The effect of increasing levels of single strain ofprobiotic (Bioplus) on performance and bloodmetabolites of laying hens

This study was conducted to evaluate the effect of increasing levels of probiotic (Bioplus) on performance, egg traits and blood serum chemical parameters of laying hens. Experiment was conducted with two hundred and ffty six Hy-line (W36) laying hens in four treatments and four replicates with 16 hens in each replicate from 45 to 55 weeks in a completely randomized design. Experimental groups included control group and experimental groups with 0.2, 0.4 and 0.6 g/kg of probiotic (Bioplus). Different levels of probiotic signifcantly affected the performance, egg traits and blood serum chemical parameters of laying hens (P<0.05). The highest amounts of feed intake (129 g/day/hen), feed conversion (2.72) and egg specifc gravity (1.089 mg/mL3) were observed with using 0.6 g/kg of probiotic. Whereas the lowest feed price for production per kilogram of egg (853.11 toman), the lowest level of egg yolk triglyceride (437.5 mg/gr) and minimum level of blood serum phosphorus (7.42 g/dl) were observed with using 0.2 g/kg of probiotic and fnally the minimum level of blood serum cholesterol (124.33 mg.dl) were observed with using 0.4 g/kg of probiotic. The overall result of this experiment showed that the using high levels of probiotic (Bioplus) has adverse effects on performance of laying hens and not recommended.