Yolk Sac Membrane Research Articles

Aberrant patterns of cellular communication in diabetes-induced embryopathy in rats: II, Apoptotic pathways

The objective was to test the hypothesis that hyperglycemia-induced injury of yolk sac cell membranes is associated with disruption of cellular apoptotic signaling pathways. Pregnant rats were induced to become diabetic by injection of streptozotocin. Fourteen normal control and 24 diabetic rats were killed on day 12 of gestation. Yolk sac membranes in 3 conceptus groups (nondiabetic, diabetic with normal, or diabetic with malformed conceptus) were collected for study. DNA was extracted from yolk sac cells and assayed for fragmentation by using gel electrophoresis, which indicates apoptosis. Protein expression was evaluated by Western blot assays. Statistical analyses were performed with the Student t -test. The level of phosphorylated Akt was significantly decreased, whereas that of the proapoptotic protein Bax was increased. These changes were correlated with the presence of DNA fragmentation in yolk sac cells of the diabetic malformed conceptuses. Hyperglycemia-induced embryopathy involves apoptosis, during which the expression of proapoptotic protein Bax is upregulated and the activity of the cell-survival factor, Akt kinase, is decreased in yolk sac cells. These observations suggest that hyperglycemia of maternal diabetes triggers apoptotic signaling pathways and inhibits cell survival pathways, leading to embryonic malformations.

Functional classification of mitochondrion-rich cells in euryhaline Mozambique tilapia (Oreochromis mossambicus) embryos, by means of triple immunofluorescence staining for Na+/K+-ATPase,Na+/K+/2Cl- cotransporter and CFTR anion channel

Mozambique tilapia Oreochromis mossambicus embryos were transferred from freshwater to seawater and vice versa, and short-term changes in the localization of three major ion transport proteins, Na+/K+-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) were examined within mitochondrion-rich cells (MRCs) in the embryonic yolk-sac membrane. Triple-color immunofluorescence staining allowed us to classify MRCs into four types: type I, showing only basolateral Na+/K+-ATPase staining; type II, basolateral Na+/K+-ATPase and apical NKCC; type III, basolateral Na+/K+-ATPase and basolateral NKCC; type IV, basolateral Na+/K+-ATPase, basolateral NKCC and apical CFTR. In freshwater, type-I, type-II and type-III cells were observed. Following transfer from freshwater to seawater, type-IV cells appeared at 12 h and showed a remarkable increase in number between 24 h and 48 h, whereas type-III cells disappeared. When transferred from seawater back to freshwater, type-IV cells decreased and disappeared at 48 h, type-III cells increased, and type-II cells, which were not found in seawater, appeared at 12 h and increased in number thereafter. Type-I cells existed consistently irrespective of salinity changes. These results suggest that type I is an immature MRC, type II is a freshwater-type ion absorptive cell, type III is a dormant type-IV cell and/or an ion absorptive cell (with a different mechanism from type II), and type IV is a seawater-type ion secretory cell. The intracellular localization of the three ion transport proteins in type-IV cells is completely consistent with a widely accepted model for ion secretion by MRCs. A new model for ion absorption is proposed based on type-II cells possessing apical NKCC.

Disturbances on Delta aminolevulinate dehydratase (ALA-D) enzyme activity by Pb 2+, Cd 2+, Cu 2+, Mg 2+, Zn 2+, Na +, K + and Li +: analysis based on coordination geometry and acid–base Lewis capacity

ALA-D (EC 4.2.1.24) is the first cytosolic enzyme in the haem metabolic pathway. Some metals compete with its major cofactor Zn 2+, modifying both enzyme structure and function. Our purpose was to contribute to the understanding of the biochemical role of metals such as Pb 2+, Cd 2+, Cu 2+, Mg 2+, Zn 2+, Na +, K + and Li + on ALA-D, using chicken embryos as experimental model. Mg 2+ and Zn 2+ showed enzyme activation in yolk sac membrane (YSM) (113% at 10 −5 M Mg 2+ and from 10 −4 M Zn 2+), and slight inactivation in liver. Cd 2+ and Cu 2+ caused a non allosteric inhibition in both tissues (100% from 10 −4 M). Surprisingly Pb 2+ was not such a strong inhibitor. Interference of cations during the Schiff base formation in enzymatic catalysis process is explained considering their Lewis acid–base capacity, coordination geometry and electron configuration of valence. Interactions among monovalent cations and biochemical substances are governed chiefly by its electrostatic potential. 0.1 M K + and 0.4 M Na + produced 30% of enzymatic inhibition by the interference on interactions among the functional subunits. Li + activated the YSM enzyme (130% at 10 −5 M) due to a more specific interaction. This study may contribute to elucidate for the first time the possible structural differences between the YSM and liver enzymes from chicken embryo.

