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Broiler stunning methods and their effects on welfare, rigor mortis, and meat quality



Broiler stunning is conducted to produce a rapid onset of insensibility prior to slaughter. Though most broiler plants use electrical stunning applications, gas stunning, and low-atmosphere pressure stunning are also available for commercial applications. All three of these stunning methods are able to meet animal welfare requirements and produce meat with acceptable quality. However, each method differs in their mechanisms of stunning, rigor mortis patterns, and physical meat characteristics. In addition, gas stunning and low-atmosphere pressure stunning have received interest over the past decade as part of an effort to further improve animal welfare. Researchers have reported that gas and low-atmosphere pressure stunning both have potential advantages over electrical stunning with respect to broiler welfare and deboning time, which has been attributed to shackling post-stunning. This review paper will focus on these three stunning methods and their impact on animal welfare, physiology, rigor mortis patterns, carcass characteristics, and meat quality.


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ABEYESINGHE, S.M., MCKEEGAN, D.E.F., MCLEMAN, M.A., LOWE, J.C., DEMMERS, T.G.M., WHITE, R.P., KRANEN, R.W., BEMMEL, H.V, LANKHAAR, J.A.C. and WATHES, C.M. (2007) Controlled atmosphere stunning of broiler chickens. I. Effects on behaviour, physiology and meat quality in a pilot scale system at a processing plant. British Poultry Science 48: 406-423.
BAL, A. (2011) Tailor-made stunning for every bird. World Poultry 6(27): 44-46.
AMERICAN VETERINARY MEDICAL ASSOCIATION, (2007) AVMA Guidelines on Euthanasia. Am. Vet. Med. Assoc., Schaumburg, IL. Accessed March 13, 2008.
BATTULA, V., SCHILLING, M.W., THAXTON, Y.V., BEHRENDS, J.B., WILLIAMS, J.B. and SCHMIDT, T.B. (2008) The effects of low atmosphere stunning and deboning time on broiler breast meat quality. Poultry Science 87: 1202-1210.
BILGILI, S.F. (1992) Electrical stunning of broilers - basic concepts and carcass quality implications: A Review. Journal of Applied Poultry Research 1: 135-146.
BILGILI, S.F. (1999) Recent advances in electrical stunning. Poultry Science 78: 282-286.
BUTLER, A.B. and COTTERILL, M.J. (2006) Mammalian and avian neuroanatomy and the question of consciousness in birds. The Biological Bulletin 211: 106-127.
CHAPMAN, M.L., VANDONGEN, H.M. and VANDONGEN, A.M. (1997) Activation-dependent subconductance levels in the drk1 k channel suggest a subunit basis for ion permeation and gating. Biophysics Journal 72: 708-719.
COENEN, A.M.L., LANKHAAR, J., LOWE, J.C. and MCKEEGAN, D.E.F. (2009) Remote monitoring of electroencephalogram, electrocardiogram, and behavior during controlled atmosphere stunning in broilers: Implications for welfare. Poultry Science 88: 10-19.
COOK, C.J. (1993) Stunning science-A guide to better electrical stunning. Meat Focus 2(3): 128-131.
COOK, C.J., DEVINE, C.E., TAVENER, A. and GILBERT, K.V. (1992) Contribution of amino acid transmitters to epileptiform activity and reflex suppression in electrically head stunned sheep. Research in Veterinary Science 52: 48-56.
COOK, C.J., DEVINE, C.E., GILBERT, K.V., SMITH, D.D. and MAASLAND, S.A. (1995) The effect of electrical head-only stun duration on electroencephalographic-measured seizure and brain amino acid neurotransmitter release. Meat Science 40: 137-147.
CRAIG, E.W. and FLETCHER, D.L. (1997) A comparison of high current and low voltage electrical stunning effects on broiler breast rigor development and meat quality. Poultry Science 71: 1178-1181.
DELL, P., HUGELIN, A. and BONVALLET, M. (1961) Effects of hypoxia on the reticular and cortical diffuse systems, in: THOMAS, C.C., GASTART, H. & MAYER, J.S. (Eds) Cerebral Anoxia and the Encephalogram, pp. 47-58 (Springfield, IL).
