Effect of selenium sources on performance and meat characteristics of broiler chickens

©2009 Poultry Science Association, Inc.

Effect of selenium sources on performance and meat characteristics of broiler chickens L. Perić,*1 N. Milošević,* D. Žikić,* Z. Kanački,* N. Džinić,† L. Nollet,‡ and P. Spring§

Primary Audience: Nutritionists, Meat Scientists, Researchers, Poultry Producers SUMMARY Selenium is an important mineral, required for many functions within animals, where it interacts with vitamin E, maximizing the efficiency of the vitamin as an antioxidant. In chickens, adequate intake of organic forms of Se may be linked to reduced drip loss in the final meat and to improved feather production. The present trial was conducted to examine the impact of feeding organic Se (Sel-Plex, Alltech Inc., Nicholasville, KY) to broilers on their productive performance, feather growth, and meat characteristics. Birds fed 0.3 ppm of organic Se had decreased drip loss from breast meat and lower levels of apparent liver damage (indicated by lower plasma concentrations of indicator enzymes). Feathering was improved at 21 d by feeding organic Se. Key words: broiler, drip loss, feathering, antioxidant, inorganic, organic, selenium 2009 J. Appl. Poult. Res. 18:403–409 doi:10.3382/japr.2008-00017

DESCRIPTION OF PROBLEM Selenium is an important antioxidant mineral in animals [1], and is known to influence the production of feathers and the maintenance of cellular integrity in tissues in avian species. Different forms of Se are available for supplementation in animal and poultry feed: inorganic sodium selenite or selenate, and yeast-derived Se. The latter is incorporated into small peptides and amino acids, such as selenomethionine, selenocysteine, and selenocystine. The organic form from yeast is similar to the Se compounds found in grains and forages. Animals and poultry have naturally adapted to take up this form from 1

Corresponding author: [email protected]

all sections of the gastrointestinal tract by using the amino acid transport mechanism. Organic Se accumulates in tissues such as the liver, brain, and muscle [1]. Absorption and transport of Se is closely linked to the chicken’s intake of the antioxidant vitamins A, C, and E. Surai [2] also noted that because Se forms an integral component of most feedstuffs, birds have evolved to metabolize and exploit the antioxidant properties of organic forms of Se. Indeed, inorganic Se is considered prooxidant and actively contributes to oxidative damage, which is implicit in its toxicity at low intake levels. The levels of Se in soils globally are decreasing because of the intensity of agricultural cropping. Animal and

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*University of Novi Sad, Faculty of Agriculture, Department of Animal Science, 21000 Novi Sad, Serbia; †University of Novi Sad, Faculty of Technology, 21000 Novi Sad, Serbia; ‡Alltech Biotechnology Centre, Dunboyne, Ireland; and §Swiss College of Agriculture, CH-3052 Zollikofen, Switzerland

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of Se supplementation, particularly from the use of organic forms. Feathering is influenced by the levels of methionine and cysteine in the diet. These amino acids can be expressed in their Se form (selenomethionine and selenocysteine), rather than their more usual sulfur configuration, when organic Se is provided in feed. The Se forms are used for keratin synthesis required for feathering, and may have a sparing effect on the cysteine reserves in liver and muscle. Because organic Se is stored in tissues, when broilers are growing quickly and require amino acids for feathers, such sparing effects may improve muscle deposition [18]. Selenium is a component of type 1 deiodinase that converts T4 thyroid hormone to its active form T3, which is also important for correct feathering [18]. The aim of this work was to investigate the influence of different sources and levels of dietary Se on broiler performance, feathering, and quality characteristics of breast meat.

