Effect of quantitative feed restriction on performance, stress index and reproduction properties in native hens of Khorasan station

Under commercial conditions broiler are feed restricted during rearing to limit growth rate. This quantitative restriction of feed intake aims at avoiding rapid growth and high body weights, which are associated with pathological conditions, such as ascites, lameness, and mortality. Feed restriction (FR) in breeder layer hens was rarely and FR used for poor reproductive results and low fertility. Native poultry population is developing and the role of these birds in the production of animal protein is increasing. Native hens of Khorasan breeding station and most stations in country feed adlibitum. Add feed intake on the one hand leads to economic loss and also leads to increase weight in laying hens that may interfere with the process of egg production and hatchability. This experiment was conducted to evaluate of different levels of quantitative feed restriction (FR) on performance, stress index and reproduction properties of native hens of Khorasan station. to investigate the effects of feed restriction, an experiment with 350 hens in the form of completely randomized design with seven treatments, five replicates and 10 hens in each replicate of age 36 to 52 Weekly implemented. Treatments based on corn, soybean and wheat with different levels of FR, including 125,120,115,110,105 and 100 g/ days for layer hens and control groups feed intake was adlibitum. During the trial period, all eggs produced by hens in each pen were measured on a daily basis. Amounts of feed added to the feed troughs were recorded daily. After each week, the weights of feed in the troughs of adlibitum fed birds were recorded. From these data, daily mean intakes per bird were calculated for this pen. During the experimental period the birds were free of water and 16 hours of light and 8 hours of darkness were used. At the end of the experiment (52 weeks) two birds of each experimental pens were slaughtered and immediately different organs weight of each birds were measured. On the same day, three hens per pen were randomly collected blood from the vein under the wing. Blood containing EDTA anticoagulant were then transferred to the laboratory and a development staining by method of May Grunwald- Giesma were prepared.  the results showed that FR as soon as 110 g/days had no significant effect on egg production (EP), but in another groups of FR (105 and 100 g/days) decreased EP. The results showed that native hens feed intake less than 110 g/ day, decreased EP. The results of this study indicated when we are to the end of the weeks of experimental periods, the EP more decline caused by FR. Levels of 100 and 110g/days FR and control group (adlibitum feed intake) has no significant effect on egg weight (p>0.05). The best feed conversion ratio (FCR) was observed in 110 g/days of FR (p