- Email: [email protected]
The Effects of Increasing Zinc Oxide on Growth Performance of Weanling Pigs1, 2
Zinc Oxide for Weanling The Professional Animal ScientistPigs 14:197–200
197
of Increasing Zinc Oxide Theon Effects Growth Performance of Weanling Pigs1,2
J. W. SMITH, II, M. D. TOKACH, R. D. GOODBAND3, PAS, S. S. DRITZ, and J. L. NELSSEN Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS 66506-0201
Abstract We conducted an experiment to determine the effects of increasing dietary ZnO on growth performance of earlyweaned pigs. Four hundred and twenty weanling pigs (initially 4.45 kg and 13 d of age) were used in a 28-d growth trial. Zinc oxide replaced cornstarch in the control diet to provide 1000, 2000, 3000, or 4000 ppm of Zn. Increasing Zn increased (linear, P<0.01) ADG, ADFI, and gain:feed ratio (G:F) from d 0 to 14 after weaning. During d 14 to 28, increasing Zn increased ADG (maximum observed in pigs fed 2000 ppm Zn; quadratic, P<0.01) and ADFI (linear, P<0.05). For the entire trial (d 0 to 28), increasing Zn increased ADG (quadratic, P<0.11) and ADFI (linear, P<0.03). These results indicate that feeding a dietary regimen of 3000 to 4000 ppm of Zn from 4 to 7 kg and 2000 ppm of Zn
1Contribution
no. 98-503-J from the Kansas Agric. Exp. Sta., Manhattan, KS 66506.
2The authors thank Brian Richert, Kevin Owen,
Jon Bergstrom, Ben Nessmith, and Rob Musser for technical assistance and data collection and Eichman Brothers Farms, St. George, KS for use of animals and facilities. 3To whom correspondence should be addressed: [email protected]
Reviewed by M. A. Brown and T. L. Stanton.
from 7 to 11 kg improves growth performance of weanling pigs. (Key Words: Pigs, Zinc, Growth, Feed Efficiency, Early-Weaning, Postweaning.)
Introduction Recent research has shown the positive effects of feeding diets containing 3000 ppm Zn from ZnO to weanling pigs (3, 9, 10, 14). Hahn and Baker (5) observed improved ADG in weanling pigs fed 3000 ppm Zn from ZnO but not other Zn sources (ZnSO4 or chelated Zn-Lys and Zn-Met). Although several experiments have examined providing 3000 ppm of Zn, little research has examined the optimum level of supplementation. LeMieux et al. (8) observed that feeding either 3000 or 6000 ppm of Zn improved growth performance of pigs weaned at 28 d of age, but feeding 12,000 ppm did not affect growth performance. Additionally, Hahn and Baker (5) observed improved growth performance when feeding 5000 ppm Zn from ZnO. However, a disadvantage of feeding pharmacological concentrations of added Zn is the potential impact on the environment from Zn accumulation in waste disposal systems. More precise knowledge of
the optimal Zn dosage to maximize growth performance of weanling pigs may help decrease the incidence of excessive Zn concentrations in swine diets. With these data in mind, the objective of this experiment was to determine the optimum level of added ZnO in diets fed to earlyweaned pigs to maximize growth performance.
