Bioavailability of zinc from inorganic and organic sources for pigs fed corn-soybean meal diets.
Two experiments were conducted with pigs 1) to determine the effect of supplemental Zn on growth performance, bone Zn, and plasma Zn in pigs fed Zn-unsupplemented, corn-soybean meal diets and 2) to assess bioavailability of Zn from inorganic and organic Zn sources. In both experiments, weanling pigs were fed a diet with no supplemental Zn for 5 wk to deplete their Zn stores. In Exp. 1, 192 pigs were fed a corn-soybean meal diet (growing diet, 32 mg/kg of Zn; finishing diet, 27 mg/kg of Zn) supplemented with feed-grade ZnSO4.H2O to provide 0, 5, 10, 20, 40, and 80 mg/kg of supplemental Zn. Supplemental Zn did not affect weight gain, feed intake, or gain/feed during either the growing or the finishing period (P > .05). However, bone and plasma Zn concentrations increased linearly (P < .01) in response to supplemental Zn at dietary Zn levels between 27 mg/kg (basal) and 47 mg/kg (breakpoint). In Exp. 2, three levels of supplemental Zn from ZnSO4.H2O (0, 7.5, and 15 mg/kg of supplemental Zn) were used to construct a standard curve (metacarpal, coccygeal vertebrae, and plasma Zn concentrations regressed on supplemental Zn intake; R2 = .93, .89, and .82, respectively). From the standard curve, the bone and plasma Zn concentrations obtained from pigs fed 15 mg/kg of supplemental Zn from ZnO and 7.5 mg/kg of supplemental Zn from Zn-methionine (ZnMET) and Zn-lysine (ZnLYS) were used to calculate bioavailable Zn via multiple linear regression, slope-ratio analysis. The estimates of Zn bioavailability differed depending on which variable was used. Overall trends indicated the following rankings: ZnSO4.H2O > ZnMet > ZnO > ZnLys.
Wedekind
K J
KJ
Department of Animal Science, University of Nebraska, Lincoln 68583-0908.
Lewis
A J
AJ
Giesemann
M A
MA
Miller
P S
PS
D000821:Animal Feed; D000818:Animals; D001682:Biological Availability; D003050:Coccyx / Q000378:metabolism; D005260:Female; D005527:Food, Fortified; D008239:Lysine / Q000493:pharmacokinetics; D008297:Male; D008663:Metacarpus / Q000378:metabolism; D008715:Methionine / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D011897:Random Allocation; D012044:Regression Analysis; D013025:Glycine max; D013431:Sulfates / Q000493:pharmacokinetics; D013552:Swine / Q000254:growth & development / Q000378:metabolism*; D003313:Zea mays; D015032:Zinc / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D017967:Zinc Compounds / Q000493:pharmacokinetics; D015034:Zinc Oxide / Q000493:pharmacokinetics; D019287:Zinc Sulfate
D009942:Organometallic Compounds; D013431:Sulfates; D017967:Zinc Compounds; C074508:zinc methionine; D019287:Zinc Sulfate; D008715:Methionine; D015032:Zinc; D008239:Lysine; D015034:Zinc Oxide