A 8-wk study was conducted to evaluate the effects of supplementing laying
hen diets with commercially produced Lactobacillus acidophilus (Micro-Bac LA) on
productive periormance. egg quality and some blood constituents unde Egyptian
summer conditions. One hundred and thirty five Hy-Line® Brown pullets (48wk of age)
were randomly allocated to one of five levels of Lactobacillus aGido~~ilus (LA)
supplementation (0. 100, 200, 300 and 400 mglKg diet). The mean cell ~unt in the
Lactobacillus preparation was 8x10⁸ cfu Ig. The group fed a basal dietlwithout LA
supplementation was considered as control group. Egg number, egg ,hass, feed
intake and feed conversion ratio were significantly (P<0.05) improved by about 7.3,
9.3, 10.9 and 11.0%; 9.9, 10.2, 11.9 and 13.2%; 3.6. 3.3. 3.6 and 2.2% a~d 5.5, 6.3,
7.7 and 9.7% in groups fed diets supplemented with 100, 200. 300. and 100 mg LAJ
Kg diet • respectively, compared to control group. Egg weight Of hens fed
supplemented diets was increased during the experimental period (48 to 56 wks of
age) however. the significant effect was observed only in groups fed 100 flnd 400 mg
LAJKg diet. Lactobacillus supplementation significantly increased albu en quality,
shell thickness and breaking strength at 52 and 56 wks of age. On the other hand,
there were no Significant differences among treated groups for albumin. yolk and shell
percentages. Albumen height was significantly (P LA supplementation.   Plasma Ca, total protein and globulin were significantly (P<0.05) Increased in
groups fed treated diets compared with control group. Lactobacillus supplementation
significantly (p < O.05) decreased plasma phosphorus and AJG ratio. In contrast.
plasma albumin was not significantly affected by feeding LA-supplemente<,:l diets. 80th
plasma and yolk cholesterol were significantly decreased with LA supplementation.
Plasma cholesterol was reduced by about 9.9, 14.5, 17.8 and 21.7% a'ld 18.3, 17.4.
24.4 and 29.9% and yolk cholesterol by about 16.5. 37.6, 40.9 and 43.a% and 26.2.
40.4, 36.9 and 41.5% for groups fed 100.200,300. and 400 mg LN Kg diet at 52 and
56 wk of age, respectively.   In conclusion. these results suggested that Lactobacllfus supplementation (0
laying hen diets had a beneficial effect on productive periormance, egg quality under
Egyptian summer conditions. In addition, Lactobacillus supplementation reduced yolk
cholesterol and consequently. reducing the dietary Intake of cholesterol tl humans