Received: 30/10/2024 Accepted: 02/01/2025 Published: 06/01/2025 1 of 8
https://doi.org/10.52973/rcfcv-e35555 Revista Cientíca, FCV-LUZ / Vol. XXXV
ABSTRACT
Broiler myopathies cause signicant economic losses in the poultry
industry, adversely affecting meat quality and animal welfare. Cobb
500 and Ross 308 are widely cultivated commercial lines globally;
however, Anadolu–T is a newly developed genotype with limited
research on the histopathological evaluation of myopathic lesions.
This study focuses on the histopathological evaluation of breast
muscle myopathies in three different broiler lines (Cobb 500,
Anadolu–T, and Ross 308). Additionally, histopathological lesions
such as lipidosis, inflammatory cell inltration, connective tissue
formation, and degeneration were compared among genotypes
using manual scoring with traditional light microscopy, as well as
less commonly utilized digital image analysis software, including
ImageJ and QuPath. Macroscopically, the Cobb genotype exhibited
the highest WB scores (mean score: 2) (P<0.05), while the
Anadolu–T genotype had the highest WS scores (1.11) (P>0.05).
In the evaluation of histopathological lesions, the highest brosis
scores were observed in the Cobb genotype (0.86), the highest
mononuclear inflammatory cell inltration scores in the Ross
genotype (2.25), the highest lipidosis scores in the Anadolu–T
genotype (3.22), and the highest degeneration scores in the Cobb
genotype (3) (P>0.05). In this study, the evaluation of myopathy
scores revealed signicant differences in myopathy susceptibility
among different genotypes. The Anadolu–T genotype was found
to be less susceptible to WB myopathy severity (P<0.05) but more
prone to WS myopathy severity (P>0.05).
Key words: Broiler; Anodolu-T; myopathy; image analysis;
histopathology
RESUMEN
Las miopatías en pollos de engorde causan pérdidas económicas
signicativas en la industria avícola, afectando negativamente la
calidad de la carne y el bienestar animal. Cobb 500 y Ross 308 son
líneas comerciales ampliamente cultivadas a nivel mundial; sin
embargo, Anadolu–T es un genotipo recientemente desarrollado
con investigaciones limitadas sobre la evaluación histopatológica
de las lesiones miopáticas. Este estudio se centra en la evaluación
histopatológica de las miopatías en los músculos pectorales de
tres líneas diferentes de pollos de engorde (Cobb 500, Anadolu–T y
Ross 308). Además, las lesiones histopatológicas como la lipidosis,
la inltración de células inflamatorias, la formación de tejido
conectivo y la degeneración se compararon entre los genotipos
utilizando puntuaciones manuales con microscopía óptica
tradicional, así como programas de análisis de imágenes digitales
menos utilizados, incluidos ImageJ y QuPath. Macroscópicamente,
el genotipo Cobb presentó las puntuaciones más altas de WB
(puntuación media: 2) (P<0,05), mientras que el genotipo
Anadolu–T tuvo las puntuaciones más altas de WS (1,11) (P>0,05).
En la evaluación de las lesiones histopatológicas, las puntuaciones
más altas de brosis se observaron en el genotipo Cobb (0,86),
las puntuaciones más altas de inltración de células inflamatorias
mononucleares en el genotipo Ross (2,25), las puntuaciones
más altas de lipidosis en el genotipo Anadolu–T (3,22) y las
puntuaciones más altas de degeneración en el genotipo Cobb
(3) (P>0,05). En este estudio, la evaluación de las puntuaciones
de miopatías reveló diferencias signicativas en la susceptibilidad
a las miopatías entre los diferentes genotipos. Se encontró que
el genotipo Anadolu–T era menos susceptible a la gravedad de
la miopatía WB (P<0,05), pero más propenso a la gravedad de la
miopatía WS (P>0,05).
Palabras Clave: Pollo de engorde; Anodolu-T; miopatía; análisis
de imágenes; histopatología
Histopathologic evaluation of wooden breast and white striping
myopathy in different broiler genotypes using light microscopy and
image analysis
Evaluación histopatológica de la miopatía de estría blanca y pechuga de madera en diferentes
genotipos de pollos de engorde mediante microscopía óptica y análisis de imágenes
Zehra Avci-Kupeli
1
* , Erdem Caglar-Kupeli
2
, Metin Petek
2
1
Bursa Uludag University, Faculty of Veterinary, Department of Pathology. Bursa, Türkiye.
