Effect of varying manganese and available phosphorus levels in the diet on egg production and eggshell quality of layers

The effects of graded levels of available phosphorus (2.5, 3.5 and 4.5 g kg−1) and added manganese (25, 50 and 75 mg kg−1) on performance of commercial layers were evaluated during the period from 42 to 52 weeks of age, in a 3×3 factorial design. All experimental diets contained 160 g kg−1 CP, 11.3 MJ kg−1 ME and 41.2 g kg−1 calcium. Manganese was supplemented from MnSO4, 5H2O. No significant effect of available phosphorus and manganese on feed consumption, feed conversion per kg of egg mass was observed. Egg production and egg weight were significantly (P<0.05) increased with supplements of 50 and 75 mg kg−1 manganese, regardless of the available phosphorus level in the diet. Eggshell thickness was not influenced by manganese levels, but in increasing the available phosphorus from 2.5 to 4.5 g kg−1, eggshell thickness was reduced significantly (P<0.05).