Sources and timing of calcium mobilization during embryonic development of the corn snake, Pantherophis guttatus

Embryos of oviparous Reptilia (=turtles, lepidosaurs, crocodilians and birds) extract calcium for growth and development from reserves in the yolk and eggshell. Yolk provides most of the calcium to embryos of lizards and snakes. In contrast, the eggshell supplies most of the calcium for embryonic development of turtles, crocodilians and birds. The yolk sac and chorioallantoic membrane of birds recover and transport calcium from the yolk and eggshell and homologous membranes of squamates (lizards and snakes) probably transport calcium from these two sources as well. We studied calcium mobilization by embryos of the snake Pantherophis guttatus during the interval of greatest embryonic growth and found that the pattern of calcium transfer was similar to other snakes. Calcium recovery from the yolk is relatively low until the penultimate embryonic stage. Calcium removal from the eggshell begins during the same embryonic stage and total eggshell calcium drops in each of the final 2 weeks prior to hatching. The eggshell supplies 28% of the calcium of hatchlings. The timing of calcium transport from the yolk and eggshell is coincident with the timing of growth of the yolk sac and chorioallantoic membrane and expression of the calcium binding protein, calbindin-D 28K, in these tissues as reported in previous studies. In the context of earlier work, our findings suggest that the timing and mechanism of calcium transport from the yolk sac of P. guttatus is similar to birds, but that both the timing and mechanism of calcium transport by the chorioallantoic membrane differs. Based on the coincident timing of eggshell calcium loss and embryonic calcium accumulation, we also conclude that recovery of eggshell calcium in P. guttatus is regulated by the embryo.

Functional morphology of chloride cells in killifish Fundulus heteroclitus, a euryhaline teleost with seawater preference

: Recent advances in the functional morphology of chloride cells in killifish Fundulus heteroclitus, a euryhaline teleost with seawater (SW) preference, were reviewed. Immunocytochemical detection of chloride cells with anti-Na+/K+-ATPase revealed transitional processes of the chloride cell distribution during early life stages. Chloride cells first appear in the yolk-sac membrane at an early embryonic stage, followed by their appearance in the body skin in the later embryonic stages. The principal site for the chloride cell distribution then shifts from the yolk-sac membrane and body skin during embryonic stages to the gills and opercular membrane in larval and later developmental stages. Morphologically distinct SW- and freshwater (FW)-type chloride cells were identified in adult killifish adapted to SW and FW, respectively. Both types of chloride cells are equally active in the two environments, but exert different ion-transporting functions. Following direct transfer of killifish from SW to FW, SW-type chloride cells were transformed into FW-type cells as a short-term response, followed by the promotion of chloride cell replacement as a long-term response. In killifish acclimated to low NaCl (0.1 mM) FW, intense immunoreactivity for vacuolar-type proton pump (V-ATPase) was detected in the basolateral membrane of FW-type chloride cells, whereas the immunoreactivity was much weaker in fish acclimated to FW with higher NaCl concentrations (1.0 and 10.0 mM). These results suggest the occurrence of active ion absorption in FW-type chloride cells and the involvement of V-ATPase in ion-absorbing mechanisms. In view of recent advances in this field, future chloride cell research should be considered in relation to the functional diversity of chloride cells.

Biosynthesis of oleic, arachidonic and docosahexaenoic acids from their C 18 precursors in the yolk sac membrane of the avian embryo