MATERIALS AND METHODS A total of 2,400 one-day-old chicks (Cobb 500 strain) [20] were assigned to 4 treatments with 8 replicates, giving 75 as-hatched birds per pen. Each floor pen measured 5 m2, to give a stocking density of 15 mixed-sex birds/m2. Continuous 24-h lighting was provided, and birds were vaccinated against Newcastle disease and infectious bursal disease according to commercial recommendations. The birds were fed ad libitum in 3 feed phases (Table 1) to give 4 dietary treatments that varied in the relative proportions of inorganic and organic Se supplied. The 4 treatments comprised 0.3 ppm of Se from inorganic sodium selenite; 0.2 ppm of inorganic Se and 0.1 ppm of organic Se from Sel-Plex [21]; 0.1 ppm of inorganic Se and 0.2 ppm of organic Se; and 0.3 ppm of organic Se. The higher levels used in the premix reflected the poorer vitamin and mineral quality of feed ingredients in Serbia and other Eastern European countries. Metabolizable energy and amino acid levels were set according to Cobb 500 commercial guidelines. Body weight and feed intake were monitored by pen at weekly intervals, and mortality was recorded daily. Birds that died were noted, and their BW was used to adjust the FCR accord-

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poultry feed therefore requires supplementation to ensure animal and poultry health, efficient performance, and good meat quality. Furthermore, Se supplementation can be used to increase the levels expressed in meat and eggs, to allow better human intakes of Se in its preferred organic form [3]. Over the past few years, consumer demands regarding meat quality have substantially increased. Consumers regard a loss of water during handling and cooking as an indicator of poor meat quality. Therefore, the water-holding capacity of breast meat is considered to be one of the most important quality characteristics. Problems referred to as drip loss, in which liquid seeps from the tissue, are considered problems in meat quality because drip loss reduces the appearance of packaged meat and the juiciness of the cooked product. In hotter climates, reduced meat weight caused by drip loss can reach 3% [4]. Increased levels of oxidation can damage cell membranes, reducing their integrity and allowing seepage of intracellular fluids. This can result in pale, exudative meat, a problem exacerbated by the prooxidant effects of inorganic sodium selenite [5]. Meat quality is thought to be influenced by antioxidants such as vitamin E and Se-dependent enzymes, including glutathione peroxidase (GSP-Px) [6–12]. Meat producers have previously relied on vitamin E to reduce these problems, but it is now known that efficient utilization of vitamin E in the body is dependent on Se-based antioxidant enzymes, and adequate Se intake is necessary to ensure the best use of this expensive vitamin. Previous trials with pigs and poultry have shown that feeding organic Se can increase levels in muscle tissue [13] and reduce drip loss in broilers [11, 14, 15]. Correct feathering is important for broiler chickens because it helps regulate body temperature and protects the skin and muscle from damage (e.g., blisters caused by direct contact with litter). Poorly feathered birds expend more energy keeping warm, potentially limiting nutrients available for productive performance [16]. In birds, feathers contain the highest amounts of Se compared with any other tissue [17], and can be used as an indicator of Se availability because they are the first tissue to accrete Se, if it is available [18]. Studies [11, 19] have documented improvements in feathering as a result

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Table 1. Composition (%) of the experimental diets Item

Grower (22–35 d)

Finisher (36–42 d)

50 23 22 — — 1.2 0.9 1.8 0.3 0.2 0.1 0.5

55 15 20 2 2 2.5 1 1.6 0.3 0.1 — 0.5

61.5 12.5 15 3 2 2.5 1.1 1.5 0.3 0.1 — 0.5

23.14 12.97 1.38 0.55 0.35 0.32 0.93 0.72 0.45

20.15 13.40 1.08 0.55 0.34 0.27 0.92 0.66 0.40

18.0 13.40 0.90 0.39 0.26 0.24 0.92 0.63 0.35

1

Vitamin-mineral mixture provides the following (per kg of diet): 25,000 IU of vitamin A; 5,000 IU of vitamin D3; 100 mg of vitamin E; 6 mg of vitamin K3; 4 mg of vitamin B1; 10 mg of vitamin B2; 30 mg of vitamin B3; 6 mg of vitamin B6; 60 mg of nicotinamide; 2 mg of folic acid; 0.06 mg of vitamin B12; 0.2 mg of biotin; 1,000 mg of choline chloride; 2 mg of Co, 4 mg of I, 120 mg of Mn, 40 mg of Fe, and 100 mg of Zn. 2 The level of Se was 0.3 ppm in each diet, provided as either sodium selenite, organic Se (Sel-Plex [21]), or their combination.

ingly. The European production efficiency factor was calculated according to the following formula: EPEF =

BW (g) ´ survival rate (%)

feed conversion ´ duration of trial (d)

´ 10.

