الفهرس 
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Abstract
The present study was carried out at the Experimental Station of Animal Production Department of Al-Azhar University, Assiut Branch, Assiut, Egypt. A total number of 160 Fayoumi and 80 Golden Mountazah pullets 24 weeks old, were used to study the effect of adding yeast (2%) or, DL-methionine (0.8%) to layer vegetable ration (corn-soy ration), on productive, reproductive performance, egg quality and digestibility coefficients.
Layers were divided randomly into four groups (40 Fayoumi hens/ group) and (20 Golden Mountazah hens / group) allotted to different feed additives to the basal diet as follows:
1- The first group fed basal ration (control group), T1.
2- The second group fed corn-soy ration (vegetable ration) supplemented
with 0. 8% DL-methionine, T2.
3-The third group fed basal ration (T1) and supplemented with 2% yeast, T3.
4- The fourth group fed corn-soy ration (vegetable ration) supplemented
with 2% yeast and 0.8 % DL-methionine, T4.
Productive traits were: feed consumption, feed conversion and egg production (number, weight, production percent and egg mass). Every month, number of 5 eggs were collected from each treatment to determine both internal and external egg quality, a number of 40 eggs from Fayoumi and 30 eggs from Golden Mountazah within each treatment were collected and incubated under the stander incubation advice to determine the fertility and hatchability percentage. At the end of the experiment digestive trail was conducted to estimate the digestion coefficients (dry matter, organic matter, crude protein, crude fiber, ether extract and nitrogen free extract).
The results can be summarized as following:
1- Productive traits:
Golden Mountazah strain was the best strain in egg production percent, egg weight, egg mass and feed conversion (kg feed/kg egg mass). While, Fayoumi strain was the best strain in feed consumption (gm / bird /month). Supplemented diet with 0.8% DL-methionine improved laying performance rather than that of T3 and control group, furthermore was the best treatment in both feed conversion.
The combination of 2% yeast and 0.8% DL -methionine as feed supplementation increased egg production percent, egg weight and egg mass, while reduced feed consumption and improved feed conversion as compared to other treatments.
Fayoumi strain within T2 was the best treatment in all-laying performances. While Fayoumi strain within T4 was the worst treatment in laying. Golden Mountazah strain within T4 was the best treatment in laying performance traits, but Golden Mountazah strain in T3 was the best treatment as compared to T1 and T2. Otherwise T2 was the best treatment rather than that of T1.
2- External parameter of egg quality:
Fayoumi strain was the best strain with egg shape, shell percent, specific gravity and SWUSA. While, Golden Mountazah strain was the best strain with egg surface area and egg surface volume.
Inclusion diet with the combination of 2% yeast and 0.8% DL-methionine as feed supplementation presented the best egg surface area, egg surface volume, specific gravity, shell percent and SWUSA. While layers fed dietary T3 presented the worst values of external egg quality.
Fayoumi strain within T2 was the best treatment in external egg quality except SWUSA, while, Fayoumi within T4 improved significantly external egg quality except egg shape but Fayoumi within T3 improved significantly egg shape.
Golden Mountazah within T2 was the best treatment in specific gravity, shell percent and SWUSA. Also, Golden Mountazah within T3 was the best treatment in egg shape, specific gravity, shell percent and SWUSA as compared to control group.
3- Internal parameters of egg quality:
Golden Mountazah strain was the best strain in albumen percent and Haugh unit. While, Fayoumi strain was the best strain in yolk index and percent. Supplemented diet with 2% yeast + 0.8% DL-methionine was the best treatment in internal parameters of egg quality when compared to all other treatments, while T3 was the worst treatment. Fayoumi strain in T4 was the best treatment in albumen percent, yolk index and Haugh unit when compared to control ration. However Golden Mountazah strain within T4 was the best treatment, but Golden Mountazah strain with T2 was the worst treatment in internal egg quality.
4- Fertility and hatchability traits:
There was significantly increase in fertility and hatchability with Fayoumi strain incorporation with Golden Mountazah strain. Supplemented diet with 2% yeast + 0.8% DL-methionine was the best treatment with fertility and hatchability percent. Fayoumi within T2 and Golden Mountazah strain within T4 were the best treatment in fertility and hatchability.
5- Digestibility traits:
Fayoumi strain was the best strain in digestibility coefficients as compared to Golden Mountazah strain. The addition of 0.8% DL-methionine gave the best values for organic matter, crude protein, ether extract and nitrogen free extract when compared to all other treatments. Golden Mountazah strain within T2 was the best treatment in digestibility traits