Carp edema virus (CEV) is a contagious pathogen affecting mostly the gills of common carp (Cyprinus carpio) and impairing the functions of this organ. Moreover, CEV was reported to cause stress activation and modulation of the hosts immune system. Last but not least, secondary bacterial infections often occur during CEV infection. In this study, we assessed the impact of CEV infection on the microbiota in the gills, foregut, and hindgut of koi. Moreover, we studied expression of genes encoding antiviral proteins, proinflammatory cytokines, mucins, and tight junction proteins. We observed increased levels of cortisol and glucose in the blood plasma of CEV-infected fish, suggesting activation of stress response. Histopathological analysis of the gills showed occlusion of the intralamellar space with the presence of apoptotic cells in CEV-infected fish, while in the gut only minor histopathological changes were recorded. Microbiota of the gills was significantly altered during infection with increased absolute abundance of several bacteria genera, including opportunistic bacteria e.g. Chryseobacterium, Flavobacteria, Aeromonas, and Pseudomonas. In the foregut, we did not observe changes in the absolute bacterial abundance between control and CEV-infected fish, while in the hindgut only absolute abundance of Aeoromonas was increased in infected fish. Moreover, CEV infection differentially altered expression of studied genes, including for example upregulation of expression of mxa, vig, il-1b, and cldn 7 in studied organs. Our study explores the effect of CEV infection on the host microbiota, which may partly explain the occurrence of secondary bacterial infections during infection with this virus.

Immune and stress responses are closely interconnected, with glucocorticoids modulating neutrophil number and activity, and cytokines influencing stress response. Neutrophils, due to their role as primary responders to infection, high sensitivity to glucocorticoid fluctuations, and critical involvement in gut microbiota homeostasis, were selected as the central focus of this study. We examined how antibiotic-induced dysbiosis affects the hypothalamus-pituitary-interrenal (HPI) axis and stress-related neutrophil dynamics in common carp (Cyprinus carpio L.). We analyzed the expression of stress-related genes and characterized neutrophil maturation and function within the hematopoietic niche. Dysbiotic fish exposed to acute stress exhibited significantly elevated cortisol levels compared to stressed fish with intact microbiota. Notably, even non-stressed dysbiotic fish showed increased cortisol level, indicating that microbiota disruption alone impairs HPI axis regulation. Antibiotic-treated and stressed fish displayed upregulation of il1β, gcsfr, cxcl8_l2, and cxcr1, suggesting enhanced granulopoiesis and neutrophil mobilization. However, systemic neutrophilia was attenuated in dysbiotic fish regardless of stress exposure. Transcriptomic profiling of neutrophils from dysbiotic, stressed fish revealed downregulation of mpx and cxcr4, and upregulation of mmp9, mhc1, trb, nlrp12, dhx58, irf3, irf7 and stat1, indicating altered maturation, increased migratory potential, and possible neutrophil-T cell interactions. In contrast, stressed fish with intact microbiota exhibited anti-apoptotic signatures and suppression of antiviral pathways. Across all stressed and dysbiotic groups, neutrophil phagocytic activity was significantly reduced. These findings underscore the pivotal role of gut microbiota in modulating stress responses, neutrophil development and trafficking, and immune function in vertebrates.

Fish are exposed to numerous stressors which negatively affect their immune response and increase infection susceptibility. The risk of bacterial infections results in the excessive and preventive use of antibiotics. Therefore, we aimed to study how antibiotic treatment and restraint stress will affect the stress response, microbiota composition, gut morphology, and inflammatory reaction in common carp. Both restraint stress and antibiotic treatment increased cortisol level. Moreover, antibiotics induced dysbiosis in fish gut, manifested by a decrease in the total abundance of bacteria, and a shift in bacteria diversity, including a reduced number of Aeromonas, Bacteroides, Barnesiellaceae, Cetobacterium and Shewanella and an increased abundance of Flavobacterium. To a lesser extent, stress modified gut microbiota, as it decreased bacteria number and slightly changed the microbiota composition by decreasing Cetobacterium abundance and increasing Vibrio abundance. Microbiota of the antibiotic-treated and stressed fish shifted from the beneficial bacterial genera - Cetobacterium and Bacteroides, to the increased presence of unfavorable bacteria such as Brevinema, Flavobacterium and Desulfovibrionaceae. Stress and antibiotic-induced changes in the gut microbiota were related to the changes in the gut morphology when the higher abundance of goblet and rodlet cells and increased secretion activity of goblet cells were observed. Moreover, up-regulation of the expression of genes encoding pro-inflammatory mediators and cytokines involved in the Th17 immune response was present in the gut of the antibiotic-treated and stressed fish. We conclude that in carp antibiotics and stress alter the abundance and composition of the microbiota and induce Th17-dependent inflammatory reaction in the gut. Moreover, our results strongly suggest the interplay of the stress axis and the brain-gut-microbiota axis.