At 3 and 5 wk of age, the feather score was determined by subjective evaluation of feathering rates on 5 regions on the body: neck, back, wings, breast, and vent region. The feather score was determined according to the method of Gyles et al. [22], which was adapted because of the changes in BW and width of the breast in modern hybrids of broilers. A score was given from 3 independent observers using a 3-point scale: 1 = poor feathering with a large amount of visible skin; 2 = medium feathering; and 3 = good feathering, showing some adult feathers. The evaluators did not know which treatment

they were evaluating. The scores for different body regions were combined to give a total whole-body feathering average. For both sampling times, a total of 80 randomly selected birds per treatment were scored. At the end of the trial (6 wk of age), 24 randomly selected birds per treatment (3 randomly selected birds per pen) were killed by cervical dislocation and weighed before and after feather removal to assess feather weight, which was expressed as a percentage of total BW. Drip loss was recorded from breast meat samples from these same sampled birds, with measurements made at 24 and 48 h postmortem, as described by Rasmussen and Andersson [23]. Breast meat was separated from the bone, and both breasts from each broiler were weighed separately and covered with a plastic bag to collect liquid. All the samples were placed in a refrigerator and stored at 4°C. After 24 h, 1 breast portion from each bird was assessed for drip loss

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Ingredient   Corn   Soybean meal   Full-fat soybeans (extruded)   Sunflower meal   Alfalfa meal   Vegetable oil   Limestone   Dicalcium phosphate   Salt   dl-Methionine   l-Lysine hydrochloride   Vitamin + mineral premix1,2 Nutrient and energy level (calculated)   CP   ME, MJ/kg   Lysine   Methionine   Cystine   Tryptophan   Calcium   Total phosphorus   Available phosphorus

Starter (1–21 d)

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Table 2. Influence of sodium selenite or organic Se (Sel-Plex1) on BW, FCR, mortality, and European production efficiency factor (EPEF) of 42-d-old broiler chickens Diet 1 2 3 4

Inorganic selenite, ppm

Organic Se, ppm

BW, g

FCR

Mortality, %

EPEF

0.3 0.2 0.1 0.0

0.0 0.1 0.2 0.3

2,173 ± 54.7 2,186 ± 42.7 2,162 ± 28.9 2,173 ± 26.6

1.95 ± 0.03 1.90 ± 0.02 1.93 ± 0.04 1.92 ± 0.01

4.48 ± 0.90 4.64 ± 0.83 4.80 ± 1.58 5.77 ± 0.28

253 261 254 254

1

[21].

RESULTS AND DISCUSSION No significant differences were observed among treatments for any performance parameters or mortality measurements made over the entire trial period (Table 2). A numeric, but not significant, difference in FCR (P > 0.05) was observed only for the broilers fed the organic Se diets. The influence of the chemical form of Se on feathering was apparent for all 3 treatments containing organic Se (Table 3). Significant differences (P < 0.05) were observed in feather score at 21 d of age, with an average of 10.6% more feathering (9.2% increase for 0.1 and 0.3 ppm of organic Se and 13.5% increase for 0.2 ppm of organic Se). These effects were not distinct at 35 d of age, perhaps because of compensatory feather production in the intervening time period. The lack of difference in performance between the birds fed inorganic or organic forms of Se, despite an improvement in feathering of the organic Se group, indicated that this form was used more efficiently in the body [19]. In agreement with the findings in our study at 42 d of age, Edens et al. [14] found that improvements in feathering with organic Se supplementation were most evident at 21 d. At 42 d of age, the weight of feathers produced as a proportion

Table 3. Influence of feeding inorganic or organic Se (Sel-Plex1) on feather score and relative feather weight of broiler chickens Feather score, 0 to 3 Diet 1 2 3 4 a,b

Inorganic selenite, ppm 0.3 0.2 0.1 0.0

Organic Se, ppm 0.0 0.1 0.2 0.3

21 d b

1.85 ± 0.05 2.02 ± 0.06a 2.10 ± 0.05a 2.02 ± 0.05a

35 d

Feather weight, % of BW at 42 d

2.19 ± 0.06 2.20 ± 0.03 2.24 ± 0.05 2.17 ± 0.05

5.97 ± 0.45b 6.79 ± 0.30ab 6.99 ± 0.31a 6.80 ± 0.37ab

Means within a column with no common superscript differ significantly (P < 0.05). [21].

