Evaluation of Growth Curves Models in Two Chicken Lines | ||
| Egyptian Journal of Veterinary Sciences | ||
| Articles in Press, Corrected Proof, Available Online from 16 November 2025 PDF (1013.14 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejvs.2025.401607.2954 | ||
| Authors | ||
| Mostafa Mostafa Helal1; Essam A. El-Gendy1; Ensaf Mohamed El-Full2; Bothina Yossef Fouad3; Ahmed Mohamed Emam* 2; Doaa Mohamed Semida2 | ||
| 1Department of Animal Production, Faculty of Agriculture, Cairo University, Giza, Egypt, 12613 | ||
| 2Department of Poultry Production, Faculty of Agriculture, Fayoum University | ||
| 3Department of Poultry Production, Faculty of Agriculture, Fayoum University, Egypt | ||
| Abstract | ||
| This study investigated growth patterns in two selected lines for rapid growth of native chickens: normal feathering (nana) and naked-neck (NANA/Nana). Body weights (BWs) of 800 chicks (400 per line) were recorded from hatch to 126 days of age at the Poultry Farm, Faculty of Agriculture, Cairo University, Egypt. Body weight data were fitted to three nonlinear regression models (Gompertz, Richards, and Logistic growth curves). Results showed significant line effects (P<0.001) on all BWs, with the nana line consistently heavier throughout the growth period. Sex effects were evident only at later ages (70, 112, and 126 days). Among the models, the Gompertz function provided the best fit across all goodness of fit criteria, followed by the Logistic model, while the Richards model ranked last. In the Gompertz model, the NANA/Nana line exhibited higher asymptotic weight and slower maturation compared with the nana line, reaching inflection points at later ages with greater body weights. The earlier maturity of the nana line may be advantageous under heat-stressed conditions, whereas the higher mature weight of the NANA/Nana line suggests potential value in breeding programs aiming at growth improvement. | ||
| Keywords | ||
| Nonlinear regression; growth models; Gompertz function; native chicken; naked-neck gene | ||
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