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Comparison of growth performance and zinc absorption, retention, and excretion in weanling pigs fed diets supplemented with zinc-polysaccharide or zinc oxide¹

C. E. Buff^*, D. W. Bollinger^*, M. R. Ellersieck^*, W. A. Brommelsiek and T. L. Veum^*,2

^* Agricultural Experiment Station and Department of Animal Sciences, University of Missouri, Columbia 65211-5300; and and Quali Tech, Inc., Chaska, MN 55318-1093

	Abstract

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Fifty weanling crossbred pigs averaging 6.2 kg of initial BW and 21 d of age were used in a 5-wk experiment to evaluate lower dietary concentrations of an organic source of Zn as a Zn-polysaccharide (Zn-PS) compared with 2,000 ppm of inorganic Zn as ZnO, with growth performance, plasma concentrations of Zn and Cu, and Zn and Cu balance as the criteria. The pigs were fed individually in metabolism crates, and Zn and Cu balance were measured on individual pigs (10 replications per treatment) from d 22 to 26. The basal Phase 1 (d 0 to 14) and Phase 2 (d 14 to 35) diets contained 125 or 100 ppm added Zn as Zn sulfate, respectively, and met all nutrient requirements. Treatments were the basal Phase 1 and 2 diets supplemented with 0, 150, 300, or 450 ppm of Zn as Zn-PS or 2,000 ppm Zn as ZnO. Blood samples were collected from all pigs on d 7, 14, and 28. For pigs fed increasing Zn as Zn-PS, there were no linear or quadratic responses (P 0.16) in ADG, ADFI, or G:F for Phases 1 or 2 or overall. For single degree of freedom treatment comparisons, Phase 1 ADG and G:F were greater (P 0.05) for pigs fed 2,000 ppm Zn as ZnO than for pigs fed the control diet or the diet containing 150 ppm Zn as Zn-PS. For Phase 2 and overall, ADG and G:F for pigs fed the diets containing 300 or 450 ppm of Zn as Zn-PS did not differ (P 0.29) from pigs fed the diet containing ZnO. Pigs fed the diet containing ZnO also had a greater Phase 2 (P 0.10) and overall (P 0.05) ADG and G:F than pigs fed the control diet. There were no differences (P 0.46) in ADFI for any planned comparison. There were linear increases (P < 0.001) in the Zn excreted (mg/d) with increasing dietary Zn-PS. Pigs fed the diet containing ZnO absorbed, retained, and excreted more Zn (P < 0.001) than pigs fed the control diet or any of the diets containing Zn-PS. In conclusion, Phase 2 and overall growth performance by pigs fed diets containing 300 or 450 ppm Zn as Zn-PS did not differ from that of pigs fed 2,000 ppm Zn as ZnO; however, feeding 300 ppm Zn as Zn-PS decreased Zn excretion by 76% compared with feeding 2,000 ppm Zn as ZnO.

Key Words: Balance • Growth • Pigs • Swine • Weanling • Zinc

	Introduction

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Pharmacological concentrations of inorganic Zn as ZnO have been widely used in nursery pig diets by the swine industry to enhance growth performance (Carlson et al., 1999; Hill et al., 2000) and decrease the incidence of post-weaning scours (Poulsen, 1995; Holm and Poulsen, 1996). Zinc oxide is the only inorganic form of Zn known to enhance growth performance in weanling swine when fed at pharmacological concentrations (Hahn and Baker, 1993; McCully et al., 1995; Smith et al., 1997). Results of a titration experiment indicated that the growth performance enhancement response from ZnO reached a plateau at 1,500 to 2,000 ppm of Zn (Hill et al., 2001). High dietary concentrations of Zn as ZnO result in large quantities of Zn excreted in the manure (Poulsen and Larsen, 1995; Hoover et al., 1997; Carlson et al., 2004), which may result in a net accumulation of Zn in the soil when applied as a crop fertilizer (Jongbloed and Lenis, 1998). Fecal Zn excretion was markedly decreased when lower concentrations of Zn from organic sources were fed to weanling pigs as a replacement for pharmacological doses of Zn as ZnO (Case and Carlson, 2002; Carlson et al., 2004).

