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Department of Animal Nutrition, Faculty of Veterinary Science, Firat University, Elazig Turkey and * Prevention Program, Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201
1To whom correspondence should be addressed. E-mail: nsahinkm{at}yahoo.com.
| ABSTRACT |
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0.05) occurred in zinc-supplemented groups reared under HS conditions. Heat exposure decreased digestibility of nutrients (P = 0.001), and these decreases were ameliorated by zinc supplementation (P
0.05). Serum vitamin C (P = 0.05), vitamin E (P = 0.01) and zinc (P = 0.001) concentrations increased linearly, whereas malondialdehyde concentrations decreased (P = 0.002) as dietary zinc supplementation increased. No significant differences in any values were observed in the TN groups (P > 0.05). Results of the present study suggest that supplementation with 60 mg zinc/kg diet protects quail by reducing the negative effects of heat stress.
KEY WORDS: zinc egg antioxidant status heat stress quail
High ambient temperature results in reduced feed intake, egg production and egg quality, and impaired antioxidant status in poultry (14). Environmental stress has been shown to increase mineral excretion (5,6) and elevate lipid peroxidation products in serum and liver, while decreasing serum and tissue levels of antioxidant vitamins (79). Antioxidants such as vitamin C, vitamin E and vitamin A, and the minerals, zinc and chromium, have been used to ameliorate the effects of environmental stress (913). Supplemental zinc is used in poultry diets because of its reported benefits to laying hens during periods of environmental stress (12,14). Serum, liver and spleen levels of zinc are reduced in stressed birds (9). Zinc has multiple important functions because it is a cofactor for >200 enzymes. One of its most important functions is its participation in the antioxidant defense system. Oxidative damage of the cell membrane by free radicals occurs during zinc deficiency (1519), thus altering the status of antioxidant enzymes and substances (2022). The mechanism by which Zn exerts its antioxidant action is not well defined. However, it has been suggested that it increases the synthesis of metallothionein, a cysteine-rich protein, which acts as a free radical scavenger (21,23). Another mode of action proposed for Zn as an antioxidant is its interaction with vitamin E, because vitamin E status is impaired in zinc-deficient animals (15,24). Furthermore, zinc can occupy iron and copper binding sites on lipids, proteins and DNA and thus exert a direct antioxidant action (19,2125). Iron is a redox active metal that can catalyze the formation of the highly reactive hydroxyl radicals from H2O2 and decompose lipid peroxides to peroxyl and alkoxyl radicals, which favor the propagation of lipid oxidation (19,20). Anderson et al. (26) reported that rats supplemented with dietary chromium and zinc had a significant reduction in malondialdehyde (MDA)1 levels in serum and tissues.
Dietary modifications are among the most preferred and practical ways to alleviate the effect of high environmental temperature on poultry performance; such methods have been used previously. The objective of this study was to evaluate the effects of zinc supplementation on egg production, digestion of nutrients, and antioxidant status in laying Japanese quail reared under heat stress (34°C).
| MATERIALS AND METHODS |
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Japanese quail (n = 180; 52-d-old) (Coturnix coturnix japanica) obtained from a commercial company (Uluova Quail Farm, Elazig, Turkey) were used in the study. The birds were fed a basal diet containing 16.8% crude protein (CP) and 11.82 MJ/kg metabolizable energy (ME) or the basal diet supplemented with 30 or 60 mg zinc/kg diet. The basal diet was formulated using NRC guidelines (27). ZnSO4 · H2O was used as the zinc source. Ingredients and chemical composition of the basal diet are shown in Table 1. Small portions of the basal diet were first mixed with the respective amounts of zinc; this small amount was then mixed with a larger amount of the basal diet until the total diet amounts were homogeneous.
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Performance variables and egg quality.
Body weights were recorded at the beginning and at the end of the study. Feed consumption was measured weekly. The number of eggs and egg weights were recorded daily. Egg quality measurements were conducted using all eggs of 1 d from all treatments. Parameters for egg quality measurement included egg shell thickness and Haugh unit (HU). The HU values were calculated using the HU formula (28) based on the height of albumen determined by a micrometer and egg weight (Saginomiya, TLM-N1010, Tokyo, Japan). Shell thickness was determined from measurements of the mean thickness at three locations on the egg (air cell, equator and sharp end) using a dial pipe gauge (Mitutoyo, 0.0120 mm, Tokyo, Japan).
Sample collection and laboratory analyses.
