Modeling the growth curve of Japanese Quail under different nutritional environments

Abstract

Previous studies on Japanese quails have fitted non-linear models to growth data and assessed resultant parameters under a restricted nutritional environment. This study modeled the growth of Japanese quails under different nutritional environments, compared them in order to choose the best fitted model and investigated the statistical interaction between sex and diet using the best fitted model. Weekly body weight (BW) records were collected from 360 quails from hatch to 56 days. Bertalanffy, Gompertz and Logistic models were used for the study. Each model was fitted separately to BW using the NLIN procedure of SAS®. Parameters were estimated for each model and comparison was based on R², AIC and BIC. Across the diets, asymptotic weight (A) for Gompertz ranged from 147.0-162.7g, Bertalanffy, 152.0-176.7g and Logistic, 135.0-146.3g Growth rate (k) for Gompertz model ranged from 0.35-0.48, Bertalanffy, 0.29-0.37 and Logistic, 0.60-0.81. A for males of 22%-20%, 22%-22% and 26%-20% combinations were significantly (P<0.05) higher than those of other diet combinations. A for females of 26%- 20% were significantly (P<0.05) higher than those of other diet combinations. No significant difference (P>0.05) was observed in the k of both the male and female under all diets combinations. The study concluded that Logistic model (R²=0.99634-0.99939; AIC=4.5392-57.9737; BIC=8.67-62.10) resulted in the best fit model.

Keywords: Nutritional environments, Non-linear models, body weight, growth rate and Japanese quails