The yolk sac membrane (YSM) of the chicken embryo is known to express δ-9 and δ-6 desaturase activities, suggesting that biosynthesis of the unsaturated fatty acids 18:1n-9, 20:4n-6 and 22:6n-3 might occur during the transfer of yolk lipids across the YSM. If so, this biosynthesis could help to satisfy the demands of the embryonic tissues for these unsaturates. To assess the ability of the YSM to perform these conversions, pieces of the tissue were incubated in vitro with the precursor fatty acids, 14C-18:0, 14C-18:2n-6 or 14C-18:3n-3, and the recovery of radioactivity in the respective products, 18:1n-9, 20:4n-6 and 22:6n-3, was determined. After 4 h of continuous incubation, radioactivity from these precursors was incorporated primarily into triacylglycerol and phospholipid of the tissue pieces. Only small proportions (0.3–4.7%) of this incorporated radioactivity were, however, recovered as 18:1n-9, 20:4n-6 or 22:6n-3. The majority of the incorporated label was retained in the form of the precursor fatty acids. After a 1-h pulse incubation with the 14C precursors, followed by a 3-h chase incubation in the absence of exogenous label, the conversion of incorporated radioactivity to the end product unsaturates was again relatively low (0.5–8.1%). Thus, although conversions of the precursors to the end product fatty acids were detectable in this system, the biosynthesis of these unsaturates is apparently a quantitatively minor pathway in the YSM. Nevertheless, since the amount of 18:2n-6 in the yolk lipids far exceeds that of 20:4n-6, the conversion of even a small proportion of the former to the latter fatty acid could significantly increase the supply of 20:4n-6 to the embryonic tissues.

Do Canada geese (Branta canadensis Linnaeus, 1758) carry infectious agents for birds and man?

Currently, large groups of Canada geese (Branta canadensis Linnaeus, 1758) aggregate in recreational areas of north-western Germany. Questions have arisen as to whether these birds represent a special risk factor as a source of zoonotic agents for humans and as a source of viruses, causing notifiable or reportable diseases, for domestic poultry and waterfowl. To answer these questions, a total of 289 eggs were collected in 2002 and 2003 on a recreation site and assayed. Chlamydia psittaci was not isolated and neither was chlamydial antigen detected by polymerase chain reaction. All virus-isolation attempts were unsuccessful. Neither Salmonella spp. nor Campylobacter spp. was isolated from embryonic tissues, chorioallantoic membranes or yolk-sac membranes. The presence of antibodies against Newcastle disease virus and influenza A virus (haemagglutinin subtypes H5 and H7) was demonstrated in egg yolk. Antibodies were also detected against the egg-drop syndrome 1976 and duck plague viruses. It is concluded that further surveillance studies are needed for a reliable risk assessment.

The Chicken Yolk Sac IgY Receptor, a Functional Equivalent of the Mammalian MHC-Related Fc Receptor, Is a Phospholipase A 2 Receptor Homolog

In mammals, IgG is transferred from mother to young by the MHC-related receptor FcRn, which binds IgG in acidic endosomes and releases it at basic pH into blood. Maternal IgY, the avian counterpart of IgG, is transferred to embryos across yolk sac membranes. We affinity-purified the chicken yolk sac IgY receptor (FcRY) and sequenced its gene. FcRY is unrelated to MHC molecules but is a homolog of the mammalian phospholipase A 2 receptor. Analytical ultracentrifugation and truncation experiments suggest that FcRY forms a compact structure containing an IgY binding site at acidic pH but undergoes a conformational change at basic pH that disrupts the site. FcRY is thus unrelated to mammalian FcRn in both its structure and mechanism for pH-dependent binding, illustrating distinct routes utilized by evolution to transfer antibodies.

Fatty acid esterification in the yolk sac membrane of the avian embryo.

The transfer of lipid from the yolk to the avian embryo is mediated by the yolk sac membrane (YSM). Some, but not all, of the published morphological evidence supports the view that the lipid undergoes a cycle of hydrolysis and re-esterification during translocation across the YSM. The present study aims to test this view by investigating the capacity of the YSM to perform esterification of free fatty acids to form acyl-lipids. YSM pieces (area vasculosa), obtained from the chicken embryo at day 10 of development, were incubated in vitro in medium containing [14C]-palmitic acid. Radioactivity was rapidly incorporated into the tissue lipid indicating a high capacity for esterification. The incorporation was linear with time during the 1-h incubation. Approximately 84% of the incorporated label was recovered in triacylglycerol, 12% was incorporated into phospholipid and less than 1% was detected in cholesteryl ester. [14C]-palmitic acid was incorporated primarily at the sn-1/3 positions in the triacylglycerol molecule and at the sn-1 position of phospholipid. The incorporation of label into tissue pieces obtained from the non-vascularized peripheral region of the YSM (area vitellina) was much more limited than that observed for the area vasculosa. The results support the hypothesis that yolk lipid is hydrolyzed and re-esterified during transfer across the YSM.

