Bull 139 BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Mutlak and Faraj Bull. Iraq nat. Hist. Mus. (2024) 18 (1): 139-150. https://doi.org/10.26842/binhm.7.2024.18.1.0139 ORIGINAL ARTICLE MORPHO-HISTOLOGICAL STUDY OF THE PROVENTRICULUS OF EURASIAN MARSH HARRIER CIRCUS AERUGINOSUS (LINNAEUS, (1766 ( AVES, ACCIPITRIFORMES, ACCIPITRIDAE) Baydaa Hussain Mutlak* and Sadama Said Faraj Department of Biology, College of Education for Pure Science/Ibn Haitham, University of Baghdad, Baghdad, Iraq. Correspoinding author: bayda.h.m@ihcoedu.uobaghdad.edu.iq Received: 29 Sept. 2023, Revised: 13 January 2024, Accepted: 30 Jan. 2024, Published:20 June 2024 This work is licensed under a Creative Commons Attribution 4.0 International License ABSTRACT The study aimed to describe the anatomical, histological, and histochemical structure of the proventriculuc of adult male Eurasian marsh harrier, Circus aeruginosus (Linnaeus, 1766) (Accipitriformes, Accipitridae). Six birds were used for this study. The histological sections of proventriculus were stained with hematoxylin and eosin, periodic acid Schiff, and alcain blue. The proventriculus, representing the upper stomach, appeared as a conical structure with a thick wall connecting the caudal end of the thoracic esophagus to the gizzard. It had a light brown color. Microscopic examination revealed that the proventriculus wall consists of the outer tunica serosa, the tunica muscularis, tunica sub mucosa, and the inner tunica mucosa. The mucous layer exhibited folds, and the sulci represented many longitudinal folds with uniform lengths on its luminal surface. A single layer of columnar cells with oval-shaped nuclei made up the lining epithelium. The second layer was the laminal layer propria, composed of a relatively dense network of connective tissue. A thin, discontinuous layer of circularly arranged smooth muscle fibers in the muscularis mucosa separates the lamina propria from the sub mucosa. The submucosa appears as a very thick layer of dense vascular connective tissue, sub-mucosal compound tubuloalveolar glands form the major bulk of this tunica. These glands are arranged in one to three series of lobules that appear in different shapes. Muscularis externa consists of smooth muscle fibers arranged in a thick inner circular layer and a thin discontinuous outer longitudinal layer. The tunica serosa was a well- developed layer constituted by loose connective tissue covered by a single layer of flattened epithelial cells of the mesothelium. The proventriculus has some similarities to other bird species as well as some variations to other species, which may be explained by its nourishing food and behavior. Keywords: Harrier bird, Histology, Morphology, Proventriculus, Stomach. BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Iraq Natural History Research Center & Museum, University of Baghdad https://jnhm.uobaghdad.edu.iq/index.php/BINHM/Home Copyright © Bulletin of the Iraq Natural History Museum Online ISSN: 2311-9799, Print ISSN: 1017-8678 https://doi.org/10.26842/binhm.7.2024.18.1.0139 https://orcid.org/0000-0002-9981-2425 https://orcid.org/0009-0000-3883-624X mailto:bayda.h.m@ihcoedu.uobaghdad.edu.iq https://creativecommons.org/licenses/by/4.0/ https://jnhm.uobaghdad.edu.iq/index.php/BINHM/Home 140 Bull. Iraq nat. Hist. Mus. 18 (1): 139-150. Morpho-histological study of the proventriculus INTRODUCTION The bird of the Eurasian marsh harrier, Cirus aeruginosus (Linnaeus, 1766), belongs to the Accipitridae family, which typically hunts by flying low over open ground, and consuming small animals, birds, or reptiles. Sometimes the young species are referred to as "ring-tail harriers" (Ferrarini et al., 2023). The stomach is a large part of the gastrointestinal tract and is responsible for storing, digesting, and transporting food to the duodenum; its structure presents variations that depend on the alimentary habits of the bird (Saran and Meshram, 2021). The proventriculus, a glandular portion of the stomach in birds, secretes the gastric juices, while the gizzard, a muscular portion, performs a mechanical role. The proventriculus is cranially continuous with the esophagus and presents an elliptical shape (AL-Taai and Hasan, 2020).The glandular stomach is