Despite significant progress in the study of the subtle mechanisms of interaction between cellular and molecular elements in immune responses, the general structure of the organs of the immune system, including the lymph node, has not been sufficiently studied, in particular in large farm animals. The lymph nodes of sexually mature camels have been studied anatomically and morphologically and advanced studies conducted using an X-ray system and a computer densitometer scanner with injection of a contrast medium. The topography and characteristics of the morphometric parameters (absolute and relative mass, linear measurements, volume) of certain somatic and visceral lymph nodes were determined. The mass of the lymph nodes studied varies according to the location and the interest of the organ in the satellite defense of the lymphoid system, For part of the x-ray examination of the lymph nodes, organs of large inguinal and axillary shape were selected after passing through a solution of tetraethyl-4,4-diamino-triphenylmethane oxalate, the lymph vessels were dilated and darkened, then iodine injections were made into the afferent lymphatic vessel of two lymph nodes; they were placed on the radiological cassette, a photograph taken on conventional radiography, for computer densitometer, the examination was made without preparation of the organs. A capsule encompasses the parenchyma of the lymph node, whose internal structure is composed of different zones, cortical, paracortical and medullary, on the one hand the lymphatic vessels were very clear especially with the conventional radiography with preparation of the organs, while the computer densitometer clearly revealed the deep texture of the parenchyma, basing it on the intensity of emission saturation from the use of computer densitometer.

The anatomy and features of the histological structure of the components of the eye of a one-humped camel were investigated. Ultrasound examinations of the eye, determination of the iridocorneal angle with a gynoscope were carried out on live animals in the clinic after the introduction of eye drops (xylocaine 2%, atropine sulfate 3%). The condition of the eye membranes was determined by histological methods. The studies were carried out on twenty eyeballs from ten clinically healthy adult camels, selected during slaughter in a meat processing enterprise. The anatomical and topographic features of the organ, its membranes and structures, absolute and relative mass, and linear measurements were determined. Thin histological sections of the eye wall were stained with hematoxylin and eosin, impregnated with silver nitrate, followed by examination under a microscope. In a one-humped camel, the eyelashes of both eyelids are very thick and long. The internal architectonics of the eyeball of a one-humped camel is similar to that of other animal species. The lens was found to be a transparent biconvex structure located inside the eyeball just behind the iris. The cornea of the eye occupies almost the entire visible part of the eye. The ciliary body is located behind the iris near the lens. The main functions of the ciliary body are the formation of intraocular fluid (aqueous humor), which fills the front of the eye. The ciliary body contains muscles that enable the eye to focus on objects located at different distances. A feature of the camel's eye is the very open iridocorneal angle. The retina is built up by nerve tissue that lines the back of the eye. The retina perceives light, generates impulses that pass through the optic nerve and are sent to the brain. The histological structure of the membranes of the eye was studied after applying routine methods. It has been established that the eyes are built by various types of tissues, in particular, epithelial (epithelium of the conjunctiva), dense loose connective tissue (the corneal substance itself), loose connective tissue and pigment tissue (choroid) and nervous tissue with a layer of melanocytes and keratinocytes.

Ten pairs of eyelids of adult, healthy cattle of the local breed from the region of Guelma, Algeria, were collected at the slaughterhouse in order to carry out research to determine the structure, the components and to make a comparison with the results of this subject in other ruminants, classical staining techniques such as Hematoxylin & eosin, Masson trichrome and silver nitrate were carried out in the histology laboratory on sections of these membranes, the studied parts were the upper eyelid and lower eyelid, medial and lateral canthus, the results observed were significant, there was a small increase in the thickness of the epidermis in the lower eyelid, and the small sebaceous glands which made the difference between the lower eyelid from local cattle, these glands originate near the basement membrane of the upper eyelids. Regarding the tarsal gland, empty its secretion onto the surface of the eyelid through a duct lined with typical stratified squamous epithelium.

