J. Appl. Poult. Res.
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J APPL POULT RES 2007. 16:219-225
© 2007 Poultry Science Association
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Research Reports

Influence of Graded Levels of Organic Zinc on Growth Performance and Carcass Traits of Broilers

P. Rossi1, F. Rutz, M. A. Anciuti, J. L. Rech and N. H. F. Zauk

Departamento de Zootecnia, Universidade Federal de Pelotas, 96010-900, Rio Grande do Sul, Brazil

Correspondence: 1 Corresponding author: rossi_patricia{at}yahoo.com.br


   SUMMARY
TOP
 SUMMARY
DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
This study investigated the effect of graded levels of organic Zn (Bioplex Zn) on growth performance and carcass traits of broilers fed diets containing organic Se (Sel-Plex). Dietary treatments consisted of adding 0, 15, 30, 45, or 60 ppm organic Zn to a basal diet containing 60 ppm Zn from an inorganic source. Feed and water were provided ad libitum. Body weight, feed intake, feed conversion, and carcass traits were evaluated. Carcass evaluation was also performed on the last day of the experimental period. Body weight, feed intake, feed conversion, and weights of individual meat cuts were not statistically influenced by increasing organic Zn levels in the diet. However, a significant increase in skin tearing strength was observed in response to increasing levels of dietary organic Zn. Zinc plays a role in epithelial cell layers and collagen synthesis, thus affecting susceptibility of skin to tearing. These data indicated that organic Zn does not affect growth performance of broilers but increases resistance of skin to tearing, therefore improving carcass quality.

Key Words: broilers • skin quality • zinc • selenium


   DESCRIPTION OF PROBLEM
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
Growth rate, feed efficiency, and carcass traits are factors that determine the performance of a broiler flock. High stocking density, low feathering, and low skin strength contribute to reduced performance and skin quality of broilers [1]. Downgrades ranging from 5 to 7% at processing have been reported due to skin tearing [2, 3]. Several nutritional factors influence those parameters, including Zn and Se trace mineral status. These minerals participate in many metabolic pathways influencing nutrient metabolism, growth, immune response, and skin quality [4].

Zinc participates as a cofactor or component of more than 240 enzymes, being important for protein and carbohydrate metabolism, growth, and reproduction [5]. Zinc is necessary for production of epithelial cells [5], the first barrier to infection [6]. Very few microorganisms can penetrate the intact skin [7]. Zinc also plays a part in thymocyte development, T-cell function, and thymic integrity [8]. Zinc deficiency results in reduced appetite, depressed growth, and abnormalities of the skin and its appendages [4].

Many investigators have added Zn in inorganic form [9, 10] or in organic form [11, 12, 13] to diets of broilers and observed an improvement in performance; however, others have seen no effect on performance (inorganic Zn [14] and organic Zn [15, 16, 17] sources).

Maximum growth rate or feed efficiency is not necessarily correlated with skin strength [3]. Skin strength is highly correlated with content of a strong, fibrous protein (collagen), which functions as an extracellular structural element in connective tissue. Therefore, skin with greater collagen content is less prone to tearing. Any nutritional factor that influences skin collagen content will therefore indirectly affect susceptibility to tearing. Zinc, among other nutrients, plays a role in collagen synthesis; therefore, deficiencies of this nutrient result in less skin collagen production [3]. In addition, Zn participates in synthesis of keratin and nucleic acid of the skin [18]. Thus, Zn participates in maintenance of skin quality [19].

Growth performance can also be influenced by Se source. Many investigators [20, 21, 22, 23] indicated that Se in organic form brings about an improvement in performance and efficiency of broilers. Selenium is a component of a wide range of selenoenzymes including the antioxidant enzyme glutathione peroxidase. Furthermore, Se deficiency reduces antibody production, cytokine synthesis, cell-mediated cytotoxicity, and lymphocyte proliferation [8].

Therefore, this study aimed to investigate the effect of increasing levels of organic Zn in diets containing organic Se on performance and carcass quality of broilers.


   MATERIALS AND METHODS
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
Experimental Chickens and Diets
A total of 1,960 Ross [24] 1-d-old male chicks were randomly distributed in litter-covered (wood shavings) floor pens with 56 birds per pen (14 birds/m2). Each pen contained 1 trough waterer and 1 trough feeder. The chicks had free access to feed and water. Birds were housed in an environmentally controlled room that had a temperature setpoint of 32°C. The temperature of the room was reduced by 3°C each week until 21 d of age. Lighting management followed the one previously proposed [25].

