Histological studies were conducted on the palatine tonsil of six male crossbred goats of six months of age. The tonsils were lined by a stratified squamous non-keratinized surface epithelium which continued into the crypts forming the non-reticular epithelium. &nbsp;At some areas in the crypts, the non-reticular epithelium associated with lymphoid follicles showed a great reduction in height with only one to two intact cell layers and were called reticular epithelium or lymphoepithelium. Propria-submucosa of the palatine tonsil was characterized by dense irregular connective, lymphoid, glandular, adipose and muscular tissues. Lymphoid tissue constituted majority of the palatine tonsil and was organized into primary and secondary lymphoid nodules and dense diffuse lymphatic tissue. Average diameter of lymphoid nodules was 684.17&plusmn;6.88&micro;m while the lymphocyte count in the nodules was 28826.54&plusmn;236.25. &nbsp;The average number of lymphatic nodules counted per field under low power magnification of microscope was 2.67&plusmn;0.42 and the internodular distance was 34.67&plusmn;1.41. Glandular tissue was present in the deeper areas of propria-submucosa. A well developed connective tissue capsule separated the lymphoid and glandular tissues of the palatine tonsil. In the immunohistochemical staining technique strong positive reaction for cytoplasmic IgG bearing B- lymphocytes was noticed within the germinal centre of lymphoid nodules, towards the base of the FAE and some cells even infiltrated the crypt epithelium. &nbsp;In the mantle zone and internodular area, reaction was very mild indicating that T- lymphocytes predominated in these areas. &nbsp;It was concluded that the palatine tonsils were histologically mature as a local defence mechanism against the harmful substances to be encountered from the environment after birth.&nbsp; 
&nbsp;

Histology and immunohistochemistry of the palatine tonsil in goats

<div>Background: Rabbit farming provides a valuable additional source of income in the rural areas of the county. Skin is the largest organ in the body and the hair coat forms the first line of defense against the invading pathogenic organisms as well as the physical environment. So far, no detailed comparative study has been conducted on the skin of various breeds of rabbits. Hence, the present work was undertaken to compare the structure and distribution of hair follicles in different breeds of rabbits commonly reared in Kerala. 
 
Methods: The study was conducted on the skin of six breeds of rabbits namely, Soviet Chinchilla, New Zealand White, Grey Giant, White Giant, Angora and crossbred. In total, 36 animals were used for the study. From each animal, skin samples were collected from eight representative areas of the body viz., dorsal nasal region, pinna, dorsal neck, dorsal thorax, dorsal abdomen, ventral abdomen, perineal and carpal regions. Standard procedures were adopted for histological studies. 
 
Result: All the six breeds of rabbits showed compound hair follicles with primary and secondary follicles with associated sebaceous glands. Arrangement of hair follicles showed differences among the breeds. There was no difference in the histology of hair/hair follicle among the breeds. This work will form a basis for further breed specific research in the area of fur and leather industry and skin penetration studies.</div>

<div>Histology of Hair Follicles in Different Breeds of Rabbits</div>

<div style="text-align: justify;">Asthenozoospermia puzzled poultry industry and little known about its characteristics. To explore the histological etiology of asthenozoospermia, we measured the sperm quality index (SQI) and Piwil1 expression in the testes of three types of asthenozoospermia roosters: field, artificial and normal. The SQI of field and artificial roosters was inferior to normal roosters. Further, busulfan could reduce sperm quality. Histological examination showed that the spermatids and spermatocyte of the seminiferous tubule was stripped layer-by-layer in field and artificial roosters. The absolute expression of Piwi11 in the normal group was significantly higher than that in the other two groups, and decreased with time. Piwi11 transcript expression rapidly decreased after 7 days post-injection (dpi); the lowest level was 13 dpi and did not change thereafter. Overall, our results indicate that busulfan causes structural damage to the seminiferous tubules, which can lead to asthenozoospermia, and that Piwil1 gene is a marker gene of asthenozoospermia.</div>

Histological verification of seminiferous tubule structure injury a cause of asthenozoospermia in chicken

<div>Background: In new age, Arsenic is a major environmental pollutant and exposure occurs through agricultural, environmental, medicinal and occupational sources. The toxicity of sodium arsenate has been shown in catfish, Clarias batrachus and the histology report suggested that the sodium arsenate may adversely effect on the catfish, Clarias batrachus. 
 
