Effect of stunning method,carcase chilling temperature and filleting time on the texture of turkey breast meat

1. Three hundred and sixty turkeys comprising 16 week‐old stags (medium stags), 22 week‐old stags (large stags) or 52 week‐old hens (hens) were stunned with either argon‐induced anoxia, 30% carbon dioxide in argon with 2% residual oxygen (gas mixture) or electric current and the carcases were processed under commercial conditions. The carcases were chilled at either 16°C or 3°C using a commercial immersion chiller and the carcases were held in a cold room (3°C).

2. Breast muscles (pectoralis major) were filleted at either 2, 3, 5 or 18 h post‐mortem, and pH and muscle temperature were measured at the time of filleting for the medium and large stags. The breast fillets removed soon after killing were stored at 3°C until transported to the laboratory.

3. All the breast fillets were cooked to an internal muscle temperature of 85°C and their texture was measured instrumentally. The fillets were weighed before and after cooking to determine the proportional cooking loss.

4. The results showed that, for electrical stunning, the rate of pH fall soon after killing differed between the bird types, and it resulted in a variable texture in the breast meat when filleting was performed soon after killing. The medium stags had a relatively slower rate of pH fall and filleting them soon after killing resulted in tougher breast meat.

5. By contrast, in all the three bird types, gas stunning resulted in a rapid pH fall soon after killing and produced tender breast meat at all the filleting times tested.

6. The cooking loss was higher in the large stags than in the medium stags or hens.

7. Stunning turkeys by anoxia or 30% carbon dioxide in argon would enable filleting to be performed soon after killing, and produce less variable‐and more tender breast meat.     

Effect of the method of killing,interval between killing and neck cutting and blood vessels cut on blood loss in broilers

1. Broiler chickens were killed using 90% argon in air, or 30% carbon dioxide and 60% argon in air or 120 mA per bird in a waterbath with a 50 Hz alternating electric current. Ventral or unilateral neck cutting was performed at 1, 3 or 5 min after killing. In addition, a group of broilers was stunned with 120 mA per bird in a waterbath using 1500 Hz alternating current and were bled out with a ventral neck cut within 20 s from stunning.

2. Blood leaving the neck wound was collected in a bin placed on an electronic balance and a computer program calculated the cumulative blood loss up to 100 s after neck cutting.

3. Bleed‐out was significantly affected by killing method and time of neck cutting. Broilers killed with the carbon dioxide‐argon mixture bled‐out less than those killed with argon or 50 Hz electric current. When compared with the 1 min neck cutting interval, a delay of 3 or 5 min resulted in a lower bleed‐out. High frequency electrical stunning and ventral neck cutting within 20 s resulted in a slightly higher bleed‐out than those recorded for the killing methods. However, within argon killing, a delay of 3 or 5 min in ventral or unilateral neck cutting had no significant effect on the bleed‐out. In broilers killed with the carbon dioxide‐argon mixture a 3 min delay in ventral neck cutting or a 5 min delay in unilateral neck cutting resulted in lower bleed‐out.

4. Neck cutting of broilers within 5 min after argon killing or 3 min after killing with the carbon dioxide‐argon mixture would result in a satisfactory bleed‐out.     

Effect of electrical and gaseous stunning on the carcase and meat quality of broilers

1. The aim of the experiment was to investigate the effect of gaseous stunning methods on the carcase and meat quality of broilers (dead weight 1.0 to 2.3 kg) in comparison with electrical stunning.

2. Two replicates of broilers (age 54 and 59 d respectively) were stunned in carbon dioxide, in argon or by electric current, and the carcases were plucked either by a mechanical plucker or by hand.

3. Carcase and meat quality were evaluated to determine the effect of these stunning treatments and plucking methods. The quality factors measured included pH at 20 min post‐mortem, ultimate pH, texture and colour of the pectoralis major muscle, and the incidence of carcase appearance defects, cooking loss, broken bones and bruises in the breast and leg muscles.

4. Stunning method had a significant effect on pH at 20 min, ultimate pH, texture and colour of breast meat. Plucking method had a significant effect on the cooking loss and texture.

5. Argon stunning resulted in fewer muscle haemorrhages, a more rapid early post‐mortem fall in pH and more tender breast meat than in the electrically stunned broilers; carbon dioxide stunned broilers had intermediate values for pH decline and meat tenderness but were not significantly different from argon stunning regarding muscle haemorrhages.