Lower dietary concentrations of an organic Zn source were found to maintain growth performance compared with pharmacological concentrations of Zn as ZnO in experiments by Ward et al. (1996) and Case and Carlson (2002), but not in experiments by Carlson et al. (2004). Therefore, the objective of this experiment was to determine whether feeding lower concentrations of Zn (450 ppm Zn) as a Zn-polysaccharide (Zn-PS) to weanling pigs would maintain growth performance and decrease Zn excretion in manure compared with feeding 2,000 ppm Zn as ZnO.

	Materials and Methods

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Animals, Housing, and Dietary Treatments
Fifty crossbred pigs (22 barrows and 28 gilts) with an average initial BW of 6.21 ± 0.43 kg were weaned at 21 ± 1 d of age and allotted to five dietary treatments by litter, weight, and sex for a 35-d experiment. Pigs were placed in individual, solid-walled, stainless steel metabolism crates (eight crates/treatment with 0.9 m²/pig and two crates/treatment with 0.7 m²/pig) equipped with stainless steel nipple drinkers, feeders, and woven wire or slotted floors, with 10 replications per treatment. Thermostatically controlled heaters and exhaust fans maintained temperature at 30 ± 1°C for wk 1, with a 1°C decrease each week thereafter. Pigs were given ad libitum access to feed and water, and feed was added to the feeders twice daily (0600 and 1400 h). Individual feed consumption was determined weekly. Pigs were weighed at the beginning of the experiment (d 0) and at the end of Phases 1 (d 14) and 2 (d 35). This experiment was approved by the University of Missouri Animal Care and Use Committee.

A basal Phase 1 diet formulated to contain 20.7% CP and 1.50% lysine (Table 1) was fed for 14 d followed by a Phase 2 diet containing 19.3% CP and 1.30% lysine for an additional 21 d. The basal Phase 1 and 2 diets met or exceeded NRC (1998) nutrient requirements and provided 125 or 100 ppm Zn, respectively, as Zn sulfate. The five dietary treatments were fed in meal form. Diet 1 was the basal Phase 1 or 2 diet with 0 ppm Zn from Zn-PS (Sea-Questra-Min Zn; Quali Tech Inc., Chaska, MN) and served as the control diet. Diets 2, 3, and 4, respectively, were the basal diets plus 150, 300, or 450 ppm of Zn as Zn-PS. Diet 5 was the basal diet plus 2,000 ppm Zn as Zn oxide (72% Zn; Prince Agri Products, Quincy, IL). The Zn-PS had a guaranteed minimum of 22% Zn and is described by AAFCO (2002) as a product resulting from complexing a soluble Zn salt with a polysaccharide solution.

Fecal grab samples (approximately 100 g of DM) and total urine collections were made twice daily from d 22 to 26. All Phase 2 diets contained 0.05% Cr₂O₃ at the expense of corn as an indigestible marker. Fecal samples were stored in plastic freezer bags. Urine was collected in plastic pails containing 40 mL of 6 N HCl. Total urine volume was recorded, and 10% was saved in 1-L screw-cap plastic bottles. Fecal and urine samples were immediately frozen at –20°C until analyzed. Each pig crate, fecal collection screen, and urine collection pail was washed immediately after collection. The 5-d fecal collections for individual pigs were thawed, pooled, mixed, and dried in an oven at 55°C for 48 h. The dried fecal samples, in addition to samples from each diet, were ground to pass a 1-mm screen. The 5-d urine collections for individual pigs also were thawed, mixed, and subsampled for mineral analysis. Fecal, feed, and urine samples were digested using nitric and perchloric acids and analyzed in triplicate for Zn, Cu, and Cr concentrations by atomic absorption spectrophotometry (AOAC, 1990). For Phase 2 Diets 1 to 5, respectively, analyzed concentrations of Zn were 162, 321, 482, 642, and 2,182 ppm (as-fed basis). Analyzed concentrations of Cu in the Phase 2 diets averaged 16.8 ppm (as-fed basis).

