Osipenko O. Digestibility of forages, metabolism and productivity of layers with different levels and ratios between sulfur and selenium in their mixed fodder

The dissertation presents theoretical and experimental data of using mixed fodders with various doses and ratios of sulphur and selenium. The productive hens' qualities, morphological, chemical and amino acid eggs composition are studied. Some changes are discovered in digestibility of nutritive matters, balance of nitrogen, calcium, phosphorus, sulphur and selenium in the organism of layers, depending on the dose of sodium sulfate and selenite as the sources of sulphur and selenium. Slaughter qualities, chemical and amino acid composition of large pectoral muscle under act of the explored factor are studied. Influencing of different levels of sulphur and selenium in the mixed fodder of laying hens is found out on the amount of red blood cells; maintenances of vitamin Е, of glutathione peroxidise activity and maintenance of MDA-active matters in blood, which leads to strengthen of the organism antioxidant status and increase of productivity. The efficiency, biological and financial viability of the use of optimum sulphur-selenium ratios in the mixed fodders for layers have been proved. For the increase of efficiency of production and biological value of food eggs it is recommended to use the mixed fodders for feeding of layers with maintenance of sulphur 2,3 g/kg and selenium - 0,3 mg/kg dry matter due to introduction of sodium sulfate and sodium selenite.