Stunning Effect Research Articles

Effect of gas stunning and modified-atmosphere packaging on the quality of meat from Spanish Manchego light lamb

The aim of the present study was to evaluate the effect of different stunning methods (using two different CO2 concentrations and exposure times) and modified atmosphere packaging systems (MA-O2: 70 O2+30 CO2vs MA-CO: 69.3% N2+30% CO2+0.7% CO) on the meat quality of Manchego Spanish male light lambs (n=50). One electrically stunned control group was used.The type of stunning affected pH value, meat tenderness and water losses (P<0.05) but did not modify most of the colour coordinates or the lipid oxidation level. Furthermore the modified atmosphere with a low CO level (MA-CO) promoted more tender meat with higher oxidative stability than the high-oxygen packed meat (MA-O2). Most likely both the CO2 gas concentration and the exposure time are relevant in the evolution of meat quality from light lambs stunned with different gas stunning systems. In addition, the use of a low CO level to pack lamb meat permits to remove the oxygen from the pack, which improves meat tenderness and the oxidative stability.

Licensing poultry CO2gas-stunning systems with regard to animal welfare: investigations under practical conditions

AbstractCarbon dioxide stunning of broilers is not permitted in Germany. However, the competent authority can license a system for testing, during which scientific evaluation with regard to animal welfare is required. Between 2004 and 2011 several aspects of three systems have been evaluated in Germany and Italy under practical conditions including: (i) supply to the stunning system; (ii) induction conditions; (iii) stunning effectiveness; and (iv) process control. The systems were: (i) LINCO progressive gas-stunning system in which broilers in their transport crates are lowered stepwise into a pit filled with CO2and exposed to slowly increasing concentrations of CO2in air up to between 50 and 65% with total dwell times between 275 and 440 s depending on birds’ weight; (ii) Stork PMT two-phase gas-stunning system (40% CO2/30% O2/30%N2for 1 min/80% CO2for 2 min) in which broilers are tipped onto a belt, on which they pass through the gas atmospheres; and (iii) Anglia Autoflow two-phase CO2-stunning system, in which the birds are exposed to the atmosphere in their crates. Results on the third system are pending as the investigation is still ongoing. In systems (i) and (ii) analysis of behaviour showed that birds were only exposed to high CO2concentration (&gt; 40%) after becoming unconscious. Stunning effectiveness was very high but, nevertheless, occasionally birds (0.027% LINCO system and 0.003% Stork PMT system) were able to regain consciousness. Examples of evaluation of behaviour during induction are presented in this paper and animal welfare aspects are compared. Controlled-atmosphere stunning systems for broilers using less than 40% CO2until animals are unconscious, show obvious advantages compared to electrical water-bath stunning, for example, the avoidance of shackling and achieving high stunning effectiveness.

Effects of on-board storage and electrical stunning of wild cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) on brain and heart activity

Cod and haddock captured with commercial trawling gear were taken immediately after landing on deck to on-board storage in dry bins for measuring brain and heart activity, and behaviour. Other groups were first stored in holding tanks and then electrically stunned with a prototype “dry stunner”. For stunning 52Vrms was applied on individual fish for 1s. As a result, the cod and haddock received an electrical current of 0.34±0.09 and 0.36±0.12Arms, respectively. Electrical activity in the brain and heart was measured before and after electrical stunning. The fish remained conscious for at least 2h after landing and during on-board storage as indicated by the electrical activity measured in brain and heart. Behavioural responsiveness to administered stimuli was absent in both species. After electrical stunning, both species showed a general epileptiform insult which was characterised by a tonic phase followed by a clonic phase and terminating with an exhaustion phase.Since the fish remained conscious after landing and storage, electrical stunning and subsequent killing with a throat cut, may provide an option for improving fish welfare on-board commercial fishing vessels. In particular, we recommend to stun and kill wild cod and haddock as soon as possible after landing on deck using a dry stunner applying 52Vrms (coupled AC/DC current) for more than 3s.