1

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by weighing the meat and calculating losses by difference. After 48 h, the second breast sample was used for the same procedure. Data from both breast samples were recorded against the identity of the originating bird. The pH of the breast muscle was measured 24 h postmortem on the cranial part of the breast by using a portable Ultra X type 90 pH meter [24]. Antioxidant status was determined by analysis of the enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which are used as indicators of oxidative damage in vulnerable tissue (e.g., liver). Blood samples were taken by cardiac puncture (3 to 5 mL) from 16 birds per treatment at 21 and 42 d of age. The activities of serum ALT and AST were determined using a Clima MC-15 spectrophotometer [25] and Bioanalytica test kits [26] by kinetic reaction, with absorbance measured at 340 nm. The AST and ALT activities were determined using the spectrophotometric method, as described by Rej and Hoder [27] and Hoder and Rej [28]. Data are presented as means ± SEM. Data were analyzed by ANOVA using GLM, followed by Duncan’s post hoc test to separate means by using StatSoft software [29]. Percentage data were converted to arcsine before analyses. Results were considered significant when P < 0.05.

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Table 4. Influence of feeding inorganic or organic Se (Sel-Plex1) on drip loss from breast meat of 42-d-old broiler chickens

Diet 1 2 3 4

Inorganic selenite, ppm

Organic Se, ppm

Drip loss after 24 h

Drip loss after 48 h

g

%

g

%

0.3 0.2 0.1 0.0

0.0 0.1 0.2 0.3

1.38 ± 0.16a 1.42 ± 0.14a 1.11 ± 0.14ab 0.95 ± 0.11b

0.91 ± 0.09a 0.91 ± 0.08a 0.79 ± 0.08ab 0.60 ± 0.06b

1.82 ± 0.15a 2.08 ± 0.14a 1.52 ± 0.10ab 1.36 ± 0.15b

1.13 ± 0.07a 1.25 ± 0.08a 1.05 ± 0.09ab 0.84 ± 0.11b

a,b

Means within a column with no common superscript differ significantly (P < 0.05). [21].

1

data and R2 = 0.61 for the 48-h data. Our results were similar to those reported by Choct et al. [11], who recorded 0.87% losses for inorganic Se and 0.69% for organic Se after 24 h in male 38-d-old broilers supplemented with 0.25 ppm of Se. More recent data from Deniz et al. [15] showed improvements from 1.08% in inorganic Se to 0.69 for organic Se fed to broilers at levels of 0.3 ppm. Significant reductions (P < 0.05) in both ALT (at 21 d of age) and AST (at 21 and 42 d of age) enzyme activities were observed from blood samples taken from chickens fed organic Se (Table 6). These data suggest less oxidative damage within sensitive tissue (e.g., liver) in birds receiving organic Se in feed. The blood enzymes measured are used as indictors of oxidative damage, often in liver tissue, because of exposure to certain toxins, such as mycotoxins [1]. Although variance within the data meant that AST data at 21 d and ALT data for 42 d did not show such clear effects as the results from the other time points, there was increasing protection against oxidative damage through an improved redox status compared with those receiving only the inorganic forms.

Table 5. Influence of sodium selenite and organic Se (Sel-Plex1) on pH of breast meat of broiler chickens Diet 1 2 3 4 1

[21].