Statistical Analyses
Growth performance and mineral balance data were analyzed by ANOVA as a completely random design (Snedecor and Cochran, 1989) using the GLM procedure of SAS (SAS Inst., Inc., Cary, NC). Individual pigs were the experimental units. The planned single degree of freedom treatment contrasts were the linear and quadratic tests for Diets 1 to 4 (0 or control, 150, 300, and 450 ppm of Zn as Zn-PS) and Diet 5 (2,000 ppm of Zn as ZnO) vs. each Zn-PS treatment individually because Diet 5 was an "extra treatment" not included in the linear and quadratic contrasts. For the blood data, the ANOVA was a repeated measurement in time (Gill and Hafs, 1971) with the same treatment comparisons as indicated previously. Significance was reported at P 0.05, with a trend between P 0.06 and P 0.10.

	Results

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Pig Growth Performance
All pigs completed this experiment. There were no linear or quadratic responses (P 0.16) in ADG, ADFI, or G:F for Phases 1 or 2 or overall (Table 2). For the Phase 1 single degree of freedom treatment comparisons, pigs fed the diet containing ZnO had a greater (P 0.05) ADG and G:F than did pigs fed the control diet or the diet containing 150 ppm of Zn as Zn-PS and a greater (P = 0.04) Phase 1 G:F than pigs fed the diet containing 300 ppm of Zn as Zn-PS. For Phase 2 and overall (d 0 to 35), the ADG and G:F for pigs fed the diets containing 300 or 450 ppm of Zn as Zn-PS did not differ (P 0.29) from those of pigs fed the diet containing 2,000 ppm of Zn as ZnO; however, pigs fed the diet containing ZnO had greater Phase 1 (P 0.05) and overall (P 0.08) ADG and G:F than did pigs fed the control diet. There were no single degree of freedom treatment comparison differences in ADFI (P 0.46) for Phases 1 or 2 or overall or for pig BW (P 0.21) on d 0, 14, or 35.

	Discussion

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Results of this experiment indicated that Phase 2 and overall growth performance by weanling pigs fed diets containing 300 or 450 ppm of Zn as Zn-PS did not differ from performance by pigs fed the diet containing 2,000 ppm of Zn as ZnO. There was no further increase in growth performance or in the apparent absorption and retention (mg/d) of Zn when dietary Zn as Zn-PS was increased from 300 to 450 ppm. Previous research with organic sources of Zn indicated that 250 ppm of Zn as Zn-methionine increased growth performance of weanling pigs equal to that of 2,000 ppm of Zn as ZnO (Ward et al., 1996). Moreoveor, feeding weanling pigs a diet containing 500 ppm of Zn as Zn-PS increased growth performance similar to that of pigs fed a diet containing 3,000 ppm of Zn as ZnO in two of three experiments (Case and Carlson, 2002), whereas feeding a diet containing 500 ppm of Zn as a Zn-amino acid complex did not improve growth performance compared with control pigs (Case and Carlson, 2002). Similarly, Carlson et al. (2004) found that diets containing various concentrations of organic Zn as Zn-proteinate (800 ppm of Zn) or Zn-PS (500 ppm of Zn) did not improve growth performance by weanling pigs, which was attributed to differences in the health status of the pigs at weaning, pig genetics, feeding duration of the Zn sources, and/or environmental stress. One or more of these factors also might be responsible for decreasing the growth performance responses of pigs fed Zn-PS or ZnO in the current experiment.

The magnitude of the growth performance responses to ZnO in our experiment were less than what has been reported for weanling pigs in other production-type experiments (Carlson et al., 1999; Hill et al. 2000, 2001). The pigs in our experiment were housed individually in solid-sided metabolism crates that prevented visual contact with other pigs, whereas the pigs in the experiments conducted by Carlson et al. (1999) and Hill et al. (2000, 2001) were group-fed in pens that allowed visual contact with adjoining pens. Feed consumption is increased on a short-term basis when group-fed pigs in adjoining pens can see each other because the social facilitation stimulates more frequent synchronized or simultaneous eating by pigs in adjoining pens (Brumm and Gonyou, 2001). The growth response with a pharmacological dose of Zn as ZnO is usually associated with an increase in ADFI (Carlson et al., 1999; Hill et al., 2000, 2001), which might not occur when pigs are housed in metabolism crates.