Methods: The histological analysis carried out during the period of 2018-19 for sodium arsenate with Clarias batrachus as test animal for 96 hour as per ideal method and determine the lethal concentration (LC50). The liver and kidney tissues were collected from the fishes exposed to sodium arsenate and standard histology procedure were followed to investigate the histological alterations. 
 
Result: Exposure of sodium arsenate causes severe histological changes in liver like nucleus blabbing, infiltration, necrosis of hepatocytes, disruption of normal architecture, shrunkeri hepatocytes, lytic hepatocytes etc. In kidney sodium arsenate exposure causes hemorrhage, inflammation and tubular atrophy in renal tubules, disruption of tubular linings, dense chronic inflammation, hemorrhage and vacoulation in Bowman&rsquo;s capsule etc. The present investigation suggests that the inorganic forms of arsenic showing the highest toxicity level.</div>

Impact of Sodium Arsenate on Histological Changes in Liver and Kidney of Fresh Water Catfish, Clarias batrachus

<div>Background: The farmers are rearing duck in small scale in semi intensive system without investing more capital but it contributes a major part to uplift the socio-economic condition of the rural poor people of Assam. The Pati duck (Anas platyrhynchos domesticus) population constitutes a major indigenous non-descript economically important duck variety in the state of Assam. The Harderian gland acts as a part of the head associated lymphoid tissue (HALT) and provides local innate immunity to the upper respiratory system,&nbsp;to the eye and oral cavity. Since literature on histological study of Harderian gland of Pati duck is scant, hence the present study was designed to establish the basic histological details on Harderian gland at different stages of postnatal development of Pati duck of Assam. 
 
Methods: The present study was conducted on total forty five (45) numbers Pati duck of Assam at different stages of postnatal development. The experimental birds were brought to the Department of Anatomy and Histology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-22 and was sacrificed according to the method of Gracy (1986). For histological study the tissue samples from the Harderian gland of all the age group were fixed in 10% neutral buffered formalin solution and processed to prepare paraffin blocks as per the procedure described by Luna (1968). The paraffin blocks were sectioned in Shandon Finesse microtome in 5 &micro;m thickness and the sections were stained by different methods as described by Luna (1968).&nbsp; 
 
Result: The Harderian gland of Pati duck had a capsule, the thickness of the capsule of the Harderian gland was increased slightly along the advancement of the age. The capsular connective tissue penetrated the parenchyma of the Harderian gland in the form of septa. The collagen, reticular, elastic and nerve fibers were observed along with the capsule and as well as in the septa. The Harderian gland of the Pati duck was compound tubular gland. The columnar epithelial cells lined the tubules. There was no cortex and medulla in the gland and the tubular structure were uniformly distributed within the lobules. A central canal was present in the gland which converged to the duct of the gland. The lymphocytes, plasma cells were found in the intertubular connective tissue. The numbers or population of plasma cell and lymphocytes were accelerated by the advancement of age. The myoepithelial cells with spindle shaped nucleus were present near the basement membrane close to the secretary cells. The histology of the duct of the Harderian gland of Pati duck was like that of typical hollow tubular organs. There were few lymphatic nodules very distinctly present extended from the lamina propria to the muscle layer.</div>

Histological Study of the Harderian Gland of Pati Duck (Anas platyrhynchos domesticus) of Assam during Postnatal Development

<div>Background: Avian tongue has a significant role in the feeding process. The current investigation was planned to study the histological and ultrastructural features of the tongue in two avians. Java sparrow (Lonchura oryzivora) and Hoopoe (Upupa epops).&nbsp; 
 
