Nonphytate P Levels Research Articles

Effect of Sodium Aluminosilicate on Phosphorus Utilization by Chicks and Laying Hens

Three experiments were conducted to evaluate the effects of sodium aluminosilicate (SAS) on performance of chicks and laying hens fed diets varying in nonphytate P (NPP), phytate, and fiber content. In two chick growth experiments a corn and soybean meal diet and a phytate and fiber-free casein-dextrose diet were used. These diets contained .1% NPP and 1.1% Ca and were fortified with 0, .05, or .10% P from KH2 PO4 and 0 or .5% SAS. A 3 × 2 factorial arrangement of treatments was used. Sodium aluminosilicate supplementation significantly (P<.05) depressed growth of chicks fed the corn and soybean meal diets containing 0 or .05% supplemental AP. Sodium aluminosilicate addition decreased (P<.05) tibia ash and total tibia P (tibia weight × P concentration) in both chick experiments, with the effect being greater for chicks fed the corn and soybean meal diet.In the laying hen experiment, birds were fed corn and soybean meal diets containing NPP levels of. 1, .45, or 1.8% and SAS levels of 0 or 1.0%. Egg production and egg yield were depressed (P<.05) by feeding diets containing .1 or 1.8% NPP, and egg specific gravity was decreased (P<.05) by feeding 1.8% NPP. Addition of SAS to the .1% NPP diet caused a large reduction (P<.05) in egg production, egg weight, and feed efficiency, whereas SAS supplementation of the 1.8% NPP diet had no significant effect. Sodium aluminosilicate supplementation increased (P<.05) egg specific gravity for hens fed the. 1 and 1.8% NPP diets. The results of the present study indicate that SAS markedly affects P utilization by poultry, and that this effect may be influenced by diet composition. The beneficial effect of SAS on eggshell quality was not influenced by dietary P level.

Influence of Different Phosphorus Phase-Feeding Programs and Dietary Calcium Level on Performance and Body Phosphorus of Laying Hens

Two nonphytate P (NPP) feeding programs (.35, −.25, −.15% NPP or .45, −.35, −.25% NPP during the age intervals of 23 to 35, 35 to 51, and 51 to 71 wk, respectively) were evaluated for White Leghorn hens in a complete factorial arrangement with 3.3 or 4.0% dietary Ca. Total P (TP) concentrations of the NPP feeding programs, as determined by analysis, were .60, −.48, and −.37 or .70, −.58, and −.46%, respectively. Egg production, feed efficiency, and egg weight over the 48-wk experiment were reduced significantly by the .35, −.25, and −.15% NPP program, irrespective of dietary Ca. Most adverse effects of the low NPP program occurred from 51 to 71 wk when hens fed .15% NPP consumed about 150 mg NPP daily as compared with NPP intake of 250 mg daily for hens fed .25% NPP. Hens fed 3.3% Ca consumed significantly more feed than did those fed 4.0% Ca, irrespective of NPP feeding program or age period. Neither NPP or Ca levels affected eggshell thickness at 71 wk nor mortality during the experiment. Dietary NPP and Ca did not significantly affect P content of the body, including feathers. Body P declined from an average of 8.6 g/hen at 23 wk of age to 7.3 g/hen at 55 and 63 wk. By 71 wk, body P returned o t 8.6 g/hen. The results show that NPP intakes of 250 mg and 150 mg/hen daily from 35 to 51 and from 51 to 71 wk, respectively, were inadequate for laying hens’ performance, but no adverse effects of these NPP intakes on body P were detected. It seems that utilization of dietary P was affected adversely by high ambient temperatures.