No abstract

The influence of an Escherichia coli-derived phytase, on nutrient utilization was investigated in broilers fed starter diets containing different concentrations of phytate. The study was conducted as a 3 x 4 factorial arrangement of treatments with 3 concentrations of phytic acid (10.4, 11.8, and 13.6 g/kg; equivalent to 2.8, 3.3, and 3.8 g of phytate P/kg) and phytase (0, 500, 750, and 1,000 FTU/kg). One unit of phytase (FTU) is defined as the quantity of enzyme that releases 1 micromol of inorganic phosphorus/min from 0.00015 mol/L of sodium phytate at pH 5.5 at 37 degrees C. The dietary phytic acid concentrations were manipulated by the inclusion of rice bran. Increasing dietary concentrations of phytic acid resulted in reductions (P < 0.01) in AME. Phytase additions tended to increase AME (P = 0.07), regardless of dietary phytate concentrations. Apparent ileal digestibility coefficients of protein and most amino acids were influenced by phytate (P < 0.05 to 0.001) and phytase (P < 0.001). Phytase improved ileal protein and amino acid digestibility at all phytate concentrations, but the trend in responses to increasing phytase additions was different at different phytate concentrations as shown by significant phytate x phytase interactions (P < 0.01 to 0.001). At the lowest phytate concentration, the ileal digestibility coefficients increased with increasing phytase supplementation. At the medium and high phytate concentrations, the greatest responses were observed at 500 FTU/kg of phytase, with little improvement attributable to further additions. Ileal digestibility of P was lowered (P < 0.01) by increasing phytate concentrations and increased (P < 0.001) with increasing additions of phytase. A significant phytate x phytase interaction (P < 0.05) was also observed, where the improvements in P absorption with added phytase were found to be greater at high phytate concentrations. These data demonstrate the anti-nutritive effects of phytic acid and the potential of microbial phytase to improve energy utilization and the availability of P and amino acids in broilers fed starter diets.

An experiment was conducted to examine the effects of adding microbial phytase (Natuphos) on the performance in broilers fed a phosphorus-adequate, lysine-deficient diet. A wheat-soybean meal-sorghum-based diet, containing 1.00% lysine and 0.45% nonphytate phosphorus, was supplemented with L-lysine monochloride to provide 1.06, 1.12, or 1.18% lysine or with 125, 250, 375, 500, 750, or 1,000 phytase units (FTU)/kg diet. Each diet was fed to six pens of 10 chicks each from Day 7 to 28 posthatching. Addition of lysine to the lysine-deficient diet linearly increased (P < 0.001) weight gain and gain per feed of broilers. The response in weight gain to added phytase reached a plateau at 500 FTU/kg diet (quadratic effect, P < 0.001). Phytase had no effect on gain per feed to 250 FTU/kg diet and then increased (quadratic effect, P < 0.05) with further additions. Assuming that the observed responses in weight gain and gain per feed to added phytase were due to the release of lysine alone and by solving linear or nonlinear response equations of lysine and phytase levels, the lysine equivalency value was calculated to be 500 FTU phytase/kg diet = 0.074% lysine. Addition of increasing levels of supplemental phytase to the lysine-deficient diet improved (P < 0.001) the digestibilities of nitrogen and all amino acids. Phytase also increased the AME, and the response reached a plateau at 750 FTU/kg diet (quadratic effect, P < 0.001). These results showed that amino acid and energy responses are responsible for the performance improvements observed when phytase was added to a wheat-soybean meal-sorghum-based diet.

No abstract

SAECG adjustments for sex, age, and MI location did not improve sensitivity and specificity but produced a more uniform predictive performance. The proposed criteria are based only on QRSd, because late potentials (VRMS and LAS) did not discriminate patients with sudden death. Duration of high-level activity during QRS (QRSd-LAS) can predict AEs, suggesting that the arrhythmogenic substate involves a large mass of myocardium.