Thte'e hundred White Bovans laying hens aged 24 weeks were used, to
evaluate the effects of dietary organic and Inorganic sources of calcium ( Ca ) and
phosphorus (P) on laying performanCe and egg quality. Hens were randomly divided
into tour experimental treatments .. Thus four isocalorlc ( ME ; 2850 kcal (kg) and
isonltrogenous (18 % CP) experimental diets were formulated, having equal Ca ( 40~. )
end available P ( 0.45% ) contentt . . Hens in ( Tr1 ) received 2.6% bone meal (B )
and 8.5% /im6stoM (lS); thosa in (Tr 2) received 2.6% BM and 8.5% eggshell me I
(ESM ); those In (Tr 3) received 1.6% dicaJclum phosphate ( DCP ) and 9.5% LS ; SF
those In (Tr 4) received 1.8% DCP and 9.5% ESM. The experiment was terminated I
torty weeks of age. The obtained results revealed thaI. layers feed a diet contaning a
comblnstioo of BM as a source of P and lS as a source of ca ( Tr1 ) , attained a
beller performance fer of egg Production, and feed conversion compeared the oth r
treatments . Means of egg weight. feed Intake and Haugh unit were not significan y
affected by the dietary treatments. However, those layers feed a diet contaning a
compination of DCP as a source of P and ESM as a source of Ca ( Tr 4 ) , achiaved
the lowest performance tor egg production • and produced eggs of thinner she Is
compared with nlhe other trealmentes . The highest values of nutrients dlgeslibdity and reteulion rates of Ca and P
were oblalned with diets of (Tr1) and (Tr 3) , fallowed by Intermedicete values for (Tr
2) ,white that of (T( 4) gave the lowest ones. Generally . ihe consistent trends of egg production and shell thicltness show d
beneficiat effects of BM: as an organic source of P, and LS: as an inorganic
source of Ca : when being added to laying hen diets, in comparison with DCP a d
ESM.