Methods: Fourteen birds were used including seven Java sparrows and seven Hoopoes during the current investigation. Careful procedures were used in the dissection process of the two avian species. Their heads were separated and four tongue samples (from each species) were taken to fixed in 10% buffered formalin for histological observations.&nbsp; 
 
Result: Histologically, the lingual glands in Lonchura oryzivora were simple-branched acinar and compound acinar. Whereas, the lingual glands in Upupa epops were simple acinar and simple-branched acinar. Three tongue samples (from each species) were taken to fixed in 2.5% of glutaraldehyde for the ultrastructural observations. The SEM findings in both species showed main three parts of the tongue; apex (anterior part), corpus (middle part) and radix (posterior part). Lonchura oryzivora&lsquo;s tongue has an elongated dart form with anterior terminal curved pointy conical papillae. Mid-dorsal trench (Sulcus medianus) extended from the apex to the anterior region of the radix. While the tongue of Upupa epops was triangular form with a convex tip and it has a V-form papillary crest. The observed findings of the histological and ultrastructural dissimilarities of Java Sparrow and Hoopoe emphasized more insight into the feeding behaviors and adaptation of the two avians.</div>

Comparative Histological and Ultrastructural Studies on the Tongue of Two Avian Species (Lonchura oryzivora and Upupa epops)

Histological studies were conducted on the tonsil of soft palate in six month-old male crossbred goats. The tonsil was located on the nasopharyngeal side of the soft palate. The tonsillar surface epithelium presented small folds and was lined by pseudostratified ciliated columnar epithelium in the rostral half and stratified squamous epithelium in the caudal part. The epithelium mounting over the lymphoid accumulation or follicle associated epithelium was modified into a lympho-epithelium and was disrupted and heavily infiltrated by lymphocytes. Distinct crypts were not seen. In the lamina propria, lymphoid tissue constituted only a small portion of the tonsil and only two to three nodules were seen per low power microscopic field. Most of the lymphoid nodules had germinal centers. The average diameter of the nodules was 131.97&plusmn;8.03 &micro;m. Loose irregular connective tissue, lymphoid tissue and glands comprised the propria submucosa. The tonsil of soft palate was not encapsulated.

Histological studies on the tonsil of soft palate in goats

<div style="text-align:justify">Background: The pesticides are known to adversely affect the quality of water and create hazards for aquatic life that results in severe damage to non-target freshwater organisms including fish. Among them, the organophosphorus pesticide, chlorpyrifos (CPF) is one of the most commonly used pesticides for controlling various kinds of pests in agriculture. Pesticides after entering in to the body of fish bring about histopathological and biochemical changes in different target and non-target organs. Hence, the present study aimed to investigate the toxicity effects of Chlorpyrifos (CPF) and associated histopathological changes in the gill, liver and kidney of the Mozambique Tilapia, Oreochromis mossambicus under the acute toxicity concentrations.&nbsp; Methods: Static bioassay was carried out for Chlorpyrifos with Oreochromis mossambicus as test animal for a period of 96 hrs as per standard methods and LC50 values were calculated through Probit analysis. The fishes were exposed to five acute concentrations (0.033, 0.066, 0.132, 0.264 and 0.528 ppb). The gill, liver and kidney tissues were collected from the fishes exposed to the pesticide and standard histology protocol was followed to investigate the histopathological changes. Result: The histological changes observed in the gill included lamellar aneurysm, curling of secondary lamellae, shortening of the secondary lamellae, hypertrophy of epithelial cell, fusion of secondary lamellae, deformation of the cartilage core, blood congestion, collapsed secondary lamellae, excessive mucus secretion, disorganization of the secondary lamellae, haemorrhage at primary lamellae, necrosis, haemorrhage at secondary lamellae. The most common histopathological changes in the liver were characterized by cellular necrosis, degeneration of hepatocytes, nuclear degeneration, fat deposition, rupture of nucleus, hypertrophied hepatocytes, blood congestion, blood sinusoids, cellular hypertrophy, increased pycnotic nucleus, cirrhosis and hemosiderosis. Further, histological changes like appearance of dilated lumen, hypertrophied epithelial cells, severe haemorrhage, blood congestion, melanomacrophage aggregation, narrowing of lumen, degenerated tubule, degenerated glomerulus, shrunken glomerulus and distended glomerulus were observed in the kidney. Thus, it is evident from the present study that Chlorpyrifos can be a potential toxicant affecting the fishes at tissue level on dose and time dependent manner which are expected to affect the other physiological processes in the long run.&nbsp;</div>

