Effects of cricket meal supplementation on estimated growth-curve parameters in Thai indigenous chickens

Sustainable poultry production increasingly relies on alternative protein sources; however, their effects on growth dynamics remain poorly understood because most studies evaluate body weight (BW) only at fixed ages. This study investigated whether cricket meal supplementation alters growth trajectories in Thai indigenous chickens using nonlinear growth-curve analysis. Betong and Nin Kaset chickens were reared under a 2 × 2 factorial arrangement and fed either a control diet or a diet containing 15% Acheta domesticus meal. Following quality-control procedures, individual BW trajectories from 108 birds were fitted using four nonlinear growth models (Brody, Gompertz, Richards, and Von Bertalanffy). Model performance was assessed using the coefficient of determination (R ²), adjusted R ², Akaike information criterion, and Bayesian information criterion. The VB model provided the most consistent fit (mean R ² ≈ 0.996) and was selected for subsequent analyses. Mixed-model analyses revealed no significant breed × feed × sex interactions. Cricket meal supplementation significantly reduced the asymptotic parameter ( A ; P = 0.0081) and integration constant ( B ; P = 0.0389), while increasing the estimated growth rate parameter ( k ; week⁻¹; P = 0.0020). Across breeds and sexes, birds receiving cricket meal exhibited higher estimated k values and correspondingly steeper fitted growth trajectories, indicating differences in estimated temporal growth dynamics rather than a uniform increase in body size. These findings demonstrate that growth-curve analysis can reveal diet-induced changes in growth trajectories that may not be evident from BW measured at fixed ages and highlight its value for evaluating alternative feeding strategies in sustainable poultry production systems.