[Effect of the manganese content in laying hen feed with different Ca and mineral levels on the egg shell quality and bone mineralization of hens].

Four experiments with 270, 44, 432 and 66800 Leghorn hens were carried out to investigate the influence of various Mn additions to diets differed in mineral or Ca contents on egg shell quality. The addition of 300 mg Mn/kg diet improved significantly egg shell breaking strength by 4 N over one year. The supply of 50-500 mg Mn/kg diet for 10-24 weeks of the second half of laying year did not influence the egg shell quality.

[The role of carbonic acid in the regulation of nitrogen metabolism in the animal body. 1. Effect of changes in CO2 concentration in tissues on the processes of NH+ metabolism in rabbits].

In two groups of rabbits of 24 animals each the dependence of NH4+-utilisation on the level of carbonic acid in the organism was investigates. The rabbits of the second group received injections into the abdominal cavity of 8 ml/kg body weight of a 5% NaHCO3-solution (enriched with CO2, pH 7.35) for the purpose of increasing the concentration of carbonic acid in the blood (pCO2: HCO3) and for the purpose of decreasing it an amount of NaCl-solution, which, in its content of Na+, was equivalent to the NaHCO3-dose.