BACKGROUND: The present study deals with the effect of different levels of synbiotic on
egg production and quality, blood parameters, hatchability and yolk cholesterol in broiler
breeder hens. OBJECTIVES:The aim of this study was to determine the best level of synbiotic
in the diet of broiler breeder hens. METHODS:The study was conducted based on a completely
randomized design with 4 treatment groups, 2 replicates and 10 controls in each experimental
unit. The experimental rations were containing 0 (control S0), 0.05 (S0.05), 0.1 (S0.1) and 0.2%
(S0.2) synbiotic. Egg quality and weight were measured daily. Blood parameters, laying rate
and hatchability were measured weekly. Yolk cholesterol, ovarian weight and number of
ovarian large follicles were evaluated at the end of the experiment. The data were analyzed
using GLM procedure. RESULTS: The results showed that yolk index in group S0.1 was
significantly lower (p<0.05) than groups S0.05 and S0.2, but was not statistically different from
the control (p>0.05). Also, synbiotic had no significant effect on other egg quality traits, egg
weight and hatchability (p>0.05). Addingy synbiotic supplement to diet reduced significantly
the laying rate, ovarian weight and number of ovarian large follicles in the group S0.2
compared with the other groups (p<0.05). Synbiotic significantly increased plasma glucose
concentration (p<0.05), but plasma triglyceride, HDL and yolk cholesterol concentrations
were not influenced by dietary symbiotic (p>0.05). Furthermore, plasma cholestrol
concentration (last week) in groups S0.1 and S0.2 were significantly lower than control group
(p<0.05). CONCLUSIONS: The results showed that it would be proper to use 0.1% synbiotic
in the diet of broiler breeder hens.