Thesis

In the poultry industry, male layer chicks are commonly culled immediately post-hatch due to poor growth performance and a lack of egg-laying capacity. This culling practice involves billions of chicks annually, eliciting severe animal welfare and ethical concerns. To address this issue, raising dual-purpose chickens (LB) for a short-term rearing period to produce compact, tender coquelet has emerged as a viable strategy balancing economic efficiency and animal welfare. The dominant culinary method for coquelet is roasting, which requires sufficient subcutaneous and intramuscular fat to ensure a crispy skin and juicy meat quality. Therefore, this study aimed to investigate the effects of three dietary metabolizable energy (ME) levels low, medium and high (3050, 3175 and 3300 kcal/kg) on the growth performance, carcass traits, and meat quality of broilers (AA), NCHU B line chicken (B) and dual purpose chickens (LB). Regarding carcass traits, the results demonstrated that the dressing percentage of LB reached 71.00%, which did not differ significantly from that of AA and was significantly superior to that of the B. Elevating dietary ME levels significantly increased the proportions of thigh meat and skin with subcutaneous fat. In terms of meat quality, the crude fat content in the breast meat of LB (0.86%) was significantly higher than that of the other two breeds, exhibiting superior water holding capacity. Concurrently, fed the medium ME diets displayed the lowest shear force values, indicating enhanced tenderness. Furthermore, the MDA content across all treatment groups remained below 1 mg MDA/kg after 7 days of refrigerated storage, ensuring appropriate flavor stability and shelf life. Sensory evaluation revealed no significant differences in consumer overall acceptability among all groups, validating the market feasibility of utilizing LB as an alternative product. In conclusion, developing LB as poussin products holds substantial commercial potential. When combined with medium to high dietary ME levels, this approach effectively promotes fat deposition, significantly improves water-holding capacity and tenderness, and meets the sensory preferences of the market. This strategy aligns with the requirements of the roasted coquelets market, offering a sustainable solution that balances economic feasibility with animal welfare.

Keywords: dual-purpose chicken, coquelet, dietary metabolizable energy, growth performance, meat quality