DREWNIAK, E.E., BAUSH, E.R. and DAVIS, L.L. (1955) Carbon dioxide immobilisation of turkeys before slaughter: USDA Circular, USDA, Washington, DC: 958.
EISELE, J.H., EGER, E.I. and MUALLEM, M. (1967) Narcotic properties of carbon dioxide in the dog. Anesthesiology 28: 856-865.
ERNSTING, J. (1965) The effect of anoxia on the central nervous system, in: GILLIES, J.A. (Ed) A Textbook of Aviation Physiology, pp. 220- 239 (London, UK, Pergamon Press).
EUROPEAN COMMISSION, (2003) Council Directive 93/119/EC. European Commission, Directorate General, Health and Consumer Protection, Brussels, Belgium.
FLEMING, B.K., FRONING, G.W., BECK, M.M. and SOSNICKI, A.A. (1991) The effect of carbon dioxide as a pre-slaughter stunning method for turkeys. Poultry Science 70: 2201-2206.
FLETCHER, D.L. (1999) Recent advances in poultry slaughter technology. Poultry Science 78: 277-281.
GERRITZEN, M.A., LAMBOOIJ, E., HILLEBRAND, S.J.W., LANKHAAR, J. and PIETERSE, C. (2000) Behavioural responses of broilers to different gaseous atmospheres. Poultry Science 79: 928-933.
GOKSOY, E.O., MC KINSTRY, L.J., WILKINS, L.J., PARKMAN, I., PHILLIPS, A., RICHARDSON, R.I. and ANIL, M.H. (1999) Broiler stunning and meat quality. Poultry Science 78: 1796-1800.
GREGORY, N.G. (1989) Stunning and slaughter, in: MEAD, G.C. (Ed) Processing of Poultry, pp. 31-63 (London, UK, Elsevier Sci. Publishers Ltd.).
GREGORY, N.G. (1992) Stunning of broilers. Proceedings of 19th World's Poultry Congress, Volume 2, Ponsen and Looijen, Wageningen, The Netherlands, pp. 345-349.
GREGORY, N.G. (1993) Causes of downgrading in chickens, turkeys and ducks. Broiler Industry 56: 42-45.
GREGORY, N.G. and AUSTIN, S.D. (1992) Causes of trauma in broilers arriving dead at processing plants. Veterinary Record 114: 286-287.
GREGORY, N.G. and WILKINS, L.J. (1989) Effect of stunning current on carcass quality in chickens. Veterinary Record 124: 530-532.
GREGORY, N.G. and WOTTON, S.B. (1989) Effect of electrical stunning on somatosensory evoked potentials in chickens. British Veterinary Journal 145: 159-164.
GREGORY, N.G. and WOTTON, S.B. (1990) Effect of stunning on spontaneous physical activity and evoked activity in the brain. British Poultry Science 31: 215-220.
GREGORY, N.G., RAJ, A.B.M., AUDSLEY, A.R.S. and DALY, C.C. (1990) Effects of carbon dioxide on man. Fleischwirtschaft 70: 1173-1174.
GREGORY, N.G., WILKINS, L.J. and WOTTON, S.B. (1991) Effect of electrical stunning frequency on ventricular fibrillation, downgrading and broken bones in broilers, hens and quails. British Veterinary Journal 147: 71-77.
GRIFFITHS, G.L. (1985) Electrocution, stunning, and chicken carcass appearance. Proceedings of Australian Stock Feed Conference, Adelaide, Australia, pp. 282-286.
GUYTON. A.C., and HALL, J.E. (2010) Textbook of Medical Physiology. Chapter 43, pp. 527-533, 12th ed. (Philadelphia, PA, Saunders Elsevier).
HEATH, G.E., THALER, A.M. and JAMES, W.O. (1994) A survey of stunning methods currently used during slaughter of poultry in commercial poultry plants. Journal of Applied Poultry Research 3: 297-302.