Materials and Methods A total of 420 crossbred weanling pigs (initially 4.45 kg and 13 d of age) was used in a 28-d growth assay to compare the effects of increasing dietary Zn from ZnO on growth performance. Eight replicate pens were used per treatment, with 10 or 12 pigs per pen. Each block had the same number of pigs per pen. Pigs were derived from crossbred sows (Yorkshire × Landrace) bred to crossbred boars (Duroc × Hampshire). At the time the study was conducted, the average sow parity for the farm was 3.2 and all sows would have been fed gestation and lactation diets containing 165 ppm of Zn. The pigs were blocked by weight equalized for sex, and assigned to one of the five dietary treatments including: control (165 ppm of Zn and 16.5 ppm of Cu) and 1000, 2000, 3000, or 4000 ppm of Zn. Pigs were maintained on the
198
assigned Zn concentration throughout the entire 28-d trial. Diets were formulated to contain 1.60 and 1.25% total dietary lysine and 0.44 and 0.35% dietary methionine from d 0 to 14 and d 14 to 28 after weaning, respectively. Both sets of diets were corn-soybean meal-based (Table 1) and were formulated to 0.90% Ca and 0.80% P. The diets fed from d 0 to 14 after weaning were pelleted and contained 25% dried whey, 7.5% spray-dried animal plasma, 1.75% spray-dried blood meal, and 5% soy oil. The diets fed from d 14 to 28 after weaning were fed in a meal form and contained 10% dried whey, 2.5% spray-dried blood meal, and 3% soy oil. Zinc oxide (feed grade, 72% Zn) replaced cornstarch to provide the experimental mineral levels.
Smith et al.
Pigs were housed in an environmentally regulated nursery in 1.5 m × 1.5 m pens with a self-feeder and two nipple waterers to allow ad libitum access to feed and water. The initial temperature of the nursery (34°C) was reduced by 1.5°C each week. The pigs were weighed and feed disappearance was measured weekly to calculate ADG, ADFI, and G:F. Feed samples were collected and analyzed for CP (1) and for minerals using nitric acid digestion followed by inductively coupled plasma analysis (2; Model J-Y 24, Jobin, Edison, NJ). Statistical Analysis. Pigs were blocked by initial weight in a randomized complete block design (eight replications). Pen was the experimental unit. Data were analyzed by analysis of variance using the GLM
TABLE 1. Diet composition (as-fed-basis). Ingredient
0 to 14a
Corn Soybean meal (48% CP) Dried whey Spray-dried animal plasma Spray-dried blood meal Soybean oil Monocalcium phosphate Limestone Medicationc Cornstarchd DL-methionine L-lysine HCl Vitamin and trace mineral premixe
36.93 19.30 25.00 7.50 1.75 5.00 1.74 0.62 1.00 0.53 0.13 0.10 0.40
14 to 28b (%)
a,bDiets
57.38 22.25 10.00 — 2.50 3.00 1.92 0.82 1.00 0.53 0.05 0.15 0.40
fed from d 0 to 14 and d 14 to 28 diets were formulated to contain 1.6% and 1.25% lysine, respectively. All diets were formulated to 0.90% Ca and 0.80% P. Analyzed Zn values were 323, 947, 1995, 2757, and 4061, for the 165, 1000, 2000, 3000, and 4000 ppm of Zn diets during d 0 to 14, respectively. Analyzed Zn values for d 14 to 28 diets were: 350, 1015, 1778, 2735, and 4723 for the 165, 1000, 2000, 3000, and 4000 ppm of Zn diets, respectively. cProvided 165 mg/kg of apramycin in d 0 to 14 and 55 mg/kg of carbadox in d 14 to 28. dZinc oxide replaced cornstarch on a wt/wt basis to provide 1000, 2000, 3000, and 4000 ppm of dietary Zn. ePremix provided per kilogram of complete diet: Mn, 12 mg; Fe, 165 mg; Zn, 165 mg; Cu, 16 mg; I, 0.3 mg; Se, 0.3 mg; vitamin A, 11,025 IU; vitamin D3, 1103 IU; vitamin E, 44 IU; menadione (menadione sodium bisulfate complex), 4.4 mg; riboflavin, 8.3 mg; d-pantothenic acid, 29 mg; niacin, 50 mg; choline, 166 mg; and vitamin B12, 33 mg.
procedure of SAS® (13) and linear and quadratic polynomials (11) were evaluated.