distinguished by its spindle shape and direct emergence from the esophagus, with an intermediate zone between it and the gizzard (isthmus) (Abdel Maksoud et al., 2022). The proventriculus differs in size in different species, typically being rather large and distensible in carnivores that consume large food items while being quite tiny in graminivores, compared to other bird species that consume seeds, the black-winged kite, Elanus caeruleus, had a stomach that was enormous in size and had a thin wall (Al-Saffar and Al-Samawy, 2015). Histologically, the stomach is composed of four tunics: the mucosa, sub mucosa, muscularis, and serosa (Khaleel et al., 2021).The three layers of the mucosa are the lining epithelium, lamina propria, muscularis mucosa, simple columnar epithelium, and several gastric glands, which meet with the stomach lumen through gastric pits. The tunica of the sub mucosa is composed of connective tissue, having blood and lymph vessels, while the muscularis tunica consists of smooth muscles, and the tunica serosa, which appears as a thin layer of connective tissue lined by mesothelium, covers the stomach from the outside (Al- Samawy et al., 2021). The current study aimed to describe the anatomical, histological, and histochemical structure of the proventriculus of adult males of Circus aeruginosus from Iraq. MATERIALS AND METHODS Specimens collections: Six adult males Harrier Circus aeruginosus (Linnaeus, 1766) were used in the current study, and collected from the commercial market. The birds were checked for their health status before being euthanized. Identification of bird species: The birds were diagnosed and classified based on the field guide to the birds of Iraq (Salim et al., 2006). Laboratory techniques: The birds were euthanized with ethyl ether. After anesthesia, the digestive tube was dissected, and specimens of the glandular stomach (proventriculus) were directly fixed in Bouin solution for 24h followed by dehydration with ascending series of ethyl alcohol (50-100%). All the specimens were embedded in paraffin wax, and transverse sections were taken using a rotary microtome at 5 µm. Haetamoxylin and eosin stain were used to determine the general structure (Suvarna et al., 2018), and periodic acid Schiff (PAS) for differentiating acidic and neutral mucins, and alcuin blue for connective tissue. The selective sections were photographed by using a light microscope with a digital camera. 141 BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Mutlak and Faraj RESULTS AND DISSCUSION Gross examination showed that the stomach of the Harrier Circus aeruginosus (Linnaeus, 1766) was in the left part of the abdominal cavity, and divided into two portions: proventriculus and gizzard which were not clearly defined from each other, the proventricular ventricular isthmus was not present so that the two organs form one large conical shape, there was no clear division internally as there was no demarcation line between proventricular and ventricular part of the stomach but differentiation from each other by their structure in which each one had its characteristic structure (Pl.1A). This result was in agreement with Abdel Maksoud et al. (2022) in hooded crow Corvus cornix, while it was in contrast with Al-Saffar and Al-Samawy (2015) who recorded that there was a short intermediate zone (isthmus) separating between these two portions of the stomach in the mallard Anas platyrhynchos. The proventriculus had a light brown colour of conical shape that distinguished it from the esophagus whitish colour, it had a number of well- developed longitudinal folds reach to 5 longitudinal folds which were separated from each other by clear longitudinal grooves (Pl.1B), where the researchers differentially described the proventriculus as being large, fusiform-shaped in mallard (Al-Saffar and Al-Samawy, 2015) and appeared as a tubular shaped in common moorhen (Jassem et al., 2016), while it was showed as a longitudinal expansion of esophagus with an apparent external gastric papillae in starling bird (AL-Taai and Hasan, 2020), and as a spindle shape in the barn owl (Maher and Hussein, 2023). These features of the proventriculus are possibly related to the dietary habits. Microscopic examination revealed that the