Survey of the incidence of post-stun behavioural reflexes in electrically stunned broilers in commercial conditions and the relationship of their incidence with the applied water-bath electrical parameters

AbstractDespite recent technological advances, stunning efficiency of broilers in commercial plants is still questionable and a major public concern. The aim of this survey was to assess the electric water-bath parameters used in poultry processing plants, establish practical ways for the assessment of stunning efficiency in these conditions, link their incidence to the applied current and propose methodology for the online evaluation of the effectiveness of electrical water-bath stunning. A total of 5,378 broilers were assessed randomly for signs of post-stun recovery at 4, 8, 13 and 25 s post-water-bath exit (WBE) through corneal reflex, rhythmic breathing, head shake and escape behaviour on three processing lines. The electric water-bath parameters used did not meet the recommended current and frequencies for effective stunning. No rhythmic breathing was detected with any of the birds at 4 s post water-bath exit, while this reflex returned by 8 s in some birds. Broilers that had their necks cut had a significantly lower incidence of breathing compared to those that missed the neck cutter. The electric water-bath stunners that were tested did not abolish the corneal reflex where 38.4% of birds tested positive, at 4 s post WBE. Pulsed DC-stunned birds that missed the knife had a significantly higher incidence of positive corneal reflexes than those that had their necks cut. Head shake was present on 26.7% of the birds when assessed at 25-30 s post WBE. The trends in incidence of behavioural reflexes with time post WBE may be used for the assessment of stunning efficiency, particularly on birds that miss the knife, but none of the assessed indicators could unequivocally demonstrate unconsciousness.

Electrical waterbath stunning: Influence of different waveform and voltage settings on the induction of unconsciousness and death in male and female broiler chickens

Stunning effectiveness of male and female broiler chickens was analyzed in response to different waveforms at 3 constant voltage levels. In total, 180 male and female broiler chickens were stunned using a sine wave alternating current (AC) of 50 Hz, rectangular AC of 70 Hz, and pulsed direct current (DC) of 70 Hz (duty-cycle 1:1) with a constant voltage of 60, 80, or 120 V, respectively. In each stunning group, 10 male and 10 female birds were stunned for 4 s. The current obtained by every bird was recorded. For stunning efficiency, the electroencephalogram (EEG) and physical reflexes were recorded and analyzed. The EEG was recorded for 120 s poststun. Simultaneously, the occurrence of spontaneous eye blinking, wing flapping, and breathing was assessed, and the corneal reflex was tested every 20 s poststun. The EEG was analyzed regarding the occurrence of a profound suppression to less than 10% of the prestun level in the 2 to 30 Hz and 13 to 30 Hz bands. Female broilers obtained a significantly lower stunning current compared with that of the males. This resulted in a lower stunning efficiency for females, when the same constant voltage was applied to males and females. The waveforms required different amounts of currents to achieve a 90% stunning efficiency. A minimum necessary stunning current of 70, 90, and 130 mA could be established for sine wave AC, rectangular AC, and pulsed DC, respectively. The low stunning efficiency of pulsed DC might be caused by the short stunning time of 4 s. This effect should be further investigated for DC stunning. Very few birds stunned with AC resumed breathing following stunning, indicating stun to kill. Pulsed DC stunning showed a lower effect on the induction of death. The level of wing flapping, indicating convulsions and possible meat quality defects, was higher for the AC treatments.

Building a better bracelet: wallpaper patterns in bead crochet

A typical bead crochet bracelet consists of a narrow tube of seed beads sewn together to form an uninterrupted hollow band. Creating symmetric colour patterns on bead crochet bracelets is challenging because the beads form a continuous spiral along the length of the bracelet, making it difficult to align design motifs uniformly. We have devised a new technique for translating bracelet patterns into plane tilings and used this to create bracelets based on wallpaper group symmetries to stunning effect. We prove that exactly 13 of the 17 wallpaper groups can be represented by bead crochet bracelets, and we outline a general method for designing a bracelet whose planar bead tiling has a given wallpaper symmetry group.

