Replacement of inorganic trace minerals by chelated minerals in pullet diets (12 to 20 weeks of age)

Aim of study: An experiment was carried out aimed to evaluate the effects of different levels and sources of trace mineral to laying pullets with two initial body weights (BWs). Area of study: The experiment was carried out in Federal University of Goias, Goiania, Goias, Brazil Material and methods: Two hundred and eighty eight Bovans White pullets aged 12 weeks old were allotted in a completely randomized design and a 2x3 factorial arrangement, wherein the main effects included initial BW (light-weight and heavy-weight) and three dietary trace mineral sources and levels (100% inorganic, 100% chelated and low-dose corresponding to 50% chelated), totalizing six treatments with eight replicates of six birds. The performance, the metabolizability coefficient of nutrients, and the onset of lay were evaluated at rearing phase (12 to 20 weeks). At 17th and 20th weeks of age, the relative weight of reproductive and digestive organs, abdominal fat, and tibia quality were assessed. A residual effect was evaluated at production phase on productive performance and egg quality. Main results: The mineral source did not affect the performance of pullets. Birds fed 50% chelated mineral produced the lowest eggshell. The heavy-weight birds showed higher egg weight and eggshell quality. The lighter birds showed lower abdominal fat weight and lower tibia robustness index. Research highlights: The replacement of 100% of inorganic mineral for chelated mineral do not result in decrease of bird performance at rearing and at production phase, but a minimum amount should be provided to ensure growth and nutrient metabolizability.