6. Appearance defects occurred to a similar extent in all the stunning methods and mechanical plucking resulted in 4 times as many defects compared with hand plucking; the incidence of broken bones was higher in mechanically plucked broilers than in hand plucked carcases.

7. Gaseous stunning of broilers produced relatively better quality carcases and meat than electrical stunning, and therefore may have commercial advantages.     

Improving the nutritional quality and shelf life of broiler meat by feeding diets supplemented with fermented pomegranate (Punica granatum L.) by-products

1. Four experimental diets containing 0, 0.5, 1.0 and 2.0% fermented pomegranate by-products (FPB) were supplied to 320d-old broilers to evaluate the effects of FPB on growth performance, nutritional composition, fatty acid profile and oxidative stability of meat.

2. Dietary supplementation of FPB linearly increased the weight gain and feed intake of broilers with linear reduction in feed conversion ratio.

3. The crude protein, iron, magnesium, and sodium content were linearly higher, whereas cholesterol was linearly lower in the breast meat of FPB-supplemented broilers. In thigh meat, linearly lower ether extract and cholesterol with higher moisture was noted in response to increasing levels of FPB.

4. The proportion of saturated fatty acids was both linearly and quadratically lower in breast and thigh meat, whereas those of monounsaturated fatty acids of breast (linear and quadratic) and n-3 fatty acids of breast and thigh (linear) meat was higher in the FPB-supplemented broilers. The n-6/n-3 ratio of breast meat was linearly lower in response to FPB supplementation. The hypocholesterolaemic to hypercholesterolaemic ratio of thigh meat was higher in the FPB-supplemented groups.

5. The thiobarbituric acid reactive substances and pH value were lower in the breast and thigh meat of FPB-supplemented broilers.

6. Thus, additive supplementation of the diet with up to 2% FPB improved the nutritional quality, fatty acid profile and shelf life of broiler meat.     

Sensory evaluation of breast fillets from argon‐stunned and electrically‐stimulated broiler carcases processed under commercial conditions

1. A comparison of eating quality of breast meat (pectoralis major) filleted at 2 h post‐mortem was made between broilers stunned with argon‐induced anoxia (less than 2% residual oxygen) and broilers which were electrically‐stunned and their carcases electrically‐stimulated under commercial conditions.

2. Fifty breast muscles were filleted from the carcases of argon stunned broilers at 2 h post‐mortem. Fifty breast muscles were also removed at the same time from the carcases of broilers which were electrically‐stunned and electrically‐stimulated. A ‘control’ group of broilers which were electrically‐stunned and electrically‐stimulated and processed under as similar conditions as possible were also filleted after overnight ageing in the air chiller.

3. Sensory analysis was performed using 10 trained panelists, who were asked to rate the fillets on a 1 to 8 hedonic scale for taste, texture, juiciness and overall liking.

4. The mean ranks for texture and overall liking differed between the groups. The mean ranks based on texture were the highest for control, intermediate for argon stunning and the lowest for electrical stimulation treatment group. The mean ranks based on overall liking were similar for the control and argon stunning groups, and their ranks were higher than that of electrical stimulation treatment group. The mean ranks for taste and juiciness did not differ significantly between the groups.

5. It is concluded that, in comparison with electrical stimulation of broiler carcases soon after plucking, stunning broilers with argon‐induced anoxia produced tender breast meat when filleted at 2 h postmortem.     

Effects of degree of fatness in broilers on other carcass characteristics: Relationship between fatness and the stability of meat and adipose tissue1

1. Three trials were carried out to compare the effects of different degrees of fatness in broilers and of dietary a‐tocopherol (AT) concentrations on the stability of meat and adipose tissue at 5 to 9 weeks of age.

2. In spite of higher concentrations of AT in carcass fat, the meat and abdominal fat of lean broilers were less stable than those of obese birds, apparently due to an increase in the unsaturation of their carcass fat.

3. Dietary AT improved significantly the stability of meat and adipose tissue, irrespective of the degree of fatness. However, the difference in the stability of these tissues between obese and lean broilers remained apparent even with 60 mg AT/kg of the diet.

4. A linear relationship was observed between dietary AT and the stability of adipose tissue, whereas the relationship between AT intake and meat stability was logarithmic.     

