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Deep pectoral myopathy: Prevalence in 7 weeks old broiler chickens in Bulgaria

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The purpose of the study was to investigate the prevalence of DPM (deep pectoral myopathy) in young broiler chickens according to their live weight during slaughtering inspection. Chickens (Ross 308 and Cobb 500) reared under intensive conditions and slaughtered on 7 weeks of age were allotted in 2 flocks of 20 000 birds each, named flock A and flock B, according to the ratio live weight / carcass weight (2.3/1.7 and 2.6/1.9, respectively). During deboning of the breast muscles, samples showing gross lesions of the m. supracoracoideus were collected and a conventional histology was performed. The overall DPM prevalence (for the 2 flocks) was 0.51% and the specific prevalence by flock was significantly higher in the flock B (P < 0.01). The frequency of early DPM lesions characterized by an acute inflammatory reaction (oedema, haemorrhages and infiltrate of macrophages and heterophils) coupled to a severe muscle discoid necrosis was significantly higher in the flock A (P < 0.05) whereas the proportion of older lesions in which the affected muscle showing a typical green colour before being replaced by fibrous or adipose tissue was dramatically increased in the heaviest chickens (flock B) (P < 0.001). These results confirm the DPM occurrence in meattype growing birds even in young broilers (7 weeks old).
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Revue Méd. Vét., 2011, 162, 6, 279-283
Introduction
Deep pectoral myopathy (DPM), also known as Oregon
muscle disease or green muscle disease, was first described
in 1968 as “degenerative myopathy” in turkeys [6]. Subsequently
it was studied at the Oregon State University by Harper [10]
and his collaborators [17]. The disease involves the wing ele-
vating muscle known as the deep pectoral muscle or M.
supracoracoidus hence; it is referred to as degenerative myo-
pathy of the supracoracoideus (DMS).
A probable analogy can be drawn between this disease of
poultry and the so-called “march gangrene” (anterior tibial
syndrome) in humans [16]. The “march gangrene”, so-named
because of its occurrence among the military personnel, is an
ischemic necrosis of the muscle in the myofascial compart-
ment on the anterior of human tibia following increased
intra-compartmental pressure, clinically characterized by
swelling, redness and pain, paralysis of the extensor digito-
rum brevis, and loss of sensation in the first interdigital cleft.
This disease is not preceded by vascular disease or trauma,
but it is usually associated with a recent period of locomotor
activity in otherwise healthy individuals [19]. The muscle is
firstly swollen, pallid and oedematous, and in untreated cases
this condition progresses to necrosis which has been described
as appearing greyish brown and wood-hard [19]. The general
reaction of the muscle is that occurring in ischemia and changes
similar to those in the broiler muscle supracoracoideus may
be seen [19].
Initial attempts to discover the cause of DPM were unsuc-
cessful. Cultured tissue from affected turkeys failed to show
evidence of bacterial or viral infection [9]. In addition, dietary
supplementation with vitamin E, methionine and selenium
also failed to reduce the incidence of DPM in turkeys [9, 19].
GRUNDER et al. [7] could not find any difference in DPM
incidence between groups of turkeys fed with corn or wheat
based rations. The cause of DPM appears to be not related to
nutrition disequilibrium or to a pathogen.
SUMMARY
The purpose of the study was to investigate the prevalence of DPM (deep
pectoral myopathy) in young broiler chickens according to their live weight
during slaughtering inspection. Chickens (Ross 308 and Cobb 500) reared
under intensive conditions and slaughtered on 7 weeks of age were allotted
in 2 flocks of 20 000 birds each, named flock A and flock B, according to
the ratio live weight / carcass weight (2.3/1.7 and 2.6/1.9, respectively).
During deboning of the breast muscles, samples showing gross lesions of
the m. supracoracoideus were collected and a conventional histology was
performed. The overall DPM prevalence (for the 2 flocks) was 0.51% and
the specific prevalence by flock was significantly higher in the flock B (P < 0.01).