Results From d 0 to 14 after weaning, increasing dietary Zn increased (linear, P<0.01) ADG, ADFI, and G:F (Table 3). From d 14 to 28, increasing dietary Zn increased ADG (quadratic, P<0.01) and ADFI (linear, P<0.05). Feed efficiency tended (P>0.10) to increase and then decrease, with the best G:F being observed for pigs fed 2000 ppm of Zn. For the entire 28 d trial, ADG increased (linear, P<0.01; quadratic, P<0.11) with increasing Zn. Average daily feed intake also increased (linear, P<0.03) with increasing Zn; however, pigs fed 3000 ppm of Zn had the greatest ADFI over the entire trial. Feed utilization was not affected (P>0.10) by dietary Zn; however, pigs fed the 2000 ppm of Zn diet had numerically the best G:F.
Discussion The benefit of feeding growthpromotional levels of Zn is well documented (5, 6, 7, 12). The growth response during d 0 to 14 in this experiment was similar to that found by LeMieux et al. (8), who observed increases in ADG and ADFI with 3000 to 6000 ppm of Zn from ZnO. Hsu et al. (7) found that feeding 4000 ppm of Zn decreased growth with diets low in Ca but increased growth performance when diets contained adequate Ca. Although the response to added Zn from d 0 to 14 after weaning was linear through 4000 ppm, producers and nutritionists may need to apply these results with caution. Based on concerns regarding Zn accumulation in swine waste and different durations of feeding high Zn diets on commercial operations, a conservative recommendation might be to provide weanling pigs a diet containing 3000 ppm of Zn up to 14 d after weaning. The response to increasing dietary Zn from d 14 to 28 of this trial
199
Zinc Oxide for Weanling Pigs
TABLE 2. Influence of increasing dietary Zn from ZnO on growth preformance of weanling pigsa. Zinc Item Day 0 to 14 ADG, g ADFI, g Gain:feed, g:g Day 14 to 28 ADG, g ADFI, g Gain:feed, g:g Day 0 to 28 ADG, g ADFI, g Gain:feed, g:g
165 ppm
Probability (P<)
1000 ppm
2000 ppm
3000 ppm
4000 ppm
CV
Linear
Quadratic
163 218 0.72
173 222 0.78
182 227 0.79
186 236 0.77
213 245 0.87
10.2 7.4 11.9
0.01 0.01 0.01
0.35 0.59 0.98
331 604 0.54
354 622 0.57
386 654 0.58
372 727 0.53
363 695 0.51
7.7 17.7 13.3
0.02 0.05 0.17
0.01 0.81 0.14
245 413 0.59
263 422 0.63
281 440 0.64
277 472 0.59
286 463 0.60
7.4 13.3 11.0
0.01 0.03 0.83
0.11 0.79 0.31
aFour
hundred twenty weanling pigs (initially 4.45 kg and 13 d of age) were used with 10 or 12 pigs per pen with eight replicate pens per treatment. Zinc oxide replaced cornstarch in the basal diet (165 ppm of Zn) to form the experimental diets.
indicates that feeding 3000 and 4000 ppm of Zn for long periods (4 wk) is not necessary for maximum growth performance and may be detrimental. Liver and peripheral Zn stores were not evaluated, and pigs did not exhibit classic signs of Zn toxicity in this experiment; therefore, the assessment of Zn toxicosis can be only conjectural. LeMieux et al. (8) did not observe toxicosis at 3000 or 6000 ppm of Zn during a 21-d trial. Cox and Hale (4) observed no differences in growth performance when feeding either 2000 or 4000 ppm of Zn for 69 d. Needless to say, lowering growth-promotional concentrations of Zn from 3000 to 2000 ppm after 14 d would decrease Zn accumulation in swine waste. Currently, many states are considering including Zn concentrations along with N and P in legislation to regulate waste disposal. Hahn and Baker (5) fed both 3000 and 5000 ppm of Zn from both ZnO and ZnSO4 and observed that pigs fed the 5000 ppm of Zn from ZnO had improved growth performance, whereas pigs fed 5000 ppm of Zn from ZnSO4 had decreased growth performance. This may stem from the greater bioavailability of Zn in ZnSO4. Wedekind et al. (15) observed
that ZnO was much less available; thus, higher concentrations were needed to achieve storage and plasma levels equal to those resulting from lower concentrations of ZnSO4. However, research by Hahn and Baker (5) indicated that, even when plasma Zn concentrations were equal, pigs fed diets containing added ZnO grew faster and more efficiently than pigs fed diets with added ZnSO4 or ZnLys. Because of environmental concerns regarding Zn accumulation in swine waste, additional research is needed to determine whether other sources of Zn (perhaps at lower concentrations) will provide the growth-promotional properties as ZnO.