2
Bursa Uludag University, Faculty of Veterinary, Department of Animal Science, Bursa, Türkiye.
Corresponding author: zehraavci07@gmail.com
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INTRODUCTION
In recent years, the global demand for poultry meat has
signicantly increased, prompting intensive genetic selection
and feed optimization in broiler production. These advancements
have resulted in faster growth rates and enhanced breast meat
yield [1]. Among the most popular commercial broiler (Gallus
gallus domesticus) genotypes known for their rapid growth and
feed efciency are Cobb 500 and Ross 308 [2, 3]. Anadolu–T is
a new broiler breed, with breeding efforts initiated in 2017 and
ofcially registered as Anadolu–T in 2020 [4].
However, it is known that these genetic selections have
contributed to the development of a group of myopathies,
particularly affecting the Pectoralis major muscle (breast muscle),
leading to defects in both appearance and function [5, 6]. Among
breast muscle myopathies, White Striping (WS), Wooden Breast
(WB), and Spaghetti Meat (SM) are more commonly observed [7,
8, 9]. SM is characterized by the degradation and separation of
muscle bers, whereas WB is dened by increased rmness, pale
coloration, and occasional petechial hemorrhaging, along with
varying amounts of clear, viscous fluid on the epimysial surface
[10]. WS is characterized by numerous white streaks running
parallel to the muscle bers [4, 11, 12].
Additionally, there is a type of myopathy known as Deep Pectoral
Myopathy (DPM), which primarily affects the supracoracoideus or
pectoralis minor muscles [13]. This condition leads to ischemic
necrosis, impairing meat quality and causing histological and
biochemical changes in the muscle tissue. Initially, the muscle
appears dark red or purplish, but as necrosis progresses, it gradually
turns to a greenish hue [5]. Although factors such as hereditary
muscular dystrophy, heat stress, trauma, exertion, nutrition, and toxic
myopathies have been identied as potential contributors to P. major
muscle myopathies [10, 14] the precise etiology of these conditions
remains unclear. However, since these myopathies are not caused
by infectious agents, they do not pose a public health concern [9].
In most studies, pathological lesions in broiler myopathies are
microscopically characterized by muscle degeneration, lipidosis,
brosis, and inflammatory cell inltration [10, 15, 16]. There are,
however, a limited number of studies focused on the histopathological
evaluation of chicken myopathies using digital image analysis software
such as QuPath and ImageJ [17, 18, 19]. Traditionally, subjective
scoring using light microscopy has been a common method in
histopathological evaluations [15, 20, 21]. In recent years, the use of
digital image analysis software has signicantly increased, particularly
due to its ability to provide more objective and reproducible results
in the scoring of pathological lesions.
In this study, pathological lesions in the P. major muscle of
different broiler breeds (Cobb 500, Anadolu–T, and Ross 308) were
evaluated both macroscopically and microscopically. Notably, there
is a lack of signicant studies in the existing literature regarding
the histopathological examination of myopathic lesions in the
Anadolu–T genotype. This study contributes to the identication
of susceptibility to myopathy across different chicken breeds,
providing valuable insights for genetic selection. The variation
in pathological lesions in the breast muscles between breeds is
expected to be valuable for improving poultry breeding programs
and enhancing poultry meat quality. This study aims to contribute
to the scientic community by providing novel and signicant data
in this eld, thereby enhancing the existing literature.
MATERIAL AND METHODS
Sample collection and preparation
The broiler muscle samples used in this study were collected
under standard conditions from three different genotypes reared at
the Poultry Breeding Unit of the Research and Application Center,
Faculty of Veterinary Medicine, Bursa Uludag University. These
genotypes included female Cobb (n=8), Anadolu–T (n=10), and
Ross (n=9) broiler chickens. The samples were refrigerated (Arcelik,
475-T, Turkey) at +4
o
C for 14 hours and subsequently examined
for muscle myopathies. As this study was conducted on muscle
samples obtained post-slaughter from animals raised for food
production, ethical approval was not required.
