THE EFFECT OF PHOTOPERIOD, LIGHT INTENSITY AND WATTAGE POWER ON EGG COMPONENTS AND EGG QUALITY
T.M. El-Sheikh, A.M. El-Gammal, M.N. Makled
A total number of 840 birds were used in this experiment to study the effect of photoperiod, light intensity and wattage power on egg quality of Dandarawi chicken. The birds were classified into seven groups, (120 birds of each) two for the light intensity, two for photoperiod, two for wattage power and one as a control for all treatments. The traits studied were: Egg components (egg weight, egg shell weight, yolk weight and albumen weight): Egg quality (specific gravity, egg shell thickness, albumen quality, yolk index, yolk colour). The results obtained in this study could be summarized as follows: 1- Egg components: The egg weight decreased as light intensity increased. The shell percentage was higher by using an intensity of 60 luxes as compared with 15 and 240 luxes. The yolk percentage increased as a light intensity decreased, the opposite was observed with albumen percentage. The increase in the light intensity was associated with a decrease of maximum egg weight. Egg weight shell and yolk percentages increased as photoperiod increased, while albumen percentage decreased with increasing photoperiod. Photoperiod accelerated and increased the maximum egg weight, since it was 46.8 grams at 38 weeks and 46.1 at 40 weeks for the groups exposed to 20 and 18 hours of light. The egg shell and yolk percentages decreased and albumen percentage increased as the age increased. Such decrease continues to 38 and 34 weeks for the groups kept at 20 and 18 hours, respectively, after which there was no decrease. Egg weight decreased as the wattage power increased. The use of 200 watt lamp power as a source of light seems to be stressful for hens. Egg shell percentage was not significantly affected by wattage power but yolk percentage was significantly decreased as the wattage power increased, while the albumen percentage increased by the increase in wattage power. Egg quality: There were no significant differences in specific gravity due to the light intensity treatments. While shell thickness, yolk colour and yolk index decreased as the light intensity increased. Hough units decreased by about of 0.6 and 2.4 units for the groups exposed to 60 and 240 luxes, respectively, as compared with that exposed to 15 luxes. However, Hough unit decreased as photoperiod increased. Specific gravity and yolk colour were not affected by lamp power, while shell thickness, yolk index and Hough unit decreased significantly with increasing lamp power, this may be due to the stressful effect resulted from high lamp power.
Key words: Dandarawi fowl, photoperiod, light intensity and wattage power, egg quality