Comparison of blood variables, fiber intensity, and muscle metabolites in hot-boned muscles from electrical- and gas-stunned broilers

The aim of this study was to compare the effects of gas stunning (GS) and electrical stunning (ES) on energy metabolism in Arbor Acres broilers. Thirty-six birds were slaughtered without stunning (control) or after stunning with the following treatments: 40% CO(2) + 21% O(2) + N(2) (G40%); 60% CO(2) + 21% O(2) + N(2) (G60%); 35 V, 47 mA, 400 Hz (E35V); 50 V, 67 mA, 160 Hz (E50V); and 65 V, 86 mA, 1,000 Hz (E65V). Muscle samples were obtained from the pectoralis major (breast) and tibialis anterior (leg) muscles in ambient temperature within 45 min postmortem and stored at -80°C. Blood pH decreased consistently with GS (G40% and G60%) compared with ES and the control (P < 0.01). No consistent differences were observed between GS and ES in the plasma variables, glycolytic potential, adenosine phosphates, or fiber intensities. Plasma lactate increased with G40% and E35V (P < 0.05), whereas plasma uric acid and urea nitrogen increased with E35V (P < 0.05) compared with the control. Compared with the control, the intensity of type IIB fibers decreased in broilers stunned with E35V and E50V (P < 0.05) and glycolytic potential increased (P < 0.01) with G60% in the breast muscle and decreased (P < 0.01) in the leg muscle with all the stunning treatments except for E50V. Energy decreased (lower adenosine triphosphate, higher adenosine monophosphate, and adenosine monophosphate:adenosine triphosphate ratio, P < 0.05) in breast muscle with G40% compared with ES at high currents (E50V and E65V). However, the adenosine phosphates with GS were not significantly different (P > 0.05) from ES at low current (E35V) in either breast or leg muscle. In conclusion, no essential difference in energy metabolism was found in broilers stunned with ES and GS when ES was based on low current and high frequency and GS was based on hypercapnic moderate oxygenation. This study indicated that G40% was potentially a superior stunning variable.

Maternal thyroid function in different conditions of iodine nutrition in pregnant women exposed to mild-moderate iodine deficiency: an observational study

We examined the effect of different conditions of nutritional iodine intake on maternal thyroid function throughout gestation in a cohort of healthy, anti-thyroid antibody-negative women from a mild-moderately iodine-deficient (ID) area. Observational cohort study. The study included 168 women receiving prenatal preparations containing 150 μg of iodine from early pregnancy (150-I group); 105 women who had regularly used (>2 years) iodized salt prior to becoming pregnant (I-salt group); 160 women neither taking iodine supplements nor using iodized salt (no-I group). Maternal TSH, FT3 and FT4 were determined throughout gestation. Mean TSH concentrations were higher among the 150-I women than in the remaining two groups, and in a high proportion of them, TSH values were found to exceed the upper limit for gestational age. Conversely, the prevalence of low free-thyroxine levels in the 150-I women was similar to that observed in the I-salt women and markedly lower than that recorded for the no-I group. The regular use of iodine-containing supplements proved effective in reducing the risk of inappropriately low FT4 levels during pregnancy. The observed TSH increase in 150-I women may be because of a transient stunning effect on the thyroid gland, occurring as a result of the abrupt increase in daily iodine intake. Whilst the importance of gestational iodine supplementation is undisputed, we believe that in mild-moderately ID areas, women considering conception should be advised to take iodine supplementation for several months prior to pregnancy.

Takotsubo Syndrome

The Takotsubo Syndrome was first described by Japanese investigators approximately 20 years ago and has been increasingly recognized in all countries. It occurs almost exclusively in postmenopausal women and is triggered by a severe emotional stress. Severe chest pain is common and the electrocardiogram often mimics that seen with an acute myocardial infarction. An echocardiogram or a left ventriculogram resembles a Takotsubo, a Japanese octopus fishing pot. In Japanese 'Takotsubo' means a 'fishing pot for trapping octopus.' These traps have a round bottom with a narrow neck. When the octopus enters the Takotsubo it is most often trapped while the fisherman pulls the device to the surface. The syndrome is reversible and over the next several weeks to months all electrocardiographic and echocardiographic changes revert to normal. It is likely that the emotionally induced catecholamine surge in an estrogen-deficient woman causes a combination of epicardial coronary artery constriction, constriction of the myocardial microvasculature, and direct cardiomyocyte toxicity producing a temporary stunning effect on the left ventricular myocardium.