The study consisted of three main groups (Cobb 500, Ross 308,
and Anadolu T), each comprising 50 female chicks. Each group was
further divided into ve replicates, with 10 chicks per replicate. A
total of 150 one-day-old chicks were raised in the experimental unit
of the faculty farm. For this experiment, the chicks were housed in
group pens measuring 1 × 1 m, each equipped with plastic slatted
floors. Housing density, lighting program, and other management
practices in the groups were arranged in accordance with the
“Regulation on Minimum Standards for the Protection of Broiler
Chickens.” The animals in the groups were raised under standard
care and feeding conditions (ad libitum) for broilers over a period of
44 days (d). After the macroscopic scoring of breast llets, 1 × 1 ×
1 cm muscle tissue samples were collected from the right P. major
muscle of each animal. Both longitudinal and transverse sections
were prepared for each tissue sample [16]. The fresh muscle tissues
collected were xed in 10% neutral buffered formalin.
The tissues were then processed through graded alcohol series.
After paraffin embedding and blocking, 4 μm thick sections
were obtained using a microtome (Leica, RM 2125, Germany) to
prepare muscle tissue slides. Hematoxylin and eosin (HE) staining
(Merck Millipore, MA, USA) was performed on slides to identify
histopathological changes, such as mononuclear cell inltration
and lipidosis, under a light microscope (Olympus Corporation,
CX41, Japan). In addition, Masson’s Trichrome (MT) staining
(Bio Optica, Italy) was used to assess muscle ber disruption,
degeneration and collagen deposition [10, 15, 16].
Macroscopic scoring of pathological lesions
The presence and severity of WS and WB myopathies were
assessed macroscopically on deboned right breast llets by two
evaluators. For WB, breast llets showing no rmness or pale
areas upon palpation, and having flexible consistency throughout,
were classied as normal breast llets (score 0). Fillets with mild
rmness in the cranial region but otherwise flexible were classied
as mildly affected (score 1). Fillets rm throughout the cranial
region but flexible in the middle to caudal regions were classied
as moderately affected (score 2). Fillets that were extremely rm
and rigid from the cranial region to the caudal end were classied
as severely affected (score 3) [22]. Breast llets exhibiting WS
were evaluated based on the presence of visible white stripes
running parallel to the muscle bers. Fillets with no visible white
stripes were classied as normal (score 0). Fillets with white
stripes less than 1 mm thick running parallel to the muscle bers
were classied as moderately affected (score 1). Fillets with white
stripes 1-2 mm thick were considered severely affected (score 2).
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Fillets where the surface was almost entirely covered by white
bands thicker than 2 mm were classied as extremely affected
(score 3) [23].
Scoring of histopathological lesions under light microscopy
The scoring of myopathic lesions in the P. major muscle of broilers
was conducted under a light microscope (Olympus Corporation,
CX41, Japan), taking into account the distribution and degree of
structural deterioration of the lesions. This assessment allowed
for a more precise determination of the severity and extent of the
myopathic lesions. The scoring system ranged from 0 to 5. A score of
(0) represents healthy muscle tissue without degeneration, brosis,
or lipidosis. A score of (1) was assigned when the lesions covered
less than 20% of the tissue, (2) when covering 20-40% of the tissue,
(3) when covering 40-60%, (4) when covering 60-80%, and (5)
when the lesions were extensive, covering greater than 80% of the
tissue. The presence of inflammatory cells was classied as none (0),
minimal (1), mild (2), moderate (3), or marked/severe (4/5) [21, 24].
Scoring pathological lesions using digital image analysis
programs
Images from ve distinct areas, where brosis and mononuclear
inflammatory cell inltration were most prominent in muscle tissue
slides, were digitized under a light microscope (Olympus Corporation,
CX41, Japan) at magnications of 100× and 200×, respectively. After
these images were uploaded to the ImageJ (v.1.53d) image analysis
software, the following steps were selected sequentially: image,
adjust, and color threshold. The threshold values used to calculate
the fibrosis area were set as follows: hue: 0-255, saturation:
0-255, and brightness: 0-177. For the calculation of mononuclear
inflammatory cell inltration areas, the threshold values were
dened as hue: 0-255, saturation: 0-255, and brightness: 0-185,
and the same threshold values were consistently applied across all
images. Subsequently, area calculations were performed using the
analyze and measure functions [17].