Effects of ascorbic acid and α-lipoic acid on performance and meat quality of broilers subjected to heat stress

1. The present study was aimed to investigate the effect of adding ascorbic acid or α-lipoic acid to to the diet of broilers exposed to heat stress on performance and meat quality.

2. Heat stress caused a decrease in final body weight and feed consumption, whilst ascorbic acid (AA) and α-lipoic acid (ALA) partly prevented the decrease in final body weight of males.

3. While heat stress increased the pH values of broiler drumsticks and breast meat, AA and ALA partly reduced this increase. For meat quality, AA and ALA reduced the adverse effects on the relative yellowness value, particularly on d 14 of storage.

4. It was determined that heat stress affected the microbiological quality of meat adversely, and that AA and ALA alleviated this effect to a certain extent.

5. In conclusion, while heat stress affected body weight gain and meat quality adversely, the supplementation of the ration with AA and ALA partly alleviated these adverse effects.     

Carcass yield and meat quality in broilers fed with canola meal

1. This study evaluated the effects of canola meal in broiler diets on carcass yield, carcass composition, and instrumental and sensory analyses of meat.

2. A total of 320 one-day-old Cobb broilers were used in a 35-d experiment using a completely randomised design with 5 concentrations of canola meal (0, 10, 20, 30 and 40%) as a dietary substitute for soya bean meal.

3. Polynomial regression at 5% significance was used to evaluate the effects of canola meal content. The following variables were measured: carcass yield, chemical composition of meat, and instrumental and sensorial analyses.

4. The results showed that carcass yield exhibited a quadratic effect that was crescent to the level of 18% of canola meal based on the weight of the leg and a quadratic increase at concentrations up to 8.4% of canola meal based on the weight of the chest. The yield of the chest exhibited a linear behaviour.

5. The chemical composition of leg meat, instrumental analysis of breast meat and sensory characteristics of the breast meat was not significantly affected by the inclusion of canola meal. The chemical composition of the breast meat exhibited an increased linear effect in terms of dry matter and ether extract and a decreased linear behaviour in terms of the ash content.

6. In conclusion, soya bean meal can be substituted with canola meal at concentrations up to 20% of the total diet without affecting carcass yield, composition of meat or the instrumental or sensory characteristics of the meat of broilers.     

Dietary limitation of isoleucine and valine in diets based on maize, soybean meal, and meat and bone meal for broiler chickens

1. The dietary limitation of isoleucine (Ile) and valine (Val) was evaluated in broilers. Common diets were given to all broilers from 0 to 28 d of age. Experimental diets were provided from 28 to 42 d of age.

2. The experimental test diet was based primarily on maize, soybean meal, and meat and bone meal, and formulated to satisfy all nutrient recommendations with the exception of Ile and Val.

3. Diets were supplemented with L-Ile and L-Val at either 0·5 or 1·0 g kg^?1 of diet, alone or in combination. A diet composed only of commercially available amino acids and formulated to satisfy all nutrient requirements served as a positive control.

4. Body weight gain was depressed by the test diet, but recovered to a weight similar to birds fed on the positive control when Val was added to the test diet either alone or in combination with Ile. Feed efficiency improved when Val and Ile were simultaneously supplemented.

5. Abdominal fat yield was reduced with the combined supplementation of Val and Ile. Breast meat yield appeared to be more sensitive to Ile supplementation than to Val.

6. The results suggest that live performance may be more sensitive to Val, while breast meat yield was maximised with Ile supplementation. However, their combination is required for optimised growth and meat yield.     

Effect of early filleting on the texture of breast muscle of broilers stunned with argon‐induced anoxia

1. Eighty broilers were stunned in batches of 10 with less than 1 % oxygen (air displaced by argon) and their chilled breasts were filleted at 2, 3, 5 or 21 h (argon control) post‐mortem. Twenty broilers were electrically stunned and their breasts filleted at 21 h post‐mortem (electrical control).

2. Meat quality variables studied included pH of the pectoralis major muscle measured at 20 min post‐mortem and at filleting, and texture at 24 h post‐mortem.

3. Argon stunning resulted in a rapid early post‐mortem pH fall, but there was no indication of heat toughening in the breast muscles.

4. Filleting at 2 h post‐mortem, after argon stunning, resulted in 5% of the p. major muscles having greater than 4 kg yield force (slightly tough).

5. Although post‐mortem ageing of argon stunned broilers improved the texture of breast muscle, it is inferred that filleting at 2 h postmortem resulted in breast muscle with acceptable texture.     

