EFFECT OF REDUCTION PHOSPHORUS CONTENT IN DIETS AND ADDITION OF PHYTASE PREPARATION ON PHOSPHORUS AND NITROGEN EXCRETION IN BROILER CHICKENS

The objective of the study was to determine whether reduction in phosphorus content in wheat-soybean-rapeseed-based diets and an addition of a phytase preparation to a low phosphorus mixture will influence phosphorus and nitrogen excretion in broiler chickens. The experiment was carried out on 60 one-day-old broiler chickens divided into three groups at 20 birds each (4 replications, 5 birds each), and were conduced over the period from the 1st to the 21st day of age. Group I (control) - chickens were fed a starter wheat-soybean-rapeseed-based diet containing 7.26 g/kg total phosphorus. Group II diet had total phosphorus content reduced to 5.91 g/kg. Group III was offered the same mixture as group II but supplemented with an enzymatic preparation containing phytase in an amount of 0.35 g/kg. Nitrogen and phosphorus balances were determined in the last week of the experiment. Chicken body weight at 21 days of age was similar in all the groups. Reduction in the total phosphorus content of the mixture offered to group II resulted in lower phosphorus content in feces. The phosphorus amount excreted by one bird over three days of feces collection and per one day was significantly lower for the experimental groups than the control group. Reduced phosphorus content in the mixture as well as phytase addition to the low phosphorus diet did not significantly influence nitrogen excretion. Despite lack of differences in the amount of nitrogen excreted, reduced phosphorus content in the diets was followed by lower phosphorus excretion in feces.