The mode of action for the improvement in growth performance in weanling pigs fed a pharmacological dose of Zn as ZnO is unknown (Holm and Poulsen, 1996; Mavromichalis et al., 2000; Case and Carlson, 2002). Feeding a pharmacological dose of Zn to weanling pigs has an enteric effect, producing deeper crypts in the duodenum with a trend for longer villi (Carlson et al., 1998). Therefore, feeding a pharmacological dose of Zn as ZnO may have an "antibiotic-like" effect similar to that observed when a pharmacological dose of Cu as CuSO₄ is fed to weanling pigs (Cromwell, 2001). This might be another reason why feeding a high dose of Zn as ZnO or Cu as CuSO₄ to weanling pigs does not increase growth performance all of the time (Carlson et al., 2004; Veum et al., 2004). In this regard, feeding pharmacological concentrations of Zn as ZnO to weanling pigs in production-type experiments did not improve growth performance in two experiments conducted by Tokach et al. (1992), one of three experiments conducted by Hahn and Baker (1993), and all three experiments conducted by Schell and Kornegay (1996). Also, feeding weanling pigs a pharmacological dose of Zn as ZnO had no effect on the number of Escherichia coli or enterococci bacteria excreted per gram of feces in one experiment (Jensen-Waern et al., 1998).

Pigs fed Zn as Zn-PS in our experiment, similar to other experiments where pigs were fed organic sources of Zn (Case and Carlson, 2002; Carlson et al., 2004), excreted markedly less Zn in the manure compared with pigs fed pharmacological concentrations of Zn as ZnO. Fecal excretion of Zn (mg/d) is directly related to the quantity of Zn consumed (mg/d), regardless of the Zn source (Carlson et al., 2004). Zinc excretion was decreased 76% by feeding 300 ppm of Zn as Zn-PS (406.4 mg/d) compared with 2,000 ppm of Zn as ZnO (1,714.3 mg/d). The apparent Zn and Cu balance responses for the treatments in the present experiment were positive and concur with the positive Zn and Cu balance responses reported for Zn-proteinate and Zn-PS by Carlson et al. (2004), but differ from the negative Zn balance responses reported by Case and Carlson (2002).

In the current experiment, plasma Zn concentrations were greater in pigs fed the diet containing ZnO than in pigs fed either the control diet or any of the Zn-PS diets, which is consistent with experiments where lower concentrations of Zn were provided as organic Zn compared with a pharmacological dose of Zn as ZnO (Case and Carlson, 2002; Carlson et al., 2004). In addition, plasma Cu concentrations were not decreased in pigs fed our basal Phase 1 and 2 diets supplemented with 2,000 ppm of Zn as ZnO or 150, 300, or 450 ppm of Zn as Zn-PS compared with pigs fed our basal (control) diets. Our basal diets provided Cu as CuSO₄ at approximately 200% of the NRC (1998) requirement, which was similar to Hill et al. (2000), and were adequate in Cu to prevent the Zn-Cu antagonism and the decrease in plasma Cu that can occur when swine are fed pharmacological concentrations of Zn (Klevay et al., 1994). The plasma Zn and Cu concentrations for weanling pigs in the current experiment are within the range of values reported in other experiments where similar dietary concentrations of Zn and Cu were fed (Hill et al., 2001; Carlson et al., 2004).

