The efficacy of a phytase enzyme fed to Hy-Line W-36 laying hens from 32 to 62 weeks of age

An experiment was conducted to determine the efficacy of a phytase enzyme (optiphos, JBs United Inc., sheridan, In) in corn-soybean meal diets fed to laying hens from 32 to 62 wk of age. Hens were fed diets consisting of a negative control diet containing 0.105% nonphytate P (nPP), a positive control (0.45% nPP), a marginal nPP level (0.20%), or supplemental phytase enzyme at 150, 250, or 15,000 phytase units (FTU)/kg added to the negative control diet. The negative control dietary treatment containing 0.105% nPP was terminated at 39 wk of age because of a severe reduction in egg production compared with all other treatments. no significant differences were observed among the other dietary treatments in BW, egg production, egg weight, egg mass, feed intake, or Fe when these parameters were evaluated over the duration of the experiment. no differences in tibia ash were seen at 62 wk of age when compared among the 5 treatments. excreta P was much higher (P < 0.05) for hens fed the 0.45% nPP diet when compared with all other diets. a diet containing 0.105% nPP and as little as 150 FTU/kg of the supplemental phytase enzyme was as efficacious as a diet containing 0.45% nPP for long-term laying hen performance. In addition, feeding low levels of nPP with supplementation of the phytase enzyme would decrease the amount of P excreted by the bird. a very high level (15,000 FTU/kg) of phytase enzyme was well tolerated and poses no safety concerns.