Comparison of Pre-Slaughter Stunning Methods on Stress Response and Flesh Quality in Fish
學生姓名:
李承諺
指導教授:
陳泰源
學 期:
113下
摘 要:
Many studies have indicated that fish can experience pain and feel fear. Therefore, stunning and slaughter methods must be fast in order to avoid pain and suffering. Improper handling can result in adverse effects reflected in blood and physicochemical parameters. Thus, the objective is to evaluate and identify the optimal stunning method that minimizes stress on fish. This study initially examined pre-slaughter treatments for rainbow trout using ice stunning and electronarcosis at 200 mA and 400 mA. It was found that ice stunning resulted in better recovery of consciousness compared to electronarcosis. Among the treatments, the 400 mA group had the lowest blood indicators, with cortisol at 5.2 ng/mL and CPK enzyme at 104 U/L. Electronarcosis also resulted in a higher initial pH value and delayed onset of rigor mortis. Additionally, it preserved the highest muscle glycogen content, indicating an effective reduction in pre-slaughter stress responses. Next, different pre-slaughter treatments including electronarcosis (EE), air asphyxiation (AA), ice asphyxiation (IA), and hypothermia followed by bleeding (HB) were compared for Arapaima gigas fillets. The EE and HB groups showed a more significant decrease in pH after 72 hours of storage and remained significantly lower at the end of storage. The EE group took the longest to enter rigor mortis, at approximately 2 hours and 30 minutes, suggesting lower pre-slaughter stress, which correlated with pH changes. After 240 hours of storage, the EE group maintained greater firmness and lower adhesiveness, likely due to a tighter muscle structure. It also exhibited the lowest average blood glucose level (66.33 mg/dL) and better L* values (lightness). These findings demonstrate that electronarcosis effectively reduces pre-slaughter stress and improves fish meat quality while aligning with fish welfare standards.
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