Osteoglossomorpha, the bony tongue fishes, show great variation in morphology, behavioural strategies, reproductive biology and gamete ultrastructure. The order Osteoglossiformes is the only vertebrate taxon, in which four types of sperm (monoflagellate, biflagellate and aflagellate aquasperm and the complex introsperm) have been described. It is also the only vertebrate lineage in which aflagellate spermatozoa exist. The aim of this study was to analyse the structure of the testis and the process of spermiogenesis in the mormyrid Campylomormyrus compressirostris during the breeding season using light and electron microscopy (transmission and scanning). Males of this species have a single testis of the anastomosing tubular type. The tubules of the anterior part of the testis contain cysts with developing germ cells, and this region is much wider than the posterior part, which consists of efferent ducts filled with sperm cells. The cysts are filled with single or mitotic spermatogonia, primary and secondary spermatocytes and early spermatids. At the stage of spermatids with fine granular chromatin, the cysts rupture and successive stages of spermatid differentiation take place in the testicular lumen; we therefore characterise this process as 'extracystic spermiogenesis'. Sperm development in C. compressirostris is extremely simple and involves chromatin condensation in the central region of the nucleus, a slight decrease in nuclear volume, the appearance of numerous vesicles in the cytoplasm that form a tubular-vesicular system at the base of the nucleus. Both centrioles and mitochondria are translocated to the peripheral region of the midpiece, which forms the opposite pole to the nucleus. There are many differences between the types of spermiogenesis described so far in teleosts and that found in C. compressirostris, including the loss of flagellum formation. This unique type of spermiogenesis is restricted to species of the families Mormyridae and Gymnarchidae, all of which possess aflagellate spermatozoa. Our data demonstrate that the spermatid differentiation and existence of the aflagellate spermatozoon are a unique phenomena not only among teleosts but also in the whole vertebrate lineage.

In this study, we assessed the ovary structure and early oogenesis in representatives of Osteoglossomorpha, one of the most basal Teleostei groups. We aimed to perform a comparative analysis between internally fertilizing Pantodon buchholzi (Pantodontidae) and externally fertilizing Osteoglossum bicirrhosum (Osteoglossidae), Marcusenius cyprinoides, Brevimyrus niger, Gnathonemus petersii and Mormyrus rume (Mormyridae). Our results indicated differences in ovary structure between P. buchholzi and the externally fertilizing species, as well as a considerable disparity in oocyte organization in all studied species. All species possess ovaries of the cystovarian type. In P. buchholzi, the epithelium lining the lumen was columnar and formed crypts with ciliated and microvillus cells as well as deep invaginations with secretory cells, whereas in the remaining species epithelium was squamous. The organization of oogonia and one-nucleolus oocytes did not differ between species, there were variations in oocytes at subsequent steps of primary growth, including symmetry/asymmetry of the inner cell structure, differences in Balbiani body formation, presence/absence of zonation of the ooplasm, and differences in the order in which cortical alveoli and oil droplets appeared. These differences may be caused by a long and separate evolution of the families as well as adaptation to insemination in the family Pantodontidae.

