This study was conducted to investigate the effect of lead acetate- polluted
diet ingestion on some productive and reproductive performance of laying hens, and
try to employ some useful properties of clay for reducing the adverse effect of lead
contamination. A total number of 180 Gimmizah laying hens at 32 weeks of age were
randomly, distributed equally into nine treatments. Birds were offered (1) basal diet;
(2) basal diet + 250 ppm Pb ;(3) basal diet + 250 ppm Pb +2.5% clay; (4) basal diet +
250 ppm Pb +5% clay; (5) basal diet + 500 ppm Pb; (6) basal diet +500 ppm Pb
+2.5% clay; (7) basal diet + 500 ppm lead+5 % clay; (8) basal diet +2.5% clay and (9)
basal diet. + 5% clay. Body weight, weight gain; egg production, feed conversion, egg
quality, fertility; hatchability and economical efficiency were determined for two times.
The first time was after the positive experimental period and the second time was after
the negative experimental period. Results obtained for the first period indicated that.
lead - polluted diets significantly decreased weight gain; egg number; hen day
percentage; egg mass (g {day); feed conversion (g feed{ g egg )day ; shell weight and
percentage, yolk weight and percentage, Haugh units score, fertility percentage and
hatchability percentage. However, feed intake, egg weight, albumen weight and
percentage and embryonic mortality percentage without piping were significantly
increased. Adding clay to lead polluted diets significantly reduced the adverse effect
of lead in the previous parameters. Supplementation of clay to the diet only
insignificantly increased, weight gain, egg production percentage, egg weight, egg
mass (g {day )and improved feed conversion, while the finial body weight; egg mass
(g {day); feed intake; egg components weight and percentage; Haugh units score;
fertility and hatchability percentages and embryonic mortality percentage without
piping were not significantly affected by feeding natural clay in laying diets. After the
negative experimental period all the previous parameters were go back around the
control and the differences were not significant except, feed intake which significantly
decreased, but egg weight, shape index, yolk weight and albumen weight were
fluctuating as compared with control. It could be concluded that supplementation the natural clay at level 5% to
layer diet contaminated with lead can prevent adverse effect of lead.