The frequency of early DPM lesions characterized by an acute inflammatory
reaction (oedema, haemorrhages and infiltrate of macrophages and hetero-
phils) coupled to a severe muscle discoid necrosis was significantly higher
in the flock A (P < 0.05) whereas the proportion of older lesions in which
the affected muscle showing a typical green colour before being replaced by
fibrous or adipose tissue was dramatically increased in the heaviest chickens
(flock B) (P < 0.001). These results confirm the DPM occurrence in meat-
type growing birds even in young broilers (7 weeks old).
Keywords: Deep pectoral myopathy, broiler chickens,
Bulgaria, histology, acute inflammatory reaction, muscle
necrosis.
RÉSUMÉ
Myopathie du pectoral profond : prévalence chez les poulets de chair
âgés de 7 semaines en Bulgarie
Le but de cette étude a été de déterminer la prévalence de la myopathie du
pectoral profond (MPP) chez de jeunes poulets de chair en fonction de leur
poids vif durant l’inspection des carcasses à l’abattoir. Des poulets (Ross
308 et Cobb 500) élevés en mode intensif et abattus à 7 semaines ont été
répartis en 2 groupes de 20000 oiseaux chacun, groupe A et groupe B, en
fonction du rapport poids vif / poids de la carcasse (respectivement 2,3/1,7
et 2,6/1,9). Durant le désossage des filets, les échantillons présentant des
lésions macroscopiques du m. supracoracoideus ont été collectés et analysés
par histologie conventionnelle. La prévalence globale de la MPP (pour les 2
groupes) a été de 0,51 % et la prévalence spécifique par groupe a été signi-
ficativement plus importante dans le groupe B (P < 0.01). La fréquence des
lésions précoces caractérisées par une réaction inflammatoire aiguë
(œdème, hémorragies, infiltrat par des macrophages et des hétérophiles)
couplée à une nécrose discoïde sévère du muscle a été significativement plus
élevée dans le groupe A (P < 0.05) alors que les lésions plus anciennes (dans
lesquelles le muscle atteint présente une coloration verte typique avant d’être
remplacé par du tissu fibreux ou adipeux) se sont avérées beaucoup plus fré-
quentes dans le groupe B, celui des poulets les plus lourds. Ces résultats
confirment l’existence de MPP chez les oiseaux sélectionnées pour la pro-
duction de viande, y compris chez des poulets jeunes (de 7 semaines).
Mots clés : Myopathie du pectoral profond, poulet de
chair, Bulgarie, histologie, réaction inflammatoire aiguë,
nécrose musculaire.
Deep pectoral myopathy: prevalence in 7
weeks old broiler chickens in Bulgaria
I. DINEV1*, D. KANAKOV2*
1Department of General and Clinical Pathology, Faculty of Veterinary Medicine, Trakia University, 6 000 Stara Zagora, BULGARIA.
2Department of Internal Medicine, Faculty of Veterinary Medicine, Trakia University, 6 000 Stara Zagora, BULGARIA.
*Corresponding author: idinev@uni-sz.bg
Revue Méd. Vét., 2011, 162, 6, 279-283
280 DINEV (I.) AND KANAKOV (D.)
It is generally recognized that DPM is an ischemic necrosis
that develops in the deep pectoral muscle (supracoracoideus
or pectoralis minor muscle) mainly because this muscle is
surrounded by inelastic fascia and the sternum, which do not
allow the muscle mass to shell in response to the physiological
changes occurring when muscles exercised, as in wing flap-
ping [12]. The lesion does not impair the general health in
birds and it is generally found during cut-up and deboning.
No public health significant problem is associated to DPM,
but it is aesthetically undesirable. The fillet should be removed,
whereas the rest of the carcass is still fit for human consumption
[12]. However, the required trimming operations determine
the downgrading of the products and produce an economic
loss for the industry, especially because it affects the more
valuable part of the carcass. Although this disease was first
recognized in adult meat-type turkey and chicken breeders, it
is becoming more and more common in meat-type growing
birds [3, 8, 13]. According to SILLER [17], DPM occurs
exclusively in birds that have been specially selected for
breast muscle development.