The ontogeny of complement component C3 in Atlantic cod ( Gadus morhua L.)—an immunohistochemical study

The complement system in fish is well developed and plays an important role in the immune response. Very little is known about the ontogeny of C3 in fish and no study has previously been done on the development of C3 in teleosts. In this study we have detected the presence of C3 in cod larvae from the age of 1 day post hatching (p.h.) till 57 days p.h., using immunohistochemistry. The specific primary antibodies used, were produced against the β-chain of cod C3. Immunostaining on cod larvae sections revealed that C3 is detectable in the yolksac membrane from day 1 p.h., and in liver, brain, kidney and muscle from day 2 p.h. C3 was also detected in other organs such as eye, notochord, stomach, intestines, pancreas, heart and gills at different stages of cod larval development. These findings suggest that complement is not only important in immune defence against invading pathogens but may also play a role in the formation and generation of different organs.

Differential incorporation of docosahexaenoic and arachidonic acids by the yolk sac membrane of the avian embryo

During avian development, lipoproteins derived from yolk lipid are assembled in the yolk sac membrane (YSM) for secretion into the embryonic circulation. To investigate how yolk polyunsaturated fatty acids, essential for the development of certain tissues, are distributed among the lipid classes of the lipoproteins, pieces of YSM were incubated in vitro with [ 14C]arachidonic and [ 14C]docosahexaenoic acids (DHA). There was a marked difference in the partitioning of these two precursors among the lipid classes of the tissue. Of the radioactivity incorporated into total lipid from [ 14C]-arachidonic acid during 1 h of incubation, 67.3% was esterified as phospholipid and 29.5% as triacylglycerol. In contrast, only 14.6% of the label incorporated from [ 14C]-DHA was esterified as phospholipid, whereas 73.2% was recovered in triacylglycerol. This pattern of differential partitioning was observed at all time points and across a 20-fold range of fatty acid concentrations. There was no evidence for conversion of the radioactive arachidonic and DHAs to other fatty acids prior to incorporation into tissue lipids. It is suggested that the selective incorporation of yolk-derived DHA into the triacylglycerol of secreted lipoproteins represents part of a mechanism for directing this polyunsaturate to particular embryonic tissues.

Early embryonic lethality caused by targeted disruption of the mouse PHGPx gene

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is the only known intracellular antioxidant enzyme that can directly reduce lipid hydroperoxide in membrane. Mitochondrial and non-mitochondrial PHGPx and sperm nuclei GPx are transcribed from one gene by alternative transcription using different first exons Ia and Ib, respectively. To examine the role of PHGPx in development, we generated mice deficient in PHGPx by a targeted disruption of all exons of the PHGPx gene. Heterozygotes are viable, fertile, and appear normal, despite having decreased levels of three types of PHGPx mRNA and protein. Embryos homozygous for PHGPx-null die between 7.5 and 8.5 days post coitum (dpc), probably developing distal apoptosis. We examined the expression of PHGPx in mouse embryos using immunohistochemical analysis with anti-PHGPx mAb. The expression of PHGPx was detected in the embryonic ectoderm and the yolk sac membrane at 7.5 dpc. The results demonstrated that PHGPx is expressed in early gastrulation stage at 7.5 dpc and that the expression of PHGPx was essential for normal mouse development.

Retinoids, LRAT and REH activities in eggs of Japanese quail following maternal and in ovo exposures to 3,3',4,4'-tetrachlorobiphenyl.

Environmental monitoring for the effects of organochlorine contaminants has identified changes in egg yolk retinoid concentrations, however underlying mechanisms are unknown. Breeding female Japanese quail, Coturnix coturnix japonica, received 3 bimonthly injections of a low dose (5 microg/g) of the coplanar polychlorinated biphenyl (PCB) 3,3',4,4'-tetrachlorobiphenyl. No overt maternal toxicity or embryotoxicity was detected. For the exposed females, oocytes (yolk deposition nearly completed) and freshly laid eggs contained higher concentrations of retinol. For PCB-exposed female quail, freshly laid eggs and fertile eggs incubated for 6 days contained higher concentrations of retinyl palmitate. These results suggest that the PCB congener caused greater deposition of retinoids in yolks during late oogenesis or greater net esterification in the yolk-sac membrane. Retinyl ester hydrolase (REH) activity, assayed in the microsomal fraction of the yolk-sac membrane, was significantly inhibited in the PCB-exposed group. Therefore, the higher retinyl palmitate concentrations may be explained by less retinyl palmitate conversion to retinol. In a second experiment, fertile quail eggs were injected with 2, 10 or 20 microg of the PCB congener and incubated for 6 days. In contrast to the maternal exposure, yolk retinol decreased and retinyl ester hydrolase increased in the PCB-injected eggs. The difference in the results of adult versus egg injections may be related to several factors including adult transformation of the PCB to toxic metabolites and differences in post-transcriptional regulation of REH expression.

