Morphometrical and immunohistochemical study of the ovary of small East African Goat
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Date
2023-03
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Sokoine University of Agriculture
Abstract
In the present study, the morphometrical and immunohistochemical changes in the
ovaries of Small East African (SEA) goat during dry and wet seasons were investigated.
In addition, the study describes seasonal morphological changes occurring in the ovary
of this breed. The findings of this study provide the insight for improving reproductive
efficiency in SEA goat. A total of 45 sexually mature female goats were utilized during
each season of dry and wet. These animals were brought for slaughter at Morogoro
Municipal slaughterhouse from various districts of Morogoro Region including Gairo,
Kilosa and Mvomero. After slaughter, ovaries were collected and measured in length,
weight and width. Thereafter, the collected ovaries were fixed in 10% buffered formalin
and processed routinely for histomorphological and immunohistochemical analysis.
Mouse and Rabbit Specific HRP/DAB IHC Detection Kit-Micro polymer (abcam,
ab64261) was used for immunohistochemical study. The results revealed that the length
of the right ovary was significantly higher than that of the left. In addition, four types of
follicles (primordial, primary, secondary and antral follicles) were identified during both
dry and wet seasons. Primordial follicles had a single layer of flat granulosa cells;
primary follicles with one layer of cuboidal granulosa cells; secondary follicles having
more than one layer of granulosa cells and antral follicles having an antrum with multiple
layers of granulosa and theca cells. It was further observed that, follicular atresia
occurred during all stages of follicular development. However, the antral follicles were
the most affected type by atresia. The affected follicles were undergoing obliterative type
atresia with primary follicular wall detachment. Furthermore, large number of atretic
follicles was observed during the dry season than in the wet season. Positive
immunostaining for desmin and smooth muscle actin was observed in the theca cells of
secondary and antral follicles as well as in the tunica media of ovarian blood vessels.
The staining intensities were varied between the healthy and atretic follicles. The atretic
follicles stained lighter than the healthy follicles. The results of this study have shown
that SEA goat ovaries undergo follicular dynamics with increased rate of follicular atresia
during dry season. Furthermore, based on immunohistochemical results, the distribution
of desmin and smooth muscle actin varied during stages of follicular development and
atresia. The dry season has bad effects on folliculogenesis as it lowers the number of
follicles and causes many follicles to be atretic. Based on the fact that, during the dry
season there is scarcity of feeds and increased heat which could affect follicular
development. This study recommends improvement in nutritional requirements of the
SEA goat by providing feed supplements during the dry seasons.
Description
Dissertation
Keywords
Follicular atresia, Histology, Immunolocalization, Morphometry, Small East African goats.