In mammals, the relationship between the immune system and behavior is widely studied. In fish, however, the knowledge concerning the brain immune response and behavioral changes during brain viral infection is very limited. To further investigate this subject, we used the model of tilapia lake virus (TiLV) infection of zebrafish (Danio rerio), which was previously developed in our laboratory. We demonstrated that TiLV persists in the brain of adult zebrafish for at least 90 days, even when the virus is not detectable in other peripheral organs. The virions were found in the whole brain. During TiLV infection, zebrafish displayed a clear sickness behavior: decreased locomotor activity, reduced food intake, and primarily localizes near the bottom zone of aquaria. Moreover, during swimming, individual fish exhibited also unusual spiral movement patterns. Gene expression study revealed that TiLV induces in the brain of adult fish strong antiviral and inflammatory response and upregulates expression of genes encoding microglia/macrophage markers. Finally, using zebrafish larvae, we showed that TiLV infection induces histopathological abnormalities in the brain and causes activation of the microglia which is manifested by changes in cell shape from a resting ramified state in mock-infected to a highly ameboid active state in TiLV-infected larvae. This is the first study presenting a comprehensive analysis of the brain immune response associated with microglia activation and subsequent sickness behavior during systemic viral infection in zebrafish.

During the early stages of oogenesis, the Balbiani body is formed in the primary oocytes. It consists of the Golgi apparatus, endoplasmic reticulum (ER), and numerous mitochondria aggregated with germ plasm, but its form may differ among animals. Hypothetically, during oogenesis oocytes become adapted to future development in two different environments depending on internal or external fertilization. We aimed to investigate, using light and transmission electron microscopy, the development of the Balbiani body during oogenesis in representatives of Osteoglossiformes, one of the most basal Teleostei groups. We analyzed the structure of oogonia and primary oocytes in the internally fertilizing butterflyfish Pantodon buchholzi and the externally fertilizing Osteoglossum bicirrhosum and Arapaima gigas to compare formation of the Balbiani body in relation to modes of fertilization. We demonstrated that the presence of the germ plasm as well as the fusion and fission of mitochondria are the conserved features of the Bb. However, each species exhibited also some peculiar features, including the presence of three types of ooplasm with different electron density and mitochondria-associated membranes in P. buchholzi; annulate lamellae, complexes of the Golgi apparatus, ER network, and lysosome-like bodies in O. bicirrhosum; as well as karmellae and whorls formed by the lamellae of the ER in A. gigas. Moreover, the form of the germ plasm observed in close contact with mitochondria differed between osteoglossiforms, with a "net-like" structure in P. buchholzi, the presence of numerous strings in O. bicirrhosum, and irregular accumulations in A. gigas. These unique features indicate that the extreme diversity of gamete structure observed so far only in the spermatozoa of osteoglossiforms is also characteristic for oocyte development in these basal teleosts. Possible reason of this variability is a period of about 150 million years of independent evolution of the lineages.

The aim of this study was to analyse spermatogenesis in the African butterflyfish,Pantodon buchholzi, using transmission electron microscopy and scanning electron microscopy.P. buchholziis the most basal teleost that exhibits insemination and produces a highly complex introsperm with the most elongate midpiece known in teleost fishes. Their early stages (spermatogonia and spermatocytes) do not differ greatly from those of other fishes, with the exception of Golgi apparatus degradation appearing as spindle-shaped bodies (SSBs). In round, early spermatids, the development of the flagellum begins after the migration of the centriolar complex towards the nucleus. Later, the elongation of the midpiece coincides with the displacement of the mitochondria and their fusion to produce nine mitochondrial derivatives (MDs). In these spermatids, the nucleus is situated laterally to the midpiece, with condensing chromatin in the centre of the nucleus. Within the midpiece, the flagellum is located within a cytoplasmic canal and is surrounded by a cytoplasmic sleeve containing fibres, MDs and a great amount of cytoplasm located on one side. During the next phase, nuclear rotation, the highly condensed chromatin is displaced to a position above the centriolar apparatus, whereas chromatin-free nucleoplasm is transferred to the cytoplasm. Later, this nucleoplasm, still surrounded by the nuclear membrane, is eliminated into the cyst lumen as the nucleoplasmic packet. Within the highly elongate spermatids, other excess organelles (SSBs, endoplasmic reticulum and mitochondria) are eliminated as residual bodies (RBs). Fully developed spermatozoa, which contain conical-shaped nuclei, eventually coalesce to form unencapsulated sperm packets (spermatozeugmata) that are surrounded by RBs at the level of the extremely elongate midpieces. Later, RBs are removed at the periphery of the cyst by means of phagocytosis by Sertoli cells.

