) electrical stunning (ES) on lipid oxidative stability, antioxidant enzyme activity and gene expression of mitogen‐activated protein kinase/nuclear factor erythroid 2‐related factor 2 (MAPK/Nrf2) signalling pathway in thigh muscle of broilers. Eighteen birds were randomly allocated to the following three treatments with six replicates per treatment and one bird per replicate: without stunning (control); water‐bath ES with sinusoidal alternating LH (86 mA, 1000 Hz, LHES) or high current/low frequency (HL) (130 mA, 60 Hz, HLES). Stunning methods did not affect malondialdehyde level (d 0 ~ d 9) or antioxidant enzymes' activity at d 0 ~ d 2. LHES enhanced glutathione S‐transferase activity at d 3 and gene expression of MAPKs and Nrf2 compared with HLES. In conclusion, LHES enhanced gene expression of MAPK/Nrf2 pathway, whereas had no superiority over HLES in lipid oxidative stability (4 °C, 9 days) of thigh muscle in broilers. [ABSTRACT FROM AUTHOR]

Mechanism of electrical stunning (ES) methods on lipid peroxidation and antioxidant protection were studied by determining meat color, serum variables, antioxidant-related enzyme activities, gene expressions of mitogen-activated protein kinases (MAPKs), nuclear factor-erythroid 2-related factor 2 (Nrf2), glutathione S-transferases (GSTs), and superoxide dismutases (SODs). Broilers were sacrificed without stunning, or after ES with 65 V, 86 mA, 1000 Hz (E65 V) or 150 V, 130 mA, 60 Hz (E150V). Serum cortisol and uric acid, muscular malondialdehyde and mRNA levels of MAPKs, Nrf2, GSTA3, GSTT1 and SOD2 were increased, whereas, serum free triiodothyronine, free thyroxine, muscular GST 1d activity were decreased in E65V compared with E150V. Overall, the serum uric acid and transcription of the MAPK/Nrf2/ARE (antioxidant responsive element) signaling pathway were elevated, but didn’t overcome the oxidative stress stimulated by low-current & high-frequency ES, leading to aggravated lipid peroxidation at 1 d and 9 d postmortem in breast muscle compared with high-current & low-frequency ES. [ABSTRACT FROM AUTHOR]