Layer feed using phytase must be formulated correctly to avoid detrimental effects on the performance and bone quality of laying hens
One of the easiest mistakes during layer feed formulation is forgetting to account for the calcium effect from phytase. Using phytase releases about 0.1 percent calcium, in addition to 0.08 percent available phosphorus. While this increase in calcium availability is of little significance in other species, especially as the primary source of calcium (calcium carbonate) is forgivingly inexpensive, this “luxury” has detrimental effects in layer hens.
As it is well known, layer hens require extremely high levels of dietary calcium (approximately 4 percent) to sustain high levels of egg production and sufficient eggshell quality throughout their lives. But, such high levels of calcium are marginal in causing bone deterioration from phosphorus deficiency (as calcium antagonizes phosphorus in the gut).
A study has just confirmed all these well-known facts; researchers fed hens diets supplemented with phytase without reducing dietary calcium, and they observed reduced performance. On another note, it was also confirmed that using phytase correctly does not affect performance and eggshell quality, as it is has been often suggested in the past.