Retinoid metabolism (LRAT, REH) in the yolk-sac membrane of Japanese quail eggs and effects of mono- ortho-PCBs

Retinoids stored in the avian egg are essential for normal development, however, laboratory and field experiments suggest that they are affected by environmental contaminants. Lecithin:retinol acyltransferase (LRAT) activity was detected in the microsomal fraction of the yolk-sac membrane of the Japanese quail at day 6 of development. LRAT activity was maximal at pH 7.0 having apparent kinetic parameters of K m=1.35 μM and V max=0.21 nmol/mg protein/h and was inhibited by the sulfhydryl modifying agent N-ethyl-maleimide. Retinol ester hydrolase (REH) activity in the microsomal fraction of the yolk-sac membrane was stimulated by the bile salt analogue 3-[(3-cholamidopropyl) dimethyl-ammonio]-1-propane sulfonate and was maximal at pH 9.0 with apparent K m=77 μM and V max=34.3 nmol/mg protein/h. Injection of the PCB congener 2,3,3′,4,4′-pentachlorobiphenyl increased both REH and LRAT activities, whereas 2,3,3′,4-tetrachlorobiphenyl stimulated LRAT. Yolk retinol concentration and the molar ratio retinol:retinyl palmitate were lower in the exposed eggs. Yolk retinol concentration decreased as LRAT increased ( R 2=0.89) suggesting that certain PCB congeners may affect vitamin A mobilization in ovo by increasing LRAT activity in the yolk-sac membrane.

The ontogeny of fatty acid-binding protein in turkey (Meleagridis gallopavo) intestine and yolk sac membrane during embryonic and early posthatch development

Experiments were conducted to confirm the existence and ontogeny of fatty acid binding protein (FABP) in the intestine and yolk sac membrane of turkey poults (Meleagridis gallopavo) during embryonic and early posthatch development. Intestinal (I-) FABP was measured using an immunoblot procedure incorporating anti-chick liver (L-)FABP antisera. FABP activity in both tissues was also confirmed with a ligand-binding assay incorporating 14C-oleic acid. I-FABP did not cross-react with chick L-FABP antisera until hatch, embryonic day 28 (ED 28), after which there was a 39% increase in I-FABP concentration through the first 3 d posthatch (PD 3). FABP concentration calculated on a total intestinal basis (ng/intestine), however, increased 10-fold through PD 6. Specific activity [disintegrations per minute (dpm)/ mg cytosolic protein] was greatest at hatch and decreased slightly thereafter, whereas specific activity of FABP in the yolk sac membrane peaked between ED 16 and ED 19 and then declined. Total yolk sac activity (dpm/yolk sac membrane), however, plateaued at ED 22 before declining to low levels by PD 3, coincident with the period of maximal lipid transfer out of the yolk.

Heat shock protein HSP86 expression during mouse embryo development, especially in the germ-line.

In addition to appearing in response to biological stresses, heat shock proteins are expressed as 'chaperones' by some cells living in physiological conditions. Among these proteins, the HSP90 family seems to function under normal growth conditions in the pathways of numerous signal transducers, cell-cycle and developmental regulators. The aim of this study was to investigate the immunohistochemical expression and the distribution of the two mammalian cytosolic isoforms of HSP90 (HSP84 and HSP86) during mouse development between E6 and E16. Our immunohistochemical investigations revealed a diffuse and ubiquitous expression of HSP84 distributed throughout the embryo in all stages. On the other hand, HSP86 was specifically noticed in diverse somatic cells such as hepatoblasts and epithelia that could traduce cellular differentiation phenomenon. More interestingly, a strong cytoplasm expression of HSP86 could be demonstrated in primordial germ cells from their appearance on the yolk sac membrane until reaching the genital crest. These results suggested a protective mechanism against the phenotypic expression of mutations induced by environmental changes in vertebrates as has been demonstrated in Drosophila.