The purpose of the study was to present the results obtained
from slaughtering inspection and histopathology in sponta-
neous cases of deep pectoral myopathy (DPM) reported for
the first time in broiler chickens in Bulgaria, according to the
age and live weight of the birds.
Materials and Methods
ANIMALS
The investigation was carried out using the material from
a large Bulgarian poultry slaughterhouse in Stara Zagora.
Chickens were originated from a farm in the same province
where they were reared under intensive conditions and were
slaughtered on 7 weeks of age. The samples showing gross
lesions were collected during the deboning of breast muscles
of broiler chickens. The statistical analysis and comparison
of the incidence of the lesions were made during inspection
of carcasses originating from two different flocks (10 000
carcasses were inspected for each flock). The flocks consisted
of 20 000 birds each, belonging to both sexes and to 2 com-
mercial strains: Ross 308 and Cobb 500, mixed dispropor-
tionately. The mean life weight to mean carcass weight ratios
were 2.3/1.7 and 2.6/1.9 in the flock A and the flock B,
respectively.
HISTOLOGICAL ANALYSIS
After macroscopic examination, 10 samples with lesions
from the m. supracoracoideus were taken from each flock
for histological investigations. The samples were fixed in
10% neutral formalin, processed routinely and embedded in
paraffin. The obtained sections approximately 5µm were
stained with haematoxylin-eosin.
STATISTICAL ANALYSIS
The data were statistically processed by a chi 2 test for
comparing the 2 flocks. Differences were considered as
significant when P < 0.05.
Results
Table I shows the incidence and distribution of the DPM
characteristic lesions for both flocks, determined on the pro-
cessing line after the breast-deboning area. The overall inci-
dence of DPM was 0.51%. The total lesions incidence was
significantly higher in the flock B with the highest live/carcass
weight ratio than in the flock A (P < 0.01). The prevalence
of early lesions was twice higher in flock “A” (the birds with
lower live/carcass weight ratio) (P < 0.05) whereas later
stage lesions occurred much more frequently (10 times) in
heavier birds (flock “B”) (P < 0.001).
Macroscopically, early lesions showed oedema, hyperaemia
and haemorrhages of the supracoracoid muscle. One or both
supracoracoid muscles were affected at a various extent. The
changes vary by intensity from separate, focal to diffuse
damage affecting the whole muscle. Commonly the lesion
was sharply confined from the unaffected part of the muscle
(figure 1). The fascia overlying and separating it from the
superficial pectoral muscle was thickened, opaque and some-
times covered by a gelatinous matter. In older cases, the
acute oedema has disappeared. The affected muscles were
intensive green in contrast to the unaffected tissue and exhi-
bited single or multiple haemorrhages (figure 2). The green
areas were generally confined to the surface but gradually
they penetrated more deeply into the necrotic tissue leading
to the occurrence of irregular green bands of varying thickness
surrounding the pale necrotic muscle in cross section. In the
oldest lesions, the colour intensity of the muscle was alleviated,
1Flocks were characterized by the ratio mean live weight / mean carcass weight;
Different superscripts a,b in the same column indicate significant differences between flocks (P < 0.05) with a chi 2 test.
Flocks1Early lesions Older lesions Total lesions
Flock A (2.3/1.7)10.32%a0.05%b0.37%b
Flock B (2.6/1.9)10.16%b0.48%a0.64%a
Total 0.24% 0.27% 0.51%
TABLE I: Incidence of DPM (Deep pectoral myopathy) in the 2 flocks of broiler chickens reared under intensive conditions in the farm
in Stara Zagora province.
Revue Méd. Vét., 2011, 162, 6, 279-283
PREVALENCE OF DPM IN BROILER CHICKENS 281
becoming pale yellow-green, and haemorrhages were reduced
(figure 3). The necrotic muscle bundles appeared dry and
brittle and usually the entire lesion was enclosed by a thick
connective tissue capsule sequestrating it from the remaining
muscle tissue. Sometimes the affected muscle appeared with
reduced volume, fibrous and hard.