The experimental design consisted of 5 treatments with 7 replicate pens per treatment. A basal diet was provided from placement to slaughter, subdivided in 1 to 7, 8 to 14, 15 to 21, 22 to 28, 29 to 37, and 38 to 42 d of age (Table 1Go). The corn-soybean meal basal diets were formulated to either meet or exceed the NRC [26]. Zinc, 60 ppm, was supplemented as ZnSO4. The basal diet received the addition of 0.2 ppm organic Se (Sel-Plex [27]) in combination with 0.1 ppm inorganic Se. This level of organic Se was added to the diets, because a previous study [22] indicated that a combination of inorganic Se (0.1 ppm) with organic Se (0.2 ppm) maximized growth performance of broilers. Dietary treatments consisted of increasing levels of organic Zn (0, 15, 30, 45, and 60 ppm as Bioplex Zn [28]) on top of the standard commercial premix containing ZnSO4.


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  		Table 1. Composition of basal diets
 
Histopathologic Analysis
At 35 and 42 d of age, 9 birds per treatment were slaughtered, and approximately 1 cm2 of skin (9 samples per treatment) from the back next to the thigh of each bird was collected. The samples were embedded in paraffin, sectioned, mounted, and stained with hematoxylin and eosin.

Skin Resistance Test
At 35 and 42 d of age, 21 birds/treatment were slaughtered, and an incision approximately 1 cm in length was made in the region between the thigh and the back and measured with a pachimeter [29]. After defeathering, the incision was again measured. The difference in incision length before and after defeathering was recorded as skin tearing.

Statistical Analysis of Data
Statistical analyses were conducted using the GLM [30]. Broiler performance, carcass trait data, skin epithelial layers, and skin tearing effects were subjected to polynomial regression analysis. Histopathologic data of incidence of inflammation and collagen content were analyzed using a linear association test and the Cochran-Mantel-Haenszel significance test (P ≤ 0.05).


   RESULTS AND DISCUSSION
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
Performance
Body weight gain, feed consumption, feed conversion and mortality (Table 2Go), and carcass yield (Table 3Go) were not influenced by addition of increasing levels of dietary organic Zn. Earlier studies with inorganic Zn [31, 32] and with organic Zn [17] have indicated that growth performance, leg abnormalities, and meat yields were unaffected when dietary Zn concentrations were provided in excess of the NRC [26] recommendations of 40 mg/kg of supplemented Zn. However, many investigators have added Zn in inorganic form [9, 10] or in organic form [11, 12, 13, 33, 34] to diets of broilers and observed an improvement in growth performance. The lack of consistent effects of dietary Zn on performance of birds may be due to the amount of Zn present in the basal diet [3] or to the amount and sources added. Furthermore, the presence of other dietary ligands, such as phytate, which forms insoluble complexes with Zn and prevents its absorption, and high dietary Ca, which increases binding of Zn by phytate [35], interferes adversely in Zn absorption.


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  		Table 2. Weight gain, feed conversion, and mortality of broilers fed increasing levels of organic Zn at 42 d of age
 

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  		Table 3. Carcass and cut-up yield of broilers fed increasing levels of organic Zn at 42 d of age
 
Skin Traits
An improvement in skin quality was observed in birds fed higher levels of organic Zn either at 35 or at 42 d of age. Even when a statistical significance was not observed, a clear tendency on the improvement of skin traits was observed due to adding organic Zn to the diets. The skin is particularly rich in Zn [4], where it plays a role in skin nucleic acid and collagen synthesis [18]. Actually, Zn regulates genetic expression once it is involved in the transcription and translation of the genetic material, perhaps accounting for its essentiality to all forms of life, as examined by many investigators [4].

An increase in the number of epithelial cell layers (Figures 1Go, 2Go, 3Go, and 4Go) was observed with increasing levels of organic Zn in the diet. The cells forming the epithelium are in close apposition. The more multiple layers covering the exterior surface of the body, the higher the protection [36]. In addition, multiple epithelial cell layers also indicate a stronger barrier against invasion by pathogens [6].