wall of the proventriculus consisted of four classical tunics: outer tunica serosa, tunica muscularis, tunica sub mucosa, and inner tunica mucosa (Pl.2); a similar arrangement was described by previous studies (Al- Nakeeb et al., 2019; Saran and Meshram, 2020; Umar et al., 2021). The current findings were not in line with Zhu (2015), who reported that the wall of the proventriculus in black–tailed crake porzana bicolor and yellow-billed grosbeak consisted of three tunics; mucosa, muscularis, and serosa. The mucous layer exhibited folds and sulci that represented many longitudinal folds with uniform lengths on its luminal surface (Pl.3), the presence of these folds may increase the secretory surface epithelium and facilitate the digestion of foods (Zhu, 2015). A single layer of columnar cells with oval-shaped nuclei located in the basal half of the cell built up the lining epithelium of the mucosa. The foamy cytoplasm of these cells was intensely stained with eosin, especially in the supra-nuclear region (Pl. 4). This observation was supported by other researchers (AL-Taai and Hasan, 2020; Khaleel et al., 2021). The second layer of mucosa was lamina propria, composed of a relatively dense network of connective tissue extending immediately inferior to the lining epithelium and also forming the central core of the mucosal folds to provide mechanical support, blood vessels, nerves, lymphoid elements, and simple tubular glands were seen within the connective tissue of lamina propria (Pl.5). These results are in line with Saran and Meshram (2020). The mucosal gland is lined by a single layer of cuboidal mucous secreting epithelial cells, and their ducts open at the bases of the sulci. These results are likely in Mallard (Al-Saffar and Al-Samawy, 2015). A thin, discontinuous layer of circularly arranged smooth muscle fibers known as the muscularis 142 Bull. Iraq nat. Hist. Mus. 18 (1): 139-150. Morpho-histological study of the proventriculus mucosa separates the lamina propria from the sub mucosa (Pl.6).The current observations were in agreement with other researchers (AL-Taai and Hasan, 2020; Khaleel et al., 2021), while the results were disagreement with Ahmed et al. (2011) who showed that the muscularis mucosae of Japanese quail were formed of two small layers of smooth muscle fibers, inner isolated longitudinal bands, and outer circular bands. The sub mucosa appears as a very thick layer of dense vascular connective tissue with a few muscle fibers extending from the muscularis mucosae and running through the deep or sub mucosal compound tubuloalveolar glands that formed the major bulk of this tunica (Pl.7), such finding agreed with AL-Taai and Hasan (2020). These glands are arranged in one to three series of lobules that appear in different forms like conic, pearl, ovoid, and elongated forms (Pl.7). The researchers did not agree in their observations on these glands in different birds; Al-Jubory (2016) observed one row of glands in Tyto alba, while Al-Saffar and Al- Samawy (2015) showed rounded branched tubular glands in Mallard, submucosal glands arranged in two rows surrounded by connective tissue in Iraqi male Guinea fowls, and barn owl, respectively (Khaleel et al., 2021; Maher and Hussein, 2023). These differences can be explained by their nourishing food and behavior. Each gland lobule is surrounded by a connective tissue capsule rich with blood vessels and contains numerous secretory units lined by a row of cuboidal cells. These cells have rounded, centrally located nuclei and deeply stained eosinophilic granular cytoplasm (Pl.8). The epithelium of the secretory units is organized in an oblique direction on the thin strands of connective tissue that form the septa between the tubules, and these cells are closely applied one to another only towards their bases, where they provide to the epithelium a dentate appearance (Pl. 9), as stated by Al-Nakeeb et al. (2019) and Beheiry (2018). Each secretory lobule drained into the central cavity, which released the gastric secretion to the lumen of the proventriculus through an excretory duct (Pl.10). One layer of columnar cells made up the lining epithelium of the excretory ducts and the central cavities that characterized by their lightly stained cytoplasm in