The histological investigations confirmed the acute inflam-
mation in early DPM lesions. Degenerative necrotic changes
or sometimes Zenker’s degeneration, increased acidophilia
and oedema were observed. An infiltrate of inflammatory
cells (mainly macrophages and some heterophil leukocytes)
was found in the affected area (figure 4). The necrosis of the
muscle bundle was arranged as a discoid form and the so-called
discoid necrosis resulted in the separation of the individual
sarcomeres (figure 5). In the more chronic lesions, the muscle
fibres were almost entirely replaced by fibrous and/or adipose
tissue (figure 6).
Discussion
In the present study, the DPM prevalence is significantly
more elevated in the heavier chickens. This finding is in
agreement with CRESPO and SHIVARPRASAD [5], sug-
gesting that DPM is mostly prevalent in heavy birds.
Moreover, as in the present study, the incidence of old
lesions, indicating the chronicity of the muscle degeneration,
was markedly higher in the biggest chickens, the DPM can
FIGURE 1: Above – early lesion of DPM (Deep pectoral myopathy) cha-
racterized by oedema, hyperaemia and discoloration of the m.
supracoracoideus. The lesion is sharply delineated (arrow) from
the unaffected part. Below – normal m. supracoracoideus.
FIGURE 2: Old lesion of DPM (Deep pectoral myopathy). The affected
muscles are intensive green (G) in contrast to the unaffected tissue
and with multiple haemorrhages (H).
FIGURE 3: Older DPM (Deep pectoral myopathy) lesion, with pale yel-
low-green colour and reduction of the haemorrhages in the affected
muscle.
FIGURE 4: Degenerative necrotic changes (Zenker’s degeneration) (zd),
increased acidophilia (a), heterophil leukocytes (h) and macrophages
(m) among dead muscle tissue, Haematoxylin-eosin, bar: 35 μm.
Revue Méd. Vét., 2011, 162, 6, 279-283
282 DINEV (I.) AND KANAKOV (D.)
be associated with the tendency to produce “heavy” broilers
(> 3kg live weight) for breast muscle [1]. Some authors [1-4,
8] have evaluated the incidence of the muscular disease in
heavy male roaster chickens reared in commercial condi-
tions. However, it is difficult to compare these results with
the current study where chickens were both males and females.
Nevertheless, DPM cases in the present study were observed
in young birds (7 weeks old) and this age was previously
reported by RICHARDSON et al. [13] as the lowest for evi-
dencing such muscular lesions. The mean live/carcass weight
ratios of the chickens with DPM lesions are among the
lowest ever reported [13]. These facts support the concept
that the DPM prevalence is higher in meat-type growing
birds [3, 8, 13] and according to SILLER [17], DPM occurs
exclusively in birds that have been specially selected for
breast muscle development, as the 2 commercial strains
(Ross 308 and Cobb 500) used in this assay. Evidence that
this condition only appears because of intensive selection is
supported by the absence of DPM in wild turkeys, even when
these birds are experimentally forced to grow [2, 4, 17].
The DPM lesions firstly exhibited an acute inflammatory
aspect with oedema, hyperaemia and haemorrhages of the
supracoracoid muscle. The lesions can be focal or diffuse,
affecting the whole muscle and can be spread to the both
supracoracoid muscles. However, the uni- to bilateral lesion
ratio was not determined in the present study. The acute
inflammation reaction was histologically confirmed by oedema
and cell necrosis and the presence of an inflammatory infiltrate
constituted mainly with macrophages and some heterophils
was noted in injuried muscles. Furthermore, lot of muscle
fibres appeared as markedly necrotic (Zenker’s degenera-
tion) and the discoid necrosis lead to the destruction of the
muscle architecture. Older lesions were mainly characterized
by a marked green colour of the affected muscles. By analogy
with bile pigments it was firstly assumed that this green colo-
ration derived from the degradation of a haemic pigment,
such as haemoglobin or myoglobin, during the development
of myopathy [15]. The resistance to acidic solvents shows
that the pigment was covalently bound to protein [14] and in
1978, SILLER and WINGHT [15] suggested that this pig-
mentation may be due to the accumulation of one cytochrome,
probably the cytochrome b. Thereafter, this pigmentation
gradually disappeared in lesions evolving for a long time
characterised by a chronic inflammation, leading to the muscle
fibrosis and to the formation of a fibrous capsule in periphery
[15]. Histologically, the muscle tissue gradually disappeared
and was substituted with fibrous then adipose tissues, the
connective tissue reaction usually beginning from the intact
tendon [18].