Feeding pharmacological concentrations of Zn increases the production of metallothionein (MT) in the body tissues, including the intestinal mucosa, where MT regulates Zn absorption by binding and temporarily storing the excess Zn in the mucosal cells until the mucosal cells are later sloughed (Carlson et al., 1999). Because MT preferentially binds Cu over Zn, Cu concentrations in the body tissues may be decreased when Cu intake is inadequate (Hill et al., 2000); however, neonatal pigs have high hepatic Cu stores that decrease the likelihood of a Cu deficiency in young pigs fed diets adequate in Cu (Hill et al., 1983). The Zn-Cu antagonism is more likely to occur when pharmacological concentrations of Zn are fed as ZnSO₄ compared with ZnO, because the bioavailability of Zn in ZnO ranges from 68 to 73% compared with ZnSO₄ at 100% for weanling and growing-finishing swine fed corn-soybean meal diets (Wedekind et al., 1994; Schell and Kornegay, 1996). The bioavailability values of different feed grade ZnO sources may vary widely (Edwards and Baker, 1999), although bioavailability has little or no effect on the growth promotion efficacy of a high dose of Zn as ZnO for weanling swine (Mavromichalis et al., 2000). Feed grade ZnO also contains elemental contaminants, including Cu, that usually are ignored in diet formulation (Carlson et al., 2004).

Zinc oxide is currently included in many nursery diets at 3,000 ppm of Zn to prevent diarrhea and to aid in growth promotion (Holm and Poulsen, 1996; Hill et al., 2001). Swine production units, however, have become specialized and may not have adequate cropland to use all of the nutrients in the manure produced, especially Zn when it is fed at pharmacological concentrations. In non-acidic soils, Zn is bound by the soil particles and may cause pollution of lakes, streams, and costal waters by runoff and soil erosion (Mohanna and Nys, 1999; Hsu and Lo, 2001). In acidic soils, the organic ligands from manure complex with Zn and contaminate the ground water by leaching (Li and Shuman, 1997a,b; Martinez and Motto, 2000). Considering the long-term impact of Zn excretion on the environment, it may be prudent to feed a much lower concentration of Zn from an organic source of Zn to maintain growth performance by weanling pigs in the nursery. Implementing feeding programs that decrease mineral excretion will be beneficial for the environment and for sustaining swine production in the future, particularly as the feeding of antibiotics for growth promotion is restricted or eliminated.

	Implications

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Supplementation of weanling pig diets with 300 or 450 ppm of Zn as ZN-PS maintained Phase 2 and overall growth performance similar to that obtained with 2,000 ppm of Zn as ZnO; however, 300 ppm of Zn as Zn-PS decreased Zn excretion in manure by 76% compared with 2,000 ppm of Zn as ZnO. This decrease in Zn excretion is a positive environmental benefit that could help sustain the swine industry if restrictions on nutrient pollution are increased and/or the feeding of subtherapeutic levels of antibiotics for growth promotion is banned.

	Footnotes

 
¹ A. Bradley is acknowledged for her assistance in data collection.

² Correspondence: 112 Animal Sciences Center (phone: 573-882-4331; fax: 573-882-6827; e-mail: VeumT{at}missouri.edu).

Received for publication December 21, 2004. Accepted for publication June 13, 2005.

	Literature Cited

Top Abstract Introduction Materials and Methods Results Discussion Implications Literature Cited

 


AAFCO. 2002. Official publication of the Association of American Feed Control Officials, Inc. Section 57, mineral products (pages 272–286). AAFCO, Oxford, IN. (http://www.aafco.org)

AOAC. 1990. Official Methods of Analysis. 15th ed. Assoc. Off. Anal. Chem., Arlington, VA.

Brumm, M., and H. W. Gonyou. 2001. Effects of facility design on behavior and feed and water intake. Pages 499–518 in Swine Nutrition. 2nd ed. A. J. Lewis and L. L. Southern, eds. CRC Press LLC, Boca Raton, FL.