Snow Rabbit, Spring Rabbit: A Book of Changing Seasons (review)

Reviewed by: Snow Rabbit, Spring Rabbit: A Book of Changing Seasons Deborah Stevenson Na, Il Sung. Snow Rabbit, Spring Rabbit: A Book of Changing Seasons; written and illus. by Il Sung Na. Knopf, 2011. [32p.] Library ed. ISBN 978-0-375-96786-3 $18.99 Trade ed. ISBN 978-0-375-86786-6 $15.99 Reviewed from galleys R 4-6 yrs. The white rabbit observes the changes in the natural world as the winter approaches: the geese fly away toward warmer climes, the bears settle in for a winter's nap, the sheep stand firm against the cold in their thick wool, the squirrels gather extra nuts, and so on. It's a quiet, simple text, with the hush of winter in its tone, and the animals included are an interesting variety of specimens (crocodiles, for instance, don't usually get much attention in winter lore, but the observations are accurate). The words are really just the occasion for the arresting illustrations, however, which combine digital and handmade elements to stunning effect. Backgrounds evince a fresco-like texture, with lacy negative patterns of stylized snowflakes and botanicals providing an air of fanciful prettiness. The animals themselves have a simplified round shape and sense of movement that recalls cave painting, but there's also a touch of Pokemon-like adorability to their big, long-lashed eyes. The visual climax—the formerly white hare turns up in its brown summer coat, winking at the audience—may need a little adult explanation, but it's certainly a biologically legitimate twist. As a gentle, creatively depicted introduction to seasonal adaptation, this animal story will provide cozy entry-level nature study from the approach of first snowfall to the stubborn final melting of that last drift in spring. Copyright © 2011 The Board of Trustees of the University of Illinois

Verification of the technical parameters of head-only electrical stunning of pigs under commercial conditions

The European Food Safety Authority recommends a minimum current of 1.3 Amps for the electrical head-only stunning of pigs. However, it is stated as well that 'the technical reference data for head-only electrical stunning of pigs such as 1.3 Amps are either rather old or worked out under experimental laboratory conditions'. This study was carried out to verify the electrical parameters of pig stunning under commercial conditions. Altogether 145 fattener pigs (body weight range: 30-150 kg, median 109 kg) were tested at four different private slaughterhouses in Hungary where head-only electrical stunners were used with different constant voltage settings. In each case the following data were recorded: individual liveweight (kg), current (A) and voltage (V) (measured with an individually developed analogue device placed in the circuit), current duration (s), effectiveness of stunning, grading of carcass. Correlations between these parameters and effectiveness were examined. Besides that, any correlation between the test parameters and impedance of head was examined. In 128 out of the 145 cases the stunning was effective (88.3%). Effectiveness was significantly related to current but not to other parameters such as voltage and duration of load. Impedance of head was not correlated with the size of the animal and the meat grading scores. Generally, it was concluded that the use of a single electrical parameter (e.g. a minimum current of 1.3 A) as a prerequisite of good stunning is not ideal.

Hemodialysis-Induced Repetitive Myocardial Injury Results in Global and Segmental Reduction in Systolic Cardiac Function

Hemodialysis (HD)-induced regional wall motion abnormalities (RWMAs) are common in HD patients and driven by ischemia. In nondialysis patients, repeated ischemia leads to chronic reduction in left ventricular (LV) function. HD-induced myocardial ischemia may initiate the same process. We examined the effect of HD-induced repetitive myocardial stunning on global and regional LV function. We analyzed data from 30 patients, previously identified as developing HD-induced myocardial ischemia. Serial echocardiographic assessments of global and regional LV performance were performed at baseline and repeated after 12 mo. Several patients developed segments with a fixed reduction in systolic function of >60% after 1 yr. In this patient group, there was a significant reduction in resting LV ejection fraction (EF) from 61.5 +/- 10.1% to 52.9 +/- 8.6% (P < 0.007). Peak LV EF in response to dialysis also decreased from 59.5 +/- 10% versus 49.9 +/- 6.5% (P < 0.003), with a consequent increase in HD-induced hypotension (P < 0.0001). HD-induced myocardial stunning may progress over 12 mo to the development of regional fixed systolic dysfunction, consistent with underlying myocardial hibernation and fibrosis. This may be an important and potentially modifiable process in the development of heart failure in HD patients.