During the last week of the experiment, 60 birds (10 birds from each group; one per replicate) were placed in individual battery cages for collection of excrement to measure the nutrient digestibilities of dry matter (DM), organic matter (OM), CP and ether extract (EE). The composite excrement samples were oven-dried at 60°C for 48 h and then ground and subsampled (1 g) for chemical analysis. Digestibility of nutrients was measured using Cr2O3 as described by Petry and Rapp (29). Chemical analyses of the diets and excrement samples were conducted using international procedures of AOAC (30). To estimate protein digestibility, excrement N was chemically analyzed according to the method of Terpstra and De Hart (31). At the end of the experiment, serum samples from 10 birds (one per replicate) randomly chosen from each group were collected. Lipid peroxidation, assessed as TBARS in serum and liver, and serum vitamins E and C were determined as described (9). Serum concentrations of Zn were measured at specific wavelengths using an atomic absorption spectrometer (Shimadzu AA-660, Kyoto, Japan). Calibrations for the zinc assay were made with a series of mixtures containing graded concentrations of standard solutions. For Zn content analysis, triplicate basal diet samples were wet-digested as described by Chang et al. (32) and were read using an atomic absorption spectrometer.
Statistical analyses.
The data were initially analyzed by two-way ANOVA using the General Linear Models procedure of SAS (33) for the factors of temperature and effects of zinc. Duncans post-hoc test was used to identify means that differed at P < 0.05. Linear and quadratic orthogonal contrasts were used to evaluate the effects of different levels of zinc.
| RESULTS |
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0.05) was detected. None of the variables differed among the three TN groups.
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| DISCUSSION |
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Results concerning the apparent digestibility of nutrients in the present study also support the benefits of supplementation by dietary zinc (Table 3). High ambient temperatures were reported to suppress nutrient digestibility in poultry (4). Wallis and Balnave (39) found that the digestibility of amino acids was decreased by high environmental temperature in broilers. Hai et al. (40) reported that the activities of trypsin, chymotrypsin and amylase decreased significantly at a high temperature of 32°C. In the present study, supplementation of dietary zinc increased digestibility of nutrients, reversing the negative effects of the stress in Japanese quail. Because zinc has a protective effect on pancreatic tissue against oxidative damage (14,41), it may help the pancreas to function properly, including secretion of digestive enzymes, thus improving digestibility of nutrients. Onderci et al. (14) reported that supplemental chromium and zinc ameliorated the decrease in digestibility of DM, CP and EE in laying hens reared under a low temperature.
Environmental stress causes increased free radical production (7) and lowers the concentrations of antioxidants such as vitamins E, C and A and minerals such as Zn and Cr in serum (9,34,42). Shaheen et al. (43) reported that dietary zinc deficiency caused increased lipid peroxidation, and this was inhibited by zinc supplementation. In the present study, significantly higher serum concentrations of vitamins C and E and Zn occurred in birds receiving zinc supplementation. Zinc supplementation decreased serum and liver MDA levels in stressed birds. Similar to our results, Onderci et al. (14) reported that Zn and chromium supplementation decreased serum MDA concentrations and increased the concentrations of vitamins C, E and A in cold-stressed laying hens.
The mode of action of zinc in antioxidant defense system in vivo is yet to be elucidated (20,44). The reduced lipid peroxidation in Zn-supplemented birds might be due to the multifunctional roles of zinc, which include the induction of metallothionein, modulation of the transition elements and its relationship with the antioxidant vitamins such as vitamin A and E (15). Zinc is a cofactor of the main antioxidative enzyme CuZn-superoxide dismutase; it may play a key role in suppressing free radicals and in inhibiting NADPH-dependent lipid peroxidation (16,45) as well as in preventing lipid peroxidation via inhibition of glutathione depletion (46). One of the proposed mechanisms of zincs action is its capacity to displace transition metals (Fe, Cu) from binding sites. Zinc can compete with iron and copper to bind to the cell membrane and decrease the production of free radicals, thus exerting a direct antioxidant action (16,25,47). Zinc induces the production of metallothionein, an effective scavenger of hydroxyl radicals and it has been suggested that Zn-metallothionein complexes in the islet cells provide protection against immune-mediated free-radical attack (16,43).
It is apparent from the results of the present study that dietary zinc supplementation offers a feasible way to reduce the losses in performance of Japanese quail reared under conditions of heat stress; supplementation with 60 mg zinc/kg diet appeared to be the most efficacious dose.
| ACKNOWLEDGMENTS |
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| FOOTNOTES |
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Manuscript received 6 May 2003. Revision accepted 27 June 2003.
| LITERATURE CITED |
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1. Smith, A. J. & Oliver, O. (1972) Some nutritional problems associated with egg production at high environmental temperatures. I. The effect of environmental temperature and rationing treatments in the productivity of pullets fed on diets of differing energy content. Rhod. J. Agric. Res. 10:3-20.