which, basally located and oval shaped nuclei surrounded by a well-marked nuclear membrane and contain one or more clear nucleoli (Pl.11). These findings were in coincidence with previous studies (Beheiry, 2018; Al- Nakeeb et al., 2019; Abdel Maksoud et al., 2022). Microscopical examination for the proventriculus sections revealed that the sub mucosal gland's ducts, mucous gastric glands, and lining epithelium of the mucosal folds all exhibited PAS-positive reaction in their apical regions (Pl.12) indicating the presence of neutral mucopolysaccharide in these cells, on the other hand, staining with alcian blue gave a strong reaction in the whole cytoplasm of the ducts of the sub mucosal glands while the lining cells of the mucosal folds and the mucous gastric glands only their apical region reacted positively to this stain indicating the presence of acid mucopolysaccharide in these cells (Pl.13). Both stains also react positively with discharging secretory material outside the cells. The current results are strengthened by the results of previous researches (Ahmed et al., 2011; Zhu, 2015) ,but they were not supported by Khaleel et al. (2021) in Guinea fowl, who reported that sub 143 BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Mutlak and Faraj mucosal glandular epithelium showed a negative reaction to mucins. Al-Jubory (2016) suggested that the mucous secretion of these cells formed a barrier to protect the epithelium. Muscularis externa consists of smooth muscle fibers arranged in a thick inner circular layer and a thin, discontin outer longitudinal layer (Pl. 14). These findings disagreed with Al- Nakeeb et al., (2019), who found the muscularis externa in Magpie Pica pica consists of three layers: very thin muscle fibers supported deep gastric glands, the middle thick longitudinal layer, and the outer circular layer. The thickness of the tunica muscularis can help for empty the secretion of the deep periventricular glands .The tunica serosa of the proventriculus in Harrier was constituted by loose connective tissue, containing many blood vessels and nerves, and covered by a single layer of flattened epithelial cells represented by the mesothelium (Pl.15). This finding was similar to results in other species of birds (Saran and Meshram, 2020; Al-Samawy et al., 2021). Areas of aggregation of adipose cells were also observed in this layer. Sultan et al. (2023) observed the presence of melanin in the connective tissue of the serosa layer . Plate (1): The alimentary canal in Harrier bird; (A) and (B) The anatomy of digestive tract. The longitudinal folds (LF) in proventriculus, (E) Esophagus, (P) proventriculus, (G) Gizzard, (H) heart, (L) Liver, (I) Intestine. Plate(2): Section in Harrier proventriculus showing the four tunics. [Tunica mucosa (TM), Sub mucosa (SM), Muscularis externa (EM), Tunica serosa (TS), H &E (10X)]. Plate (3): Section in Harrier proventriculus showing the folds and sulci. [Longitudinal folds (LF), Sulci (S), H & E (40X)]. 144 Bull. Iraq nat. Hist. Mus. 18 (1): 139-150. Morpho-histological study of the proventriculus Plate (4): Section in Harrier proventriculus showing: Lining epithelium (LE), Foamy cytoplasm (FC), Nucleus (N), H&E (40X)] Plate (5): Section in Harrier proventriculus showing: Lamina propria (LP), Lining epithelium (LE), Blood capillaries (BC), H&E (40X). Plate(6): Section in Harrier proventriculus showing: Muscularis mucosae (MM), Lamina propria (LP), Lining epithelium (LE), Blood capillaries (BC), H&E (40X)]. Plate (7): Section in Harrier proventriculus showing sub mucosal glands. [Glandular lobules (GL), Gland duct (GD), H&E (10X)]. Plate (9): Section in Harrier proventriculus. [Lining epithelium of sub mucosal glands (LE), Lamina propria (LP), Main duct (MD) H&E (40X)]. Plate (8): Section in Harrier proventriculus showing lining of mucosal glands. [Lining epithelium (LE), Connective tissue septum (CTS), Main duct (MD), H&E (40X)]. 