Effect of protease and sex on carcass quality and abdominal fat of slow-growing hybrid of chic

Abstract

Broiler chickens have high needs for all nutrients for intensive growth. This also determines the high cost of broiler feed, and thus the cost-effectiveness of production. Therefore, alternative diets for poultry are being researched. One of the solutions that is often proposed is to reduce the content of some nutrients with the use of feed additives that will improve their digestibility. Potential profits of low-protein diets include reducing the cost of feeding, nitrogen emissions from livestock production, and environmental impact (Attia et al., 2020), which were advantageous in enhancing survivability (Amer et al., 2021). Enzymes (phytase, protease, and other enzyme combinations) are used to enhance nutrient maintenance in growing chickens. The efficacy of enzyme addition can be affected by various variables, including feed composition, avian age, environmental conditions, enzyme type and dosage, and interactions with other feed additives (Radhi et al., 2023). Also, protease improves the utilization of energy from food (Qiu et al., 2023), an increase in nitrogen digestion in a main protein-based ration (Cowieson et al., 2017), increases the growth rate of broilers (Lee et al., 2023), and reduce uric acid levels in manure (Rodríguez-Soriano et al., 2025). In studies of protease enzymes in broilers, emphasis is most often placed on production results and digestibility of nutrients, while there is much less data on its influence on slaughter indicators and meat quality. Based on the above considerations, this study was conducted to evaluate the effects of exogenous protease (0.2 or 0.3%) in diets and sex of slow-growing hybrid Master Gris chickens on some carcass quality parameters (carcass weights, abdominal fat weight, dressing percentages and abdominal fat percentage.