The aim of this study was to perform three-dimensional reconstruction of the metatarsal and phalangeal bones using computed tomography, to obtain osteometric data and to determine biometric differences in terms of sexual dimorphism in the obtained measurements in Van cats, an endemic species living in the Van province region of eastern Türkiye and named after this region. Computed tomography images of a total of 16 adult and healthy Van cats, eight females and eight males, were used in the study. Three-dimensional modelling of the images and osteometric measurements were obtained using MIMICS 20.1 software. When the osteometric data of the bones were analysed, it was observed that all of the morphometric measurements of metatarsal, phalanx media, phalanx distalis and phalanx proximalis bones, except the greatest breadth of the distal end of the phanax proximalis-III, the greatest breadth of the proximal end of the right phalanx proximalis-II, left phalanx proximalis-IV and left phalanx proximalis-V, were higher in male cats than females. The length order of the metatarsal bones in Van cats was found as IV, III, V and II, respectively. It was determined that there were positive and significant correlations between the osteometric measurement parameters of metatarsal and phalangeal bones with age and body weight. In conclusion, basic morphological images and osteometric data of the metatarsal and phalangeal bones in Van cats were obtained. These findings will be valuable for studying anatomy, aiding veterinary medicine students in clinical practice and contributing to the fields of zooarchaeology and veterinary forensic anthropology.

The present avian anatomists have shown a renewed interest in looking at whether the structure of the avian eyelid is accommodated by the kinetic achievement for each eyelid. The current work utilised both histological and anatomical methods to explore the eyelid's structural association with their kinetic, utilising the hoopoe and cattle egret as natural models. The third lid moved only without implicating other lids. Wrinkles on the edge of the hoopoe's eyelid became less pronounced during the opening phase, in contrast to, the edge of the egret's eyelid. The elevator muscle was visible only in the hoopoe, while both birds possessed the retractor anguli oculi muscles. The two later muscles collaborate with the depressor muscle during the closure phase. Two types of collagen I and III were detected within the stroma of the eyelids of both bird species; the elastic fibres was observed; few were in the hoopoe's eyelids. The eyelid edge of the hoopoe has more of the elastic fibres than those in its eyelid skin. The hoopoe's eyelid's epithelial layers contained more cytokeratin (AE1/AE3) than the egret. In conclusion, the anatomical traits of the hoopoe eyelids contribute to its greater motion compared to the egret eyelids.

Relatively little research has been conducted regarding Choloepus didactylus and studies that have been done have mainly covered physiology and morphology, as well as studies on its respiratory system. The objective of this study was to describe the components of the respiratory system of the two-toed sloth and compare it with other species already described in the literature. For this purpose, eight adult animals were used. Macroscopic analyses were carried out on the organs that make up the respiratory system, which confirmed the existence of four cartilages of the larynx, trachea with an average of 37 incomplete tracheal cartilages and lung, highlighting the absence of the accessory pulmonary lobe being composed only of the right cranial and caudal, left cranial and caudal lobes. After the standard protocol, microscopic analyses of fragments of the organs evidenced in the macroscopic study were carried out, using optical microscopy and scanning electron microscopy, in addition to chest x-rays with positive contrast media through orotracheal intubation. Finally, we conclude that microscopically the respiratory system of the two-toed sloth is like other Xenarthra and some domestic animals. Macroscopically, the nose is like Choloepus hoffmanni, the nasal cavity to other species of Xenarthra already described in addition to domestic animals. The trachea differs from other species in terms of the number of tracheal rings and extension. As for the lungs, they were the ones that differed most when compared to other Xenarthra and to domestic animals as it was the species with the least lobation.

Collared Peccary (Pecari tajacu, Linnaeus, 1758) is a mammalian Tayassuidae species from tropical to semi-arid areas. The morphological features of the oral cavity in this species were identified and described. Tonsils are secondary lymphoid organs essential for contact with antigens due to food and air intake. This study aimed to describe histological characteristics and three-dimensional morphology of the soft palate tonsil mucosa. Therefore, the samples (n = 10) were analysed by stereomicroscope for morphology, light microscopy (n = 4) for structural characterisation, and scanning electron microscopy (n = 6) to reveal three-dimensional aspects of the epithelial surface and connective tissue cores (CTC). Our findings revealed a pair of soft palate tonsils separated by a median raphe. A keratinised squamous stratified epithelium characterised the tonsil. The epithelial surface had several orifices, and these were associated with a lymph nodule organisation. After epithelial removal, the three-dimensional aspect of the lamina propria was evidenced by conical projections throughout the region, even on the crypt's edge and inside them. The soft palate tonsils mucosa was like the previous description; however, the revealed CTC had a conical morphology, a new feature in this organ.