Images from ve distinct areas with the most intense myobril
degeneration and lipid infiltration were digitized under 100×
magnication using a light microscope. These images were then
uploaded to QuPath software (v.0.4.3), a cell image analysis software.
To calculate lipid inltration areas, the “wand tool” measurement
tool was manually applied to delineate lipid inltration regions.
For the assessment of myobril degeneration, the following steps
were conducted sequentially: classify, pixel classication, train pixel
classier, and full (downsample = 1.00) segments were selected.
Next, using the annotation module, the regions with myobrillar
degeneration were selected via the “wand tool” and classied as
degeneration areas. Regions containing healthy muscle myobrils
and regions to be excluded (interstitial space) were separately
classied and visualized with different colors. Subsequently, the
“live prediction” mode was chosen to identify the areas of the
classied measurements [18]. In both image analysis programs,
the designated areas were calculated in pixels and then converted
to square micrometers (μm²) for quantitative analysis.
Statistical analysis
All macroscopic measurements, including hardness for WB
and white streak for WS, as well as the scores obtained from
microscopic assessments, were tested for normal distribution
using the Shapiro-Wilk normality test. Since the data did not follow
a normal distribution, the Kruskal-Wallis test, a nonparametric
method, was employed. A significance level of P<0.05 was
considered statistically significant. All results are presented
as mean ± standard deviation (SD). Statistical analyses were
performed using SPSS Statistics (v.20), and graphs were generated
using GraphPad Prism (v.8.4.2).
RESULTS AND DISCUSSIONS
Macroscopic results
In the tactile evaluation of breast llets, no pathological lesions
were observed in the P. major muscle samples taken from one
specimen in each group (FIG. 1A). Breast llets exhibiting WB
were characterized by distinctly rm areas, pale discoloration,
an outwardly bulging appearance, and widespread petechial
hemorrhages (FIG. 1B). Macroscopically, the severity of WB
was moderate in Cobb and Ross genotypes, while it was mild in
Anadolu–T. Cobb exhibited the highest WB scores (mean score: 2),
followed by Ross (1.88) and Anadolu–T (0.78) groups, respectively
(P<0.05) (FIG. 2A, TABLE I). The macroscopic evaluation of breast
fillets for WS revealed the presence of numerous fine white
striations, each less than 1 mm in width, aligned parallel to one
another on the muscle surface (FIG. 1C). In all genotypes, the
severity of WS was mild. The Anadolu–T genotype exhibited the
highest mean WS score (1.11), followed by the Ross (0.75) and
Cobb (0.57) groups, respectively, with no statistically signicant
differences observed among the groups (P>0.05) (FIG. 2A,
TABLEI). WB and WS myopathies were observed simultaneously
in all animals. In this study, the evaluation of myopathy scores
revealed that across the three genotypes, Anadolu–T was less
susceptible to the severity of WB myopathy but more prone to the
severity of WS myopathy (P<0.05) (FIGS. 2A and 2B).
Previous studies have investigated the prevalence of WB and
WS myopathies in commonly used broiler genotypes (Ross 308,
Cobb 500) [25] or examined susceptibility to myopathies focusing
FIGURE 1. Macroscopic changes observed in the Pectoralis major muscle in
myopathies. A) Normal appearance of the P. major muscle. B) WB. Pale and
scattered petechial hemorrhages on the surface of the P. major muscle (arrow)
(Cobb, score: 2. C) WS. Numerous white streaks less than 1 mm in size running
parallel to myobers in the P. major muscle (arrow) (Anadolu–T, score: 1), (P<0.05)
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Similar results were obtained in this study, with WB scores being of
moderate severity in both genotypes. However, this study identied
a statistically signicant difference in WB scores for the Anadolu–T
genotype compared to other genotypes. This nding suggests
that the Anadolu–T genotype may exhibit a distinct sensitivity to
WB, potentially influenced by genetic or environmental factors.
White fatty striations on breast meat have been identied as
a key pathognomonic feature of WS myopathy [15, 23, 30, 31].
