the effects of captive bolt and electrical stunning

8/12/2019 The Effects of Captive Bolt and Electrical Stunning

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Presentado por:Sebastin Acevedo; Gerson Meza; Eder RondnSeminario de Investigacin II

Medicina Veterinaria y ZootecniaUniversidad Cooperativa de Colombia

Bucaramanga, 2012

Institute for Animal Science and Health, ID-DLO, P.O. Box 65, 8200 AB,Lelystad, The Netherlands


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ABSTRACTThe effects of captive bolt stunning

using air pressure, compared to

electrical water bath stunning, onbroiler carcass and meat quality wereevaluated. The birds were shackled orplaced in a cone.


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Electrical stunning is normally used to induceunconsciousness during cutting and bleeding forreasons of animal welfare in the EU or to induce

immobilization to facilitate automatic neck cutting inthe U.S

This recommended minimum current for broilers inthe EU increases quality defects (hemorrhages,

broken bones) of carcasses and broiler meat(Veerkamp and de Vries, 1983; Gregory and Wilkins,1989a). It is apparent that there is a conflict betweenwelfare and meat quality under the electrical water

bath stunning and killing procedure

INTRODUCTION


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Therefore, alternative methods for stunning broilers

have to be explored. Novel methods of stunning usinggases have been developed (Raj et al., 1990a;Hoenderken et al., 1994); however, gaseous stunninginvolves an induction phase that can be stressful tothe birds.

In order to find a slaughter technology that satisfiesmost of the welfare and quality requirements,alternative methods have to be explored. In a previous

study (Hillebrand et al., 1996a), the effects ofconventional electrical water bath stunning, electricalhead-only stunning, and mechanical captive boltstunning on broiler meat quality were compared


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The development of the latter two alternative stunningmethods for poultry makes it essential to prevent thepost-stun convulsions caused by these stunning methods.Nevertheless, head-only and captive bolt stunning arepromising alternatives to the conventional electricalstunning procedure with respect to hemorrhaging

Compared to water bath stunning, fewer hemorrhages inbroiler breast and thigh muscles were observed afterhead-only and captive bolt stunning. Reducing the

number and intensity of convulsions is consideredpositive, even though hemorrhaging or bird welfare arenot necessarily negatively affected by it. However,convulsions are objectionable on aesthetic grounds


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Moreover, a motionless animal is required forneck

cutting. An extremely high frequency current appliedthrough the whole body, a so-called relaxationcurrent, is one of the means that is used to attemptblocking spinal cord reflexes after head-only

stunning. Administering of a relaxation current didnot always


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OBJETIVE GENERAL

determine the best method of stunning method doesnot affect the quality of the meat and get betterperformance


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MATERIALS AND METHODS

Experimental Design:

Two experimental trials were conducted using a totalof 160 female broilers (5 to 6 wk of age, average live

weight 1.5 0.1 kg for all treatment groups) todetermine the influence of two stunning and tworestraining methods on meat quality.

In both trials, 80 broilers were used and randomly

assigned to one of four following stunning-restrainingtreatments:


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1) whole-body electrical stunning in a saline

waterbath while broilers were shackled by theirfeet (10 s, 116 15 mA, 300 Hz, sinusoidal AC; n =20 per trial)

2) placed in a cone (10 s, 108 25 mA, 300 Hz,sinusoidal AC; n = 20 per trial)

3) air pressure stunning with an injection time of0.5 s and an air pressure of 2 atm while broilers

were shackled (n = 20 per trial) 4) placed in a cone (n = 20 per trial)


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Neck cutting was performed 10 to 15 s from the end ofthe application of stunning procedure. Birds wereexsanguinated for 3 min. Carcasses were transferred toprocessing shackles and moved into a scalder (4 min,50 C).


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Measurements:

The degree of muscle reactions (convulsions) duringstunning and exsanguination was subjectively scored(scores 0, 1, 2, and 3 represent no, mild, moderate, and

severe convulsions, respectively).

Blood loss was determined by the difference in body

weight before neck cutting and after 3 minexsanguination


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Temperature and pH in breast muscle (P. major) was

measured after evisceration (20 min postmortem),after the fast chilling phase (60 min postmortem),after the slow chilling phase (140 min postmortem)

Temperature and pH in thigh muscle (Flexor crurismedialis) was measured after the slow chilling phase(60 min postmortem) only Muscle pH was measuredwith a portable pH measuring device 2 (Scott Gerate,

type CG 818) connected to an Ingold electrode 2(Xerolyt, type LOT 406-M6-DXK-S7/25), andtemperature with a digital thermometer 3 (Testo 901).


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Fractures of pectoral bones (clavicle, scapula, and

coracoid; present or absent), and wing hemorrhageswere scored subjectively (categories 1, 2, and 3represent mild, moderate, and severe hemorrhaging,respectively) when breast muscles and thighs were

excised from the carcasses by cutting off the lateralsurface.

Hemorrhages in breast (dorsal side of P. major and

minor) and left and right thigh muscles (medial side)were quantified by a visual grading system.


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The packaged breast muscles were heated in a double-

plated contact grill (2 min, 180 C). Samples werepresented to a trained sensory panel immediately aftercooking.

Tenderness, juiciness, and intensity of taste of the breast

meat were assessed by means of a line scale.


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Statistical Analysis

The effect of trial, stunning, and restraining procedureand interacting effects on the continuous parameters,blood loss, temperature, pH, color values, cookingloss, and sensory quality parameters were analyzedwith analysis of variance models.


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The replicates by stunning or restraining

interactions were not significant; therefore

the data were combined across trials.

Results of the measurements indicate

interactions of stunning and restrainingeffects for two measurements only.


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TABLE 1. Blood loss, breast and thigh muscle pH and

temperature, meat quality parameter means and

standard deviations, and incidence of pectoral bone

fractures of broilers electrically whole-body1 or airpressure2 stunned

while shackled or restrained in a cone (n = 80 per

stunning or restraining method)


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CONTINUOUS PARAMETERS

Muscle Reactions Blood Loss CookingLoss

ColorPectoral Bone

FracturesMuscle pH andTemperature Hemorrhaging


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whole-body electrical stunning (10 s,110 mA, 300 Hz) in a water bath or air

pressure stunning (0.5 s, 2 atm) whilebroilers were shackled by their feet orplaced in a cone

RESULTS TABLE 1


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Air pressure stunning caused a higher (P < 0.01)

degree of convulsions and a lower (P < 0.01) degreeof blood loss than electrical stunning, andreduced the prevalence of broken clavicles (P

the effects of captive bolt and electrical stunning

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