Anatomically the tongue of Gallus gallus domesticus (Galliformes: Phasianidae) is distinguished into sharp rostral apex, body and root with numerous conical papillae arranged in rows in different sizes in the free portion and the root of the tongue. The epithelium covered the dorsal and ventral surfaces of the free portion and the dorsal surface of the root of the tongue. Numerous orifices of the salivary glands were scattered in the root of the tongue. SEM investigation of the connective tissue cores after maceration of the tongue in 10% NaOH showed the presence of thread-like structures of the connective tissue cores in the rostral apex of the tongue, rod-shaped protrusions in the middle of the free portion and ring-like process posteriorly, while in the conical papillae, they appeared like thin parallel striations. The connective tissue core formed sheaths around the orifices of the salivary glands. While the connective tissue cores of the laryngeal area showed saw-shaped protrusions. Ventrally, the connective tissue core of the lingual nail was arranged in longitudinal parallel rows. SEM investigation revealed that the connective tissue core of the epithelium covered the tongue and closely conformed to the form and size of the filiform papillae.

The coypu (Myocastor coypus bonariensis) is an annual polyestrous hystricomorph rodent with variable-length oestrous cycles, which ovarian histoarchitecture during this period is not fully described. This study analyses variations in ovarian morphology during the oestrous cycle, focusing on follicular development and atresia. Eighteen sexually mature virgin females aged 7-9 months, weighing 4.795 ± 0.3996 kg, were used. Daily colpocytological analyses were performed to establish the cycle duration, followed by euthanasia at different phases-prooestrus, estrus, meteostrus, and on days 5, 10, and 20 of dioestrus. Morphology and superficial appearance of the ovaries, weight, and volume at each stage were recorded, and volume increase over time was analysed. A morphological classification and size ranges every 100 μm for follicular development analysis were used. Relative area analysis determined the proportions of different ovarian components and the absolute and relative frequencies of atretic and/or luteinized structures. Our study revealed differences between prooestrus, meteostrus, and all dioestrus phases, as well as between oestrus and metoestrus, and dioestrus at 10 and 20 days. Ovarian surface exhibited variations across different oestrous cycle stages, and atretic follicles were observed in all analysed stages. These findings provide new data and contribute to the understanding of the reproductive cycle in this species.

The aim of the study was to investigate the shape of the mandible in Wistar albino rats using the geometric morphometric method. However, 'Is the shape of the mandible different in rats depending on gender?' the question formed the hypothesis of the study. For this purpose, a total of 52 rat mandibles, 31 female and 21 male rats, were used in the study. The right mandible was photographed from the lateral aspect. A total of 16 landmarks were marked on the photographs. In the study, principal component analysis (PCA) and discriminant function analysis were performed with the MorphoJ program. As a result of the study, 28 principal components (PC) were calculated. The values of variance of the first three PC were explained as 54.887% of the total shape difference. Principal component analysis showed the shape changes were more in mandibular ramus. However, no shape change was observed, especially the most top point of the ventral edge of the mandible at the rostral side. In the graph of PCA, the groups according to gender did not show a clear distinction. According to cross-validation scores, 24 females and 17 males showed correct grouping. In the study, the shape characteristics of the rat mandible from the lateral aspect were revealed. However, it was determined that the most difference in shape by gender was in the condylar process, coronoid process and angular process. As a result, despite the formal differences, when all the data were evaluated, it was concluded that gender discrimination could be made mostly (77% female, 80% male) according to shape of the rat mandible.

