EFFECT OF FORCE MOLTING INDUCED CONVENTIONALLY OR BY HIGH DIETARY ALUMINUM ON EGG AND SHELL QUALITY OF LAYING HENS

Eggs used in this study were obtained from Saudi Arabian Baladi laying hens which were divided into four experimental groups and subjected to the following treatments: Commercial laying ration (17% CP, 3.6% Ca and 0.343%, available P) fed ad libitum as a control (C); Conventional force molting, feed removal for 10 days followed by 18 days full-feed of cracked corn (F); 15 days ad libitum intake of the control ration supplemented, to initiate forced-molt, with 0.35% aluminum as the sulfate (ALS) or the chloride (ALC). The hens were in production for 52 weeks and 17 months of age at the start of the trial and the post-treatment period lasted 36 weeks. During the treatment period F and AL treated groups had similar egg and shell weight, egg surface area, shell thickness and shell weight per unit of surface area but significantly (p<0.05) lower than the control. F had significantly (p<0.05) the highest and the control the lowest Haugh unit values whereas AL fed groups had significantly (p<0.05) lower meat spot incidence compared with the control which tended to have higher value than F group. ALC and F had significantly (p<0.05) the lowest yolk color grade whereas ALC had significantly (p<0.05) lower egg index than ALS and the control. During the post-treatment period the control had significantly (p<0.05) the highest egg index and blood spots incidence and ALS the lowest shell diensity compared with other groups. ALS had significantly (p<0.05) lower shell weight than ALC and the control whereas F and AL treated hens had significantly (p<0.05) the highest Haugh unit values and yolk color grades respectively. F had significantly (p<0.05) lower meat spots incidence than ALC and the control. The same results were observed for ALS compared with the control.