Carlson, M. S., C. A. Boren, C. Wu, C. E. Huntington, D. W. Bollinger, and T. L. Veum. 2004. Evaluation of various inclusion rates of organic zinc either as a polysaccharide or proteinate complex on the growth performance, plasma, and excretion of nursery pigs. J. Anim. Sci. 82:1359–1366.[Abstract/Free Full Text]

Carlson, M. S., G. M. Hill, and J. E. Link. 1999. Early- and traditionally weaned nursery pigs benefit from phase-feeding pharmacological concentrations of zinc oxide: Effect of metallothionein and mineral concentrations. J. Anim. Sci. 77:1199–1207.[Abstract/Free Full Text]

Carlson, M. S., S. L. Hoover, G. M. Hill, J. E. Link, and J. R. Turk. 1998. Effect of pharmacological zinc on intestinal metallothionein concentration and morphology in the nursery pig. J. Anim. Sci. 76(Suppl. 2):53. (Abstr.)

Case, C. L., and M. S. Carlson. 2002. Effect of feeding organic and inorganic sources of additional zinc on growth performance and zinc balance in nursery pigs. J. Anim. Sci. 80:1917–1924.[Abstract/Free Full Text]

Cromwell, G. L. 2001. Antimicrobial and promicrobial agents. Pages 401–426 in Swine Nutrition. 2nd ed. A. J. Lewis and L. L. Southern, eds. CRC Press LLC, Boca Raton, FL.

Edwards, H. M., III, and D. H. Baker. 1999. Bioavailability of zinc in several sources of zinc oxide, zinc sulfate, and zinc metal. J. Anim. Sci. 77:2730–2735.[Abstract/Free Full Text]

Gill, J. L., and H. D. Hafs. 1971. Analysis of repeated measurements of animals. J. Anim. Sci. 33:331–336.

Hahn, J. D., and D. H. Baker. 1993. Growth and plasma zinc responses of young pigs fed pharmacological levels of zinc. J. Anim. Sci. 71:3020–3024.[Abstract]

Hill, G. M., G. L. Cromwell, T. D. Crenshaw, C. R. Dove, R. C. Ewan, D. A. Knabe, A. J. Lewis, G. W. Libal, D. C. Mahan, G. C. Shurson, L. L. Southern, and T. L. Veum. 2000. Growth promotion effects and plasma changes from feeding high dietary concentrations of zinc and copper to weanling pigs (regional study). J. Anim. Sci. 78:1010–1016.[Abstract/Free Full Text]

Hill, G. M., P. K. Ku, E. R. Miller, D. E. Ullrey, T. A. Losty, and B. L. O’Dell. 1983. A copper deficiency in neonatal pigs induced by a high zinc maternal diet. J. Nutr. 113:867–872.

Hill, G. M., D. C. Mahan, S. D. Carter, G. L. Cromwell, R. C. Ewan, R. L. Harrold, A. J. Lewis, P. S. Miller, G. C. Shurson, and T. L. Veum. 2001. Effect of pharmacological concentrations of zinc oxide with or without the inclusion of an antibacterial agent on nursery pig performance. J. Anim. Sci. 79:934–941.[Abstract/Free Full Text]

Holm, A., and H. D. Poulsen. 1996. Zinc oxide in treating E. coli diarrhea in pigs after weaning. Compend. Cont. Educ. Prac. Vet. Food Anim. Med. Manage. Suppl. 18:S26–29, S48.

Hoover, S. L., M. S. Carlson, G. M. Hill, J. E. Link, T. L. Ward, and T. M. Fakler. 1997. Evaluation of excretion and retention of zinc from inorganic and organic sources in diets fed to weanling pigs. J. Anim. Sci. 75(Suppl. 1):209. (Abstr.)

Hsu, J.-H., and S.-L. Lo. 2001. Effect of composting on characterization and leaching of copper, manganese, and zinc from swine manure. Environ. Pollution 114:119–127.[Medline]

Jensen-Waern, M., L. Melin, R. Lindberg, A. Johannisson, L. Petersson, and P. Wallgren. 1998. Dietary zinc oxide in weaned pigs—effects on performance, tissue concentrations, morphology, neutrophil functions and faecal microflora. Res. Vet. Sci. 64:225–231.[Medline]

Jongbloed, A. W., and N. P. Lenis. 1998. Environmental concerns about animal manure. J. Anim. Sci. 76:2641–2648.[Abstract/Free Full Text]

Klevay, L., W. Pond, and D. Medeiros. 1994. Decreased high density lipoprotein cholesterol and apoprotein A-1 in plasma and ultra structural pathology in cardiac muscle of young pigs fed a diet high in zinc. Nutr. Res. 14:1227–1239.