There is a genetic predisposition of large-breasted birds to
this muscular disease. Possible aetiology explanation for this
disease may be related to an inadequate vasculature in meat-
type birds [17]. Some evidence has been produced for a here-
ditary susceptibility of DPM [11]. The selection of these
breeds would be associated with a gene mutation leading to
apoptosis of myocytes frequently coupled to cytochrome
accumulation in cytoplasm and inherent caspase activation
or leading directly to the accumulation of the haemic proteins
which in turn provoke the caspase cascade. Moreover, this
data suggests that genetics may play an important role in the
determination of DMP.
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... In chronic cases, the muscle is necrotic and green in color. The cut surface of a lesioned muscle is dry and friable [2,3] . All lesions in the present study were chronic and characteristic because of the older and heavier birds. ...
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... In latest studies, it has been reported an incidence of DPM of 16.7% of the total carcasses studied in Italy (Bianchi et al., 2006), 0.06% in Polonia (Kijowski & Konstańczak, 2009), 0.51% in Bulgaria (Dinev & Kanakov, 2011), and 0.33% in Iran (Pajohi-alamoti et al., 2016). Bilgili and Hess (2008) developed an industrial classification, divided into three categories based only on the visual appearance of the Pectoralis muscle. ...
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The growth of poultry production has led to an increase in the incidence of internal defects in chicken and turkey broilers, such as Deep Pectoral Myopathy (DPM). DPM is an ischemic hemorrhage or necrosis caused by the inadequate blood supply of Pectoralis minor and major muscles. Currently, visual appearance is the only parameter used to categorize the damage level. The aim of this research was to develop a scientific methodology to determine the level of damage in poultry breast tenders affected by this myopathy. For this purpose, microstructure, pH, protein and ion content and color were studied. Results allowed identifying three damage levels: normal, hemorrhagic samples with hematomas and blood clots, and necrotic tissues, based on significant variables (p<0.05) measured in Pectoralis minor (pH, L* and a*), where muscles with myopathy presented L* values lower than 47, and necrotic muscles presented pH values higher than 6.05.
... The cross section of muscles with myopathy revealed cells without the characteristic polygonal shape, whereas individual cells changed into disc-shaped derivatives. Dinev and Kanakov [28] investigated the prevalence of DPM in young broiler chickens according to their live weight during slaughtering inspection. They showed that the muscle tissue was almost completely replaced by fibrous and/or adipose tissue as a result of degeneration. ...
Article
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Changes in the biophysical traits of the pectoral muscles of chickens with deep pectoral myopathy (DPM) were analysed with selected instrumental techniques. For comparative purposes, the research used both samples of pectoralis minor muscles of 39–42-day-old Cobb 500 broiler chickens and pectoralis major muscles with DPM symptoms, as well. Computer Image Analysis (CIA) revealed that the pectoral minor muscles with DPM were characterised by smaller area of muscle fibres’ cross-sectional area (CSA) than normal muscles. A longitudinal section of DPM muscles also confirmed the presence of large spaces between the bundles of muscle fibres. The results of Differential Scanning Calorimetry (DSC) analysis showed that all the temperatures of transformations referring to minor muscles with myopathy symptoms were significantly lower than the temperatures noted in the muscles without DPM. The enthalpy values observed in both pectoral muscles with DPM were significantly lower than the values noted in healthy muscles. The water dynamics analysed by low-field NMR showed that the values of spin–lattice relaxation time T1 in p. major muscles without DPM were higher than the values in the muscles with the defect. On the other hand, an inverse dependence was observed in p. minor muscles samples. The value of the long relaxation time T22 was reduced in both muscles with pathological lesions. In conclusion, three advanced analytical tools used in this study (CIA, DSC, and LF NMR) provide new insight into the characterization of protein changes observed in the pectoral muscles of chicken broilers with DPM.