Figure 1
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  		Figure 1. Epithelial cell layers of broilers fed organic Zn + inorganic Zn (A) or only inorganic Zn (B).

 

Figure 2
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  		Figure 2. Epithelial cell layers of broilers fed increased levels of organic Zn from 1 to 35 d of age.

 

Figure 3
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  		Figure 3. Epithelial cell layers of broilers fed increased levels of organic Zn from 1 to 42 d of age.

 

Figure 4
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  		Figure 4. Epithelial cell layers of broilers (35 + 42 d of age) fed increased levels of organic Zn from 1 to 42 d of age.

 
An increase in collagen content of skin was found in broilers fed higher levels of organic Zn (Figures 5Go, 6Go, and 7Go). Collagen is the major fibrous element of skin. The higher collagen content in birds fed higher levels of organic Zn serve to hold the cells more tightly together in discrete units [37]. Furthermore, collagen gives flexibility and resilience to the skin.


Figure 5
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  		Figure 5. Collagen content, epithelial cell layers, and keratin of broilers fed organic Zn + inorganic Zn (A) or only inorganic Zn (B).

 

Figure 6
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  		Figure 6. Skin collagen content of broilers fed increasing levels of organic Zn from 1 to 35 d of age.

 

Figure 7
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  		Figure 7. Skin collagen content of broilers fed increasing levels of organic Zn from 1 to 42 d of age.

 
The reduction in skin inflammation with increasing dietary organic Zn indicates an improvement in immune response of the birds. This effect was very clear at 35 d of age (Figure 8Go) but not at 42 d of age (Figure 9Go). The ability of the immune system to be a highly proliferating cell system strictly depends on the availability of Zn in several species [38]. Providing diets containing organic Zn brought about a reduction in Escherichia coli plasma level in turkeys [39] and a decreased incidence of cellulitis in broilers [40, 19]. However, using Zn from an inorganic source, some investigators [9] have not shown an improvement in immune function of chicken.


Figure 8
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  		Figure 8. Skin inflammation of broilers fed increasing levels of organic Zn from 1 to 35 d of age.

 

Figure 9
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  		Figure 9. Skin inflammation of broilers fed increasing levels of organic Zn from 1 to 42 d of age.

 
Because of the higher number of epithelial cell layers, higher collagen content, and reduced inflammation of the skin, a reduction in skin tearing was observed (Figures 10Go and 11Go). This response is important considering that about 5 to 7% of downgrades at processing are due to skin tears [2, 3].


Figure 10
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  		Figure 10. Skin tearing of broilers fed increasing levels of organic Zn from 1 to 35 d of age.

 

Figure 11
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  		Figure 11. Skin tearing of broilers fed increasing levels of organic Zn from 1 to 42 d of age.

 

   CONCLUSIONS AND APPLICATIONS
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
REFERENCES AND NOTES
 
  1. Organic Zn (Bioplex Zn) had no effect on growth performance of broilers.
  2. Organic Zn minimized skin tearing, thereby improving carcass appearance.
  3. A minimum of 45 ppm Zn added as Bioplex Zn was required to improve skin.


