Calcium level affects the efficacy of supplemental microbial phytase in corn-soybean meal diets of weanling pigs1

Abstract

A 2 x 2 x 2 factorial experiment was conducted with 64 pigs (4 wk old, 8.04 +/- .50 kg BW) to determine the effect of various dietary concentrations of Ca, vitamin D, and microbial phytase (Aspergillus niger) on phytate-P utilization. A low-P, corn-soybean meal diet was supplemented with two levels of phytase (unit/gram), 750 (suboptimal) and 1,200 (optimal); of vitamin D (international unit/kilogram), 660 (normal) and 6,660 (high); and of Ca (percentage), .4 (low) and .8 (normal). Pen feed consumption and individual pig weights, plasma inorganic P and Ca concentrations, and plasma alkaline phosphatase (AP) activity were measured at d 10, 20, and 30. The normal dietary Ca concentration had an adverse effect (P < .05) on all the response measures. The depressive effect of the normal dietary Ca on performance was greater (P < .05) at the normal vitamin D level or at the optimal phytase level than at the other levels of these two factors. The elevation in plasma AP activity in pigs fed the normal dietary Ca was greater (P < .05) at the suboptimal than at the optimal phytase level. The decreases in plasma inorganic P concentration and increases in plasma Ca concentration associated with the normal dietary Ca were substantial. In conclusion, the normal level of Ca in the diet greatly reduced the efficacy of supplemental phytase. Raising vitamin D in the diet partially offset this adverse effect but did not produce further improvement when the Ca level was low.

Digestible phosphorus requirement of grower pigs

“…1). In the present study, increasing digestible P intake or plasma P coincided with decreasing plasma alkaline phosphatase; an inverse relationship similar to the one reported by Lei et al (1994). However, plasma alkaline phosphatase decreased linearly; thus, it was not used to determine a digestible P requirement.…”

Supplementing corn or corn-barley diets with an E. coli derived phytase decreases total and soluble P output by weanling and growing pigs

“…1 were older. Lei et al (1994) however, found a depressive effect of dietary Ca level on phytase activity in weanling pigs, and Liu et al (1998) showed that P utilization in growing-finishing pigs in the presence of phytase was improved at a Ca:P ratio of 1 rather than 1.5, indicating that age does not affect this response. The inhibitory effect of Ca on phytase efficacy was shown to be less at pH 2.5 than at pH 6.5; probably because of decreased solubility of the complex at the higher pH (Tamin et al 2004).…”

“…The efficacy of A. niger phytase in corn and soybeanmeal-based diets was mitigated at high dietary Ca:P ratios (Lei et al 1994;Liu et al 1998). Similarly, the beneficial effects of a P. lycii phytase on reducing faecal P excretion, observed when the Ca:P ratio in the diet was 1.15:1, was no longer evident when added to a diet with a ratio of 1.85:1 (Brady et al 2002).…”

Effects of Aspergillus fumigatus phytase on phosphorus digestibility, phosphorus excretion, bone strength and performance in pigs

“…The action of plant (EC 3.1.3.26) [15,28,30,42]. Dietary microbial phytase supplementation can thus improve phytic-P digestive utilization and consequently reduce P pollution by animal excreta [17,18,23,37,38]. Furthermore, improved nutrient digestibility in animals fed supplemental phytase has been reported in pigs and in poultry [3,4,22,24,25,46,47].…”