Tilapia lake virus (TiLV; genus: Tilapinevirus, family: Amnoonviridae) is a recently characterised enveloped virus with a linear, negative-sense single-stranded RNA genome, which causes high mortality in tilapia species. In the present study, we demonstrated that zebrafish (Danio rerio) larvae are susceptible to TiLV infection upon systemic injection. TiLV replicated in zebrafish larvae and caused their high mortality (of about 70%). Histopathological examination revealed that TiLV infection caused pathological abnormalities in zebrafish larvae that were well visible within the brain. Moreover, gene expression analysis revealed that TiLV infection induced up-regulation of the expression of the immune-related genes encoding pathogen recognition receptors involved in sensing of viral dsRNA (rig-I (ddx58), tlr3, tlr22), transcription factors (irf3, irf7), type I interferon (infϕ1), antiviral protein (mxa), and pro-inflammatory cytokine (il-1β). We also demonstrated the protective role of the recombinant zebrafish IFNϕ1 on the survival of zebrafish larvae during TiLV infection. Our results show the importance of type I IFN response during TiLV infection in zebrafish larvae and demonstrate that zebrafish is a good model organism to study interactions between TiLV - a newly emerging in aquaculture virus, and fish host.

AbstractDuring development, cells may adjust their size to balance between the tissue metabolic demand and the oxygen and resource supply: Small cells may effectively absorb oxygen and nutrients, but the relatively large area of the plasma membrane requires costly maintenance. Consequently, warm and hypoxic environments should favor ectotherms with small cells to meet increased metabolic demand by oxygen supply. To test these predictions, we compared cell size (hindgut epithelium, hepatopancreas B cells, ommatidia) in common rough woodlice (Porcellio scaber) that were developed under four developmental conditions designated by two temperatures (15 or 22°C) and two air O2 concentrations (10% or 22%). To test whether small‐cell woodlice cope better under increased metabolic demand, the CO2 production of each woodlouse was measured under cold, normoxic conditions and under warm, hypoxic conditions, and the magnitude of metabolic increase (MMI) was calculated. Cell sizes were highly intercorrelated, indicative of organism‐wide mechanisms of cell cycle control. Cell size differences among woodlice were largely linked with body size changes (larger cells in larger woodlice) and to a lesser degree with oxygen conditions (development of smaller cells under hypoxia), but not with temperature. Developmental conditions did not affect MMI, and contrary to predictions, large woodlice with large cells showed higher MMI than small woodlice with small cells. We also observed complex patterns of sexual difference in the size of hepatopancreatic cells and the size and number of ommatidia, which are indicative of sex differences in reproductive biology. We conclude that existing theories about the adaptiveness of cell size do not satisfactorily explain the patterns in cell size and metabolic performance observed here in P. scaber. Thus, future studies addressing physiological effects of cell size variance should simultaneously consider different organismal elements that can be involved in sustaining the metabolic demands of tissue, such as the characteristics of gas‐exchange organs and O2‐binding proteins.

In all teleosts the testes are mainly paired organs composed of seminiferous tubules or lobules entering the testicular main ducts and the spermatic duct forming an unpaired structure opening at the genital papilla. The interstitial tissue and the germinal epithelium consist of germinal cells (spermatogonia, spermatocytes, spermatids, spermatozoa) supported by somatic (=Sertoli) cells. During spermatogenesis the germinal and somatic cells form spermatocysts, which are the functional unit providing a blood testis barrier. This cyst starts to develop when Sertoli cells processes enclose a single spermatogonium comprising an isogenic clone of secondary spermatogonia and all germinal cells at further stages of spermato- and spermiogenesis. The testes in more basal taxa are tubular with anastomosing tubules. The tubules in the testes of most externally fertilizing species show a similar structure alongside the entire testis, but in species practicing insemination, different morphological adaptations coupled with dividing testis into a spermatogenic and a aspermatogenic part occur. The spermatogenic part is a place filled with cysts containing developing spermatozoa, while the aspermatogenic part is a storage organ for spermatozoa as well as sperm bundles called spermatozeugmata or spermatophores. In more derived taxa the testes are lobular. Additionally, according to the distribution of spermatogonia, the lobular testis are classified as: a) unrestricted spermatogonial testis type, where spermatogonia are situated along the lobules (e.g. in Percidae), and b) restricted spermatogonial testis type, where spermatogonia are situated only at the distal end of the lobule just beneath the tunica albuginea as in Atherinomorpha. Independent of testis type the process of spermatogenesis finally leads to the development of species-specific spermatozoa, which in all teleosts are anacrosomal. The spermatozoal ultrastructure shows a great diversity in shape and size of the head (mainly the nucleus), location and number of mitochondria, number of flagella or their lack, mutual arrangement of centrioles and the intercentriolar apparatus as well as the presence of additional structures such as pseudoflagella, striated rootlet, accessory microtubules, lateral fins, cytoplasmic sleeve, fenestrated membrane, dense fibers etc. According to the mode of fertilization and the presence or lack of the flagellum, the spermatozoa are classified as aquasperm (aflagellate, uniflagellate and biflagellate) or introsperm with a simple or complex structure.

