GROWTH CURVES MODELS IN TWO LINES OF JAPANESE QUAIL SELECTED FOR HIGH BODY WEIGHT | ||||
| Egyptian Poultry Science Journal | ||||
| Article 13, Volume 40, Issue 4, December 2020, Page 915-928 PDF (679.45 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/epsj.2021.135682 | ||||
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| Author | ||||
| Ahmed Mohamed Emam | ||||
| Poultry Production Department,Faculty of Agriculture, Fayoum University, Fayoum, Egypt | ||||
| Abstract | ||||
| This study was carried out at the Poultry farm of the Agricultural Experiments and Research Center, Faculty of Agriculture, Fayoum University. A total number of 598 Japanese quail chicks from the same hatch at the eighth generations of selection for high body weight at 28 days of age (BW28) were used to draw the growth curves for two lines using Gompertz, Richards and Logistic growth functions. Line significantly affected all studied body weights (BWs) except BW at hatch favoring selected line. Males had significantly higher BW7 and BW14 than females which had significantly higher BW42. The selected line had the highest asymptotic weight parameter (β0) and relative growth rate (β2) values than the control line for both sexes. The selection program has affected clearly on increasing body weight and growth pattern in the selected line compared to the control line. The β2 values were higher in males under all models indicting that male birds have grown faster than females and reached earlier their weight at inflection point (IPW) and β0. Regardless of growth model, the selected line had higher age at inflection point (IPT) and IPW values than the control line in both sexes. Females had higher IPT and IPW values than males reflecting that females reached mature weight after males. Selection for high BW28 modifies all studied growth curves and alter their parameters in both sexes favoring the selected line. Also, sexual dimorphism had a pronounced effect on studied growth curves. All studied models have considerably high and similar coefficient of determination (R2) values (close to 1) which ranged from 0.9938 to 0.9995. Gompertz was the best model to describe the growth curve of females and males in both lines which had the lowest AIC, BIC, Mean square error (MSE) values and the highest R2value. | ||||
| Keywords | ||||
| Selection; high body weight; growth curves; Gompertz; Richards; Logistic and Japanese quail | ||||
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