HILLEBRAND, S.J.W., LAMBOOIJ, E. and VEERKAMP, C.H. (1996a) The effects of alternative electrical and mechanical stunning methods on hemorrhaging and meat quality of broiler breast and thigh muscles. Poultry Science 75: 664-671.
HILLEBRAND, S.J.W., PIETERSE, C. and LAMBOOIJ, E. (1996b) Air pressure stunning of broilers-changes in the spontaneous electroencephalogram, immobilisation and hemorrhaging aspects. Proceedings of the 42nd International Congress of Meat Science and Technology, Lillehammer, Norway, pp. 456-457.
HOEN, T. and LANKHAAR, J. (1999) Controlled atmosphere stunning of poultry. Poultry Science 78: 287-289.
HUMANE METHODS OF SLAUGHTER ACT, (1978) United States Code Annotated. United States Department of Agriculture. Title 7: Agriculture, Chapter 48. Sections 1901-1907.
KANG, I.S. and SAMS, A.R. (1999) Bleedout efficiency, carcass damage, and rigor mortis development following electrical stunning or carbon dioxide stunning on shackle line. Poultry Science 78: 139-143.
KANNAN, G. and MENCH, J.A. (1996) Influence of different handling methods and crating periods on the plasma corticosterone concentration in broilers. British Poultry Science 37: 21-31.
KOTULA, A.W., DREWNIAK, E.E. and DAVIS, L.L. (1957) The effect of carbon dioxide immobilisation on the bleeding of chickens. Poultry Science 36: 585-589.
KOTULA, A.W., DREWNIAK, E.E. and DAVIS, L.L. (1961) Experimentation with in-line carbon dioxide immobilisation of chickens prior to slaughter. Poultry Science 40: 213-216.
KRANEN, R.W., LAMBOOIJ, E., VEERKAMP, C.H., VAN KUPPEVELT, T.H. and VEERKAMP, J.H. (2000) Hemorrhages in muscles of broiler chickens. World's Poultry Science Journal 56: 93-126.
KRANEN, R.W., SCHEELE, C.W., VEERKAMP, C.H., LAMBOOIJ, E., VAN KUPPEVELT, T.H. and VEERKAMP, H. (1998) Susceptibility of broiler chickens to hemorrhages in muscles. The effect of stock and rearing temperature regimen. Poultry Science 77: 334-341.
LAMBOOIJ, E., GERRITZEN, M.A., ENGEL, B., HILLEBRAND, S.J.W. and PIETERSE, C. (1999) Behavioral responses during exposure of broilers to different gas mixtures. Applied Animal Behavior Science 62: 255-265.
LAMBOOIJ, E., REIMERT, H.G.M. and HINDLE, V.A. (2010) Evaluation of head-only electrical stunning for practical application: Assessment of neural and meat quality parameters. Poultry Science 89: 2551-2558.
LYON, C.E. and LYON, B.G. (1990) Texture profile of broiler pectoralis major as influenced by post-mortem deboning time and heat method. Poultry Science 69: 329-40.
MCKEEGAN, D.E.F., ABEYESINGHE, S.M., MCLEMAN, M.A., LOWE, J.C., DEMMERS, T.G.M., WHITE, R.P., KRANEN, R.W., VAN BEMMEL, H., LANKHAAR, J.A.C. and WATHES, C.M. (2007) Controlled atmosphere stunning of broiler chickens: II. Effects on behavior, physiology and meat quality in a commercial processing plant. British Poultry Science 48: 430-442.
MELDRUM, B. (1975) Epilepsy and GABA-mediated inhibition. International Review of Neurobiology 17: 1-36.
OFFICIAL JOURNAL OF THE EUROPEAN UNION, (2009) Council Regulation (EC) No. 1099/2009 of 24 Sept. 2009 on the Protection of Animals at the time of killing. pp. 1-30.
OLSON, R. (2002) GABA. in: DAVIS, K., CHARNEY, D., COYLE, J. & NEMEROFF, C. (Eds) Neuropsychopharmacology: The Fifth Generation of Progress (Philadelphia, PA, Lippincott Williams and Wilkins).