Computed tomographic (CT) characterisation of abdominal vessels is poorly studied. The objectives of this retrospective study were to assess during growth, by CT angiography, the evolution of the aorta (Ao), caudal vena cava (CVC), portal vein (PV), length of the second lumbar vertebra (L2) and different ratios between these structures; and to determine the influence of weight and age on the vessels' sizes and ratios. The first group included six beagles scanned every month from 4 to 12 months old, then every 3 months up to 24 months old. The second group included 26 dogs of different breeds and weights that were considered haemodynamically normal. These dogs were divided into three weight intervals: < 10, 10-30 and > 30 kg. The measurements were repeated three times by three operators. The diameter of the Ao, CVC and PV, the aortic length and the L2 length increased up to 7 months. Similarly, the different ratios, such as CVC/Ao, VP/Ao, Ao/L2 and CVC/L2, were variable up to 7 months old and became stable after 7 months. The diameter of the Ao, CVC and PV, the previously cited ratios and L2 length were variable between weight intervals but stable within one interval. The adult vascular standards and ratios published in the literature should not be used in medium-size dogs younger than 7 months old. As variability is observed between the weight intervals, measurements should be used with care in very small or very large dogs.

The Bardhoka sheep breed, also known as Dukagjini white sheep (Ovis aries), is considered to be a medium-sized sheep that is a typical grazing ruminant. The aim of this study was to investigate and measure the parameters of the gastrointestinal tract (GIT) of Bardhoka sheep to determine the morphometry, volume, ratio and surface areas of its different parts. The GIT of eight adult healthy Bardhoka sheep with an average body mass (BM) of 57.63 kg, aged from one to three years, was evaluated immediately after slaughter. Descriptive statistics, including mean values, standard deviations, coefficients of variation and correlations, were calculated using SPSS (version 22). Detailed measurements of the forestomach and intestines were described. The full and empty average weight of the GIT was approximately 23.92% and 5.64% of BM, respectively. The weight of the rumenoreticulum tissue, after removing the content, was about 2.02% of BM. The percentages of the small and large intestines, full and empty, were about 12.28% and 21.55%, and 14.25% and 24.31% of the GIT, respectively. These percentages were 2.94%, 1.24%, 3.45% and 1.37% of the BM, respectively. The allometry ratio of the total intestinal length, small intestine and large intestine to the average BM was 0.68, 0.53 and 0.15, respectively. The length ratio between the small and large intestines was 1:3.54, while the full weight ratio between the two segments of the intestine was 1:1.15 in favour of the large intestine. In conclusion, this study detailed the morphometry parameters of all GIT parts of Bardhoka sheep. This study can serve as a basis for comparative studies and as a database for other similar research.

This study aimed to investigate the macroscopic, light microscopic (LM) and scanning electron microscopic (SEM) characteristics of the pecten oculi in common kestrels (Falco tinnunculus). A total of six eyeballs from three common kestrels were used as the study material. The examination revealed that the bulbus oculi was spherical in shape and its diameter exceeded the axial-global length. In the equatorial section of the eyeball, the pecten oculi were observed to be situated on the retina layer where the optic nerve enters the eyeball, showing a posterior-to-anterior distribution. The pecten oculi appeared dark brown, with a convoluted structure, comprising approximately 15-17 vascular folds. Scanning electron microscopic examination revealed dense capillary vascular folds on the surface of the pecten oculi. Within these capillary vessels, a few hyalocytes were noted, and melanocytes were found at the edges of the folds. Light microscopic examination detected numerous large, medium and small diameter vessels within the folds of the pecten oculi, especially at the periphery of the folds and the apical parts of the pecten oculi. The findings of this study were compared with the morphological characteristics of the pecten oculi in other bird species, revealing both similarities and differences.