Replacement of maize by triticale in broiler diets

1. The nitrogen‐corrected metabolisable energy contents of the triticale varieties Multi Graze, Graze Grain 70, 204 and 131 were 12.28, 12.69, 12.37 and 12.03 MJ/kg respectively.

2. Increasing proportions (0, 25, 50 or 75%) of the maize of a diet were replaced by triticale 131 to provide diets of equal energy and nitrogen contents for broilers. These diets resulted in weight gains of 1.775, 1.782, 1.713 and 1.808 kg respectively at 8 weeks and there were no significant differences among efficiencies of food conversions.

3. Dressed carcass weights as percentages of body weight were 74.38, 75.01, 73.98 and 74.50 respectively and did not differ significantly.

4. Triticale in the diet did not seem to influence the relative weights of either liver or gizzard.

5. The flavour of the meat seemed to become less acceptable as the triticale in the diet increased but there were no significant differences in tenderness and juiciness of the meat caused by the treatments.     

Comparative studies on the histochemical properties of M. iliotibialis lateralis from Kumamoto Cochin crossbred roaster and broiler chickens

1. Histochemical properties of M. iliotibialis lateralis were compared between Kumamoto Cochin (a Japanese native breed) crossbred roasters (KC roasters, 112 d of age) and normal broilers (56 d of age).

2. Myofibres were divided into Types II‐R, II‐I and II‐W showing high, moderate and low reduced nicotinamide adenine dinucleotide dehydrogenase (NADH‐DH) activities, respectively.

3. Subsarcolemmal formazan granules indicating very strong NADH‐DH activity in Type II‐R fibres were observed only in KC roasters. In both sexes the percentage of Type II‐R fibres present was greater in KC roasters than in broilers.

4. These results indicated marked differences in histochemical properties and meat quality between KC roasters and broilers.     

Use of ambroxol and bromhexine as mucolytics for enhanced diffusion of furaltadone into tracheobronchial secretions in broilers

1. Ambroxol and bromhexine were evaluated as mucolytics and to enhance the passage of furaltadone into tracheobronchial secretions (TBS) in chronic complicated respiratory disease‐affected broilers.

2. Viscosity of TBS was noticeably increased in the ambroxol‐treated birds and only slightly increased in the bromhexine groups; however, the physical (nature) of TBS was superior in the ambroxol‐treated broilers.

3. There was a clear increase in the passage of furaltadone into tracheobronchial secretions only in the ambroxol‐treated birds.

4. Everyday use of ambroxol in broilers is discussed.     

Evaluation of putative appetite suppressants in the domestic fowl (Gallus domesticus)

1. The effectiveness of the appetite suppressants fenflur‐amine, furanone and crotonolactone were evaluated in a series of experiments with adult male layers and growing broilers of both sexes fed on diets with concentrations of up to 1000 mg/kg.

2. Fenfluramine produced a curvilinear decrease in food intake and body weight in adult layers and growing broilers.

3. Inconsistent responses to furanone and crotonolactone were obtained with adult layers and broilers in cages, but a similar decrease in food intake and body weight for both drugs was recorded in male broilers raised in floor pens.

4. The responses to subcutaneous injection of 20 mg/kg of each drug on food intake over 24 h were comparable to those for dietary inclusion. Fenfluramine, however, produced a greater response in male compared with female broilers and induced signs of hyper‐thermia in broilers and layers.

5. Subcutaneous injection of 50 mg crotonolactone/kg was associated with decreases in the food intakes of 4 strains and there was evidence of different responses between lines.

6. It was concluded that none of the drugs used were likely to be suitable for the control of food intake in broiler breeder flocks.     

Ratification of broiler carcase condemnations in poultry meat inspection

1. In the years 1985 to 1989 decisions (approvals and condemnations) made by poultry meat inspectors were examined by the individual reinspection of 26,815 broiler carcases.

2. The extent of agreement between inspection and revision ranged between 83.2 and 86.2%.

3. Agreement between inspectors and revisors was higher for the category of approved birds than for the condemned category.

4. Differences in the criteria used to assess the birds were observed.

5. The conclusion was drawn that findings in meat inspection require further discussion to reach an agreed standard.     

Fumigation of poultry food with methyl bromide: Effects on flavour and acceptability of broiler meat

1. Broilers were fed on control and treated commercial diets to test the effects of fumigation with methyl bromide gas at 69% and 25% over the value recommended for the elimination of salmonellae.