2. Wolfenson, D., Feri, Y. F., Snapir, N. & Berman, A. (1979) Effect of diurnal or nocturnal heat stress on egg formation. Br. Poult. Sci. 20:167-174.[Medline]
3. Donkoh, A. (1989) Ambient temperature: a factor affecting performance and physiological response of broiler chickens. Int. J. Biometeorol. 33:259-265.[Medline]
4. Ensminger, M. E., Oldfield, J. E. & Heinemann, W. W. (1990) Feeds and Nutrition 1990:8-110 The Ensminger Publishing Company Clovis, CA.
5. El Husseiny, O. & Creger, C. R. (1981) Effect of ambient temperature on mineral retention and balance of the broiler chicks. Poult. Sci. 60(suppl. 1):1651 (abs.).
6. Smith, M. O. & Teeter, R. G. (1987) Potassium balance of the 5 to 8-week old broiler exposed to constant heat or cycling high temperature stress and the effects of supplemental potassium chloride on body weight gain and feed efficiency. Poult. Sci. 66:487-492.[Medline]
7. Halliwell, B. E. & Gutteridge, J.M.C. (1989) Lipid peroxidation: a radical chain reaction. Free Radicals in Biology and Medicine 2nd ed. 1989:188-218 Oxford University Press New York, NY.
8. Klasing, K. C. (1998) Comparative Avian Nutrition 1998 University Press Cambridge, UK.
9. Sahin, K., Kucuk, O., Sahin, N. & Sari, M. (2002) Effects of vitamin C and vitamin E on lipid peroxidation status, some serum hormone, metabolite, and mineral concentrations of Japanese quails reared under heat stress (34°C). Int. J. Vitam. Nutr. Res. 72:91-100.[Medline]
10. National Research Council (1997) The Role of Chromium in Animal Nutrition 1997 National Academy Press Washington, DC.
11. Bollengier-Lee, S., Mitchell, M. A., Utomo, D. B., Williams, P.E.V. & Whitehead, C. C. (1998) Influence of high dietary vitamin E supplementation on egg production and plasma characteristics in hens subjected to heat stress. Br. Poult. Sci. 39:106-112.[Medline]
12. Sahin, N., Onderci, M. & Sahin, K. (2002) Effects of dietary chromium and zinc on egg production, egg quality and some blood metabolites of laying hens reared under low ambient temperature. Biol. Trace Elem. Res. 85:47-58.[Medline]
13. Lin, H., Wang, L F., Song, J L., Xie, Y M. & Yang, Q M. (2002) Effect of dietary supplemental levels of vitamin A on egg production and immune responses of heat-stressed laying hens. Poult. Sci. 81:458-465.
14. Onderci, M., Sahin, N., Sahin, K. & Kilic, N. (2003) The antioxidant properties of chromium and zinc: in vivo effects on digestibility, lipid peroxidation, antioxidant vitamins and some minerals under a low ambient temperature. Biol. Trace Elem. Res. 92:139-150.[Medline]
15. Salgueri, M. J., Zubillaga, M., Lysionek, A., Sarabia, M. I., Caro, R., De Paoli, T., Hager, A., Weill, R. & Boccio, J. (2000) Zinc as essential micronutrient: a review. Nutr. Res. 20:737-755.
16. Burke, J. P. & Fenton, M. R. (1985) Effect of a Zn-deficient diet on lipid peroxidation in liver and tumor cellular membranes. Proc. Soc. Exp. Biol. Med. 179:187-191.[Abstract]
17. Olin, K. L., Shigenaga, M. K., Ames, B. N., Golub, M. S., Gershwin, M. E., Hendrickx, A. G. & Keen, C. L. (1993) Maternal dietary Zn influences DNA strand break and 8-hydroxy-2'deoxyguanosine levels in infant rhesus monkey liver. Proc. Soc. Exp. Biol. Med. 203:461-466.[Abstract]
18. Oteiza, P. I., Olin, K. L., Fraga, C. G. & Keen, C. L. (1995) Zn deficiency causes oxidative damage to proteins, lipids and DNA in rat testes. J. Nutr. 125:823-829.
19. Prasad, A. S. & Kucuk, O. (2002) Zinc in cancer prevention. Cancer Metastasis Rev 21:291-295.[Medline]
20. Zago, M. & Oteiza, P. I. (2001) The antioxidant properties of zinc: interactions with iron and antioxidants. Free Radic. Biol. and Med. 31:266-274.
21. Oteiza, P. I., Olin, K. L., Fraga, C. G. & Keen, C. L. (1996) Oxidant defense systems in testes from Zn deficient rats. Proc. Soc. Exp. Biol. Med. 213:85-91.[Abstract]
22. Powell, S. R. (2000) The antioxidant properties of zinc. J. Nutr. 130:1447S-1454S.
23. Webb, M. & Cain, K. (1982) Functions of metallothionein. Biochem. Pharmacol. 31:137-142.[Medline]
24. Kim, E. S., Noh, S. K. & Koo, S. I. (1998) Marginal zinc deficiency lowers the lymphatic absorption of
-tocopherol in rats. J. Nutr. 128:265-270.