Implications The results of these experiments indicate that Zn supplementation from ZnO is a viable means of increasing growth performance of weanling pigs. Feeding a dietary regimen of 3000 to 4000 ppm of Zn from ZnO from 4 to 7 kg and 2000 ppm from 7 to 11 kg improves growth performance of the weanling pig.
Literature Cited 1. AOAC. 1990. Official Methods of Analysis. (15th Ed.). Association of Official Analytical Chemists, Arlington, VA. 2. Arthington, J. D., L. R. Corah, F. Blecha, and D. A. Hill. 1995. Effect of copper depletion and repletion on lymphocyte blastogenesis and neutrophil bactericidal function in beef heifers. J. Anim. Sci. 73:2079. 3. Carlson, M. S., G. M. Hill, J. E. Link, G. A. McCully, D. W. Rozeboom, and R. L. Weavers. 1995. Impact of zinc oxide and copper sulfate supplementation on the newly weaned pig. J. Anim. Sci. 73 (Suppl. 1):72 (Abs.). 4. Cox, D. H., and K. L. Harris. 1960. Effects of excess dietary zinc on iron and copper in the rat. J. Nutr. 70:514. 5. Hahn, J. D., and D. H. Baker. 1993. Growth and plasma zinc responses of young pigs fed pharmacologic levels of zinc. J. Anim. Sci. 71:3020. 6. Holm, A., 1988. Eschericha coli-betinget fravaenningsdiearr’e hos gris. Zinkoxid tilsat foderet som antibakteriel princip? (E. coli associated diarrhea in weaner pigs: Zinc oxide added to the feed as an antibacterial principle?) Dan. Veterinaertidsskr. 72:1118. 7. Hsu, F. S., L. Krrok, W. G. Pond, and J. R. Duncan. 1975. Interactions of dietary
200
calcium with toxic levels of lead and zinc in pigs. J. Nutr. 195:112. 8. LeMieux, F. M., L. V. Ellison, T. L. Ward, L. L. Southern, and T. D. Bidner. 1995a. Excess dietary zinc for pigs weaned at 28 days. J. Anim. Sci. 73 (Suppl. 1): 72 (Abs.). 9. LeMieux, F. M., L. L. Southern, T. L. Ward, and T. D. Bidner. 1995b. Growth performance of weanling pigs fed excess dietary zinc. J. Anim. Sci. 73 (Suppl. 1): 172 (Abs.). 10. McCully, G. A., G. M. Hill, J. E. Link, R. L. Weavers, M. S. Carlson, and D. W.
Smith et al.
Rozeboom. 1995. Evaluation of zinc sources for the newly weaned pig. J. Anim. Sci. 73 (Suppl 1.): 72 (Abs.). 11. Peterson, R. G. 1985. Design and Analysis of Experiments. Marcel Dekker, Inc., New York, NY. 13, Poulson, H. D. 1995. Zinc oxide for weanling piglets. Acta. Agric. Scand., Sect. A., Anim. Sci. 45:159. 13. SAS. 1988. SAS/STAT® User’s Guide. (Release 6.03 Ed.). SAS Inst. Inc., Cary, NC.
14. Smith, J., II, W., 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. 15, Wedekind, K. J., A. E. Hortin, and D. H. Baker. 1992. Methodology for assessing zinc bioavailability: Efficacy estimates for zincmethionine, zinc sulfate, and zinc oxide. J. Anim. Sci. 70:178.
