Effects of feed supplementation with manganese from its different sources on performance and egg parameters of laying hens

The objective of this study was to compare the effects of feed supplementation of laying hens with manganese from its inorganic and organic sources on performance and some parameters of egg quality. Ninety-six hens at 20 weeks of age were randomly allocated to 4 dietary treatments, each consisting of 6 replicates (4 birds per replicate). The control group was fed unsupplemented basal diet (BD) with only natural background Mn level of 46.4 mg/kg feed. For the three experimental treatments, the BD was supplemented with 120 mg Mn/kg either from Mn-sulphate or Mn-chelate of protein hydrolysate (Mn-Pro) or Mn-chelate of glycine hydrate (Mn-Gly). After 8 weeks of dietary treatments the egg production, egg weight, feed intake, and feed efficiency were not affected by dietary treatments. Regardless of the sources, Mn supplementation to feed resulted in significantly decreased percentages of cracked eggs compared to the unsupplemented control group. The thickness, weight, proportion, and index of eggshell were significantly elevated in all groups supplemented with Mn. The intake of Mn-Gly resulted in considerably increased Mn deposition in egg yolk compared to the control eggs. In the control and Mn-sulphate groups yolk malondialdehyde (MDA) started to increase after 20 and 30 days of egg storage respectively, whereas in eggs from hens given organic Mn-sources this parameter was not affected up to 40 days. Although there were no significant differences in MDA values between the treatments until 20 days of storage, the Mn-sulphate group showed significantly higher MDA concentration in yolks compared to the control group after 30 days of storage. These results demonstrate that supplementation of hens’ diet with Mn has positive effects on eggshell quality. Feed supplementation with Mn from organic sources appears to be more effective in preventing yolk lipid oxidation during cold storage of eggs than that from Mn-sulphate.