... The first two stages are also defined as 'acute' lesions. The estimated minimum and maximum incidence of DPM under commercial conditions ranged from 0.0 to 1.88% in Poland ( Kijowski and Konstanczak 2009), from 0.0 to 16.67 in Italy ( Bianchi et al. 2006) and from 0.05 to 0.51% in Bulgaria ( Dinev and Kanakov 2011). It is not yet clear whether DPM is associated with body weight of broilers. ...
Article
1. The objective of this study was to determine muscle structure and gene expression in pectoralis major (p. major) muscle of broilers in response to deep pectoral myopathy (DPM) induction. 2. A total of 160 chickens from slow- and fast-growing broilers were raised under same conditions. Half of the broilers from each strain were encouraged to wing flap when they reached to 2800 g body weight. Pectoralis minor (p. minor) muscle of the broilers was inspected for the occurrence of DPM and p. major samples were collected from broilers with or without DPM. The muscle fibre area and number, capillary number and the signaling pathways of vascular development (vascular endothelial growth factor A, VEGFA) and muscle contraction regulation (actin alpha 1, ACTA1; myosin light chain kinase 2, MYLK2 and ATPase Ca⁺² transporting gene 1, ATP2A1) were studied in p. major muscle. 3. DPM induction increased fibre area of p. major muscle with a greater rate in the slow- growing strain compared to fast-growing. Although the capillary number was higher in slow-growing broilers compared to fast-growing, in the case of DPM induction, the number of capillaries was similar between strains. 4. Expression of VEGFA, MYLK2 and ATP2A1 was greater in slow- than in fast-growing broilers. DPM induction increased expression of ACTA1, VEGFA and ATP2A1 in p. major muscle of broilers from both strains; however, MYLK2 expression was downregulated. 5. Changes in capillary density and expression of VEGFA found in the p. major muscle of broilers with DPM suggest increased blood flow to increase oxygen availability. The upregulation of ATP2A1 by DPM induction could be attributable to alterations in calcium ion transportation from the cytoplasm into the sarcoplasmic reticulum. 6. The results are evidence of changes in muscle structure and gene expression pathways in p. major muscle of broilers with DPM.
... The first two stages are also defined as 'acute' lesions. The estimated minimum and maximum incidence of DPM under commercial conditions ranged from 0.0 to 1.88% in Poland (Kijowski and Konstanczak 2009), from 0.0 to 16.67 in Italy (Bianchi et al. 2006) and from 0.05 to 0.51% in Bulgaria (Dinev and Kanakov 2011). ...
Article
1. Two experiments were conducted to determine the effect of slaughter weight on the incidence and intensity of deep pectoral myopathy (DPM) of M. pectoralis minor (p. minor muscle) in commercial conditions in Turkey and to evaluate the impact of DPM on meat quality traits of pectoralis major (p. major) muscle in broilers. 2. In Experiment 1, a total of 116 250 carcasses from 59 Ross-308 broiler flocks, classified according to slaughter weight as 2.0-2.2, 2.2-2.4, 2.4-2.6 and >2.6 kg, were evaluated for occurrence of DPM. In Experiment 2, p. major samples from unaffected broilers and each DPM stage were evaluated for meat quality, oxidant and antioxidant properties, nutritional value and fatty acid profile. DPM was characterised as 1: muscles with coagulative necrosis, 2: muscles with fibrous tissue texture and pink to plumb and 3:” muscles with green necrotic area. 3. The average incidence of DPM was found to be 0.73% in Experiment 1 and independent of slaughter weight. 4. In Experiment 2, p. major muscle of broilers with DPM 1 and 2 had higher pH values with higher redness and drip loss. All DPM stages resulted in an increase in lipid content and malondialdehyde activity and lowered ash content of p. major muscle compared with unaffected birds. DPM 2 increased superoxide dismutase and glutathione peroxidase activities in M. p. major. The p. major of broilers with DPM had lower content of C18:2 conjugated linoleic and C20:3n-6 fatty acids than those of unaffected broilers. Lower Δ6 desaturase and thiosterase activities and 18:2n-6 to 18:3 n-3 ratio were observed for all DPM stages compared to Normal. 5. It was concluded that these changes obtained in p. major muscle of broilers with DPM might indicate biochemical characteristics of muscle degenerations.