197
of Increasing Zinc Oxide Theon Effects Growth Performance of Weanling Pigs1,2
J. W. SMITH, II, M. D. TOKACH, R. D. GOODBAND3, PAS, S. S. DRITZ, and J. L. NELSSEN Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS 66506-0201
Abstract We conducted an experiment to determine the effects of increasing dietary ZnO on growth performance of earlyweaned pigs. Four hundred and twenty weanling pigs (initially 4.45 kg and 13 d of age) were used in a 28-d growth trial. Zinc oxide replaced cornstarch in the control diet to provide 1000, 2000, 3000, or 4000 ppm of Zn. Increasing Zn increased (linear, P<0.01) ADG, ADFI, and gain:feed ratio (G:F) from d 0 to 14 after weaning. During d 14 to 28, increasing Zn increased ADG (maximum observed in pigs fed 2000 ppm Zn; quadratic, P<0.01) and ADFI (linear, P<0.05). For the entire trial (d 0 to 28), increasing Zn increased ADG (quadratic, P<0.11) and ADFI (linear, P<0.03). These results indicate that feeding a dietary regimen of 3000 to 4000 ppm of Zn from 4 to 7 kg and 2000 ppm of Zn
1Contribution
no. 98-503-J from the Kansas Agric. Exp. Sta., Manhattan, KS 66506.
2The authors thank Brian Richert, Kevin Owen,
Jon Bergstrom, Ben Nessmith, and Rob Musser for technical assistance and data collection and Eichman Brothers Farms, St. George, KS for use of animals and facilities. 3To whom correspondence should be addressed: [email protected]
Reviewed by M. A. Brown and T. L. Stanton.
from 7 to 11 kg improves growth performance of weanling pigs. (Key Words: Pigs, Zinc, Growth, Feed Efficiency, Early-Weaning, Postweaning.)
Introduction Recent research has shown the positive effects of feeding diets containing 3000 ppm Zn from ZnO to weanling pigs (3, 9, 10, 14). Hahn and Baker (5) observed improved ADG in weanling pigs fed 3000 ppm Zn from ZnO but not other Zn sources (ZnSO4 or chelated Zn-Lys and Zn-Met). Although several experiments have examined providing 3000 ppm of Zn, little research has examined the optimum level of supplementation. LeMieux et al. (8) observed that feeding either 3000 or 6000 ppm of Zn improved growth performance of pigs weaned at 28 d of age, but feeding 12,000 ppm did not affect growth performance. Additionally, Hahn and Baker (5) observed improved growth performance when feeding 5000 ppm Zn from ZnO. However, a disadvantage of feeding pharmacological concentrations of added Zn is the potential impact on the environment from Zn accumulation in waste disposal systems. More precise knowledge of
the optimal Zn dosage to maximize growth performance of weanling pigs may help decrease the incidence of excessive Zn concentrations in swine diets. With these data in mind, the objective of this experiment was to determine the optimum level of added ZnO in diets fed to earlyweaned pigs to maximize growth performance.
Materials and Methods A total of 420 crossbred weanling pigs (initially 4.45 kg and 13 d of age) was used in a 28-d growth assay to compare the effects of increasing dietary Zn from ZnO on growth performance. Eight replicate pens were used per treatment, with 10 or 12 pigs per pen. Each block had the same number of pigs per pen. Pigs were derived from crossbred sows (Yorkshire × Landrace) bred to crossbred boars (Duroc × Hampshire). At the time the study was conducted, the average sow parity for the farm was 3.2 and all sows would have been fed gestation and lactation diets containing 165 ppm of Zn. The pigs were blocked by weight equalized for sex, and assigned to one of the five dietary treatments including: control (165 ppm of Zn and 16.5 ppm of Cu) and 1000, 2000, 3000, or 4000 ppm of Zn. Pigs were maintained on the
198
assigned Zn concentration throughout the entire 28-d trial. Diets were formulated to contain 1.60 and 1.25% total dietary lysine and 0.44 and 0.35% dietary methionine from d 0 to 14 and d 14 to 28 after weaning, respectively. Both sets of diets were corn-soybean meal-based (Table 1) and were formulated to 0.90% Ca and 0.80% P. The diets fed from d 0 to 14 after weaning were pelleted and contained 25% dried whey, 7.5% spray-dried animal plasma, 1.75% spray-dried blood meal, and 5% soy oil. The diets fed from d 14 to 28 after weaning were fed in a meal form and contained 10% dried whey, 2.5% spray-dried blood meal, and 3% soy oil. Zinc oxide (feed grade, 72% Zn) replaced cornstarch to provide the experimental mineral levels.
