TY - JOUR
T1 - Response of turkey poults to tiered levels of Natuphos phytase added to soybean meal-based semi-purified diets containing three levels of nonphytate phosphorus.
AU - Ravindran, V.
AU - Kornegay, E. T.
AU - Denbow, D. M.
AU - Yi, Z.
AU - Hulet, R. M.
PY - 1995/11
Y1 - 1995/11
N2 - A 3-wk feeding trial using 920 day-old turkey poults was conducted to evaluate the addition of seven levels of phytase (Natuphos; 0, 200, 400, 600, 800, 1,000, and 1,200 U/kg of diet) to diets containing three levels of nonphytate P (nP) (.27, .36, and .45%). A positive control diet contained .60% nP. Semi-purified basal diets contained soybean meal as the only protein source. The increase in BW gain from added phytase was greatest for the lowest nP diet (nP by phytase interaction, P < .001). At .27% nP, gains improved (P < .001) to 800 U of phytase/kg of diet and then reached a plateau. At .36 and .45% nP, increases in gains were observed only for 200 U of phytase/kg of diet. The highest phytase addition to.36 and .45% nP diets produced gains equal to those of the positive control diet. Feed intake increases paralleled those of BW gains. Gain:feed was lowest for the .27% nP diets without phytase, but improved (P < .001) to 800 U of phytase/kg of diet and then reached a plateau. The high incidence of leg disorders and high mortality (40%) observed for the poults fed the .27% nP diet without added phytase declined with the addition of 200 to 400 U of phytase/kg of diet. Ash percentage of toes and tibias increased as the levels of nP (P < .001) and phytase (P < .01) increased; the magnitude of the response to phytase decreased as nP in the diet increased, resulting in an nP by phytase interaction (P < .001). Tibial shear force and stress responded in a similar manner to increasing levels of nP and added phytase. Results show that 652 U of microbial phytase is equivalent to 1 g of P from defluorinated phosphate in turkey starter diets using soybean meal as the only source of phytate P. The response per 100 U of phytase decreased as the total amount of phytase added was increased.
AB - A 3-wk feeding trial using 920 day-old turkey poults was conducted to evaluate the addition of seven levels of phytase (Natuphos; 0, 200, 400, 600, 800, 1,000, and 1,200 U/kg of diet) to diets containing three levels of nonphytate P (nP) (.27, .36, and .45%). A positive control diet contained .60% nP. Semi-purified basal diets contained soybean meal as the only protein source. The increase in BW gain from added phytase was greatest for the lowest nP diet (nP by phytase interaction, P < .001). At .27% nP, gains improved (P < .001) to 800 U of phytase/kg of diet and then reached a plateau. At .36 and .45% nP, increases in gains were observed only for 200 U of phytase/kg of diet. The highest phytase addition to.36 and .45% nP diets produced gains equal to those of the positive control diet. Feed intake increases paralleled those of BW gains. Gain:feed was lowest for the .27% nP diets without phytase, but improved (P < .001) to 800 U of phytase/kg of diet and then reached a plateau. The high incidence of leg disorders and high mortality (40%) observed for the poults fed the .27% nP diet without added phytase declined with the addition of 200 to 400 U of phytase/kg of diet. Ash percentage of toes and tibias increased as the levels of nP (P < .001) and phytase (P < .01) increased; the magnitude of the response to phytase decreased as nP in the diet increased, resulting in an nP by phytase interaction (P < .001). Tibial shear force and stress responded in a similar manner to increasing levels of nP and added phytase. Results show that 652 U of microbial phytase is equivalent to 1 g of P from defluorinated phosphate in turkey starter diets using soybean meal as the only source of phytate P. The response per 100 U of phytase decreased as the total amount of phytase added was increased.
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U2 - 10.3382/ps.0741843
DO - 10.3382/ps.0741843
M3 - Article
C2 - 8614693
AN - SCOPUS:0029397303
SN - 0032-5791
VL - 74
SP - 1843
EP - 1854
JO - Poultry science
JF - Poultry science
IS - 11
ER -