Radiation-Induced Thyroid Stunning: Differential Effects of 123I, 131I, 99mTc, and 211At on Iodide Transport and NIS mRNA Expression in Cultured Thyroid Cells

Recent clinical and experimental data demonstrate that thyroid stunning is caused by previous irradiation and may influence the efficacy of (131)I radiation therapy of thyroid cancer and possibly hyperthyroidism. To avoid stunning, many clinics have exchanged (131)I for (123)I for pretherapeutic diagnostic imaging and dose planning. Furthermore, recent in vitro studies indicate that (131)I irradiation reduces iodide uptake by downregulating the expression of the sodium iodide symporter (NIS). The rationale for this study was therefore to study effects on iodide transport and NIS messenger RNA (mRNA) expression in thyrocytes exposed to both (123)I and (131)I in addition to some other potentially interesting radionuclides. Thyrotropin-stimulated thyroid cell monolayers were exposed to 0.5 Gy of (123)I, (131)I, (99m)Tc, or (211)At, all being radionuclides transported via NIS, in the culture medium for 6 h, or to various absorbed doses of (123)I or (131)I for 48 h. NIS mRNA expression was analyzed using quantitative reverse-transcriptase polymerase chain reaction. Iodide transport and NIS mRNA expression were reduced by all radionuclides. At the same absorbed dose, iodide transport was reduced the most by (211)At, followed by (123)I and (99m)Tc (equally potent), whereas (131)I was least effective. The onset of NIS downregulation was rapid (<1 d after irradiation) in cells exposed to (123)I or (211)At and was delayed in cells irradiated with (131)I or (99m)Tc. Iodide transport and NIS expression were recovered only for (211)At. (123)I reduced the iodine transport and the NIS mRNA expression more efficiently than did (131)I at an equivalent absorbed dose, with a relative biological effectiveness of about 5. The stunning effect per unit absorbed dose is more severe for (123)I than for (131)I. Despite the lower absorbed dose per unit activity for (123)I than for (131)I, stunning by (123)I cannot be excluded in patients. The degree to which iodide transport capacity and NIS mRNA expression are reduced seems to be related to the biological effectiveness of the type of radiation delivering the absorbed dose to the target, with (211)At (which has the highest relative biological effectiveness) causing the highest degree of stunning per unit absorbed dose in the present study.

Species‐specific welfare aspects of the main systems of stunning and killing of farmed Carp

Species‐specific welfare aspects of the main systems of stunning and killing of farmed Carp

Electroencephalographic responses to concussive non-penetrative captive-bolt stunning in halothane-anaesthetised calves

AIM: To investigate the electroencephalographic (EEG) and cardiovascular responses of halothane-anaesthetised calves to non-penetrative captive-bolt stunning. METHODS: Ten calves were minimally anaesthetised with halothane, using an established anaesthesia protocol. The EEG, blood pressure and electrocardiogram (ECG) were recorded before and after non-penetrative captive-bolt stunning. Visual inspection and alterations in the total power of the EEG (Ptot) were used to investigate the effects of stunning. RESULTS: Captive-bolt stunning significantly altered cerebrocortical function in all animals. In four animals, Ptot decreased immediately following stunning and remained low throughout the recording period. In another five animals, Ptot responded to stunning in a biphasic manner characterised by an immediate decrease followed by a transient increase and then a final decrease to values similar to those of the non-biphasic animals. CONCLUSIONS: Non-penetrative captive-bolt stunning significantly altered cerebrocortical function in halothane-anaesthetised calves. The changes in cerebrocortical function would be sufficient to produce insensibility within 0 to 14 seconds in conscious animals.