This study investigates the gross morphological and morphometric characteristics of thoracic and lumbar intervertebral discs (IVDs) in guinea pigs, utilising micro-CT imaging and anatomical dissection. The findings reveal 13 thoracic and six lumbar IVDs were identified, with thoracic discs transitioning from rounded forms at T1-T3 to triangular and heart-shaped structures at T4-T13, while lumbar IVDs exhibited a consistently flattened heart shape. Morphometric analysis revealed statistically significant differences, with lumbar IVDs being larger in lateral and dorsoventral width, disc area, annulus fibrosus (AF) area and nucleus pulposus (NP) area, and ventral height compared to thoracic discs. Specifically, significant increases in lateral width and disc area were observed in lumbar segments L5 and L6, while thoracic IVDs demonstrated fluctuating alterations in some parameters, such as dorsal and ventral height. Histologically, both thoracic and lumbar IVDs feature a well-organised NP, AF and endplates (EP). The EP was composed of cartilaginous materials, including hyaline cartilage, fibrocartilage and calcified cartilage, and bony materials, including extensive secondary ossification centres with many large vascular channels and bone trabeculae. In conclusion, this study indicates that although thoracic and lumbar IVDs conserve key histological properties, their distinct morphological and morphometric characteristics in guinea pigs reflect their adaptations to biomechanical demands. However, due to some fundamental differences between human and guinea pig, use of this species as a model for human IVD research and interpreting the extracted data should be cautious.

This study aimed to analyse the growth plate fusion and secondary ossification centres of the hind limbs in maned wolves (Chrysocyon brachyurus) using radiographs. Data from three maned wolves estimated to be 3-4 months old were utilised. The right and left hind limbs were radiographed in the mediolateral and craniocaudal views once a month until 11-12 months of age and then every 2-3 months until 18-19 months of age. The growth plates identified in the hind limbs and their closure times were as follows: proximal femur (13-15 months), distal femur (13-15 months), proximal tibia (17-19 months), tibial tuberosity (17-19 months), distal tibia (11-13 months), proximal fibula (13-15 months) and calcaneal tuber (8-9 months). Measurements of the areas of the secondary ossification centres of the proximal epiphysis of the femur, distal epiphysis of the tibia, patella and fibular tarsal bone epiphysis showed a significant difference between the first assessment and 6-7 months. The distal femoral epiphysis, proximal tibial epiphysis and tibial tuberosity showed a statistically significant difference between the first assessment and 7-8 months. The difference in the proximal epiphysis of the fibula was observed between 4 to 5 months and 7 to 8 months. In conclusion, the information obtained regarding the growth plates and secondary ossification centres of the maned wolves may support other studies and help understand the normal patterns of the species.

Cockatiels (Nymphicus hollandicus) are birds present in several countries, commonly kept as pets and, therefore, are frequently encountered as patients in veterinary hospitals. Knowledge of the morphology of the cockatiel's digestive tract is essential for understanding its digestive problems and clinical care. The objective of this study is to describe the digestive tract morphology of these birds. Six cockatiels were dissected and all parts of the digestive tract were measured and processed for histological analysis. The measured data were highly variable for some parts. The oesophagus is divided into a cervical part with the ingluvies (crop) and celomic portion. Mucosal folds and a stratified non-cornified epithelium in the oesophagus and ingluvies were observed. No oesophageal glands were observed in the cervical portion and ingluvies, however, in the celomic portion submucosal glands were abundant. The cockatiel's stomach is subdivided into a glandular and a muscular part. The glandular stomach has a simple columnar epithelium with PAS+ cells and gastric glands. The muscular stomach exhibits a gastric cuticle, and simple columnar epithelium with branched tubular glands, and its muscular layers are organised in inner circular and outer longitudinal bundles. The intestine of cockatiels is subdivided in the small intestine with duodenum, jejunum, ileum and the short large intestine is represented by the colorectum. The Tunica mucosa of the small intestine forms villi lined with simple columnar epithelium with goblet cells. Simple tubular glands extend into the lamina propria mucosae. The wall of the large intestine contains simple tubular glands and a circular and thin layer of smooth muscles. Despite the absence of lymph nodes, there are numerous lymphocytes in the lamina propria. The digestive tract and histological characteristics observed are consistent with other avian species, however, well-defined species-specific particularities were observed.

Osteometric studies of the mandible are useful for identifying polymorphisms that are affected by general factors of anatomical variation, such as breed and gender, but age-related changes have not yet been reported in sheep. Our results showed that the morphometric parameters of the mandible were significantly affected by the age of the lambs. However, at 155 days of age, the mandible already presents all the morphological characteristics observed in adult animals. Furthermore, this study revealed, by analysing Person's correlation coefficient, that the position of the mental and mandibular foramen is already established at 155 days of age and will not be affected by the proportional growth of the mandible. These data have direct implications for veterinary practice, as they can increase the precision and effectiveness of clinical and anaesthetic procedures on the mandible. This contributes to maintaining the health and well-being of animals, improving productive performance in farming systems.