145 BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Mutlak and Faraj Plate (11): Section in Harrier proventriculus. [Lining epithelium of main duct (MD), Simple cuboidal epithelium (SCuE), Connective tissue septum (CTS), Simple columnar epithelium (SCE), H&E (40X)]. Plate (10): Section in Harrier proventriculus [Main duct (MD), Connective tissue septum(CTS), Glandular lobule(GL), H&E (10X) ]. Plate (12): Section in harrier proventriculus showing: pas reaction (arrows) pas stain (10X). Plate (13): Section in Harrier proventriculus showing: [Alcian reaction (Arrows) Alcian blue stain (10X)]. Plate(14): Section in Harrier proventriculus showing: Muscularis externa (ME), Circular layer (CL), Longitudinal layer (LL), Adipose tissue (AT), Arteriole (Ar), Venule (Ve), H & E (40X). Plate(15): Section in Harrier proventriculus showing: Tunica serosa (TS), Connective tissue (CT), Mesothelium (Me), Blood capillary (BC), Adipose tissue (AT), Nerve fiber (NF), H & E (40X). 146 Bull. Iraq nat. Hist. Mus. 18 (1): 139-150. Morpho-histological study of the proventriculus CONCLUSIONS The current study investigated the histological structures of the proventriculus of Circus aeruginosus (Linnaeus, 1766), the findings show that the proventriculus represents the upper stomach, the proventricular ventricular isthmus is not present so that the two organs form one large conical shape with a thick wall, and it has a number of well- developed longitudinal folds that reach to five longitudinal folds. Microscopic examination of the proventriculus consists of four classical tunics: outer tunica serosa, tunica muscularis, tunica sub mucosa and inner tunica mucosa. The proventriculus has some characteristics in similarities to other bird species as well as some variations from other species, which may be explained by its nourishing food and behavior. ACKNOWLEDGMENTS The authors are grateful to the Department of Biology, College of Education for Pure Science-Ibn Al-Haitham, University of Baghdad, for the slaughterhouse tools and anesthesia material. CONFLICT OF INTEREST STATEMENT The authors have no conflicts of interest to declare. We "the authors" have followed and signed the scientific research ethics announced by the journal. LITERATURE CITED Abdel Maksoud, M. K. M., Ibrahim, A. A. H., Nabil, T. M. and Moawad, U. K. 2022. Histomorphological, histochemical and scanning electron microscopic investigation of the proventriculus (Ventriculus glandularis) of the hooded crow (Corvus cornix). Anatomia Histologia Embryologia, 51(3): 1-10. [ResearchGate] Ahmed, Y. A. E., Kamel, G. and Ahmed, A. A. E. 2011.Histomorphological studies on the stomach of the Japanese quail. Asian Journal of Poultry Science, 5(2): 56-67. [CrossRef] Al-Jubory, R. W. 2016. Comparative anatomical and histological study on the digestive tract in two Iraqi birds, common wood pigeon Colimba palumbus L. and barn owl Tyto alba. Ph. D. Thesis, Department of Biology, College of Science, Babylon University, 250pp. Al- Nakeeb, G. D., Abid, S. A. and Fadhil, L. A. 2019.Comparative histological study of the stomach in two species of Iraqi vertebrates Magpi Pica pica L. and small Asian Mongoose Herpestes javanicus Baghdad Science Journal,16(2): 281-290. [CrossRef] Al-Saffar, F. J. and Al-Samawy, E. R. M. 2015.Histomorphological and histochemical studies of the stomach of the Mallard (Anas platyrhunchos). Asian Journal of Animal Sciences, 9(6): 280-292. [CrossRef] Al-Samawy, E. R. M., Waad, S. K., Al-Uboody, W. S. H. and Hasan, M. S. 2021.Histomorphometric and histochemical finding of the proventricular and ../../../../../../../../Downloads/researchgate ../../../../../../../../Downloads/CrossRef ../../../../../../../../Downloads/CrossRef ../../../../../../../../Downloads/CrossRef 147 BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Mutlak and Faraj ventricular stomach between the African Grey Parrot (Psittacus erithacus) and Black Francolin (Francolins) in south Iraq. Medico-Legal Update, 21(1): 1457-1465 [ResearchGate] AL-Taai, S. A. H. and Hasan, M. S. 2020. Histomorphological study of proventricular and gizzard in adult starling birds (Sturnus vulgaris). Plant Archives, 20 (1): 1671-1678. [CrossRef]. Beheiry, R. R. 2018.Histochemical and scanning electron microscopy of proventriculus in turkey Journal of Advanced Veterinary and Animal Research, 5(3): 290-298. [Click here]. Ferrarini, A., Clevi, E., Brozzetti, D., Colle, A., De Santis, A., Laurenti, S., Savo, E. and Gustin, M. 2023. Optimized monitoring and conservation of farmland bird species through bayesian modelling: The Montagu’s Harrier Circus