The two main pregastric compartiments of ruminants: rumen and reticulum work as anaerobic fermenter which allows them to use energetic and nitrogen substrates which are indigestible by monograstric animals. They have a major importance in this fermenter, also these microbes : bacteria, protozoa and fungi, on the degradation of cell-wall carbohydrates: cellulose, hemicelluloses, pectic substances, on nitrogen digestion and finally on the utilisation of the major minerals and trace elements. The objective of this study is to identify and quantify the protozoa populations in the rumen of Algerian bovines local breed, adult animals living in a relatively humid climate, basic ration based on straw and pastures during hot days. Whereas in cold weather rations are based on straw, cereals and grass forage. Usually not 2 to 5 × 10 6 ml of rumen containing organisms however, under certain feeding conditions, they represent at least 50 % of the rumen microbial biomass. Due to the difficulties in cultivate in vitro, their role and their metabolism are less known than those of bacteria. Ciliated protozoa are capable of transforming a large number of food and bacterial constituents in metabolites and cellular compounds which will then be used by the host animal. The importance of these activities is however still very controversial since in the absence of protozoa in the rumen, Isolation carried out on rumen fluid sampled of 20 cows. Rumen fluid was diluted in formaldehyde 10 % solution, and distributed in Sedgewick Rafter chamber. Then observed in optical microscope using Lugol's iodine coloration. Classified in three genders according to size. 11 different genders were identified; a considerable population of rumen protozoa was identified and classified for first time on Algerian local breed (Atlas).

The current research aimed to establish a method for measuring the percentage of diaminobenzidine (DAB) staining on immunohistochemical slides with high accuracy and efficiency. The R programming language was utilized in this endeavor. A total of 50 slides were collected from various types of tissue, and were stained using an anti-cytokeratin antibody and the DAB detection method. These slides were then scanned using a high-resolution scanner, and the resulting images were analyzed using R, a custom script was specifically developed to segment the tissue and DAB-positive areas, and calculate the percentage of DAB staining on the slide. The results were then compared to manual measurements of DAB staining performed by a trained technician. The R-based method was found to be highly accurate, with a mean absolute error of only 0.76 % compared to manual measurements, this study provides evidence that the use of R for DAB quantification is a fast and reliable alternative to manual methods, enabling the analysis of large numbers of slides in a short period of time. It offers a valuable tool for researchers and technicians in the field of histopathology, enabling them to quickly and accurately analyze DAB staining on immunohistochemical slides, which is essential for the diagnosis and treatment of various diseases.

The lymph nodes are organized lymphoid organs in which lymphocytes are located inside reticular stroma. The lymphoid parenchyma of lymph nodes is divided into separated cell zones, the most developed one is parenchyma in which the deep cortex located. The lymph nodes of small mammals, which are often used for laboratory research, The investigated lymph nodes in this research were Somatic (superficial cervical and axillary) and visceral (hepatic and mediastinal) lymph nodes were selected from mice (n = 5), guinea pigs (n = 5), hamsters (n = 3) and rabbits (n = 5). We used classical histological methods (determination of general histological structure of organs), morphometric (determination of the relative area of individual structural and functional zones), immunohistochemical (determination of location of individual cell populations). It was shown that the deep cortex of the parenchyma of the lymph nodes composed by separate structures «deep cortex units», and some of them are combined into complexes. Each unit is represented by a semicircular structure formed by lymphocytes and reticular fibers. The size of units is approximately the same in all studied animals and does not depend on the size of their bodies. The most developed units of the deep cortex were found in the superficial cervical ganglion, and the largest-in rabbits, where their size reached 3 mm. In all studied animals, units of the deep cortex are located at the same level, along the subcapsular sinus. The most developed component tissue of the studied lymph nodes is the lymphoid parenchyma, in laboratory mice it occupies a significantly larger area than in other animal species. The least developed were the central sections of units in the deep coating crust.

Thymus of lambs of the Ouled-Djellal breed from eastern Algeria, aged one to 10 months, were used to study the anatomical, histological and cytological characteristics of these organs. Modern techniques have been used to demonstrate the morphometric parameters and masses of the thymus at different ages, a regression of the morphometric and mass indexes has been visualized according to the age of the lambs. Staining techniques with Hematoxylin and eosin revealed the normal structure of the thymus with its tissue components. The thymus is bilobed. The lobe is surrounded by a thin capsule and subdivided into lobules separated by septae, the cortical and medullary areas were clearly visible, the interlobular blood vessels enter the lobule in all its aspects to continue its way as interlobular blood vessels. From the changes observed in the involution of the thymus according to the age of the animals which occur relatively late, the percentage of the surface found for the capsule was very variable, which increases from the first to the tenth month, the demarcation of the cortex and the medulla beginning during the second month of age of the animal. The interlobular connective tissue (ILC) presents sums, the maximum of which was found in the fourth month of age of the animal, while the minimum was found in the thymus of ninth month lambs Concerning the Hassal corpuscles, their sums are in high extension until the tenth month, rich in T lymphocytes, whose use of immunohistochemistry, the anti-CD 157+ antibody allowed us to visualize to locate them clearly, which invade and form most of the thymus cortex. In conclusion, the significant changes in thymus development in sheep of the Ouled-Djellal breed are similar to those of other species.

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