Systems stunning with CO 2 gas on Manchego light lambs: Physiologic responses and stunning effectiveness

Effect of four stunning treatments using different CO 2 concentrations and exposure times (G1: 80%90 s; G2: 90%90 s; G3: 90%60 s; G4: 80%60 s) on hormonal, haematological and biochemical parameters in Manchego breed light lambs and their stunning effectiveness (% animals correctly stunned) was studied. An electrically stunned control treatment (G5) was used. G1 showed the highest plasmatic hormonal, red cell distribution (RDW) and lactate levels. Haemoglobin, mean corpuscular volume (MCV), mean cell haemoglobin (HbCM), glucose, lactate deshydrogenase (LDH), sodium, potassium and creatine kinase (CK) were highest in G5. Stunning effectiveness was maximum (100%) in G3 and G5, only 50% in G1 and G2 and minimum (30%) in G4. A discriminant analysis showed a function for discriminating between G5 and the gas stunned groups, and another one for discriminating between gas stunned groups. Only potassium and adrenaline variables marked the difference among groups.

The success of 131I ablation in thyroid cancer patients is significantly reduced after a diagnostic activity of 40 MBq 131I

Dosimetry studies have shown that activities of 131I as small as 10-20 MBq may cause a stunning effect. A result of this stunning effect may be a lower success rate of the ablative 131I therapy for differentiated thyroid carcinoma (DTC). The aim of this study was to determine whether pre-therapeutic uptake measurement with 40 MBq 131I causes a lower success rate of ablation. retrospective chart review study. In two hospitals the ablation protocols differed in one respect only: in the one hospital no diagnostic 131I was applied before ablation (group 1, n = 48), whereas in the other hospital a 24-h uptake-measurement with 40 MBq 131I was performed (group 2, n = 51). Included were all DTC patients without distant metastases who had undergone 131I ablation between July 2002 and December 2005, and who had returned for 131I follow-up. Successful ablation was defined as absence of pathological 131I uptake on diagnostic whole-body scintigraphy and undetectable thyroglobulin-levels under TSH stimulation. Overall, ablation was successful in 31/48 patients (65%) in group 1 and in 17/51 patients (33%) in group 2 (p=0.002). Multivariate analysis showed that pre-therapeutic uptake measurement using 40 MBq 131I was an independent determinant for success of ablation (p = 0.002). After applying a diagnostic activity of 40 MBq 131I before ablation, the success rate of ablation is severely reduced. Consequently, the routine application of 131I for diagnostic scintigraphy or uptake measurement prior to 131I ablation is best avoided.

Liver Function as Assessed by Breath Tests in Patients With Hepatocellular Carcinoma

Little is known on hepatic function in patients with hepatocellular carcinoma (HCC). Metabolic changes were explored in HCC patients before/after nonsurgical therapy. HCV-related Child-Pugh A cirrhotic patients with (n = 37) or without HCC (n = 14) and healthy controls (n = 23) were enrolled. Subjects underwent breath testing with (13)C-methacetin or (13)C-ketoisocaproate for exploring microsomal and mitochondrial function, respectively. HCC patients repeated the tests 1-2, 30, and 180 d after radiofrequency ablation (n = 27, RFA) or transarterial chemoembolization (n = 10, TACE). At baseline, cirrhotic patients showed decreased methacetin demethylation capacity compared with controls (8.1 +/- 2.1 versus 13.7 +/- 1.3% cum. dose exhaled at 60 min, M +/- CI, P < 0.001) and minor changes in ketoisocaproate decarboxylation. HCC patients had methacetin demethylation comparable to cirrhotic subjects, but a significantly lower ketoisocaproate decarboxylation (8.5 +/- 1.0 versus 11.6 +/- 1.9% cum. dose exhaled at 60 min, P < 0.001). Methacetin metabolism was significantly decreased following TACE (-28%, P < 0.05) but not RFA. Ketoisocaproate decarboxylation was unaffected by TACE but decreased after RFA (-27%, P < 0.05). A recovery was noticed with ketoisocaproate as a probe after 1 and 6 mo (P < 0.003). HCC recurrence was associated with early decrease of ketoisocaproate decarboxylation. Liver mitochondrial function is decreased in cirrhotic patients with HCC suggesting a possible tumor-induced suppressant effect. RFA but not TACE appears to spare residual (microsomal) liver mass, but induces such a transient stunning effect on mitochondrial function. Improved mitochondrial function after 1 and 6 mo from RFA may represent an additional parameter of treatment efficacy. Breath test assessing liver function may have potential applications in HCC management.