Smith et al.
Pigs were housed in an environmentally regulated nursery in 1.5 m × 1.5 m pens with a self-feeder and two nipple waterers to allow ad libitum access to feed and water. The initial temperature of the nursery (34°C) was reduced by 1.5°C each week. The pigs were weighed and feed disappearance was measured weekly to calculate ADG, ADFI, and G:F. Feed samples were collected and analyzed for CP (1) and for minerals using nitric acid digestion followed by inductively coupled plasma analysis (2; Model J-Y 24, Jobin, Edison, NJ). Statistical Analysis. Pigs were blocked by initial weight in a randomized complete block design (eight replications). Pen was the experimental unit. Data were analyzed by analysis of variance using the GLM
TABLE 1. Diet composition (as-fed-basis). Ingredient
0 to 14a
Corn Soybean meal (48% CP) Dried whey Spray-dried animal plasma Spray-dried blood meal Soybean oil Monocalcium phosphate Limestone Medicationc Cornstarchd DL-methionine L-lysine HCl Vitamin and trace mineral premixe
36.93 19.30 25.00 7.50 1.75 5.00 1.74 0.62 1.00 0.53 0.13 0.10 0.40
14 to 28b (%)
a,bDiets
57.38 22.25 10.00 — 2.50 3.00 1.92 0.82 1.00 0.53 0.05 0.15 0.40
fed from d 0 to 14 and d 14 to 28 diets were formulated to contain 1.6% and 1.25% lysine, respectively. All diets were formulated to 0.90% Ca and 0.80% P. Analyzed Zn values were 323, 947, 1995, 2757, and 4061, for the 165, 1000, 2000, 3000, and 4000 ppm of Zn diets during d 0 to 14, respectively. Analyzed Zn values for d 14 to 28 diets were: 350, 1015, 1778, 2735, and 4723 for the 165, 1000, 2000, 3000, and 4000 ppm of Zn diets, respectively. cProvided 165 mg/kg of apramycin in d 0 to 14 and 55 mg/kg of carbadox in d 14 to 28. dZinc oxide replaced cornstarch on a wt/wt basis to provide 1000, 2000, 3000, and 4000 ppm of dietary Zn. ePremix provided per kilogram of complete diet: Mn, 12 mg; Fe, 165 mg; Zn, 165 mg; Cu, 16 mg; I, 0.3 mg; Se, 0.3 mg; vitamin A, 11,025 IU; vitamin D3, 1103 IU; vitamin E, 44 IU; menadione (menadione sodium bisulfate complex), 4.4 mg; riboflavin, 8.3 mg; d-pantothenic acid, 29 mg; niacin, 50 mg; choline, 166 mg; and vitamin B12, 33 mg.
procedure of SAS® (13) and linear and quadratic polynomials (11) were evaluated.
