The experiment was carried out at the Animal Research Laboratory the Department of Animal Science of the Federal University of Lavras - UFLA, in Lavras - MG, Brazil, with objective of evaluating the physical-chemistries characteristics of limestones used in the laying hens feeding. The experimental design was completely randomized in a 4x5 factorial arrangement, being four limestones extracted in different areas of Minas Gerais (Ijaci, Barroso, Iguatama and Formiga) in five particle size standardized (0.15-0.30, 0.30-0.60, 0.60-1.20, 1.20-2.00 and 2.00-4.00 mm), amounting twenty treatments, with eight replications. The limestones were directed to the laboratory where was determined the mineral composition and the in vitro solubility, certain for the method of the weight loss. The mineral analysis of the limestones, indicated some numerical differences mainly in elements as iron and manganese, besides detecting the presence of zinc and copper in smaller amount. There was interaction (P<0.01) among the limestones and the particle size for the in vitro limestones solubility and all the limestones presented reduction in the in vitro solubility with the particle size increase (P<0.01), however, presenting cubic response. The Barroso limestone the most soluble was shown (P<0.01) in all the particle size and your in vitro solubility was superior to 12.5%, in the largest particle size studied (2.00-4.00 mm) what represented a rate of solubility of 33.3% above the certain value for the Formiga limestone, that was it that less soluble (P<0.01) in the same particle size. Through the found results it was verified that the in vitro limestone solubility is not only determined by the particle size in that the limestone comes.
Limestone; solubility; particle size; calcium; poultry; laying hens