Comparison of two stunning/slaughtering methods on stress response and quality indicators of European sea bass ( Dicentrarchus labrax)

Two stunning/slaughtering methods, ice asphyxia and carbon dioxide narcosis, as common capture procedures in commercial farms, were compared with asphyxia without ice in order to assess their suitability as stunning methods for European sea bass. In this study we have analyzed the stunning effects on the stress response related to fish welfare, and on the meat quality. Sampling was performed 0, 2, 9, 24, 48, 72 and 96 h after death, and for all sampling times, rigor mortis assessment, muscle pH, eye refraction index and sensory evaluation were determined as quality parameters. Moreover, osmolality, glucose, lactate and cortisol were determined as stress indicators. The muscle pH values were significantly lower in CO 2 narcosis group from the first 9 h until the end of the study in comparison to the respective zero time. If we compared muscle pH values between each slaughtering method with the asphyxia group through sampling time, we observed statistically higher values in CO 2 and ice asphyxia throughout the study. The sensorial evaluation showed a progressive decrease in the three groups analysed versus the respective zero time, although the comparison with the control group showed statistical differences only at zero and nine hours sampling time. Regarding stress indicators, all of them showed significant higher levels after both slaughtering methods compared with the undisturbed group and significant lower levels if compared with the asphyxia group. Our results also show that asphyxia produced a five-fold increase in glucose levels whereas other methods studied only produced a 1.5–1.7-fold increase. Cortisol levels increased 8-fold after asphyxia whereas the other slaughtering methods provoked a 5-fold increase. In summary, the results indicate that both methods are suitable to process fish although the CO 2 treatment showed lower lactate and cortisol response compared to asphyxia in ice. In terms of quality, differences between methods are minor.

The Effects of Low-Atmosphere Stunning and Deboning Time on Broiler Breast Meat Quality

A randomized complete block design with 3 replications (n = 432, 72 broilers per treatment) was used to evaluate the effects of electrical (ES) and vacuum stunning (VS) on broiler breast meat quality. Electrical stunning was performed by applying 11.5 V, <0.05 mA, AC to DC current for 3 s for each broiler. Vacuum stunning was accomplished by exposing the birds to a low atmospheric pressure of 597 to 632 mmHg in an airtight decompression chamber. Breast removal was then performed at 0.75, 2, and 4 h postmortem for each stunning method. Color, pH, cook loss, and shear force values were measured on breasts that were removed from the right side of the carcass. Breasts removed from the left side of the carcass were used for consumer acceptability testing. The L* values were lower (P < 0.05) for VS than ES at 4-and 2-h deboning times. On average, 15-min and 24-h postmortem pH values were not different (P > 0.05) for both stunning method and deboning time. Shear force did not differ (P > 0.05) between stunning methods but decreased (P < 0.05) as deboning time increased. On average, no differences (P > 0.05) existed in consumer acceptability (appearance, texture, flavor, overall) among breast meat from ES or VS birds that were deboned at 2 or 4 h. However, consumers could be clustered into 8 groups based on preference and liking of samples regarding overall and texture acceptability. Sixty-five percent of consumers (3 clusters) liked all broiler breast treatments. Within these 3 clusters, some consumers preferred (P < 0.05) 4-h deboned samples over those deboned at 2 h (cluster 7), and other consumers preferred (P < 0.05) those deboned at 2 h over 4-h samples (cluster 6). Data revealed that both stunning methods provided high-quality breast meat with minimal product differences.