Pojawienie się inseminacji w ewolucji kręgowców pozytywnie wpłynęło na sukces rozrodczy zwierząt, gdyż zwiększyło prawdopodobieństwo fuzji gamet męskich i żeńskich, a tym samym możliwość zapłodnienia. Przetrzymywanie plemników w układzie rozrodczym samic umożliwiło wydłużenie żywotności i zdolności do zapłodnienia plemników poprzez zapewnienie im odpowiednich warunków otaczającego środowiska. W tym celu u samic wielu gatunków kręgowców zostały wykształcone struktury wyspecjalizowane do przechowywania plemników. Okres magazynowania plemników jest bardzo zróżnicowany wśród kręgowców, ale znacznie dłużej są one przechowywane u gatunków zmiennocieplnych niż stałocieplnych.

The development of histological techniques for the past five centuries was propelled by the invention of the microscope and the improvement of its magnification and resolution. The greatest improvement of methods, allowing observation of plant and animal tissues, dates from the 18th and 19th centuries; whereas in the 20th century mainly the development of electron microscopical and other methods such as fluorescence and freezing techniques, as well as histochemistry and immunohistochemistry proceeded. Independent of the microscope type used for the observation each sample requires specific histoprocessing techniques including fixation (chemical or physical), dehydration (e.g. in series of alcohols), embedding (e.g. in paraffin wax or plastic media) and staining (e.g. hematoxylin and eosin, trichrome methods, toluidine, and methylene blue etc.). High resolution and magnification achieved in transmission electron microscopy requires specific methods of fixation (e.g. double fixation with glutaraldehyde and osmium tetroxide), infiltration and embedding in polymerizing plastics like epoxy or acrylic resins, cutting for ultrathin sections with diamond knifes and contrasting with uranyl acetate and lead citrate, whereas samples for scanning electron microscopy require drying after dehydration and vacuum sputtering with carbon or gold before observation.

Pantodon buchholzi is the only extant member of a primitive group within the fish order Osteoglossiformes producing complex sperm and sperm bundles, but neither mode of sperm bundle formation nor testis structure was previously described, therefore our studies provide more details on the reproductive biology of this species' testes based on light and electron microscopy (TEM, SEM). Males of P. buchholzi possess paired testes divided into anterior spermatogenic and posterior aspermatogenic regions modified into testicular glands. The spermatogenic part contains anastomosing seminiferous tubules filled with spermatocysts arranged peripherally around a central lumen filled with secretion. Within the cysts germ cells develop synchronously. At the end of spermiogenesis all spermatids have their heads oriented parallel and in the same direction, surrounded by spherical residual bodies, which are phagocytized by Sertoli cells. This arrangement of spermatozoa is maintained during spermiation and within sperm bundles released into the luminal secretion. Sperm bundles are then transported to the testicular gland, where are stored within the glandular secretion. In addition to tutoring sperm bundles, the testicular gland is also involved in the steroidogenic process. Given that modifications of testis structure, coupled with sperm bundle formation, were features previously described only in species with insemination, it is likely that insemination also occurs in P. buchholzi. However, presence of a testicular gland was only noted as a part of the testis of externally fertilizing species. Therefore P. buchholzi appears to be the most primitive teleost species with insemination in which sperm packets are stored in the secretory product of epithelial cells of the testicular gland. (c) 2019 Elsevier GmbH. All rights reserved.

