Different calcium relations: available phosphorus and phytase in diets of UFSM-V laying hens: productive performance, egg quality and bone tissue/Diferentes relacoes calcio:fosforo disponiveis e fitase em dietas de poedeiras UFSM-V: desempenho produtivo, qualidade dos ovos e tecido osseo

The study aimed to determine the effects of different calcium relations: phosphorus (Ca:Pd) and phytase in diets based on corn and soybean meal on egg quality and production on the performance of brown egg layers. It was used 144 UFSM-V layers, aging from 28th to 36th weeks. The experiment was a completely randomized design with treatments arranged in a 3x2 factorial arrangement, and three different Ca relations were tested: Pd (8:1, 11:1, 14:1) and two phytase levels (0 and 300FTU [kg.sup.-1] diet) with six replicates of four layers each. The parameters evaluated were: body weight, feed intake, feed conversion by egg mass, egg production, albumen height, egg mass, egg specific gravity, Haugh units and percentage of calcium and phosphorus in the tibia. The production indices were not affected by the Ca:Pd relation or by the use of the enzyme, and the weight of the birds ranged from 1.927kg and 2.118kg, and feed intake averaged 120g of feed [bird.sup.-1] [day.sup.-1]. Internal egg quality also showed no significant differences, the average albumen height was 8. 78mm and the unit Haugt average was of 94.66. Diets with Ca:Pd of 8:1 showed interaction with the enzyme, improving the level of Ca in the Hens' tibia (Ca in tibia=20.63%), with a Ca: Pd greater than or equal to 11:1. There was no interaction with phytase, but there was higher percentage of Ca in the tibia (Ca in tibia [+ or -]22%).