Abstract
Background:
Animal slaughter in accordance with halal standards and animal welfare plays a crucial role in meat quality. One of the main factors influencing meat quality is the animal’s stress level during slaughter, which can be measured through corticosterone and superoxide dismutase (SOD) levels, which are biomarkers of stress.

Aim:
This study aimed to evaluate the effects of knife sharpness by juru sembelih halal (JULEHA) certified and non-JULEHA (non-certified) on stress levels and meat quality in broiler chickens.

Methods:
This study employed a completely randomized design. A total of 120 broiler chickens aged 4 weeks were randomly assigned to four treatments (T): T1 (JULEHA + knife sharpened for 20 s), T2 (JULEHA + knife not sharpened), T3 (Non-JULEHA + knife sharpened for 20 s), and T4 (Non-JULEHA + knife not sharpened). Each treatment consisted of 30 chickens. All slaughtering procedures were conducted using knives (new with the same merk) that met halal slaughter and animal welfare requirements, ensuring that all knives were initially sharp. The measured parameters included corticosterone levels and superoxide dismutase (SOD) activity as stress biomarkers and meat quality (hardness, springiness, gumminess, and chewiness). Corticosterone and SOD data were analyzed using one-way analysis of variance (ANOVA) followed by Duncan’s post hoc test, while meat texture data were analyzed using the Kruskal–Wallis test followed by pairwise comparisons with Bonferroni correction. All statistical analyses were performed using SPSS v.29.0 (IBM, NY, USA) with a 95% confidence level (α = 0.05).

Results:
Corticosterone levels in T1 were significantly different from those in T2 and T4, showing that T1 decreased stress levels. The results on springiness showed that T1 was significantly different from the other treatments, whereas the chewiness parameters of T1 and T2 were significantly different from those of T3 and T4, indicating that T1 had lower springiness and chewiness values, indicating softer and more tender meat, suggesting improved textural quality and potentially reduced physiological stress during slaughter.

Conclusion:
T1 (JULEHA + knife sharpened for 20 s) proved to be the most effective halal slaughtering method, reducing broiler stress levels, such as decreasing corticosterone levels during slaughter, and producing better meat quality, especially reduced springiness and chewiness.

Key words: Corticosterone; Halal; Knife sharpened; Meat quality; Superoxide dismutase.