   REFERENCES AND NOTES
TOP
 SUMMARY
 DESCRIPTION OF PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 

  1. Fallavena, L. C. B. 2001. Lesões cutâneas em frangos de corte: Causas, diagnóstico e controle. Pages 205–216 in Proc. Conf. APINCO 2001 Ciênc. Tecnol. Avícolas. FACTA, Campinas, São Paulo, Brazil.
  2. Mendes, A. A. 2001. Rendimento e qualidade de carcaça em frangos de corte. Pages 79–99 in Conf. APINCO 2001 Ciênc. Tecnol. Avícolas. FACTA, Campinas, São Paulo, Brazil.
  3. Leeson, S., and J. D. Summers. 2005. Commercial Poultry Nutrition. Univ. Books, Guelph, Ontario, Canada.
  4. McDowell, L. R. 2003. Zinc. Pages 357–396 in Minerals in Animal and Human Nutrition. Elsevier Science, Amsterdam, the Netherlands.
  5. Costa, M. A. G. Maio/Junho 2005. O papel do zinco e do cromo no desempenho das porcas. Porkworld (ano 4, no. 26):58.
  6. Jonhson, R. W., J. Escobar, and D. M. Webel. 2001. Nutrition and immunology of swine. Pages 545–562 in Swine Nutrition. A. J. Lewis and L. L. Southern, ed. CRC Press., Boca Raton, FL.
  7. Widmaier, E. P., H. Raff, and K. T. Strang. 2004. Defense mechanisms of the body. Pages 695–738 in Vander, Sherman, and Luciano’s Human Physiology: The Mechanisms of Body Function. E. P. Widmaier, H. Raff, and K. T. Strang, ed. McGraw-Hill, Boston, MA.
  8. Powell, J., A. T. Borchers, S. Yoshida, and M. E. Gershwin. 2000. Evaluation of immune system in the nutritionally at-risk host. Pages 21–34 in Nutrition and Immunology: Principles and Practice. E. Gershwin, J. B. German, and C. L. Keen, ed. Humana Press, Totowa, NJ.
  9. Pimentel, J. L., M. E. Cook, and J. L. Greger. 1991. Immune response of chicks fed various levels of zinc. Poult. Sci. 70:947–954.[ISI][Medline]
  10. Edwards, H. M., and D. H. Baker. 2000. Zinc bioavailability in soybean meal. J. Anim. Sci. 78:1017–1021.[Abstract/Free Full Text]
  11. Johnson, A. B., and T. M. Fakler. 1998. Trace minerals in swine and poultry nutrition. Pages 1–24 in Technical Bulletin. Zinpro Corp., Eden Prairie, MN.
  12. Sandoval, M., P. R. Henry, R. C. Littell, R. D. Miles, G. D. Butcher, and C. B. Ammerman. 1999. Effect of dietary zinc source and method of oral administration on performance and tissue trace mineral concentration of broiler chicks. J. Anim. Sci. 77:1788–1799.[Abstract/Free Full Text]
  13. Yu, Z. P., G. W. Le, and Y. H. Shi. 2005. Effect of zinc sulphate and zinc methionine on growth, plasma growth hormone concentration, growth hormone receptor and insulin-like growth factor-I gene expression in mice. Clin. Exp. Pharmacol. Physiol. 32:273–278.[ISI][Medline]
  14. Wang, X., G. J. Fosmire, C. V. Gay, and R. M. Leach. 2002. Short-term zinc deficiency inhibits chondrocyte proliferation and induces cell apoptosis in the epiphyseal growth plate of young chickens. J. Nutr. 132:665–673.[Abstract/Free Full Text]
  15. Kidd, M. T., N. B. Anthony, and S. R. Lee. 1992. Progeny performance when dams and chicks are fed supplemental zinc. Poult. Sci. 71:1201–1206.[ISI][Medline]
  16. Kidd, M. T., N. B. Anthony, L. A. Newberry, and S. R. Lee. 1993. Effect of supplemental zinc in either a corn-soybean or a milo and corn-soybean meal diet on the performance of young broiler breeders and their progeny. Poult. Sci. 72:1492–1499.[ISI]
  17. Hudson, B. P., B. D. Fairchild, and J. L. Wilson. 2004. Breeder age and zinc source in broiler breeder hen diets on progeny characteristics at hatching. J. Appl. Poult. Res. 13:55–64.[Abstract/Free Full Text]
  18. Close, W. H. 1999. Organic minerals for pigs: An update. Pages 51–60 in Biotechnology in the Feed Industry. Proc. Alltech’s 15th Ann. Symp. T. P. Lyons and K. A. Jacques, ed. Nottingham Univ. Press, UK.
  19. Downs, K. M., J. B. Hess, K. W. Macklin, and R. A. Norton. 2000. Dietary zinc complexes and vitamin E for reducing cellulitis incidence in broilers. J. Appl. Poult. Res. 9:319–323.[Abstract/Free Full Text]
