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Morphological changes in the late‐embryo‐stage gastrointestinal tract of Nigerian indigenous chicken were investigated using anatomical techniques. The paraffin‐embedded sections were stained with haematoxylin and eosin and periodic acid Schiff‐Alcian blue (pH 2.5) stains. During the late pre‐hatch period, the framework of the stomach was already established, but glands were yet poorly developed. Randomly oriented pre‐glandular cells in the lamina propria mucosae at embryonic day (ED) 14 became organized into elongated simple tubular glands at ED 19 and assumed adult morphology at post‐hatch day (PD) 1. Acidic and neutral mucin deposits were associated with the glandular cells. In the small intestine, enterocytes of the tunica epithelialis mucosae transformed from cuboidal‐shaped cells (at ED 14) to tall columnar cells (at PD 1). Short crypts of Lieberkühn, goblet cells, microfold cells and enteroendocrine cells were evident at ED 19, while the lamina propria mucosae and submucosa contained mesenchymal cells, reticular cells and isolated lymphoblasts. Similarly, the crypts, lymphoblasts, mesenchymal and reticular cells were also associated with the lamina propria mucosae and submucosa of the caecum and colorectum at ED 19. It was inferred from these findings that extensive cellular and tissue modifications occur in the gastrointestinal tract within the narrow window of the late pre‐hatch period. The definitive gut tunics, epithelium, glandular tissues, immune‐competent cells and tissues are formed as a result. Thus, the embryonic gut of the bird is made capable of assuming its necessary functions of food digestion, nutrient absorption, water and ion re‐absorption, immune surveillance, antibody production and immune responses at hatch. [ABSTRACT FROM AUTHOR]

The developmental morphology of the bursa of Fabricius (BF) of broiler chicken was evaluated in this study using gross anatomical, histological, reticulin histo-chemical, and transmission electron microscopic techniques. The result showed that the short plica of the BF at embryonic day (ED) 14 was a mesenchymal tissue that contained cells, including mesenchymal cells and lymphoblasts. The organo-somatic index (OSI) of the BF peaked at ED 17, while the BF of ED 19 showed well delineated follicle-associated and inter-follicular epithelial (IFE) cells. Whereas, the IFE contained apical vacuoles which increased in size with age, the BF contained lymphoid follicles which were first observed at ED 17, and increased steadily in mean diameter from ED 19 to post-hatch day (PD) 28. The framework of the interfollicular areas and the follicular capsules were composed of collagen type III fibres. Moreover, the cortico-medullary basement membranes were well established with peripheral and corticomedullary basement capillaries becoming very consistent between PDs 5 and 7. The lymphoid follicle contained lymphocytes with mitotic figures, and plasma cells which showed extensive network of rough endoplasmic reticulum at PD 21, while macrophages contained increasing evidence of phagocytosis from PDs 35 to 56. In conclusion, the morphological features of the BF of broiler chicken in this study reveals that the key function of B-cell maturation within the BF may occur between the first 3 to 4 weeks after hatching, and thereafter, may primarily produce immunoglobulins until involution occurs. [ABSTRACT FROM AUTHOR]

Morphological development of the lamina epithelialis mucosae (LEM) of the ileum of broiler chicken was evaluated using light and transmission electron microscopic techniques. Ileal sections were collected on embryonic days (ED) 14, 17 and 19, as well as post‐hatch days (PD) 1, 3, 5, 7, 14, 21, 28, 35, 42 and 56. The result showed that the ileal LEM, which were poorly defined at embryonic days 14 and 17, consisted of enterocytes and some atypically shaped goblet cells. Apico‐lateral tight junctions and irregularly shaped microvilli were associated with the enterocytes at ED 14 and 17. The enterocyte microvilli were more uniform in shape and distribution at ED 19. The embryonic goblet cells were varied in shape and possessed basally displaced, star‐shaped nuclei and small apical cytoplasmic vacuoles. During the post‐hatch ages, the LEM was a typical epithelium with a single layer of columnar‐shaped enterocytes that became highly elongated at post‐hatch day (PD) 7. The goblet cells were characteristically 'wine‐glass' shaped. Follicle‐associated epithelium (FAE) showing numerous lymphocytes among the enterocytes occurred in the post‐hatch LEM. The intra‐epithelial lymphocytes (IEL) were first encountered at PD 1, but increased several folds within the first two weeks post‐hatch. Entero‐endocrine cells were observed in the epithelium from PD 21. Finally, from this study, it is obvious that enterocytes and small atypically shaped goblet cells occur in the ileal LEM during the pre‐hatch period, but these cells assume adult morphological characteristics after hatch. Thus, the cells of the ileal LEM play strategic absorptive, secretory and protective roles in the gut. [ABSTRACT FROM AUTHOR]