PAPINAHO, P.A. and FLETCHER, D.L. (1995) Effect of stunning amperage on broiler breast muscle rigor development and meat quality. Poultry Science 74: 1527-1532.
PAPINAHO, P.A. and FLETCHER, D.L. (1996) The effect of stunning amperage and deboning time on early rigor development and breast meat quality of broilers. Poultry Science 75: 672-676.
PAPINAHO, P.A., FLETCHER, D.L. and BUHR, R.J. (1995) Effect of electrical stunning amperage and peri-mortem struggle on broiler breast rigor development and meat quality. Poultry Science 74: 1533-1539.
POOLE, G.H. and FLETCHER, D.L. (1998) Comparison of a modified atmosphere stunning-killing system to conventional electrical stunning and killing on selected broiler breast muscle rigor development and meat quality attributes. Poultry Science 77: 342-347.
POULTRY PRODUCTIONS INSPECTION ACT, (1957) United Stated Department of Agriculture. Title 21: Food and Drugs, Chapter 10: Poultry and Poultry Products Inspection. P.L. 85-172. Sections 451-472. pp. 413-415.
PURSWELL, J.L., THAXTON, J.P. and BRANTON, S.L. (2007) Identifying process variables for a low atmospheric stunning-killing system. Journal of Applied Poultry Research 16: 509-513.
RADHAKRISHNAN, V., SCHILLING, M.W., THAXTON, V.Y. and CHRISTENSEN, K.D. (2010) The effects of low-atmospheric pressure and electrical stunning on the sensory quality of broiler breast deboned at 45 Minutes and four hours. Institute of Food Technologists Annual Meeting, Chicago, IL, July 17th-20th, 235-11.
RAJ, A.B.M. (1994) Effect of stunning method, carcass chilling temperature and filleting time on the texture of broiler pectoralis muscle. British Poultry Science 35: 77-89.
RAJ, A.B.M. (1998) Welfare during stunning and slaughter of poultry. Poultry Science 77: 1815-1819.
RAJ, A.B.M. and GREGORY, N.G. (1990) Investigation into the batch stunning/ killing of chickens using carbon dioxide or argon-induced hypoxia. Research in Veterinary Science 49: 364-366.
RAJ, A.B.M. and GREGORY, N.G. (1991) Effect of argon stunning, rapid chilling, and early filleting on texture of broiler breast meat. British Poultry Science 32: 741-746.
RAJ, A.B.M., GREY, T.C., AUDSELY, A.R. and GREGORY, N.G. (1990a) Effect of electrical and gaseous stunning on the carcass and meat quality of broilers. British Poultry Science 31: 725-733.
RAJ, A.B.M., GREGORY, N.G. and AUSTIN, S.D. (1990b) Prevalence of broken bones in broilers killed by different stunning methods. Veterinary Record 127: 285-287.
RAJ, A.B.M., GREGORY, N.G. and WILKINS, L.G. (1992) Survival rate and carcass downgrading after the stunning of broilers with carbon dioxide-argon mixtures. Veterinary Record 130: 325-328.
RAJ, A.B.M., WILKINS, L.J., RICHARDSON, R.I., JOHNSON, S.P. and WOTTON, S.B. (1997) Carcass and meat quality in broilers either killed with a gas mixture or stunned with an electric current under commercial processing conditions. British Poultry Science 38: 169-174.
RAJ, A.B.M., WOTTON, S.B., MCKINSTRY, J.L., HILLENBRAND, S.J.W. and PIERTERSE, C. (1998) Changes in the somatosensory evoked potentials and spontaneous electroencephalogram of broiler chickens during exposure to gas mixtures. British Poultry Science 39: 686-695.
RICHARDS, S.A. and SYKES, A.H. (1967) Physiological effects of stunning and venesection in the fowl. Research in Veterinary Science 8: 361-368.
SAMS, A.R. (1996) Stunning basics. Broiler Industry 59: 36-38.
SAMS, A. (1999) Commercial implementation of post mortem electrical stimulation. Poultry science 78: 290-294.
