Jump to Main Content
Gas stunning with CO2 affected meat color, lipid peroxidation, oxidative stress, and gene expression of mitogen-activated protein kinases, glutathione S-transferases, and Cu/Zn-superoxide dismutase in the skeletal muscles of broilers
- Xu, Lei, Zhang, Haijun, Yue, Hongyuan, Wu, Shugeng, Yang, Haiming, Wang, Zhiyue, Qi, Guanghai
- Journal of animal science and biotechnology 2018 v.9 no.1 pp. 37
- blood serum, breast meat, breast muscle, breasts, carbon dioxide, color, correlation, cortisol, enzyme activity, gene expression, genes, glutathione transferase, lipid peroxidation, lipid peroxides, meat quality, messenger RNA, mitogen-activated protein kinase, nitrogen, oxidative stress, oxygen, skeletal muscle, storage, storage temperature, stunning methods, superoxide dismutase, thiobarbituric acid-reactive substances, triiodothyronine
- BACKGROUND: Meat color and lipid peroxidation are important traits related to meat quality. CO₂ concentration is a critical factor that can affect meat quality in the commercial use of gas stunning (GS). However, the effect and mechanism of CO₂ stunning on meat color and lipid peroxidation during long-term storage remain poorly studied. We aimed to study the effects of GS methods, especially CO₂ concentration, on meat color and meat lipid peroxidation in broilers during long-term storage at 4 °C and to explore the potential mechanism of meat color change via lipid peroxidation and the inner lipid peroxide scavenging system. METHODS: Eighteen broilers were sacrificed after exposure to one of the following gas mixtures for 90 s: 40% CO₂ + 21% O₂ + 39% N₂ (G40%), 79% CO₂ + 21% O₂ (G79%), or no stunning (0% CO₂, control). Meat color, serum variables, enzyme activities, and the gene expression of mitogen-activated protein kinase (MAPK), nuclear factor-erythroid 2-related factor 2 (Nrf2), glutathione S-transferase (GST) and superoxide dismutase (SOD) were determined. RESULTS: The concentrations of serum triiodothyronine (T3, P = 0.03) and the ratio of serum free triiodothyronine/free thyroxine (FT3/FT4, P < 0.01) were decreased, whereas levels of serum cortisol (P < 0.01) were increased in the 40% CO₂ group compared with the control group. Additionally, the thiobarbituric acid-reactive substances (TBARS) ₃ d (P < 0.01) and TBARS ₆ d (P = 0.01) in breast meat and the TBARS ₃ d in thigh meat (P < 0.01) were increased in the 40% CO₂ group compared with the control group. Serum T3 was negatively correlated with TBARS₆ d both in the breast and thigh meat (r = − 0.63, P < 0.01 and r = − 0.47, P = 0.05 respectively). T3/T4 was negatively correlated with TBARS₆ d in the breast meat and in the thigh meat (r = − 0.57, P = 0.01; and r = − 0.53, P = 0.03 respectively). Compared with the control group, Lightness (L*) ₁ d (P = 0.03) and L*₉ d (P < 0.01) were increased, whereas total chromatic aberration (E*) ₁ d (P = 0.05) and E*₃ d (P < 0.01) were decreased in the breast meat of both the G40% and G79% groups. The values of yellowness (b*) ₃ d (P = 0.01), b*₆ d (P < 0.01) and E*₆ d (P < 0.01) in the thigh meat were lower in both the G40% and G79% groups than in the control group. In the breast muscle, the mRNA levels of c-Jun N-terminal kinase 2 (JNK2, P = 0.03), GSTT1 (P = 0.04), and SOD1 (P = 0.05) were decreased, and the mRNA levels of JNK1 (P = 0.07), Nrf2 (P = 0.09), and GSTA3 (P = 0.06) were slightly lower in both the G40% and G79% groups compared with the control group. However, among these genes, only the mRNA level of JNK1 was decreased in the G40% group compared with the control group and the G79% group (P = 0.03) in the thigh muscle. CONCLUSIONS: Compared with the control group, meat color quality in the breast meat was decreased, and the expression of genes in the MAPK/Nrf2/ARE (antioxidant responsive element) antioxidant pathway in breast muscle was partly suppressed by GS of both 40% and 79% CO₂. However, oxidative stress and meat lipid peroxidation during storage were aggravated by GS with 40% CO₂ compared to GS with 79% CO₂ and no GS.