Article
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The fast growth rates in commercially reared chickens could lead to the changes in their muscle tissue structure and cause breast muscle myopathies, including deep pectoral myopathy (DPM). The incidence of DPM depends on various factors including rearing conditions, age, sex, weight and genetic strain. The aims of the present paper were to report a case of DPM in broiler chickens bought in a supermarket and review important information regarding this disease from the available literature, especially its effect on meat quality parameters and consumer preferences.
Article
p>Animal-based measures (ABM) can be used effectively in the on-farm evaluation of broiler welfare in relation to laws, codes of practice, quality assurance schemes, management and also partly for ante-mortem inspection. Some ABM can also be taken post-mortem at the slaughterhouse. Non-animal-based measures can be used when the association between them and the welfare outcome is strong and when they are more efficient than ABM as a means to safeguard welfare. They can also be useful predictors of welfare in broilers. The choice of animal-based measures will depend upon the specific objectives of the assessment. The full list is comparable to a ‘toolbox’, from which the appropriate set of measures can be selected. The Welfare Quality<sup>®</sup> protocol provides information on the majority of the welfare outcomes for the main factors identified in the EFSA Scientific Opinions but not those where time limitation prevents it. There is a lack of research on the use of ABM on-farm and in the slaughterhouse to assess pain, frustration, boredom and other negative or positive emotional states in the standard broiler. There are limited management options to prevent poor welfare when the flock is still in the house e.g. to improve the ventilation system. The same applies to negative consequences arising from genetic selection. There is a need for more systematic flock monitoring and surveillance programmes in the broiler industry. Visual inspection has a very high potential to improve animal welfare in broiler production when a range of appropriate ABM is used in the slaughterhouse. Benchmarking can be used to document welfare changes over time, including automatic monitoring and assessment systems. Attention should also be paid to initial and ongoing training of assessors in the field and in the abattoir to ensure valid and robust measurements.</p
Article
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Turkeys were fed either corn based or wheat based rations and necropsied between 28 and 118 weeks of age. Practically all birds affected with degenerative myopathy were detected among those killed between 77 and 85 weeks of age. The incidence of the disease was 0% among 125 males and 7.9% among 139 females. No significant difference in incidence was observed between birds fed corn based and birds fed wheat based rations.
Article
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Deep pectoral myopathy (DPM) is a disease that affects commercial poultry selected for large breast muscle development. The muscle affected by the disease is the supracoracoid muscle and usually one side of the breast musculature atrophies. The necrotic muscle has a characteristic pale green color. Heavy breeds of turkeys and broilers can be induced to show DPM by electrical stimulation of the breast muscle itself or by vigorous wing flapping; older birds are more susceptible. The cause of DPM is a fascial compartment too small to accommodate the enclosed supracoracoid muscle during vigorous exercise when the muscle increases its weight (and overall size) by about 20%. The inelastic compartment essentially strangulates the swollen, activated muscle. A possible means of correcting DPM is to train or exercise the flight muscles during the rapid growth phase of chicks or poults. Feed, for example, could be positioned above floor level so that birds would have to flutter up to reach it. There is also evidence to suggest a genetic component to the disease. Hence, an indicator such as high plasma creatine kinase levels may be used as a selection criterion.
Article
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Eighty degenerative myopathy line turkeys were fed from day old through fifty-two weeks of age on rations with or without added vitamin E (44 I.U./kg.), dl-methionine (0.10 percent) and sodium selenate (1 p.p.m.). Growth, mortality and expression of the hereditary myopathy trait were not altered by the supplements as compared to turkeys fed unsupplemented rations. At the end of the experiment, 35.3 percent of the supplemented and 40.0 percent of the control turkeys were observed with the profundus myopathy. Viral and bacteriological cultures of the affected tissue were negative.
