We studied anatomy and histology of different segments of the digestive tract in postnatal growing broiler chickens with regard to their location, shape, size and weight. A group of four chickens, each at day 1 (D 1) , days 14 (D 14) and days 28 (D 28) , total 12, were killed, their digestive tracts were dissected and described and shape, size and weight of different segments were recorded. Samples from different segments were prepared and stained with haematoxylin and eosin staining technique to study the histology under light microscope. The average lengths (cm) and weights (gm) of esophagus, proventriculus (glandular stomach), gizzard (muscular stomach), small intestine and large intestine were significantly higher (P<0.01) in chickens at D 28 than that at D 14 and at D 1. The histological layers of digestive tract were lamina epithelia, lamina propria, lamina muscularis, submucosa, tunica muscularis and serosa with the exception in esophagus where outer adventitia was found. The esophageal glands were significantly more in numbers at D 1 (in cross section, 12 in number per focus under 100x) than at D 14 (6 in number per focus under 100x) and at D 28 (2 in number per focus under 100x). The proventriculus consisted of macroscopic papillae with numerous microscopic folds with lamina propria comprised of simple glands, which converged into a common cavity near the surface. In gizzard, the cuticle, in the form of wavy lines ran parallel to the surface. The villi of small intestine and large intestine were lined by simple columnar epithelium. The apical parts of villi of the duodenum were slightly pointed and the basal parts of the villi were thicker than jejunum and ileum, whereas, the villi of the jejunum and ileum became shorter and broader than duodenum and most of the villi had blunt apical part and the basal parts were wider. The numbers of goblet cells were numerous in number in ileum than duodenum and jejunum. Plicae ran along the inner surface of the distal two thirds of the cacea. However, in the colorectum, the villi appeared as numerous long flat leaf-shaped structures which filled a large proportion of the lumen. The average lengths and widths of villi of small and large intestine were significantly higher (P<0.01) in chickens at D 28 than that at D 14 and at D 1. The number of goblet cells in lamina epithelium and intestinal glands of the lamina propria were numerous in number at D 28 than the chickens at D 14 and at D 1.

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Mobilization of immunoglobulins (Igs)-containing plasma cells (IgA, IgG and IgM) in the spleen, bursa of Fabricius and thymus was investigated in broiler chickens that were vaccinated with Newcastle disease virus (NDV) vaccine. In the thymus, the Igs-containing plasma cells were distributed in the cortex and medulla. Their frequency and distribution were higher at D 14 and at D 28 . The number of IgG-and IgM-positive cells was greater than IgA-positive cells in thymus. In the bursa of Fabricius, Igs-containing plasma cells were distributed beneath the capsules; within and around the bursal follicles. Their frequency of occurrence significantly peaked at D 14 and at D 28 in comparison to day-old chickens, and IgG-positive cells were significantly greater than the IgA-and IgM-positive cells in the bursa of vaccinated chickens. In the spleen, Igs-containing plasma cells were distributed in the white pulp, around the trabeculae, and in the periarterial lymphatic sheath. In this secondary lymphatic tissue, IgG-and IgM-positive cell numbers significantly greater than IgA-positive cells. In conclusion, mobilization of more Igs-positive cells in lymphoid tissues of broiler chickens is due to the effect of NDV vaccine as well as the advancement of age.ª 2014 Production and hosting by Elsevier B.V. on behalf

Histomorphological changes of epididymis and ductus deferens in male Black Bengal goat due to arsenic were studied. A total of 12 male Black Bengal goats, in which 6 were collected from arsenic affected areas of Mymensingh district and another 6 were collected from hill tracts of Chittagong which were arsenic free.The goats were sacrificed by piercing carotid artery and the samples (Epididymis and Ductus deferens) were collected immediately. Samples were prepared and stained with haematoxylin and eosin stain technique to study the histology under light microscope. In the morphological study, measurement of length, width, breadth and weight of epididymis and ductus deferens were observed. The gross study revealed that there were slight variations in the gross morphology of epididymis and ductus deferens of arsenic affected Black Bengal goat, but this variation was statistically insignificant. In the histological study, arsenic affected goat showing increased thickness of epididymal covering (P<0.05) and trabeculae compared to control group of epididymis. The diameter of ductule efferentes of arsenic affected goat was narrower (P<0.01), width between intertubular space of ductuli efferentes was wider (P<0.01), lumen of ductules contain smaller in amount of spermatozoa compared to control group. The wall of the ductus deferens was thicker in arsenic affected goats than the control group (P<0.01). It may be concluded that environmental health hazard of arsenic might have adverse effects on the male reproductive organs.

Melanocytes are melanin pigment-producing cells responsible for skin, hair, and eye pigmentation. Melanocytes also reside in the inner ear and heart, where they play important roles in maintaining auditory and cardiac functions (Levin et al., 2009;Tachibana, 1999).During development, precursors for pigment-producing melanocytes (melanoblasts) emerge in the neural crest and migrate throughout the embryo toward specific body locations where they finally reside.In mice, melanoblasts predominantly migrate into the developing hair follicles, where they form the hair follicle pigmentary unit together with surrounding keratinocytes and dermal cells to maintain the regenerative hair pigmentation cycle throughout life (Nishimura et al., 2002). Hair pigmentation is mediated by the melanogenic