Relative bioavailability of manganese in relation to proteinate and sulfate sources for broiler chickens from one to 20 d of age

The objective of this study was to evaluate the relative bioavailability (RB) of manganese (Mn) proteinate compared to Mn sulfate for broilers fed a diet based on corn and soybean meal for 20 d. The diets of 1,350 male Cobb broilers were supplemented with 0, 35, 70, 105, or 140 mg of Mn/kg of feed in the form of Mn sulfate or Mn proteinate. Weight gain, feed intake, feed conversion, bone strength, and Mn concentration in the tibia and liver, as well as the concentration of type I collagen in the tibia, were evaluated. No differences were observed for performance variables (P > 0.05) or for type I collage concentration in broiler tibia (P > 0.05), regardless of the source and level of supplementation used. Relative bioavailability was determined using bone strength values and Mn concentration in the tibia and liver, assuming Mn sulfate as the standard source (100%) by the slope-ratio method. The RB of Mn proteinate based on bone strength was 111%, based on liver Mn concentration was 128%, and based on tibia Mn concentration was 105%. Manganese proteinate was more bioavailable than Mn sulfate; it can be an important source of supplementation to improve bone quality in broilers.