Inorganic selenite, ppm

Organic Se, ppm

pH of breast meat

0.3 0.2 0.1 0.0

0.0 0.1 0.2 0.3

5.89 ± 0.17 5.86 ± 0.19 5.81 ± 0.15 5.87 ± 0.18

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of total BW was between 14 and 17% higher for birds receiving any of the dietary treatments containing organic Se, a difference that attained significance for the 0.1 ppm of inorganic Se + 0.2 ppm of organic Se treatment. The improvements observed in feathering for broilers fed organic Se agreed with the published findings of Edens et al. [19], who reported that organic forms of Se increased feathering rates in broiler chickens, without any loss in bird growth performance. Correct feathering is important to maintain a protective covering for the skin of the birds and to regulate body temperature. Breast meat analysis (Table 4) revealed that birds fed diets containing 0.3 ppm of Se from organic sources had significantly (P < 0.05) less drip loss. The significant response seen between adding 0.1 and 0.3 ppm of organic Se indicated that the higher dose was required for improvements in drip loss. Treatments caused no significant differences in pH of the breast meat (Table 5). All mean values were within the range that would be considered normal, although the numerically highest average pH value (5.89) was found in the breasts of birds from the group fed sodium selenite as the sole Se source, and the lowest pH (5.81) was found in breast muscles of the experimental group fed a combination of 0.1 ppm of inorganic Se + 0.2 ppm of organic Se. No correlation was found between drip loss and breast muscle pH (P > 0.05). The reduced levels of drip loss recorded for the birds fed organic Se agree with the findings of other researchers who noted decreased drip loss with organic Se supplementation [11, 14]. Simple linear regression revealed an inverse relationship between organic Se inclusion in the diet and drip loss, with R2 = 0.86 for the 24-h

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Table 6. Effect of feeding inorganic or organic Se (Sel-Plex1) on the activity of alanine aminotransferases (ALT) and aspartate aminotransferases (AST) in blood samples from broiler chickens

Diet 1 2 3 4

ALT activity, IU/L

AST activity, IU/L

Inorganic selenite, ppm

Organic Se, ppm

21 d

42 d

21 d

42 d

0.3 0.2 0.1 0.0

0.0 0.1 0.2 0.3

23.1 ± 4.54a 7.0 ± 1.63b 9.8 ± 0.94b 8.1 ± 1.37b

7.9 ± 1.63b 12.1 ± 1.47a 12.2 ± 1.29a 6.8 ± 0.86c

363.2 ± 50.10a 222.8 ± 13.45b 249.5 ± 20.42b 271.8 ± 31.19ab

435.3 ± 40.61a 419.1 ± 39.42ab 321.2 ± 24.19b 330.6 ± 17.08b

a–c

Means within a column with no common superscript differ significantly (P < 0.05). [21].

1





1. Breast meat from birds receiving organic Se had less drip loss. 2. Broiler chickens fed organic sources of Se as part of their diet formulation showed improved feathering at d 21 and heavier feather weights at 42 d. 3. Blood plasma tests indicated that broilers fed organic Se might have less liver damage.