The thickness of these striations has been correlated with the
severity of WS and is characterized by greater lipid inltration
in the muscle tissue compared to other breast myopathies [12].
Another study in the literature conducted on Ross 308 and Cobb
500 genotypes reported that WS was of mild severity (score 1)
on d 42 [29]. Similarly, in this study, WS scores were found to
be of mild severity in both genotypes. However, no statistically
signicant differences were observed in intergroup comparisons
regarding WS. This nding suggests that WS may have a more
homogeneous distribution across genotypes. This study also
observed the simultaneous occurrence of WS and WB myopathies.
This nding aligns with previous literature [5, 27], supporting
the notion that both myopathies may be associated with similar
pathophysiological mechanisms. In particular, oxidative stress,
hypoxia, and disruptions in muscle protein metabolism are thought
to play signicant roles in these mechanisms.
Histopathology results
In this study, the histopathological lesions in the P. major
muscle of broiler chickens affected by myopathies were evaluated.
Specically, the presence of brosis in the muscle tissue was
conrmed through minimal collagen detection using MT staining.
In the transverse and longitudinal sections examined, myobrils
were observed as red, collagen as blue, and degenerated myobrils
as yellow-orange in the interstitial areas (FIGS. 2A and 3C). The
collagen area was highlighted in red and visualized using the
ImageJ analysis software (FIG. 3B). Among the genotypes analyzed,
Cobb exhibited the highest observed brosis scores (mean score:
0.86), followed by Ross (0.75) and Anadolu–T (0.67) groups, with
no statistically signicant differences between them (P>0.05)
(FIG. 2B, TABLE II). Mild multifocal mononuclear inflammatory
cell inltration (mononuclear inltration) was observed around
interstitial areas and fragmented myobrils in muscle tissue (FIG.
3C). This inltration area was highlighted in red using the ImageJ
analysis software (FIG. 3D). The highest mononuclear inltration
scores were observed in the Ross genotype (mean score: 2.25),
followed by Cobb (2.14) and Anadolu–T (1.78) groups (P>0.05)
(FIG. 2B, TABLE II). Mild to moderate multifocal endomysial lipid
inltration areas appeared as white vacuolar deposits between
muscle bundles (FIG. 4A). The lipid infiltration areas were
visualized in green using the QuPath analysis software (FIG. 4B).
The severity of lipidosis was moderate in the Anadolu–T and Cobb
genotypes, while it was mild in the Ross genotype. Anadolu–T
exhibited the highest recorded lipidosis scores (mean score: 3.22),
followed by Cobb (2.86) and Ross (2.4) groups, with no statistically
signicant differences among them (P>0.05) (FIG. 2B, TABLE II).
In transverse sections of muscle tissue, moderately severe
multifocal degenerated myobrils with non-polygonal shapes and
varying diameters were conrmed using HE and MT staining. In
HE staining, the degenerated myobrils were observed as hyper-
eosinophilic amorphous structures with the loss of cross-striations
on a single genotype [16, 26, 27]. However, studies comparing
WB and WS myopathy scores across different genotypes remain
limited [28, 29]. In particular, the macroscopic evaluation of WB
and WS in a novel genotype such as Anadolu–T has not yet been
conducted. Previous literature reported that macroscopic scoring
performed on d 42 in Ross 308 and Cobb 500 genotypes revealed
that WB was of moderate severity (score 2) in both genotypes [28].
TABLE I
Macroscopic scoring of myopathies in three dierent genotypes
Cobb (n=7) Ross (n=8) Anadolu–T (n=9)
Mean score
(0-3)
SD
Mean score
(0-3)
SD
Mean score
(0-3)
SD
WB 2
a
* 0.93 1.88
a
* 1.03 0.78
b
0.92
WS 0.86 0.64 0.75 0.33 1.11 0.43
*
a-b
P<0.05. According to the Kruskal-Wallis test, a signicant dierence was observed
for WB in the comparison between genotypes, whereas no signicant dierence
was found for WS.
