GROWTH CURVES OF MALE GUINEA PIGS (Cavia porcellus) OF THE PERUVIAN BREED THROUGH NON-LINEAR MODELS IN COLOMBIA

Background: Animal growth modeling is a tool that enables the acquisition of parameters to evaluate animal performance and predict outcomes for decision-making. Objective: To describe the growth of male guinea pigs of the Peruvian breed using the non-linear Brody, Gompertz, Logistic, and Von Bertalanffy models. Methodology: Twelve male guinea pigs with an initial weight of 393 ± 55 g were housed in metabolic cages with ad libitum feeding of a complete pellet diet. They were weighed every seven days for 13 weeks until reaching 1197 ± 84 g. Criteria used to assess the model's fitting ability included the Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC), coefficient of determination (R2), concordance correlation coefficient (CCC), and mean squared prediction error (CMEP). Results: The Logistic model consistently predicted maturity weight (1421g), initial weight (187g), age (65 days), and weight (711g) at the growth curve inflection point. Gompertz and Von Bertalanffy's models tended to overestimate adult weight (A) and exhibited the lowest maturity index (k). Among Gompertz, Logistic, and Von Bertalanffy models, AIC, BIC, R2, CCC, and CMEP fitting criteria showed no significant differences (p > 0.05). Implications: The Brody model was the only one with biologically inconsistent parameters. Conclusion: Considering the biological significance of parameters and residual analysis, the Logistic model is more suitable for describing the growth curve of male guinea pigs of the Peruvian breed.