Article
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In a deep pectoral myopathy selected (DPMS) line, forced wing exercise (FWE) at 20 weeks of age resulted in the same level of expressed deep pectoral myopathy (DPM) as seen in unexercised DPMS turkeys by 72 weeks of age. The FWE at 15 and 17 weeks of age in DPMS line females increased the incidence of DPM to 30 and 50% compared to 5% in unexercised controls. There is an apparent developmental age × exercise relationship in the expression of DPM. In varieties, lines, and crosses without a history of DPM, FWE does not induce the myopathy. Additional evidence confirms the modifier effect in the polygenic DPM defect. Body weight and breast width measurements in genetically susceptible turkeys were not closely or consistently associated with expression of the myopathy. The results suggest FWE of turkeys at 20 weeks of age or later as a method for detecting genetic carriers at prebreeding ages.
Article
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The incidence of degenerative myopathy of the Musculus supracoracoideus (DMS) was calculated in 23 strains comprising 1868 meat-type chickens. Twenty strains were commercial parent stocks and three strains were experimental strains from Ottawa similar to commercial broiler stocks of some 15 to 20 years ago. In the commercial strains DMS incidence ranged from 0 to 43% in males and 0 to 22% in females at ages ranging from 49 to 68 weeks. The three experimental strains did not have DMS. Data from strains with DMS were analyzed for associations between DMS and each of a number of body size and egg production traits. The DMS-positive birds had a larger breast angle (P less than .05) measured at 6 weeks of age (93 vs. 89 degrees) and a larger body weight (P less than .01) at 52 weeks (3748 vs 3594 g) than DMS-free birds. No significant relationships with other body size or egg production traits were detected.
Chapter
Metabolic disorders have been a continuous challenge in poultry production for the last 70 years, exacerbated by huge improvements in the genetic potential for growth and feed efficiency. Metabolic problems in poultry production cause morbidity, mortality, or both, but are not related to infectious diseases. Diseases described in this chapter have been classified by primarily affected body system; however, the initial part of the chapter covers disorders induced by environment or management conditions and diseases that are not associated with a specific body system. The chapter covers metabolic conditions of major importance commonly seen in commercial poultry. Before determining a condition is a metabolic problem, it is essential to rule out infections as well as nutritional or toxicological causes because the pathology may be similar. Intervention strategies vary with the specific problem, but in general interventions are associated with manipulation of environment, nutrition, and genetics.
Article
In a previous publication evidence was produced indicating that deep pectoral myopathy (Oregon disease) of turkeys and broilers may be analogous to "march gangrene" of man, a condition which results from strangulation of exercised anterior tibial muscles in a tight, inelastic myofascial compartment. A similar situation pertains in the heavy-chested domestic birds, where the supracoracoid muscle is also enclosed in an osteofascial compartment which prevents the normal enlargement of exercised muscle. In the present experiment it is shown that the supracoracoid myopathy induced experimentally by indirect muscle stimulation can be prevented by surgical incision of the constricting fascia. This would confirm the pathogenesis we have suggested for experimental and spontaneous deep pectoral myopathy. In light-weight, laying strains deep pectoral fasciotomy is ineffective in preventing the development of similar lesions brought about by experimental vascular occlusion.
Article
The gross and microscopic pathology of deep pectoral myopathy was studied in 35 turkey breeder hens. In this disease the lesions, consisting of strictly focal ischaemic necrosis, were confined entirely to the supra-coracoid (deep pectoral) muscles of one or both sides. Vascular lesions consisting of thrombosis, intimal proliferation and aneurysm formation were located in, and immediately around, the necrotic muscle tissue. Although this peripheral vascular disease would perhaps be sufficient to account for the focal ischaemic necrosis, we have no evidence at present to prove its primary involvement. Furthermore other factors such as stress or trauma may play a contributory part in the development of this condition.