Results From d 0 to 14 after weaning, increasing dietary Zn increased (linear, P<0.01) ADG, ADFI, and G:F (Table 3). From d 14 to 28, increasing dietary Zn increased ADG (quadratic, P<0.01) and ADFI (linear, P<0.05). Feed efficiency tended (P>0.10) to increase and then decrease, with the best G:F being observed for pigs fed 2000 ppm of Zn. For the entire 28 d trial, ADG increased (linear, P<0.01; quadratic, P<0.11) with increasing Zn. Average daily feed intake also increased (linear, P<0.03) with increasing Zn; however, pigs fed 3000 ppm of Zn had the greatest ADFI over the entire trial. Feed utilization was not affected (P>0.10) by dietary Zn; however, pigs fed the 2000 ppm of Zn diet had numerically the best G:F.
Discussion The benefit of feeding growthpromotional levels of Zn is well documented (5, 6, 7, 12). The growth response during d 0 to 14 in this experiment was similar to that found by LeMieux et al. (8), who observed increases in ADG and ADFI with 3000 to 6000 ppm of Zn from ZnO. Hsu et al. (7) found that feeding 4000 ppm of Zn decreased growth with diets low in Ca but increased growth performance when diets contained adequate Ca. Although the response to added Zn from d 0 to 14 after weaning was linear through 4000 ppm, producers and nutritionists may need to apply these results with caution. Based on concerns regarding Zn accumulation in swine waste and different durations of feeding high Zn diets on commercial operations, a conservative recommendation might be to provide weanling pigs a diet containing 3000 ppm of Zn up to 14 d after weaning. The response to increasing dietary Zn from d 14 to 28 of this trial
199
Zinc Oxide for Weanling Pigs
TABLE 2. Influence of increasing dietary Zn from ZnO on growth preformance of weanling pigsa. Zinc Item Day 0 to 14 ADG, g ADFI, g Gain:feed, g:g Day 14 to 28 ADG, g ADFI, g Gain:feed, g:g Day 0 to 28 ADG, g ADFI, g Gain:feed, g:g
165 ppm
Probability (P<)
1000 ppm
2000 ppm
3000 ppm
4000 ppm
CV
Linear
Quadratic
163 218 0.72
173 222 0.78
182 227 0.79
186 236 0.77
213 245 0.87
10.2 7.4 11.9
0.01 0.01 0.01
0.35 0.59 0.98
331 604 0.54
354 622 0.57
386 654 0.58
372 727 0.53
363 695 0.51
7.7 17.7 13.3
0.02 0.05 0.17
0.01 0.81 0.14
245 413 0.59
263 422 0.63
281 440 0.64
277 472 0.59
286 463 0.60
7.4 13.3 11.0
0.01 0.03 0.83
0.11 0.79 0.31
aFour
hundred twenty weanling pigs (initially 4.45 kg and 13 d of age) were used with 10 or 12 pigs per pen with eight replicate pens per treatment. Zinc oxide replaced cornstarch in the basal diet (165 ppm of Zn) to form the experimental diets.
indicates that feeding 3000 and 4000 ppm of Zn for long periods (4 wk) is not necessary for maximum growth performance and may be detrimental. Liver and peripheral Zn stores were not evaluated, and pigs did not exhibit classic signs of Zn toxicity in this experiment; therefore, the assessment of Zn toxicosis can be only conjectural. LeMieux et al. (8) did not observe toxicosis at 3000 or 6000 ppm of Zn during a 21-d trial. Cox and Hale (4) observed no differences in growth performance when feeding either 2000 or 4000 ppm of Zn for 69 d. Needless to say, lowering growth-promotional concentrations of Zn from 3000 to 2000 ppm after 14 d would decrease Zn accumulation in swine waste. Currently, many states are considering including Zn concentrations along with N and P in legislation to regulate waste disposal. Hahn and Baker (5) fed both 3000 and 5000 ppm of Zn from both ZnO and ZnSO4 and observed that pigs fed the 5000 ppm of Zn from ZnO had improved growth performance, whereas pigs fed 5000 ppm of Zn from ZnSO4 had decreased growth performance. This may stem from the greater bioavailability of Zn in ZnSO4. Wedekind et al. (15) observed
that ZnO was much less available; thus, higher concentrations were needed to achieve storage and plasma levels equal to those resulting from lower concentrations of ZnSO4. However, research by Hahn and Baker (5) indicated that, even when plasma Zn concentrations were equal, pigs fed diets containing added ZnO grew faster and more efficiently than pigs fed diets with added ZnSO4 or ZnLys. Because of environmental concerns regarding Zn accumulation in swine waste, additional research is needed to determine whether other sources of Zn (perhaps at lower concentrations) will provide the growth-promotional properties as ZnO.
