Effects of Superdosing Phytase B On Egg Production and Quality in Laying Hens

Abstract A trial was conducted to evaluate the addition of phytase B (PhyB) to a diet for laying hens. In the feeding trial with laying hens, three feeds were tested: a negative control diet (group I) without the addition of monocalcium phosphate, a negative control group with the addition of 0.05% (6575 AcPU/kg) phytase B (group II) and a positive control diet with recommended levels of calcium and phosphorus (group III). The experiment was carried out on 36 hens of the Bovans Brown variety, 12 birds were assigned to each test group. During the experiment, the number and weight of eggs laid by each hen, individual changes in the body mass of birds, and feed consumption were registered. From the 50th to the 54th day of the experiment, the amounts of the feed ingested and the excreta were measured in order to determine the retention of calcium and phosphorus. In order to examine the effect of diet on egg quality, 36 eggs from each study group were randomly selected for analysis. The research included measurements of physical and morphological parameters determining the quality of egg albumen, yolks and eggshells. Phytase B added to the feed for laying hens did not significantly affect feed conversion and feed consumption per egg but significantly increased the daily feed intake. Hens that consumed phytase B showed higher egg production indicators, including the number of eggs, the mean egg weight, and daily egg mass, as compared to hens from the negative control group (I). The addition of phytase B allowed obtaining similar calcium and phosphorus retention as in hens fed the positive control group diet (III) and showed reduced amounts of phosphorus in the manure. There were also significant positive effects of the addition of phytase B on the color intensity of the yolk and quality of eggshell by increasing its mass, density, and strength.