Dorset sheep (Ovis aries) are common models in translational cardiovascular research due to physiologic and anatomic similarities to humans. While employing ovine subjects to study single-ventricle physiology, we repeatedly observed position-based changes in central venous pressure (CVP) which could not be explained by hydrostatic (gravitational) effects. Inferior vena cava (IVC) narrowing or compression has been demonstrated in numerous species, and we hypothesised that this phenomenon might explain our observations in O. aries. This study aimed to characterise position-dependent morphology of the IVC in O. aries using catheter-based hemodynamic and dimensional measurements, three-dimensional MRI reconstruction and histological analysis. Baseline measurements revealed a significant reduction in IVC dimensions at the level of the diaphragm (dVC) compared to the abdominal vena cava (aVC) and thoracic vena cava (tVC). We also observed a transdiaphragmatic pressure gradient along the IVC, with higher pressures in the aVC compared to the tVC. We found that variation of position and fluid status altered IVC haemodynamics. Histological data showed variable muscularity along the length of the IVC, with greater smooth muscle content in the aVC than the tVC. These findings will improve understanding of baseline ovine physiology, help refine experimental protocols and facilitate the translation of findings to the clinic.

In vitro maturation (IVM) of immature oocytes is a valuable method to enhance the rate of mature oocytes available for fertilisation. In the current study, platelet-rich plasma (PRP) was employed in IVM medium of immature oocytes. Harvested germinal vesicle stage oocytes with cumulus cells from female mature BALB/c mice divided into two groups of control and experiment. In the experimental group, GV oocytes matured in the IVM medium supplemented with 5% PRP, while in the control group, GV oocytes matured in the IVM medium without PRP. The percentage of GV, MI, MII and degenerated oocytes, zona pellucida thickness, perivitelline space size, diameter of mature oocytes, gene expression of apoptosis-related factors and subsequent development of matured oocytes were assessed. The PRP group displayed significantly improved outcomes in various parameters, including a higher proportion of MII and fertilised oocytes, cleavage and blastocyst embryos, compared to the control group. Moreover, the thickness of the zona pellucida was significantly lower in the PRP group than in the control group (p < 0.05). Furthermore, the PRP group demonstrated a significant decrease in the expression of transcripts associated with apoptosis (Bax and caspase-3); however, in the PRP group, a substantial increase in the expression of Bcl2l1, an apoptosis inhibitor, was observed when compared to the control group (p < 0.05). In conclusion, addition of PRP to the IVM culture media significantly increased oocyte maturation rate, leading to improved fertilisation and subsequent embryonic development. This enhancement highlights the positive influence of PRP on overall in vitro maturation efficiency and early embryonic stages.

Pre-determined anatomical locations in the oral cavity were biopsied, and their histomorphology was characterised using haematoxylin and eosin staining (H&E). The most abundant cell type was of dendritic morphology. Lymphocyte foci were not evident in the palatoglossal folds or the gingiva. Immunohistochemical staining (IHC) for validated leukocyte markers followed, including CD3, CD20, CD79α, CD204, and Iba1. Consistent with H&E findings, CD204 immunoreactivity predominated amongst all niches. With the exception of the alveolar mucosa and palatoglossal folds, we also demonstrate a significant difference in the population of macrophages by region for only the Iba1 antigen (p < 0.0001). B lymphocytes were found, and a significant difference was noted in the sub-epithelium where CD20-positive cells outnumbered those labelled as CD79a positive (p = 0.001), suggesting the possibility that these cells are in an active state in health. A similar significant difference was found in the subepithelial tissue for myeloid cells, as there were more cells labelled as CD204 positive over Iba1, which, along with their distribution pattern, indicates a possible functional and morphological overlap between these cells. No significant difference was found in epithelial tissues for cells of either myeloid or lymphoid origins. The results from this study suggest different regions of the oral cavity exhibit variations in the distribution of immune cells, particularly macrophages and B lymphocytes. Though more studies would be needed to confirm these findings, these differences may have implications for the immune response and overall health of the oral mucosa.

