LAUSR

Abstract Background Manganese (Mn) is an important trace element for laying hen's nutrition, which is required in small amounts in the diet. Its deficiency results in lowered production performance and eggshell quality. Objectives This experiment was conducted to investigate the influence of different sources and levels of Mn on egg production performance and eggshell quality in aged laying hens. Methods A total of 720, 83‐week‐old Hy‐Line W‐36 laying hens were fed a non‐Mn supplemented basal diet for 4‐week (to ime Mn‐exhaustion of body) and then were allocated to a completely randomized design with 10 treatments, six replicates and 12 birds each. Concentration of Mn in the non‐Mn supplemented basal diet was 10.34 mg/kg (treatment 1), the added doses of dietary Mn were included 30, 60, and 90 mg/kg of three different sources (Mn‐oxide, Mn‐sulphate, and Mn‐organic) for treatments 2‐10, respectively. The experiment lasted for 12 week. Results Dietary supplementation with either organic or inorganic Mn sources significantly enhanced egg production (EP), egg mass (EM), feed conversion ratio (FCR), and relative eggshell weight (RESW) compared with the non‐Mn supplemented diet. However, the experimental diets did not influence feed intake (FI), egg weight, and other eggshell quality traits. Based on the broken line regression models, the performance traits were optimized at 30–40 mg/kg Mn concentration when supplemented by Mn‐sulphate or Mn‐organic. Although, it was 80–90 mg/kg when supplemented by Mn‐oxide. The relative bio‐efficacy of inorganic Mn sources include Mn‐oxide and Mn‐sulphate in compare with Mn‐organic were estimated 45% and 87% (for EP trait), 30% and 94% (for EM trait), 36% and 99% (for FCR trait), and 37% and 78% (for RESW trait), respectively. Conclusions In the aged laying hens, Mn requirement is higher than the NRC's recommendation. Sulphate and organic sources of Mn are more effective than Mn‐oxide.