SAMS, A.R. and DZUIK, C.S. (1995) Gas stunning and post mortem electrical stimulation of broiler chickens. Poultry Meat Quality. Proceedings of XII European symposium on the Quality of Poultry Meat, Zaragoza, Spain, pp. 307-314.
SAVENIJE, B., SCHREURS, F.J.G., WINKELMAN-GOEDHART, H.A., GERRITZEN, M.A., KORF, J. and LAMBOOIJ, E. (2002) Effects of Feed Deprivation and Electrical, Gas, and Captive Needle Stunning on Early Post mortem Muscle Metabolism and Subsequent Meat Quality. Poultry Science 81: 561-571.
SCHILLING, M.W., SCHILLING, J.K. CLAUS, J.R., , MARRIOTT, N.G., DUNCAN, S. E. and WANG, H. (2003) Instrumental texture assessment and consumer acceptability of cooked broiler breasts evaluated using a geometrically uniform-shaped sample. Journal of Muscle Foods 14: 11-23.
SMITH, D.C. (1965) Methods of euthanasia and disposal of laboratory animals, in: GAY, W.I. (Ed) Methods of Animal Experimentation, Vol. 1, pp. 167-195 (New York, NY, Academic Press).
THAXTON, Y.V., CHRISTENSEN, K.D., SCHILLING, M.W. BUHR, R.J., and THAXTON, J.P. (2010) A new humane method of stunning broilers using low atmospheric pressure. Journal of Applied Poultry Research 19: 341-348.
TURCSAN, Z.S., SZIGETI, J., VARGA, L., FARKAS, L., BIRKAS, E. and TURCSAN, J. (2001) The effects of electrical and controlled atmosphere stunning methods on meat and liver quality of geese. Poultry Science 80: 1647-1651.
TURCSAN, Z.S., VARGA, L., SZIGETI, J., TURCSAN, J., CSURAK, I. and SZALAI, M. (2003) Effects of electrical stunning frequency and voltage combinations on the presence of engorged blood vessels in goose liver. Poultry Science 82: 1816-1819.
UIJTTENBOOGAART, T.G. (1997) Effects of gas and electrical stunning methods on meat quality, in: LAMBOOIJ, E. (Ed) Proceedings Symposium: Alternative Stunning Methods for Poultry, pp. 25-33 (The Netherlands, Utrecht).
VAN LAACK, R.L.J.M., LIU, C.H., SMITH, M.O. and LOVEDAY, H.D. (2000) Characteristics of pale, soft, exudative broiler breast meat. Poultry Science 79: 1057-1061.
VEERAMUTHU, G.J. and SAMS, A.R. (1993) The effects of carbon dioxide and electrical stunning on rigor mortis and toughness development in early-harvested broiler breast fillets. Poultry Science 72(1): 147.
VEERKAMP, C.H. (1988) What is the right current to stun and kill broilers? Poultry Misset 4: 30-31.
VEERKAMP, C.H. and DE VRIES, A.W. (1983) Influence of electrical stunning on quality aspects of broilers, in: EIKELENBOOM, G. (Ed) Stunning of Animals for Slaughter, pp. 197-207 (Boston, MA, Martinus Nijhoff Publishers).
WOTTON, S.B. and GREGORY, N.G. (1991) How to prevent pre-stun shocks in water bath stunners. Turkey 39: 15-30.
WOOLLEY, S.C. and GENTLE, M.J. (1988) Physiological and behavioural responses of the domestic hen to hypoxia. Research in Veterinary Science 45: 377-382.
XU, L., JI, F., YUE, H.Y., WU, S.G., ZHANG, H.J., ZHANG, L. and QI, G.H. (2011a) Plasma variables, meat quality, and glycolytic potential in broilers stunned with different carbon dioxide concentrations. Poultry Science 90: 1831-1836.
XU, L., ZHANG, L., YUE, H.Y., WU, S.G., ZHANG, H.J., JI, F. and QI, G.H. (2011b) Effect of electrical stunning current and frequency on meat quality, plasma parameters, and glycolytic potential in broilers. Poultry Science 90: 1823-1830.



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