Abstract
BACKGROUND: Ducks are used to produce a significant amount of meat in some regions of the world. The enhancement of duck production systems necessitates the development of parameterized mathematical models that accurately depict duck growth, encompassing the assessment of various management and nutritional strategies. OBJECTIVE: This research aimed to elucidate the growth trajectory of Danish and French Pekin ducks by applying nonlinear modelling techniques. METHODS: A total of 10 nonlinear mathematical functions (Brody, negative exponential, logistic, Gompertz, Von Bertalanffy, Richards, Schumacher, Morgan, Lomolino and Weibull) were employed in this study. The performance of the models was systematically evaluated, and the behaviour of the models was scrutinized throughout the process of fitting nonlinear regression curves. The overall goodness-of-fit for each model to a variety of data profiles was determined through the application of the adjusted coefficient of determination, root mean square error, Akaike's information criterion and Bayesian information criterion. RESULTS: The adjusted coefficient of determination values associated with each model exhibit generally elevated levels, signifying that the models demonstrate a strong overall compatibility with the data. According to the established goodness-of-fit criteria, the Gompertz model emerged as the most suitable mathematical function for accurately representing the growth trajectory of Danish and French Pekin ducks. In contrast, the Brody model exhibited the least favourable fit to the growth patterns of Danish and French Pekin ducks. Analysing the first derivative of the Gompertz model, the absolute growth rates for Danish and French Pekin ducks as a function of time indicated a progressive increase in these rates with advancing age, peaking at 23 and 24 days of age, respectively, before subsequently declining. CONCLUSION: An analysis of the various growth models employed in this research revealed that nonlinear functions have the ability to fit Pekin duck body weight records.