Cobb Anadolu-T Ross Cobb Anadolu-T Ross
WS WB
0
1
2
3
4
* *
*
P
<0.05
Fibrosis Lipidosis Infiltration Degeneration
0
1
2
3
4
5
Cobb Anadolu-T
Ross
A
B
FIGURE 2. Representation of macroscopic and histopathologic findings in
statistical graphs. A) Macroscopic ndings score. B) Histopathologic ndings
score. WB: Wooden breast, WS: White striping, *P<0.05, ns: not signicant. All
data are presented as mean ± standard deviation (SD)
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(necrosis) (FIG. 3C). In MT staining, degenerated myofibrils
appeared yellow-orange (FIG. 4C). Myofibrillar degeneration
areas were visualized in green using the QuPath analysis software
(FIG. 4D). The Cobb genotype exhibited the highest observed
degeneration scores (mean score: 3), followed by Ross (2.88) and
Anadolu–T (2.67) groups, with no statistically signicant differences
between them (P>0.05) (FIG. 2B, TABLE II). In this study, similar
results were obtained in the scoring of histopathological lesions
using both light microscopy and digital image analysis software.
When comparing histopathological lesions across the three
genotypes, it was noted that only lipidosis showed higher scores
in the Anadolu–T genotype, while other lesions were recorded at
lower scores (FIG. 2B).
Previous studies have investigated the histopathological lesions
associated with WS [11, 19] and WB [9] myopathies in Ross 308
and Cobb 500 genotypes. However, research focusing on the
comparison of microscopic lesions between these genotypes has
been limited [8] Additionally, the histopathological evaluation of WB
and WS myopathies in a new genotype such as Anadolu–T has not
been previously conducted. In this study, no statistically signicant
differences were found in the comparison of histopathological
lesions among the genotypes. However, it is suggested that the
variations in histopathological lesions observed in these genotypes
could provide valuable insights into the interactions between
muscle development mechanisms and genetic factors.
Consistent with previous studies, this research demonstrated
that WB and WS myopathies exhibit similar pathological features
at both macroscopic and microscopic levels. Despite their distinct
macroscopic appearances, the presence of similar histopathological
characteristics in WB and WS myopathies suggests the involvement
of shared mechanisms in their development [7, 12, 20, 30]. WS
myopathy is typically associated with lipid accumulation (lipidosis)
in the perimysial region, whereas WB myopathy is characterized by
localized or diffuse hardening of the P. major muscle. This hardening
often leads to a marked thickening of the perimysial network due
to connective tissue proliferation (brosis) [15, 16, 32].
A study demonstrated that the presence of hardened muscle
tissue in WB and WS myopathies, without brotic tissue, indicates
that brosis is not the sole cause of muscle stiffness [10, 33]. The
low brosis scores observed in this study are consistent with these
ndings in the literature. Additionally, it has been reported in the
literature that muscle ber degeneration and brosis collectively
contribute to muscle stiffness [21]. In this study, the observation of
TABLE II
Histopathologic scoring of myopathic lesions in three dierent genotypes
Cobb (n=7) Ross (n=8) Anadolu–T (n=9)
Mean score
(0-5)
SD
Mean score
(0-5)
SD
Mean score
(0-5)
SD
Fibrosis 0.86 0.35 0.75 0.43 0.67 0.47
Inltration 2.14 0.64 2.3 0.97 1.78 0.92
Lipidosis 2.86 1.36 2.4 1.32 3.22 1.13
Degeneration 3 1.07 2.88 1.27 2.67 1.25
According to Kruskal-Wallis test, there was no signicant dierence between genotypes
in terms of histopathologic lesions
P>0.05
A
B
C D
FIGURE 3. Histopathological ndings and ImageJ analysis. A) Fibrosis. In longitudinal and transverse sections, the connective tissue (collagen) separating the muscle bers
in the perimysium appears blue (arrows), while myobrils appear red (MT; 10×). B) The collagen area is displayed in red using the ImageJ analysis program (MT; 40×). C)
Mononuclear inammatory cell inltration. Appearance of mononuclear inammatory cell inltrates around fragmented myobrils showing loss of striations in longitudinal
and transverse sections (arrow) (HE; 20×). D) The area of mononuclear inammatory cell inltration is shown in red with ImageJ analysis analysis program (arrow) (HE; 40×)
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higher rates of brosis and myodegeneration in the Cobb genotype
compared to other genotypes suggests a strong association
between this genotype and WB myopathy [16, 34]. As reported in a
previous study, this study also conrmed the association between
WS and lipid accumulation through macroscopic and microscopic
analyses [12]. Furthermore, free lipids around venous vessels
are thought to play a signicant role in the initiation of reactive
lesions (e.g., phlebitis, myositis, brosis) and the progression of
myopathies. The inflammatory effects of lipid accumulations may
trigger immune responses, leading to mononuclear inltrations [35,
36]. This mechanism is considered signicant in clearing necrotic
and degenerative muscle tissue.
