Effects of dietary organic and inorganic manganese supplementation on performance, egg quality and bone mineralisation in laying hens

The aim of this study was to investigate the effects of different dosages of organic and inorganic manganese supplementation into diets on performance, egg quality and bone mineralization in laying hens. One hundred and fifty, 49 weeks old, H&N Brown Nick laying hens were assigned to 10 equal groups according to the diet regimen consisting in standard diet (based on corn and soybean meal) supplemented with Mn inorganic (Mn-sulphate) or organic (Mn-Bioplex) sources at 5 increasing doses (15, 30, 45, 60 and 75 mg/kg) for 12 weeks. Compared to the inorganic form, the Mn-Bioplex supplementation has significantly increased the body weight gains and the egg weight and reduced the percentage of damaged eggs. In parallel, the tibia cortex thickness and its cross area section were significantly enhanced, leading to a slight improvement in bone resistance. The bone proportions of mineral Ca and P elements have significantly increased according to the Mn doses but were not significantly affected by the Mn forms whereas the Mg percentage was significantly depressed with Mn-Bioplex. The tibial contents of Zn and Cu were maximal when low doses of Mn, mainly as Mn-sulphate, were used whereas the Mn accumulation in bone was mainly observed when Mn-Bioplex with doses above 30 mg/kg were used. These results sustained that organic Mn form supplementation positively affects the element distribution in the organism leading to improvement in the weight growth, the egg weight and in the bone solidity in laying hens.