本试验旨在研究屠宰前不同二氧化碳（CO₂）浓度的混合气体致晕（控制气体击晕）对肉鹅肝脏颜色、脂质氧化及抗氧化能力的影响。试验选取56只85日龄的扬州鹅公鹅，随机分成7个组（1个对照组，6个试验组），每组8个重复，每个重复1只。对照组不致晕直接屠宰，试验组屠宰前由不同CO₂浓度的混合气体致晕。6个试验组致晕混合气体组成如下：G40组，40% CO₂+21%氧气（O₂）+39%氮气（N₂）；G50组，50% CO₂+21% O₂+29% N₂；G60组，60% CO₂+21% O₂+19% N₂；G70组，70% CO₂+21% O₂+9% N₂；G79组，79% CO₂+21% O₂。上述5组致晕时间均为7 min。G40+G79组，40% CO₂+30% O₂+30% N₂致晕2 min，然后79% CO₂+21% O₂致晕5 min。结果显示：G79组肉鹅的放血率最低，与对照、G40、G50、G70和G40+G79组均存在显著差异（P<0.05）。G40组肝脏在屠宰后1和4 d的亮度值及在屠宰后1 d的黄度值均显著高于G79和G40+G79组（P<0.05）。屠宰后1 d，G40组肝脏中丙二醛（MDA）含量显著低于G70和G79组（P<0.05）；屠宰后4和7 d，G79组肝脏中MDA含量显著低于G40组（P<0.05）。屠宰后0 d，G79组肝脏1，1-二苯基-2-三硝基苯肼（DPPH）自由基清除能力最低，G40组最高，但组间差异不显著（P>0.05）。屠宰后1、4和7 d，G40组肝脏中谷胱甘肽过氧化物酶（GSH-Px）活性均显著低于G79组（P<0.05）。屠宰后4 d，G40组肝脏中总超氧化物歧化酶（T-SOD）活性显著高于G79组（P<0.05）。综上所述，肉鹅屠宰前采用40% CO₂混合气体（40% CO₂+21% O₂+39% N₂）致晕可以改善肝脏颜色，且在短期（0~1 d）内肝脏DPPH自由基清除能力最高，脂质氧化程度较低，而高浓度（79%）CO₂混合气体（79% CO₂+21% O₂）致晕可以缓解中长期（4~7 d）储存时肝脏的脂质氧化。

This experiment was conducted to investigate the effects of pre-slaughter gas mixture stunning (controlled atmosphere stunning) with different carbon dioxide (CO₂) concentrations on liver color, lipid oxidation and antioxidant capacity of meat geese. Fifty-six 85-day-old Yangzhou male geese were selected and randomly divided into 7 groups (one control group and six test groups) with eight replicates per group and one goose per replicate. The geese in the control group were slaughtered without stunning, and those in test groups were stunned by gas mixture with different CO₂ concentrations. The gas mixture composition of six test groups as follows:G40 group, 40%CO₂+21% oxygen (O₂)+39% nitrogen (N₂); G50 group, 50%CO₂+21%O₂+29% N₂; G60 group, 60%CO₂+21%O₂+19% N₂; G70 group, 70%CO₂+21%O₂+9% N₂; G79 group, 79%CO₂+21%O₂; G40+G79 group, 40%CO₂+30%O₂+30%N₂ stunning for 2 min, and then 79%CO₂+21%O₂ stunning for 5 min. The stunning time for the first 5 groups was 7 min. The results showed as follows:the bleed out efficiency of G79 group was the lowest, which had significant difference compared with that of control, G40, G50, G70 and G40+G79 groups (P<0.05). Liver lightness value of G40 group was significantly higher than that of G79 and G40+G79 groups at 1 and 4 days after slaughter (P<0.05). Liver yellowness value of G40 group was significantly higher than that of G79 and G40+G79 groups at 1 day after slaughter (P<0.05). At 1 day after slaughter, the malondialdehyde (MDA) content in liver of G40 group was significantly lower than that of G70 and G79 groups (P<0.05); at 4 and 7 days after slaughter, the MDA content in liver of G79 group was significantly lower than that of G40 group (P<0.05). At 0 day after slaughter, the liver 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity of G79 group was the lowest, and it of G40 group was the highest, but there was no significant difference among groups (P>0.05). The activity of glutathione peroxidase (GSH-Px) in liver of G40 group was significantly lower than that of G79 group at 1, 4 and 7 days after slaughter (P<0.05). The activity of total superoxide dismutase (T-SOD) in liver of G40 group was significantly higher than that of G79 group at 4 days after slaughter (P<0.05). In conclusion, pre-slaughter gas mixture stunning with 40% CO₂ (40%CO₂+21%O₂+39%N₂) can improve liver color. The liver DPPH free radical scavenging activity is the highest and lipid oxidation degree is the lowest when geese stunned with 40% CO₂ at the initial stage of storage (0 to 1 day), whereas, the lipid oxidation at a longer storage time (4 to 7 days) is lower in geese stunned by gas mixture (79%CO₂+21%O₂) with high concentration (79%) of CO₂.