Postnatal Morphogenesis, Histogenesis and Scanning Electron Microscope of Spleen in Local Awassi Sheep
Aisha Ayoub Essa
*
Department of Anatomy and histology, College of Veterinary Medicine, Al-Qasim Green University, Babylon, 51013, Iraq.
Jafar Ghazi Abbas Al-Jebory
Department of Anatomy and histology, College of Veterinary Medicine, Al-Qasim Green University, Babylon, 51013, Iraq.
*Author to whom correspondence should be addressed.
Abstract
The spleen plays a crucial role in the immune system during early life. The study investigated the postnatal development of the spleen in local Awassi sheep through morphological, histological, and scanning electron microscopic (SEM) approaches. The study collected ten spleen specimens from healthy lambs at 2-3 month, where the age approximate the animals that are determined depending on formula of milk teeth and eruption age of teeth using the following formula: [2(0\3 + 0\1 + 3\3) = 20], while the formula for the permanent teeth is [2(0\3 + 0\1 + 3\3 + 3\3) =32]. Moreover, the information attainable from the owner is used to detect the exact age. Gross morphological examination was conducted to evaluate the location, shape, colour, and biometric parameters of the spleen. Histological analysis was performed using routine staining techniques to describe the structural organisation of the spleen, including the capsule, trabecula, white pulp, red pulp, lymphocytes, reticular cells, and macrophages. In addition, scanning electron microscopy was employed to elucidate the surface architecture and ultrastructural characteristics of the splenic tissue. The results revealed that the spleen in postnatal Awassi sheep is well-developed during early life, exhibiting clear formation of capsule and parenchyma. Histologically, the spleen appears large and highly active, consisting of stroma and parenchyma, where the first portion is composed of capsule and trabeculae, while the second one composed of white and red splenic pulp. The scanning electron microscope observations of the spleen exhibited a highly organised and mature surface architecture, a thick fibrous capsule surrounding the developing organs and the trabeculae. Full development of splenic pulp. Progressive structural changes were observed with increasing postnatal age, indicating gradual splenic involution. This study provides comprehensive morphological, histological, and ultrastructural data on the postnatal spleen in Awassi sheep, contributing valuable baseline information for comparative anatomy, veterinary histology, and immunological studies in small ruminants.
Keywords: Awassi sheep, lamb, postnatal development, SEM