INFLUENCE OF OVIPOSITION TIME ON SOME FUNCTIONAL PROPERTIES OF EGG SHELL OF THE DOMESTIC FOWL KEPT IN WARM HUMID TROPICS

Résumé

Investigations on the influence of oviposition time on the functional properties of egg shell of the domestic fowl were conducted. The eggs used for the study were laid by commercial Lohmann pullets - a temperate hybrid. The laying birds were managed singly in battery cages, fed a layer's diet of about 17% crude protein and supplied water. The results showed the mean shell thickness was 0.31, 0.33,0.34 and 0.35mm for eggs laid between 0600 - 0900, 0900 - 1200, 1200 - 1500 and 1500 - 1800 hours, respectively. Shell conductance was 11.93, 11.67, 11.72 and 1133 mg day^-1  torr^-1, respectively. The respective moisture losses were 3.80,3.75,3.80,3.72 mgcm ^-2 for 0600-0900, 0900 - 1200, 1200 - 1500 and 1500 - 1180 hours, respectively. In the same order, the pore counts were 15,096, 15,280, 14,668 and 14, 927 egg^-1 while the respective pore diameters were 21.76, 21.17, 22.35 and 23.49µ at the different oviposition times. Significant differences (P<0.05) were observed at the different oviposition times in these shell properties except for shell conductance and moisture loss. Shell conductance and moisture loss were found to be highly correlated (P <0.01). Eggs laid between 1500 - 1800 hours appeared to exhibit better shell functional properties.