  20. Arruda, J. S., F. Rutz, and E. A. Pan. 2004. Influence of replacing dietary inorganic with organic selenium (Sel-Plex) on performance of broilers. Page 13 in Nutritional Biotechnology in the Feed and Food Industries. Proc. Alltech’s 20th Annu. Symp. Suppl. 1. T. P. Lyons and K. A. Jacques, ed. Nottingham Univ. Press, UK.
  21. Edens, F. W. 2001. Involvement of Sel-Plex in physiological stability and performance of broiler chickens. Pages 349–376 in Biotechnology in the Feed Industry. Proc. Alltech’s 17th Annu. Symp. T. P. Lyons and K. A. Jacques, ed. Nottingham Univ. Press, UK.
  22. Anciutti, M. A., F. Rutz, L. A. Silva, R. C. Conseza, and R. G. Silva. 2004. Effect of replacement of dietary inorganic by organic selenium (Sel-Plex) on performance of broilers. Page 14 in Nutritional Biotechnology in the Feed and Food Industries. Proc. Alltech’s 20th Annu. Symp. Suppl. 1. T. P. Lyons and K. A. Jacques, ed. Nottingham Univ. Press, UK.
  23. Choct, M., A. J. Naylor, and N. Reinke. 2004. Selenium supplementation affects broiler growth performance, meat yield and feather coverage. Br. Poult. Sci. 45:677–683.[ISI][Medline]
  24. Ross chicks, Aviagen, Huntsville, AL.
  25. Classen, H. 1996. Principios sobre el manejo de luz en pollos de engorde. Rev. Avicultura Prof. 14:22–27.
  26. NRC. 1994. Nutrient Requirements of Poultry. Natl. Acad. Press, Washington, DC.
  27. Sel-Plex, Alltech Inc., Nicholasville, KY.
  28. Bioplex, Alltech Inc.
  29. Electronic digital caliper. Starret Industria e. Comércio Ltda, Itu, São Paulo, Brazil.
  30. SAS Institute. 1996. SAS User’s Guide. SAS Inst. Inc., Cary, NC.
  31. Mehring, A. L., J. H. Brumbaugh Jr., and H. W. Titus. 1956. A comparison of the growth of chicks fed diets containing different quantities of zinc. Poult. Sci. 35:956–958.[ISI]
  32. Wang, X., G. J. Fosmire, C. V. Gay, and R. M. Leach Jr. 2002. Short-term zinc deficiency inhibits chondrocyte proliferation and induces cell apoptosis in the epiphyseal growth plate of young chickens. Biochemical and molecular action of nutrients. J. Nutr. 132:665–673.[Abstract/Free Full Text]
  33. Hudson, B. P., W. A. Dozier III, J. L. Wilson, J. E. Sander, and T. L. Ward. 2004. Effect of dietary zinc source on reproductive performance and immune status of broiler. J. Appl. Poult. Res. 13:349–359.[Abstract/Free Full Text]
  34. Burrell, A. L., W. A. Dozier, A. J. Davis, M. M. Compton, M. E. Freeman, P. F. Vendrell, and T. L. Ward. 2004. Responses of broilers to dietary zinc concentrations and sources in relation to environmental implications. Br. Poult. Sci. 45:225–263.
  35. Oberleas, D., M. E. Muhrer, and B. L. O’Dell. 1966. Dietary metal complexing agents and zinc bioavailability in the rat. J. Nutr. 90:56–62.[Abstract/Free Full Text]
  36. Ross, M. H., E. J. Reith, and L. J. Romrell. 1989. Epithelium. Pages 51–82 in Histology: A Text and Atlas. Williams & Wilkins, Baltimore, MD.
  37. Stryer, L. 1988. Protein conformation, dynamics, and function. Pages 143–314 in Biochemistry. W. H. Freeman and Co., New York, NY.
  38. Dardenne, M., and J. M. Bach. 1993. Rationale for mechanism of zinc interation in the immune system. Pages 501–509 in Nutrient Modulation of the Immune Response. S. Cunningham-Rundles, ed. Marcel Dekker Inc., New York, NY.
  39. Kidd, M. T., M. A. Qureshi, P. R. Ferket, and L. N. Thomas. 1994. Blood clearance of Escherichia coli and evaluation of mononuclear-phagocytic system as influenced by supplemental dietary zinc-methionine in young turkeys. Poult. Sci. 73:1381–1389.[ISI][Medline]
  40. Hess, J. B., R. A. Norton, K. M. Downs, K. S. Macklin, and S. F. Bilgili. 2000. Pages 1–6 in Trace minerals complexes found to reduce avian cellulitis levels in broiler studies. Trace mineral focus. Zinpro Corp., Eden Prairie, MN.




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