Evaluation of pre‐slaughter low‐current/high‐frequency electrical stunning 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

Abstract

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.

Evaluation of the Effects of Pre-Slaughter High-Frequency Electrical Stunning Current Intensities on Lipid Oxidative Stability and Antioxidant Capacity in the Liver of Yangzhou Goose (Anser cygnoides domesticus)

“…No research has been done to study the ES effects on antioxidant capacity in meat goose liver. The activity of glutathione S-transferase (an antioxidant related enzyme) was decreased at d 3 in breast meat [10] and increased at d 1 in thigh meat of broilers that were stunned with 150 V/130 mA/60Hz as compared with 65 V/86 mA/1000 Hz in our previous study [12]. At 4 d postmortem, the DPPH•EA in control, E30V, and E60V groups were higher than that in the E120V group (p < 0.05, Figure 1C).…”

“…The reduction of the antioxidant enzyme may due to the proteins' cross-linking during storage [24]. Differently, the activity of T-SOD was observed to increase at d 1 compared to d 0 in the thigh muscle of broilers that were exposed to ES [12]. The enzyme activity of GSH-PX decreased on d 2 and then rose on d 4 in all the treatments (p < 0.05), except that E60V had a stable level from d 0 to d 4 (p > 0.05).…”

“…The enzyme activity of GSH-PX decreased on d 2 and then rose on d 4 in all the treatments (p < 0.05), except that E60V had a stable level from d 0 to d 4 (p > 0.05). However, in the thigh muscle of broilers, the activity of glutathione S-transferase was observed to decrease at d 3 compared with d 0 [12]. These antioxidant enzymes worked together leading to a higher DPPH•EA at d 2-…”

“…The storage time is also an important factor for lipid oxidation. In our previous study, the malondialdehyde (MDA) level in raw thigh meat that stored at 4 • C dropped to the minimum level from day 0 (d 0) to day 6 (d 6) and recovered to the level of d 0 again at day 9 (d 9) [12].…”

“…Lipid oxidation can lead to unpleasant odors or tastes, color deteriorations, degradation in proteins, and decline in the shelf life of food [6,7]. The factors that affect lipid oxidation in poultry products include poultry diet, oxidative stresses in the live birds, pre-slaughter stunning methods, food processing methods, and storage conditions [8][9][10][11][12]. The storage time is also an important factor for lipid oxidation.…”