REFERENCES AND NOTES 1. Surai, P. F. 2002. Natural Antioxidants in Avian Nutrition and Reproduction. Nottingham University Press, Nottingham, UK. 2. Surai, P. F. 2006. Selenium in Nutrition and Health. Nottingham University Press, Nottingham, UK. 3. Jacques, K. A. 2000. Alltech Inc., Nicholasville, KY. Personal communication. 4. Northcutt, J. K., E. A. Foegeding, and F. W. Edens. 1994. Water holding capacity of thermally preconditioned chicken breast and leg meat. Poult. Sci. 73:308–316. 5. Mahan, D. C., T. R. Cline, and B. Richert. 1999. Effects of dietary levels of selenium-enriched yeast and sodium selenite as selenium sources fed to grower-finisher pigs on performance, tissue selenium, serum glutathione peroxidase activity, carcass characteristics and loin quality. J. Anim. Sci. 77:2172–2179. 6. Ahn, C. N., H. S. Chae, D. W. Kim, Y. M. Yoo, Y. K. Kim, and Y. C. Rhee. 1998. Effects of full fat flax seed, α-tocopherol, ascorbic acid and selenium on the storage of broiler meats. J. Livest. Sci. 40:96–102. 7. Edens, F. W. 1996. Organic selenium: From feathers to muscle integrity to drip loss. Five years onward: No more selenite. Pages 165–185 in Biotechnology in the Feed Industry. Proc. Alltech’s 12th Annu. Symp. Nottingham University Press, Nottingham, UK. 8. Edens, F. W. 1997. Potential for organic selenium to replace selenite in poultry diets. Zootec. Int. 20:28–31. 9. 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. Nottingham University Press, Nottingham, UK. 10. Mahan, D. C., and Y. Y. Kim. 1999. The role of vitamins and minerals in the production of high quality pork. Asian-Aust. J. Anim. Sci. 12:287–294. 11. 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. 12. Sheehy, P. J. A., P. A. Morrissey, D. J. Buckley, and J. Wen. 1997. Effects of vitamins in the feed on meat quality in farm animals: Vitamin E. Pages 3–27 in Recent Advances in Animal Nutrition. Nottingham University Press, Nottingham, UK. 13. Ku, P. K., W. T. Ely, A. W. Groce, and D. E. Ullrey. 1972. Natural dietary selenium, α-tocopherol and the effect on tissue selenium. J. Anim. Sci. 34:208–211. 14. Edens, F. W., T. A. Carter, and A. E. Sefton. 1996. Influence of dietary selenium sources on post mortem drip loss from breast meat of broilers grown on different litters. Poult. Sci. 75(Suppl. 1):60. (Abstr.) 15. Deniz, G., S. S. Genzen, and I. I. Turkmen. 2005. Effects of two supplemental dietary selenium sources (mineral and organic) on broiler performance and drip-loss. Rev. Med. Vet. 156:423–426. 16. Glatz, P. C. 2001. Effect of poor feather cover on feed intake and production of aged layers in winter. Asian-Aust. J. Anim. Sci. 14:553–558. 17. Arnold, R. L., O. E. Olsen, and C. W. Carlson. 1974. Tissue selenium content and serum tocopherols as influenced by dietary type, selenium and vitamin E. Poult. Sci. 53:2185–2192. 18. Edens, F. W. 2000. Feathering of broilers: Influences of amino acids and minerals. Pages 81–100 in Proc. Conferência Apinco de Ciência e Tecnologia Avícolas, Campinas, São Paulo, Brazil. 19. Edens, F. W., C. R. Parkhurst, G. B. Havenstein, and A. E. Sefton. 2001. Housing and selenium influences on feathering in broilers. J. Appl. Poult. Res. 10:128–134. 20. Cobb Vantress, Iradia, Novi Sad, Serbia. 21. Alltech Inc., Nicholasville, KY. 22. Gyles, N. R., J. Kan, and R. M. Smith. 1962. The heritability of breast blister condition and breast feather coverage in a White Rock broiler strain. Poult. Sci. 41:13–17. 23. Rasmussen, A. J., and M. Andersson. 1996. New method for determination of drip loss in pork muscles. Pages 286–287 in Proc. 42nd Int. Congr. Meat Sci. Technol. Lillehammer, Norway.

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CONCLUSIONS AND APPLICATIONS

Perić et al.: SELENIUM AND BROILER MEAT QUALITY 24. HANNA Instruments, Srl., Padova, Italy. 25. RAL, Barcelona, Spain. 26. Bioanalitika doo, Beograd, Serbia. 27. Rej, R., and M. Hoder. 1983. Aspartate aminotransferase. Pages 416–433 in Methods of Enzymatic Analysis. 3rd ed. H. U. Bergmeyer, J. Bergmeyer, and M. Grassl. Verlag-Chemie, Weinheim, Germany.

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28. Hoder, M., and R. Rej. 1983. Alanine transaminase. Pages 380–401 in Methods of Enzymatic Analysis. 3rd ed., H. U. Bergmeyer, J. Bergmeyer, and M. Grassl. Verlag-Chemie, Weinheim, Germany. 29. StatSoft. 2005. Statistica 7. StatSoft Inc., Tulsa, OK.

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