Electrolyte and Water Balance of the Early Avian Embryo: Effects of Egg Turning

Formation of sub-embryonic fluid (SEF) is a key aspect of the physiology of the early avian embryo.Here we review the process of SEF formation and the factors which influence its composition and the rate of SEF production and depletion in the Japanese quail and domestic fowl.There is particular emphasis on the role of turning of the egg during incubation and we briefly consider the broader role of egg turning during avian incubation. The bulk of the review deals with the growth of the area vasculosa of the yolk sac membrane, the cellular processes of SEF formation, and the water and electrolyte physiology of the avian embryo during the first half of incubation.We conclude with a brief discussion of the areas for future investigation.

Ontogeny of 5-aminolevulinic dehydratase and porphobilinogen deaminase activities in the yolk sac membrane and liver of chick embryos

1. Chick embryos of 7, 9, 11, 12, 13, 14, 15, 17 and 19 d of embryonic development were examined to determine the activities of 5-aminolevulinic dehydratase (ALA-D, EC 4.2.1.24) and porphobilinogen deaminase (PBG-D, EC 4.3.1.8). 2. Liver and yolk sac membrane ALA-D specific activities showed a maximum between 12 and 13 d of embryonic development, yolk sac membrane PBG-ase activity a maximum at 9 d and at 7 d in liver. Total activities of ALA-D and PBG-D were not constant during the course of embryonic development but probably related to the changes of intensity of haem synthesis. 3. ALA-D and PBG-ase activities were higher in yolk sac membrane than in liver, showing the importance of the yolk sac membrane as erythropoietic tissue. PBG-D catalysed the rate-limiting reaction of the cytosolic steps in the biosynthetic pathway in both tissues.

Chloride cells during early life stages of fish and their functional differentiation

Recent advances in studies on osmoregulation in early life stages of fish are reviewed with special reference to extrabranchial chloride cells. Numerous chloride cells are present in the yolk-sac membrane of Mozambique tilapia embryos and larvae adapted to fresh water (FW) and seawater (SW). Chloride cells in SW often form multicellular complexes together with adjacent accessory cells, whereas chloride cells exist individually in FW. Chloride testing and X-ray microanalysis have shown that the SW-type, chloride cell complexes have the definitive function of chloride secretion. According to in vivo sequential observations on chloride cells in the yolk-sac membrane of tilapia, single FW-type chloride cells are transformed into multicellular SW-type cells in response to SW transfer, suggesting plasticity in the ion-transporting functions of chloride cells. A unique in vitro experimental model, named a ‘yolk-ball’ incubation system, has been established recently, in which the yolk sac is separated from the embryonic body and subjected to in vitro incubation. In the yolk balls prepared from FW tilapia embryos, chloride cells form multicellular complexes after SW transfer, indicating that chloride cells are equipped with an autonomous mechanism of functional differentiation that is independent of embryonic endocrine and nerve systems. The yolk-ball incubation system definitely serves as an excellent experimental model for further studies on chloride cell differentiation and functions. As chloride cells are commonly observed in the yolk-sac membrane and other body surfaces of fish embryos and larvae, it could be generalized that extrabranchial chloride cells play central roles in osmoregulation until gill chloride cells become functional.

Antioxidant systems of the developing quail embryo are compromised by mycotoxin aurofusarin

The effects of aurofusarin in the quail diet on the antioxidant systems of the developing embryo are investigated. Thirty eight 45-day-old Japanese quails ( Coturnix japonica) were divided into two groups and were fed on a corn-soya diet or the same diet supplemented with aurofusarin at the level of 26.4 mg/kg feed in the form of Fusarium graminearum culture enriched with aurofusarin. Eggs obtained after 7 weeks of feeding were incubated. Samples of quail tissues were collected at day 17 of embryonic development and from day old hatchlings. Antioxidants and malondialdehyde were analysed by HPLC-based methods. Inclusion of aurofusarin in the maternal diet was associated with decreased concentrations of α- and γ-tocopherols, α- and γ-tocotrienols, retinol, lutein and zeaxanthin in egg yolk. The vitamin E (tocopherols and tocotrienols) concentration in the liver and yolk sac membrane (YSM) of the day 17 embryos and the hatchlings from aurofusarin-fed group was significantly decreased. Alpha-tocopherol concentration was also reduced in kidney, lung, heart, muscle and brain of day-old quails. In the liver of day-old quails, concentrations of lutein, zeaxanthin, retinol, retinyl linoleate, retinyl oleate, retinyl palmitate and retinyl stearate were also reduced. As a result of these diminished antioxidant concentrations, tissue susceptibility to lipid peroxidation was significantly increased. It is suggested that a compromised antioxidant system of the egg yolk and embryonic tissues could predispose quails to increased mortality at late stages of their embryonic development.