THE EFFECT OF DIETARY MICROBIAL PHYTASE ON PHOSPHORUS OUTPUT IN LAYING HEN DROPPINGS

An enzymic preparation containing phytase (phytase CZ) was used in an experiment on laying hens of ISA BROWN HYBRID; the preparation was pro duced by a fermentation procedure using recently isolated strain 921 o f Aspergillus niger (phytase activity 490 PU/g). A total of 72 laying hens at the age of 19 weeks were included in the experiment. The exper iment had a two-factor design with replications according to the formu la A(2) x B(6) x (6), where factor A represented two dicalcium phospha te concentrations and factor B the different phytase concentrations. B alance observations were carried out during the experiment - at the be ginning, peak and end of laying period in order to determine phosphoru s and calcium outputs in droppings. These parameters were studied in l aying hens: total feed consumption from the beginning to the end of la ying and daily consumption per laying hen, feed consumption per 1 kg o f egg content and per egg, number of produced eggs and egg content pro duction per layer, average egg weight, egg-shell weight, yolk weight, yolk and albumen indexes. The results indicate that the total exclusio n of DiCaP from diets for laying hens containing an enzymic preparatio n with phytase did not have any negative effect on the parameters of f eed consumption under observation, on egg production, laying and quali ty. Applications of the different concentrations of enzymic preparatio n with phytase did not yield any significant effect either. The object ive of the experiment was to investigate the effect of the different c oncentrations of enzymic preparation with phytase in diets without DiC aP and with 50% DiCaP on phosphorus and calcium outputs in laying drop pings. A significantly lower (P < 0.05) phosphorus output was observed in laying hens receiving diets without DiCaP, at the beginning, at th e peak and at the end of laying period. The values of calcium output w ere only insignificantly different in this case in all three balance o bservations. Phosphorus output in droppings of laying hens receiving d iets without DiCaP determined at the beginning. peak and end of laying period in relation to the different concentrations of enzymic prepara tion with phytase, was used to calculate the most efficient concentrat ion of this preparation by the method of parabolic regression. When di ets without DiCaP but with the different phytase concentrations were f ed to laying hens, the calculation of inflection point showed the most efficient phytase concentration 84.5 g/100 kg of feed at the beginnin g of laying period while inflection point for the peak of laying was a t a concentration of 72 g/100 kg and inflection point at the end of la ying was at 77.6 g/100 kg of diet.