Implications The results of these experiments indicate that Zn supplementation from ZnO is a viable means of increasing growth performance of weanling pigs. Feeding a dietary regimen of 3000 to 4000 ppm of Zn from ZnO from 4 to 7 kg and 2000 ppm from 7 to 11 kg improves growth performance of the weanling pig.
Literature Cited 1. AOAC. 1990. Official Methods of Analysis. (15th Ed.). Association of Official Analytical Chemists, Arlington, VA. 2. Arthington, J. D., L. R. Corah, F. Blecha, and D. A. Hill. 1995. Effect of copper depletion and repletion on lymphocyte blastogenesis and neutrophil bactericidal function in beef heifers. J. Anim. Sci. 73:2079. 3. Carlson, M. S., G. M. Hill, J. E. Link, G. A. McCully, D. W. Rozeboom, and R. L. Weavers. 1995. Impact of zinc oxide and copper sulfate supplementation on the newly weaned pig. J. Anim. Sci. 73 (Suppl. 1):72 (Abs.). 4. Cox, D. H., and K. L. Harris. 1960. Effects of excess dietary zinc on iron and copper in the rat. J. Nutr. 70:514. 5. Hahn, J. D., and D. H. Baker. 1993. Growth and plasma zinc responses of young pigs fed pharmacologic levels of zinc. J. Anim. Sci. 71:3020. 6. Holm, A., 1988. Eschericha coli-betinget fravaenningsdiearr’e hos gris. Zinkoxid tilsat foderet som antibakteriel princip? (E. coli associated diarrhea in weaner pigs: Zinc oxide added to the feed as an antibacterial principle?) Dan. Veterinaertidsskr. 72:1118. 7. Hsu, F. S., L. Krrok, W. G. Pond, and J. R. Duncan. 1975. Interactions of dietary
200
calcium with toxic levels of lead and zinc in pigs. J. Nutr. 195:112. 8. LeMieux, F. M., L. V. Ellison, T. L. Ward, L. L. Southern, and T. D. Bidner. 1995a. Excess dietary zinc for pigs weaned at 28 days. J. Anim. Sci. 73 (Suppl. 1): 72 (Abs.). 9. LeMieux, F. M., L. L. Southern, T. L. Ward, and T. D. Bidner. 1995b. Growth performance of weanling pigs fed excess dietary zinc. J. Anim. Sci. 73 (Suppl. 1): 172 (Abs.). 10. McCully, G. A., G. M. Hill, J. E. Link, R. L. Weavers, M. S. Carlson, and D. W.
Smith et al.
Rozeboom. 1995. Evaluation of zinc sources for the newly weaned pig. J. Anim. Sci. 73 (Suppl 1.): 72 (Abs.). 11. Peterson, R. G. 1985. Design and Analysis of Experiments. Marcel Dekker, Inc., New York, NY. 13, Poulson, H. D. 1995. Zinc oxide for weanling piglets. Acta. Agric. Scand., Sect. A., Anim. Sci. 45:159. 13. SAS. 1988. SAS/STAT® User’s Guide. (Release 6.03 Ed.). SAS Inst. Inc., Cary, NC.
14. Smith, J., II, W., 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. 15, Wedekind, K. J., A. E. Hortin, and D. H. Baker. 1992. Methodology for assessing zinc bioavailability: Efficacy estimates for zincmethionine, zinc sulfate, and zinc oxide. J. Anim. Sci. 70:178.