pygargus population in central Italy. Sustainability, 15(5): 4426. [CrossRef] Jassem, E. S., Hussein, A. J. and Sawad, A. A. 2016. Anatomical ,histological and histochemical study of the proventriculus of common Moorhen (Gallinula chloropus). Basrah Journal of Veterinary Research, 14(4): 73-82. [Click here] Khaleel, I. M., Hasan, M. S. and Alkhazraji, K. I. 2021. A comparative histomorphological and histochemical study of the proventriculus between Iraqi male Guinea fowls. Annals of the Romanian Society for Cell Biology, 25(1): 6062-6072. [CrossRef] Maher, M. A. and Hussein, S. 2023. Anatomical distribution of celiac artery with histochemical investigation to the proventriculus of barn owl (Tyto alba). Zoomorphology, 142: 201-213. [CrossRef] Salim, A. M., Borter, R. F. Hansn, S. B., Christian, S. and AL-Jbour, S. 2006. The field guide to the birds of Iraq. Iraqi Nature Organization, Baghdad, Iraq, 36pp. [Google Scholar] Saran, D. and Meshram, B. 2021.Histomorphological and histochemical studies on proventriculus in Guinea fowl (Numida meleagris). Indian Journal Animal Research, 55(7): 806-80. [CrossRef] Sultan, G. A., Al-Haaik, A. G. and Hasso, A. A. 2023.Morphometrical and Histochemical study of glandular stomach (Proventriculus) in local domestic male ducks (Anase platyrhchos). Iraqi Journal of Veterinary Sciences Iraq, 37(1): 65-71 [Click here] Suvarna, S. K., Layton, C. and Bancroft, J. D. 2018. 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Iraq nat. Hist. Mus. 18 (1): 139-150. Morpho-histological study of the proventriculus Umar, Z., Qureshi, A. S., Shahid, R. and Deepa, F. 2021. Histological and histomorphometric study of the cranial digestive tract of ostriches (Struthio camelus) with advancing age. Veterinary Medicine, 66(4): 127-139. [CrossRef] Zhu, L. 2015.Histological and histochemical study on the stomach (proventriculus and gizzard) of black –tailed crake (Porzana bicolor). Pakistan Journal of Zoology, 47(3): 607-616. [Research Gate] ../../../../../../../../Downloads/CrossRef ../../../../../../../../Downloads/Research%20Gate 149 BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Mutlak and Faraj Bull. Iraq nat. Hist. Mus. (2024) 18 (1): 139-150. نسجية للمعدة االمامية لطائر مرزة البطائح -دراسة شكالئية Circus aeruginosus (Linnaeus, 1766) (Aves, Accipitriformes, Accipitridae) فرج سيد صدامةو حسين مطلك بيداء قسم علوم الحياة, كلية التربية للعلوم الصرفة, أبن الهيثم, جامعة بغداد, بغداد,العراق. 20/6/2024، النشر: 30/1/2024القبول: ،13/1/2024املراجعة: ، 29/9/2023االستالم: الخالصة هدفت الدراسة إلى وصف التركيب التشريحي والنسيجي والكيميائي النسجي للمعدة Circus aeruginosus (Linnaeus, 1766)االمامية للذكور البالغين ملرزة البطائح (Accipitriformes, Accipitridae). من الطائر نماذج استخدم في هذه الدراسة ستة , االمامية بملون الهيماتوكسلين وااليوسين وحمض شيف للمعدة املقاطع النسجية لونت تمثل املعدة االمامية الجزء العلوي من املعدة وتظهر كتركيب .الدوري وازرق املثيل مخروطي ذو جدار سميك يربط الطرف الذيلي للمريء الصدري بالقانصة. كان لونها بني من الغاللة املصلية فاتح. كشف الفحص املجهري أن جدار املعدة االمامية يتكون .الغاللة تحت املخاطية, والغاللة املخاطية الداخلية ,الخارجية, الغاللة العضلية أظهرت الطبقة املخاطية طيات و التلم وتمثل العديد من الطيات الطولية وبأطوال موحدة على سطح التجويف. تتكون البطانة الظهارية من طبقة واحدة من الخاليا ذات النوى البيضاوية . كانت الطبقة الثانية الصفيحة االصيلة واملكونة من العمودية شبكة كثيفة نسبيا من النسيج الضام. تفصل العضلية املخاطية املكونة من طبقة رقيقة متقطعة من االلياف العضلية امللساء املرتبة بشكل دائري بين الصفيحة االصيلة . و الغاللة تحت املخاطية الغاللة تحت املخاطية كطبقة سميكة جدا من النسيج الضام الكثيف تظهر الوعائي, وتشكل الغدد األنبوبية السنخية املركبة تحت املخاطية الجزء األكبر من هذه الغاللة. يتم ترتيب هذه الغدد في سلسلة واحدة إلى ثالث فصيصات والتي تظهر بأشكال 150 Bull. Iraq nat. Hist. Mus. 18 (1): 139-150. Morpho-histological study of the proventriculus ة من ألياف عضلية ملساء مرتبة في طبقة تتكون الغاللة العضلية الخارجي .مختلفة دائرية داخلية سميكة وطبقة طولية خارجية رقيقة متقطعة. كانت الغاللة املصلية عبارة عن طبقة متطورة تتكون من نسيج ضام مفكك تغطيه طبقة واحدة من الخاليا في تميزت املعدة االمامية ببعض الخصائص .الظهارية املسطحة من الظهارة املتوسطة أوجه التشابه مع أنواع الطيور األخرى فضال عن بعض االختالفات مع األنواع األخرى, . والتي يمكن تفسيرها من خالل طبيعة التغذية والسلوك