The negative effect of high doses of phytase in laying hens

ENGLMAIEROVÁ, Michaela, SKŘIVAN, Miloš a VLČKOVÁ, Jana., 2018 The negative effect of high doses of phytase in laying hens. In Poultry Days 2018. Brno: Mendel University, s. 15. ISSN
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The aim of the study was to investigate the effect of 3 different additions of 6-phytase OptiPhos (F; 0, 300 and 1500 phytase units (FTU)/kg) and 2 calcium levels (Ca, 35 or 42 g/kg) in the feed mixture on the performance and egg quality. The non-phytate phosphorus (NPP) content was the same in all diets (1.8 g/kg). Hisex hens at 24 weeks of age were divided into 6 groups. Each group consisted of 4 enriched cages with 10 hens per cage. The experiment lasted 12 weeks. A significant interaction of F x Ca (P = 0.029) was determined in the egg production. Diet with 35 g/kg of Ca and the highest dose of F (1500 FTU/kg) resulted in a decrease of egg production (84.1%) compared to other diets (values ​​between 91.5 and 88.6%). High doses of F negatively influenced egg mass production (P = 0.001) and feed conversion (P = 0.018). Neither F nor Ca level in the feed influenced eggshell ash content. Both levels of F supplement in the feed mixture reduced Haugh units (P