25. Tate, D. J., Miceli, M. V. & Newsome, D. A. (1999) Zn protects against oxidative damage in cultured human retinal pigment epithelial cells. Free Radic. Biol. Med. 26:704-713.[Medline]
26. Anderson, R. A., Roussel, A. M., Zouari, N., Mahjoub, S., J Matheau, J. M. & Abdelhamid Kerkeni, A. (2001) Potential antioxidant effects of zinc and chromium supplementation in people with type 2 diabetes mellitus. J. Am. Coll. Nutr. 20:212-218.
27. National Research Council (1994) Nutrient Requirements of Poultry 9th rev. ed. 1994 National Academy Press Washington, DC.
28. Eisen, E. J., Bohren, B. B. & McKean, H. E. (1962) The Haugh unit as a measure of egg albumen quality. Poult. Sci. 41:1461-1468.
29. Petry, H. & Rapp, W. (1971) Zur Problematik der Chromoxidebestimmung in Verdauungsversuchen. Z. Tierphysiol. Tierernaehr. 27:181-189.
30. Association of Agricultural Chemists (1990) Official Methods of Analysis 1990 AOAC Arlington, VA.
31. Terpstra, K. & De Hart, N. (1974) The estimation of urinary nitrogen and fecal nitrogen in poultry excreta. Z. Tierphysiol. Tierernaehr. Futtemittlkd. 32:306-312.[Medline]
32. Chang, X, Mowat, D. N. & Spiers, G. A. (1992) Carcass characteristics and tissue-mineral contents of steers fed supplemental chromium, Can. J. Anim. Sci. 72:663-668.
33. SAS Institute Inc. (1996) SAS Users Guide, Version 6.12 1996 SAS Institute Cary, NC.
34. Beisel, W. R. (1982) Single nutrients and immunity. Am. J. Clin. Nutr. 35:442-451.
35. Brandae-Neto, J., Stefan, V., Mendonca, B. B., Bloise, W. & Castro, A. W. B. (1995) The essential role of zinc in growth. Nutr. Res. 15:335-358.
36. Kourtou, S., Patiroglu, T. E & Karakas, S. E. (1995) Effect of growth hormone on epiphysial growth plates in zinc deficiency. Tokai J. Exp. Clin. Med. 12:325-329.
37. Nishi, Y. (1996) Zinc and growth. J. Am. Coll. Nutr. 15:340-344.[Abstract]
38. Moreng, R. E., Balnave, D. & Zhang, D. (1992) Dietary zinc methionine effect on eggshell quality of hens drinking saline water. Poult. Sci. 71:1163-1167.[Medline]
39. Wallis, I. R. & Balnave, D. (1984) The influence of environmental temperature, age and sex on the digestibility of amino acids in growing broiler chickens. Br. Poult. Sci. 25:401-407.[Medline]
40. Hai, L., Rong, D. & Zhang, Z. Y. (2000) The effect of thermal environment on the digestion of broilers. J. Anim. Physiol Anim. Nutr. 83:57-64.
41. Pond, W. G., Church, D. C. & Pond, K. R. (1995) Zinc. Basic Animal Nutrition and Feeding 4th ed. 1995:190-193 John Wiley and Sons New York, NY.
42. Feenster, R. (1985) High temperatures decrease vitamin utilization. Misset Poult 38:38-41.
43. Shaheen, A. A. & Abd El-Fattah, A. A. (1995) Effect of dietary zinc on lipid peroxidation, glutathione, protein thiols levels and superoxide dismutase activity in rat tissues. Int. J. Biochem. Cell Biol. 27:89-95.[Medline]
44. Bettger, W. J. & ODell, B. L. (1993) Physiological roles of zinc in the plasma membrane of mammalian cells. J. Nutr. Biochem. 4:194-207.
45. Prasad, A. S. (1997) The role of zinc in brain and nerve functions. Connor, A. eds. Metals and Oxidative Damage in Neurological Disorders 1997:95-111 Plenum Press New York, NY. .
46. Gibbs, P.N.B., Gore, M. G. & Jordan, P. M. (1985) Investigation of the effect of metal ions on the reactivity of thiol groups in human 5-aminolaevulinate dehydratase. Biochem. J. 225:573-580.[Medline]
47. Girotti, A. W., Thomas, J. P. & Jordan, J. E. (1985) Inhibitory effect of Zn (II) on free radical lipid peroxidation in erythrocyte membranes. Free Radic. Biol. Med. 1:395-401.
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