The cervix which changes with the reproductive cycle, history and age of the females, provides a natural communication between the uterus and the outside environment. This study investigated the chronological and morphological changes of the cervix of the West African Dwarf (WAD) goat during postnatal development. Forty-five female WAD goats ranging from birth, Weeks 2, 4, 8, 12, 16, 20, 24 and 28 of five goats each were used. The cervices were exteriorised, examined and morphometric parameters obtained and then prepared for histological examinations. The cervix is a firm body in all the age groups and internally bore thick muscular cervical rings which increased with age. The straight cervical canal is straight and can be easily penetrated by an artificial insemination pipette. The gross morphometry of the cervix increased significantly (p < 0.05) with age. The lamina propria-submucosa lacked cervical glands. The tunica muscularis showed histological evidence of postnatal development with increase in age of WAD goat. The epithelium of the cervix was initially pseudostratified columnar at birth but became simple columnar by week 12. Periodic Acid Schiff (PAS) stain showed some mucus secretory activities at week 4. In conclusion, the study revealed that the cervix of WAD goat is not fully developed at birth but undergoes a postnatal development. The onset of secretory activities is associated with adenogenesis of uterine glands. Thus, the WAD goat probably attains puberty at week 16, earlier than previously reported. [ABSTRACT FROM AUTHOR]

The study investigated seasonal changes in the morphology of the seminal vesicles of Eidolon helvum in a typical African tropical environment. Seminal vesicles of forty‐eight bats were examined during the early rainy, late rainy and peak dry seasons, using gross anatomical, histological and ultrastructural techniques. The interlobular connective tissue septa from the external capsule demarcated the glandular parenchyma into numerous lobules of tubulo‐alveolar glands. A simple cuboidal epithelium of mono‐ or bi‐nucleated cuboidal cells lined the glandular mucosa during the rainy season. This was replaced by a bistratified cuboidal epithelium, whose upper layer of cells showed evidence of degeneration, during the dry season. The PAS‐positive secretory products appeared to be numerous during the rainy season, but few and clumped together during the dry season. The mean gross weight, interlobular septal thickness, acini diameter and epithelial height of the glands varied significantly with season. Ultrastructural features of the secretory cells during the rainy season showed well‐developed cytoplasmic organelles, numerous electron lucid secretory vesicles and electron‐dense granules. Secretory epithelial cells of the seminal vesicles are very active during the rainy season, while regeneration of degenerated epithelium in preparation for the next reproductive cycle occurs during the dry season. [ABSTRACT FROM AUTHOR]

The objective of this study was to highlight the postnatal development of the uterine tubes of the West African Dwarf goat from birth to 28 weeks of age by gross examination and light microscopy. There was a caudal migration of the paired uterine tubes from behind the paired kidneys at birth to the pelvic inlet at week 8 of age. Each uterine tube exhibited three segments namely; infundibulum, ampulla and isthmus. A marked flexure, the utero-tubal junction, was the point at which the uterine tubes joined the uterine horns. The length and absolute weight of the uterine tubes increased from 4.95 ± 0.28 cm and 0.02 ± 0.01 g at birth to 14.98 ± 2.79 cm and 0.22 ± 0.03 g at week 28 of age, respectively. The mucosa of the infundibulum and the ampulla showed long, branched and anastomosing primary, secondary and tertiary mucosal folds which decreased in height towards the isthmus. The mucosal folds within the isthmus were short and lacked the anastomosing pattern. The epithelia of all three segments were pseudostratified columnar. Numerous secretory blebs and extruded nuclei became apparent from week 16 of age. The thickness of the tunica muscularis varied with the segments.