The masticatory muscles of the horse are arranged in an asymmetrical pattern. Four individual muscles on the medial side of the mandible are opposed by one muscle (M. masseter) on the lateral side. However, recent studies on various herbivorous mammals indicate that the masseter muscle features a complex stratigraphic structure that might account for a functional diversity resembling an arrangement of several individual muscles. The functional consideration of the multidirectional equine masticatory movements leads to a similar hypothesis. In order to elucidate the detailed anatomy of the equine masseter muscle, eight cadaveric equine heads were dissected. Additional 29 skull specimens were assessed with regard to the masseteric attachment within the Fossa masseterica. A constant arrangement of nine individual muscular layers within the masseteric muscle was determined. The individual layers were clearly separated by tendon plates and their attachment areas at the masseteric fossa of the mandible were arranged in a constant pattern of bony ridges. With similar consistency, the main trunk of the masseteric nerve was found to run from dorsocaudal to ventrorostral: On that course, the nerve penetrated between the muscular layers from medial to lateral at constant positions. The findings of this study serve as a basis for further studies with the aim of developing biomechanical concepts of equine masticatory movement.

Morphological studies concerning salivary glands have emerged as an exciting tool to understand feeding habits. In this sense, this study aimed to describe capybara salivary glands morphology to understand potential morphological associations to this species feeding habits. Macroscopic dissections and microscopic analyses were performed on eight specimens. The findings indicate that capybaras have three pairs of major (parotid, mandibular and sublingual) and two pairs of minors (dorsal and ventral buccal) salivary glands. The parotid gland, the largest, is irregularly shaped, forming small macroscopic lobes. The mandibular gland is rounded and found syntopically alongside the mandible angle and arranged medially to the ventral projection of the parotid gland. The sublingual gland is a compact elongated and semicircular mass. The dorsal and ventral buccal glands are located in the buccal portion of the buccinator muscle. Histologically, the parotid and mandibular glands are composed of serous acini, while the sublingual and buccal (dorsal and ventral) glands consist of mucous tubules containing serous demi-lunes at their periphery. Capybara salivary glands reveal morphological associations with a predominantly herbivorous diet. The parotid gland, for example, notably developed in size and volume, suggests a specialisation for increased saliva production, necessary for chewing, forming the food bolus, swallowing fibrous foods, and protecting the oral cavity ecosystem.

The Arabian goby, Cryptocentroides arabicus (Gobiidae: Gobiinae), is a significant species in marine and brackish water ecosystems. However, limited information is available about the reproductive biology and the early life history of this species. This study aimed to understand the embryonic and pre-larval development of C. arabicus under controlled laboratory conditions using light microscopy. Ten fish pairs were placed in five 70-L glass aquaria, and environmental parameters were carefully monitored. After 4 months, spawning began, with each event yielding between 700 and 1500 eggs, totaling 10 spawning events. The elliptical-shaped eggs, measuring 3.9 ± 0.1 mm in length and 1.6 mm in maximum width, hatched after 7 days and 4 h at a water temperature of 28°C. This process resulted in the identification of eight distinct larval developmental stages. Parental care by both the male and female was observed during the incubation period. Documenting the morphological changes during incubation contributes to a better understanding of the reproductive behaviour and early life history of C. arabicus. This is essential for the conservation management of marine and brackish water environments.

Amazona aestiva, a member of the Psittacidae family, belongs to the genus Amazona. These animals are endowed with adaptations in their digestive systems that allow a natural diet composed of seeds and fruits, with anatomical characteristics that facilitate the acquisition and use of nutrients from these food groups. Although it is an important species, no previous information is available regarding the histology and histochemistry of its digestive tract. This study aimed to describe the morphological and histochemical characteristics of the digestive tract of this species. Fragments of the tongue, oesophagus, crop, proventriculus, ventriculus, small intestine, large intestine, liver and pancreas were collected from seven specimens without any clinical alterations in the digestive tract. A. aestiva's digestive tract observed the presence of an extremely developed tongue, a proventriculus with more delicate walls and a ventricle with less-developed musculature. Here, we present a detailed morphological and histochemical description of the Turquoise-fronted Parrot's digestive tract.