In the lungs of 13 species of Amphibia investigated so far, solitary neuroendocrine (NE) cells, as well as a group of these cells called "neuroepithelial bodies" (NEB), have been observed. They are located mainly in the ciliated epithelium covering the apical part of the 1st and Und order septa deeply protruding into the air space of the lung and may monitor gas composition. In two anuran species, Hymenochirus and Xenopus, the ciliated epithelium is absent and the NE cells do not occur, as in apodan amphibians. Substantial diversity in the structure of the NEBs has been observed. In anurans the NEBs are composed of 20–100 small NE cells, while in tailed amphibians they comprise 3–6 large cells. The NEBs are mostly of the "closed type" and the NE cells are covered by a thin layer of surrounding cells that are ciliated, goblet or pneumocytes. Only in two species, Bufo marinus and Ambystoma tigrinum, the NEBs are of "open type" and communicate with the air space via single cell equipped with microvilli and one atypical cilium with an 8+1 microtubule arrangement. NE cells possess characteristic dense-cored vesicles (DCVs) of various diameter, in which the serotonin and several neuropeptides have been demonstrated by immunohistochemical methods. The basal part of NEBs and some NE cells is innervated by sensory nerve terminals morphologically of afferent and efferent type. In ontogeny the NE cells in anuran amphibians appears after metamorphosis. In respiratory organs such as lungs and air bladders of the air-breathing fishes, solitary NE cells with or without innervation are found. As in other vertebrates, in the lungs of amphibians and air-breathing fishes the NE cells form an epithelial endocrine system that acts as endocrine or paracrine receptors.

Aquaculture ResearchVolume 48, Issue 9 p. 5139-5145 Short Communication Hormonal treatment affects sperm motility in the spined loach (Cobitis taenia, Pisces, Cobitidae) Beata Irena Cejko, Corresponding Author Beata Irena Cejko b.cejko@pan.olsztyn.pl Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland Correspondence: B I Cejko, Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Bydgoska 7 Str., 10-243 Olsztyn, Poland. E-mail: b.cejko@pan.olsztyn.plSearch for more papers by this authorSylwia Judycka, Sylwia Judycka Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, PolandSearch for more papers by this authorDorota Juchno, Dorota Juchno Department of Zoology, University of Warmia and Mazury, Olsztyn, PolandSearch for more papers by this authorAlicja Boroń, Alicja Boroń Department of Zoology, University of Warmia and Mazury, Olsztyn, PolandSearch for more papers by this authorAnna Leska, Anna Leska Department of Zoology, University of Warmia and Mazury, Olsztyn, PolandSearch for more papers by this authorOlga Jabłońska, Olga Jabłońska Department of Zoology, University of Warmia and Mazury, Olsztyn, PolandSearch for more papers by this authorAnna Pecio, Anna Pecio Department of Comparative Anatomy, Institute of Zoology, Jagiellonian University, Krakow, PolandSearch for more papers by this authorRadosław Kajetan Kowalski, Radosław Kajetan Kowalski Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, PolandSearch for more papers by this author Beata Irena Cejko, Corresponding Author Beata Irena Cejko b.cejko@pan.olsztyn.pl Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland Correspondence: B I Cejko, Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Bydgoska 7 Str., 10-243 Olsztyn, Poland. E-mail: b.cejko@pan.olsztyn.plSearch for more papers by this authorSylwia Judycka, Sylwia Judycka Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, PolandSearch for more papers by this authorDorota Juchno, Dorota Juchno Department of Zoology, University of Warmia and Mazury, Olsztyn, PolandSearch for more papers by this authorAlicja Boroń, Alicja Boroń Department of Zoology, University of Warmia and Mazury, Olsztyn, PolandSearch for more papers by this authorAnna Leska, Anna Leska Department of Zoology, University of Warmia and Mazury, Olsztyn, PolandSearch for more papers by this authorOlga Jabłońska, Olga Jabłońska Department of Zoology, University of Warmia and Mazury, Olsztyn, PolandSearch for more papers by this authorAnna Pecio, Anna Pecio Department of Comparative Anatomy, Institute of Zoology, Jagiellonian University, Krakow, PolandSearch for more papers by this authorRadosław Kajetan Kowalski, Radosław Kajetan Kowalski Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, PolandSearch for more papers by this author First published: 06 August 2016 https://doi.org/10.1111/are.13170Citations: 4Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume48, Issue9September 2017Pages 5139-5145 RelatedInformation