<div style="text-align: justify;">Effects of Acute Toxicity of Chlorpyrifos (EC 50%) and Associated Histological Alterations in Gills, Liver and Kidney of Mozambique Tilapia, Oreochromis mossambicus (Peters, 1852)</div>

<div>Background: Launaea angustifolia (LAN) is a wild plant grown in several Arabian countries in West Asia and North Africa. Launaea is a polymorphic inter- and intraspecific genus that includes about 54 species and 10 subspecies and is classified into eight sections. This study illustrates the effects of Launaea angustifo LAN (LAn) extract on male and female body weight and blood serum enzymes alanine aminotransferase (LAT) and Alkaline phosphatase LAN, with the histology of liver and kidneys used as an animal model for humans. 
 
Methods: A quantity of 100 mg of the extract powder was dissolved in 1 L of DMSO. Experimental rats were divided into five groups with 10 in each group (A, B, C, D, E: 100, 50 and 10 mg/kg and positive control and negative control, respectively).&nbsp;</div>

<div> 
Result: No significant differences were observed between the treated and control-group females. However, the mean male body weight showed some variation within the 5th group (E) given the negative control (DMSO) and all treated groups presented lower body weights than the normal control (C). Analysis of the enzymatic activities of (ALT) alanine aminotransferase showed that the females in treatment group A (100 mg) and B (50 mg) had higher levels of ALT than those of group D females (10 mg) at P&lt;0.05 and females in group E at P&lt;0.001). The histology section of the liver and kidney and the histological structure of the rat kidney also showed no differences in all groups. Launaea angustifolia&nbsp;extract (LAn) was found to be safe, especially in the histology of the liver and kidney and for ALT and ALP blood parameters.&nbsp; &nbsp; &nbsp;</div>

<div style="text-align:justify">&nbsp;</div>

Evaluation of Launaea Angustifolia Extract Treatment on Rat Blood Serum Enzymes and Histology of Liver and Kidney

Background: Theileria Spp. is the causative agent of the economically significant hemoprotozoan disease known as theileriosis in cattle. In dairy animals, it results in death and decreased productivity. This study aimed to clarify the effects of Theileria annulata (T. annulata) infection on the histological and haemato-biochemical parameters in infected cattle. 
&nbsp; 
Methods: Between December 2022 and May 2023, 200 cattle were randomly selected from the slaughterhouse and blood samples were collected from them to assess the hemato-biochemical parameters and screen for T. annulata infection using a Giemsa-stained blood smear, furthermore, the histological profile of the spleen, lymph nodes and liver. 
&nbsp; 
Result: T. annulata was detected in 26.5% of the cattle based on blood smear microscopy. The haematological analysis showed a notable increase in lymphocytes and a significant drop in platelets, haemoglobin, total leukocyte count and total erythrocyte count. In cattle infected with T. annulata, biochemical examination showed a significant increase in alanine aminotransferase (ALT), aspartate aminotransferase (AST), high density lipoprotein (HDL) and triglyceride, also increase in bilirubin. Histological examination revealed necrotic degenerations of splenic nodules, oedema, parenchymal necrotic degeneration, increased intercellular spaces, depletion of lymphocytes, increased sinuses in lymph nodes and focal necrosis of hepatocytes with infiltration of inflammatory cells and vacuolar degeneration of hepatocytes.