Citric acid does not improve phosphorus utilization in laying hens fed a corn-soybean meal diet

Data previously obtained from our laboratory have indicated that citric aci d was very effective at improving phytate-P utilization in chicks fed a P-d eficient corn-soybean meal (SBM) diet. The objective of the current study w as to determine if citric acid would have similar effects in a commercial s train of Single Comb White Leghorn laying hens (n = 432) fed a corn-SBM die t containing 0.10% available P (AP). Dietary treatments were a corn-SBM bas al diet (0.10% AP, 3.8% Ca, and 17% CP) supplemented with 0, 1, 2, 3, or 4% citric acid and a positive control diet containing 0.45% AP. Each of the s ix dietary treatments were fed to six replicate groups of 12 hens from 22 t o 40 wk of age. No significant differences in performance were observed among treatments du ring the first 4 wk of the experiment. Hen-day egg production, feed consump tion, feed efficiency, and egg yield were subsequently depressed in hens fe d 0, 1, 2, 3, or 4% citric acid compared with hens fed 0.45% AP. The result s of this study indicate that citric acid does not improve the utilization of dietary P in laying hens fed a corn-SBM diet containing 3.8% Ca.