Introduction: An experiment was conducted to investigate the effect of two inorganic and organic forms of manganese on performance, egg quality and resources of manganese of body`s in older laying hens. Materials & Methods: 250 Leghorn laying hens (w 36) with 80 weeks of age were divided into 5 treatments and 5 replications in a completely randomized design. Treatments were: control (without manganese supplement), treatments containing 100% manganese sulfate (diet 1), 75% manganese sulfate and 25% organic manganese chelated (diet 2), 50% manganese sulfate and 50% organic chelated (diet 3) 25% sulfate Manganese and 75% organic chelated (diet 4). Result: The results showed that there was a significant increase in feed intake, laying percen, egg weight and egg mass between diets 3 and 4 with control treatment (P <0.05). Also, egg weight in diets 1 and 2 increased significantly compared to basal diet. Feed conversion ratios in diets 3 and 4 showed a significant decrease (P<0.05). No significant difference in egg quality traits was observed between experimental treatments (P<0.05). Tibial manganese increased significantly in diets 2, 3 and 4 compared to basal diet (P<0.05). Yolk and egg shell manganese concentrations increased in diets 1, 3 and 4 compared to basal diet (P<0.05). Experimental treatments significantly increased serum and liver concentrations of manganese (P<0.05). Conclusion: Increased manganese bioavailability could be a reason for more uptake of manganese in the diet, which improved the production performance of older laying hen

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