In two different studies, the lesion scores of mild WS myopathy
were different from each other in the histopathologic evaluation
of breast fillets in Ross genotype. In one of these studies,
degeneration/necrosis score was mild, lipidosis was moderate,
fibrosis and infiltration were not observed [30], while in the
other study, degeneration/necrosis and inltration scores were
moderate, brosis and lipidosis were mild-moderate [19]. In
this study, similar ndings were observed in Ross genotype WS
myopathy, with lipidosis being mild to moderate and degeneration
of moderate severity. In another study on the Cobb genotype,
myopathic lesions, brosis, and lipidosis scores were reported
as mild to moderate in cases of moderate WS myopathy, whereas
in severe WS, brosis was mild, and the scores for other lesions
were of moderate severity [14]. In this study, similar to severe WS
myopathy, lipidosis and degeneration were found to be of moderate
severity. In a study on the Ross genotype, mild WB myopathy was
reported to exhibit predominantly moderate myodegeneration,
severe vasculitis/mononuclear inltration, and moderate adipose
tissue/lipidosis. In cases of severe WB myopathy, myodegeneration
and vasculitis were severe, and adipose tissue/lipidosis was also
reported to be severe [16].
In this study, similar to mild WB myopathy, degeneration was
found to be of moderate severity. The variability in histopathological
lesion scores identied in these studies is thought to result from
multiple factors, including genetic diversity between genotypes, sex,
age, type and severity of myopathy, rearing conditions, nutritional
regimen, the anatomical region of the muscle tissue examined,
and differences in histopathological evaluation methods used.
CONCLUSION
In this study, macroscopic and microscopic examinations of
breast llets obtained from female Cobb, Anadolu–T, and Ross
genotypes revealed the presence of both White Striping (WS) and
Wooden Breast (WB) myopathies in all three genotypes. WB was
recorded with the highest score in the Cobb genotype, while WS
was observed with the highest score in the Anadolu–T genotype.
Microscopic examinations identied brosis, lipidosis, degeneration,
and mononuclear inflammatory cell inltration. Fibrosis was most
frequently observed in the Cobb genotype, while lipidosis was
most prominently detected in the Anadolu–T genotype. The use
of light microscopy and digital image analysis software in the
evaluation of microscopic lesions has enhanced the consistency
and reliability of the results obtained in this study. This study
A
B
C D
FIGURE 4. Histopathological ndings and QuPath analysis. A) Lipidosis. appearance of white areas of lipid inltration around the interstitium, muscle bers, and
muscle bundles in longitudinal and transverse sections (arrow) (HE; 10×). B) The area of lipid inltration is shown in green using the QuPath analysis program (HE;
40×). C) Degeneration. Yellow-orange appearance of ber separation, segmental myobril disruption, ber size changes, and ocular or vacuolar degeneration in
longitudinal and transverse sections (arrow) (MT; 10×). D) Degeneration area highlighted in green using the QuPath analysis program. The larger image is shown at
MT; 10× magnication, while the smaller image is at MT; 40× magnication (arrow)
Histopathologic evaluation in Broiler / Avci-Kupeli et al.________________________________________________________________________________
_________________________________________________________________________________________________Revista Cientica, FCV-LUZ / Vol.XXXV
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demonstrated signicant differences in the susceptibility of different
genotypes to WB and WS myopathies. Notably, the resistance of the
Anadolu–T genotype to WB myopathy highlights the need for further
investigation into the mechanisms underlying the susceptibility and
resilience of this genotype to muscle pathologies.
ACKNOWLEDGEMENTS
We would like to thank Bursa Uludag University, Department of
Veterinary Pathology Laboratory for their support in performing
our laboratory analyzes.
Conflict of Interest
The authors declare no conflict of interest.
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