purpose was to investigate and evaluate the histological structure peculiarities of the atrial myocardium and their scallop
muscles of an Anglo-Nubian goat and establish the morphometric data of the histological structures of the scallop
muscles and cardiac muscle of the atria.
MATERIALS AND METHODS
There were used dated materials for the study obtaining during slaughter from the farm "Gzhel Podvorie" in the Russian
Federation's Moscow region. The dated material was presented by sixteen corpses of Anglo-Nubian goats older than one
which it was embedded in paraffin according to the generally accepted technique (Muzhikyan et al., 2014). Then sections
with a thickness of 3-5 μm were made, stained with hematoxylin and eosin. According to McManus, some of the sections
were stained with Trichrome according to Masson, toluidine blue, and Schiff-iodic acid. The histological preparations
analysis was carried out using a Carl Zeiss Axioskop 2 Plus light-optical microscope (Germany) at a magnification of 40,
100, 400, 1000. Microphotography was performed using a digital camera (CarlZeiss Axio Cam ERc5s, Germany) and the
AxioVision 4.8 software. Morphometric measurements were performed manually using the AxioVision 4.8 software
(Image J, Germany).
The variational-statistical processing of the research results was carried out on IBMPС / AT and "Pentium IV" in
Windows 2000, using the data analysis package in the program "Excel Windows Office XP" and "Statistika 6.0" (Statsoft,
USA) with the calculation of the arithmetic mean and its standard error (M ± m). In the statistical analysis of the data
obtained, the Student's t-test was used for independent samples, while the differences were considered significant at
p<0.05. All anatomical and histological terms correspond to the "International Veterinary Anatomical Nomenclature,"
fifth edition, translation and Russian terminology of Zelenevsky (2013) and International histological nomenclature
Ethical regulation of study
This research was conducted in accordance with tin accordance with ethical standards for the use of animals for
scientific purposes, referred to Federal Law of 24.04.1995 N 52-FL (as amended on 08.12.2020) "On the animal world".
The main research technique was chosen to study the microstructure of the atrial myocardium and scallop muscles - the
production of histological preparations for sampling the material under study on fresh hearts of Anglo-Nubian goats. The
material was taken by the method of fine anatomical preparation (Minutes No. 134 dated 09/15/2020).
RESULTS AND DISCUSSION
The atrial myocardium of an Anglo-Nubian goat is formed by tightly adjacent contractile (working) cardiomyocytes,
forming long multidirectional strands (Figures 1 and 2). A more tortuous course of muscle fibers and wider gaps between
them are noted in the studied animals than in the interventricular septum. The contractile cardiomyocytes in this section
are elongated. The cell thickness varies in the range of 16-20 microns and averages 17.6 ± 1.5 microns. The area of cells
on a cross-section averages 294.5±31.6 μm2. In general, in this part of the heart, cardiomyocytes are characterized by
structural heterogeneity; in cells less differentiated in terms of contractile activity, perinuclear clearances and secretory
granules are determined, which are not found in cardiomyocytes of the interventricular septum (Figure 3). The nuclei of
cells are oval, slightly elongated, normochromic, with a uniform distribution of small-lumpy chromatin. In some of the
cells, the nuclei are elongated, flattened, moderately hyperchromic. The average values for a large core diameter are 10.1
± 1.1 μm, for a small one, 4.3 ± 0.4 μm. The average area of the nuclei of contractile cardiomyocytes varies within 40-48
μm2 and averages 42.7 ± 3.2 μm2.
According to Masson, staining with trichrome between the muscle elements of the myocardium, layers of loose,
small-cell, unformed connective tissue of different thickness, containing capillary-type blood vessels and single small
groups of adipocytes, are revealed (Figures 4 and 5). Along the periphery, thin cords of collagen fibers pass into a loose,
unformed connective tissue of the endocardium, covered with one layer of flattened endothelial cells (Figure 6). The
endocardium thickness in this section varies within 13-25 microns and averages 17.2 ± 2.2 microns. The nuclei of
endothelial cells are predominantly oval and elongated. The large and small diameter of the endothelial cell nucleus
averages 7.8 ± 1.5 and 4.8 ± 0.6 microns.
The scallop muscle in the Anglo-Nubian goat is formed by tightly adjacent contractile (working) cardiomyocytes,
forming long multidirectional cords (Figures 7 and 8). The contractile cardiomyocytes in this section are elongated. The
cell thickness varies within 12-24 microns and averages 18.9 ± 1.6 microns. The area of cells on a cross-section averages
278.3 ± 24.1 μm2. The nuclei of cells are oval, slightly elongated, normochromic, with a uniform distribution of small-
lumpy chromatin. In some of the cells, the nuclei are elongated, flattened, moderately hyperchromic. The average values
for the large diameter of the nucleus are 12.7 ± 1.3 μm, for the small diameter - 4.2 ± 0.4 μm. The average area of the
nuclei of contractile cardiomyocytes varies within 40-45 μm2 and averages 42.9 ± 3.2 μm2.
Citation: Khvatov V and Shchipakin M. (2021). Histological features the atrial myocardium and scallop muscles of an Anglo-Nubian goat. Online J. Anim. Feed Res.,