2. A trained sensory panel found significant taint in roasted meat from birds fed on the fumigated food. More than half of the consumers in the home panel rated the control birds better than the birds fed on the fumigated food.

3. Growth of broilers was not affected by the treatment.     

Cross‐contamination during the scalding and plucking of broilers

1. Experiments were carried out in two poultry slaughtering plants to estimate cross‐contamination occurring during the scalding and plucking of broilers.

2. To simulate the external (dust and feather) and internal (intestinal) contamination of broilers the carcasses were artificially contaminated with a strain of Escherichia coli K12.

3. Cross‐contamination occurred at both stages in the processing when the carcasses had been contaminated externally; when the broilers had been contaminated internally slight cross‐contamination occurred only during plucking.

4. Broilers which were contaminated externally before scalding resulted in more numerous carcasses that were contaminated after the whole slaughtering procedure than those contaminated internally.

5. In one processing plant there were fewer contaminated carcasses after cooling than after plucking, while in the other plant no differences were found in the number of positive carcasses after these two stages in processing.     

Effects of dietary chromium chloride,nicotinic acid and copper sulphate on meat of broilers

1.?Combinations of chromium and copper were added to the diet to assess their effects on broiler meat characteristics.

2.?For this purpose 175 one-day-old broiler chicks were divided into 7 equal groups and were given treatment feeds containing copper sulphate, chromium chloride and nicotinic acid in different combinations.

3.?The study was carried out for 5 weeks and samples were collected at the end of 15, 29 and 35 d of treatment and at 42 d after a withdrawal period of one week.

4.?Cholesterol content had decreased significantly in breast meat at d 29 in all treatment groups. In thigh meat, it decreased significantly at d 29 in groups receiving two concentrations of chromium + two concentrations of copper. Cholesterol content remained lower even after withholding the treatment for one week.

5.?Crude fat content decreased significantly in breast meat in all treatment groups. In thigh meat, at d 29, a significant reduction in crude fat was observed only in birds receiving low chromium and high copper.

6.?Crude protein at d 29 increased significantly in breast meat of birds receiving low chromium and high copper, and low or high chromium, while it decreased significantly in treatment groups after withholding the treatment. In thigh meat, at d 29, it increased significantly in treatment groups but decreased significantly after withholding the treatment.

7.?It was concluded that chromium and copper, along with nicotinic acid, have modulating effects on broiler meat under tropical conditions.     

Effect of environmental temperature,dietary energy,age and sex on broiler carcase portions and palatability

1. Two environmentally‐controlled houses, one at a constant 21°C (low temperature), the other diurnally cycling at 21 to 30°C (high temperature) and two diets of 13.0 MJ ME/kg (low energy, LE) and 13.8 MJ ME/kg (high energy, HE) were used to study the effects of age and sex on broiler carcase portions, dissected tissue proportions, and meat quality.

2. Slaughtering at 54 d instead of 34 d produced broilers with breast and leg weights of 277 and 308 instead of 284 and 319 g/kg carcase respectively, and a higher cutting loss (31 versus 6 g/kg carcass).

3. Males had lower proportions of breast, breast meat and fat, but higher proportions of leg, leg bone, and total meat to fat ratio than females.

4. Cycling high temperature resulted in higher breast, and lower leg proportions than constant low temperature.

5. High dietary energy content increased cutting loss, proportion of breast fat and lowered meat to fat ratio when compared to low energy, but did not affect the flavour of the meat, which was improved by age and high environmental temperature.     

Effect of Melissa officinalis supplementation on growth performance and meat quality characteristics in organically produced broilers

1. A trial was conducted to study the effect of Melissa officinalis supplementation on organic broiler performance and meat chemical, microbiological, sensory and nutritional quality.

2. Male and female day-old Ross 308 chicks were fed on a standard commercial diet containing 0, 2.5, 5 or 10 g/kg feed ground M. officinalis for 84 d before slaughter.

3. Weight gain and feed conversion ratio were significantly improved in the broilers receiving either 5 or 10 mg M. officinalis/kg feed.

4. Inclusion of M. officinalis did not affect muscle chemical and fatty acid composition.

5. On the basis of microbiological and sensory experimental data and subsequent extension of meat shelf life, M. officinalis did not reduce the microbial populations of the meat, but was effective in limiting lipid oxidation.