Li, Z., and L. M. Shuman. 1997a. Mobility of Zn, Cd, and Pb in soils as affected by poultry litter extract. I. Leaching in soil columns. Environ. Pollution 95:219–226.[Medline]

Li, Z., and L. M. Shuman. 1997b. Mobility of Zn, Cd, and Pb in soils as affected by poultry litter extract. II. Redistribution among soil fractions. Environ. Pollution 95:227–234.[Medline]

Martinez, C. E., and H. L. Motto. 2000. Solubility of lead, zinc, and copper added to mineral soils. Environ. Pollution 107:153–158.[Medline]

Mavromichalis, I., C. M. Peter, T. M. Parr, D. Ganessunker, and D. H. Baker. 2000. Growth-promoting efficacy in young pigs of two sources of zinc oxide having either a high or low bioavailability of zinc. J. Anim. Sci. 78:2896–2902.[Abstract/Free Full Text]

McCully, G. A., G. M. Hill, J. E. Link, R. L. Weaver, M. S. Carlson, and D. W. Rozeboom. 1995. Evaluation of zinc sources for the newly weaned pig. J. Anim. Sci. 73(Suppl. 1):72. (Abstr.)[Free Full Text]

Mohanna, C., and Y. Nys. 1999. Effect of dietary zinc content and sources on the growth, body zinc deposition and retention, zinc excretion, and immune response in chickens. Br. Poult. Sci. 40:108–114.[Medline]

NRC. 1998. Nutrient Requirements of Swine. 10th ed. Natl. Acad. Press, Washington, DC.

Poulsen, H. D. 1995. Zinc oxide for weanling piglets. Acta Agric. Scand. 45:159–167.

Poulsen, H. D., and T. Larsen. 1995. Zinc excretion and retention in growing pigs fed increasing levels of zinc oxide. Livest. Prod. Sci. 43:235–242.

Schell, T. C., and E. T. Kornegay. 1996. Zinc concentration in tissues and performance of weanling pigs fed pharmacological levels of zinc from ZnO, Zn-Met, Zn-Lys, or ZnSO₄. J. Anim. Sci. 74:1584–1593.[Abstract]

Smith, J. W., II, M. D. Tokach, R. D. Goodband, J. L. Nelssen, and B. T. Richert. 1997. Effects of the interrelationship between zinc oxide and copper sulfate on growth performance of early-weaned pigs. J. Anim. Sci. 75:1861–1866.[Abstract/Free Full Text]

Snedecor, G. W., and W. G. Cochran. 1989. Statistical Methods. 8th ed. Iowa State Univ. Press, Ames.

Tokach, L. M., M. D. Tokach, R. D. Goodband, J. L. Nelssen, S. C. Henry, and T. A. Marsteller. 1992. Influence of zinc oxide in starter diets on pig performance. Page 411 in Proc. Am. Assoc. Swine Pract., Nashville, TN.

Veum, T. L., M. S. Carlson, C. W. Wu, D. W. Bollinger, and M. R. Ellersieck. 2004. Copper proteinate in weanling diets for enhancing growth performance and reducing fecal copper excretion compared with copper sulfate. J. Anim. Sci. 82:1062–1070.[Abstract/Free Full Text]

Ward, T. L., G. L. Asche, G. F. Louis, and D. S. Pollmann. 1996. Zinc-methionine improves growth performance of starter pigs. J. Anim. Sci. 74(Suppl. 1):182. (Abstr.)

Wedekind, K. J., A. J. Lewis, M. A. Giesemann, and P. S. Miller. 1994. Bioavailability of zinc from inorganic and organic sources for pigs fed corn-soybean meal diets. J. Anim. Sci. 72:2681–2689.[Abstract]

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