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Ilkuk Chang - One of the best experts on this subject based on the ideXlab platform.
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primordial germ cell mediated chimera technology produces viable pure line houbara bustard offspring potential for repopulating an endangered species
PLOS ONE, 2010Co-Authors: Ulrich Wernery, Vijay Baskar, Zhor Guerineche, Shazia Saleem, Darren K Griffin, Kamal Khazanehdari, Jorg Kinne, Renate Wernery, Ilkuk ChangAbstract:Background The Houbara bustard (Chlamydotis undulata) is a wild seasonal breeding bird populating arid sandy semi-desert habitats in North Africa and the Middle East. Its population has declined drastically during the last two decades and it is classified as vulnerable. Captive breeding programmes have, hitherto, been unsuccessful in reviving population numbers and thus radical technological solutions are essential for the long term survival of this species. The purpose of this study was to investigate the use of primordial germ cell-mediated chimera technology to produce viable Houbara bustard offspring. Methodology/Principal Findings Embryonic gonadal tissue was dissected from Houbara bustard embryos at eight days post-incubation. Subsequently, Houbara tissue containing gonadal primordial germ cells (gPGCs) was injected into White Leghorn Chicken (Gallus gallus domesticus) embryos, producing 83/138 surviving male chimeric embryos, of which 35 chimeric roosters reached sexual maturity after 5 months. The incorporation and differentiation of Houbara gPGCs in chimeric Chicken testis were assessed by PCR with Houbara-specific primers and 31.3% (5/16) gonads collected from the injected Chicken embryos showed the presence of donor Houbara cells. A total of 302 semen samples from 34 chimeric roosters were analyzed and eight were confirmed as germline chimeras. Semen samples from these eight roosters were used to artificially inseminate three female Houbara bustards. Subsequently, 45 Houbara eggs were obtained and incubated, two of which were fertile. One egg hatched as a male live born Houbara; the other was female but died before hatching. Genotyping confirmed that the male chick was a pure-line Houbara derived from a chimeric rooster. Conclusion This study demonstrates for the first time that Houbara gPGCs can migrate, differentiate and eventually give rise to functional sperm in the chimeric Chicken testis. This approach may provide a promising tool for propagation and conservation of endangered avian species that cannot breed in captivity.
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primordial germ cell mediated chimera technology produces viable pure line houbara bustard offspring potential for repopulating an endangered species
PLOS ONE, 2010Co-Authors: Ulrich Wernery, Vijay Baskar, Zhor Guerineche, Shazia Saleem, Darren K Griffin, Kamal Khazanehdari, Jorg Kinne, Renate Wernery, Chunhai Liu, Ilkuk ChangAbstract:Background The Houbara bustard (Chlamydotis undulata) is a wild seasonal breeding bird populating arid sandy semi-desert habitats in North Afric population has declined drastically during the last two decades and it is classified as vulnerable. Captive breeding programmes have, h reviving population numbers and thus radical technological solutions are essential for the long term survival of this species. The purpo investigate the use of primordial germ cell-mediated chimera technology to produce viable Houbara bustard offspring. Methodology/Principal Findings Embryonic gonadal tissue was dissected from Houbara bustard embryos at eight days post-incubation. Subsequently, Houbara tissue germ cells (gPGCs) was injected into White Leghorn Chicken (Gallus gallus domesticus) embryos, producing 83/138 surviving male ch chimeric roosters reached sexual maturity after 5 months. The incorporation and differentiation of Houbara gPGCs in chimeric Chicken with Houbara-specific primers and 31.3% (5/16) gonads collected from the injected Chicken embryos showed the presence of donor H semen samples from 34 chimeric roosters were analyzed and eight were confirmed as germline chimeras. Semen samples from these artificially inseminate three female Houbara bustards. Subsequently, 45 Houbara eggs were obtained and incubated, two of which wer male live born Houbara; the other was female but died before hatching. Genotyping confirmed that the male chick was a pure-line Hou rooster.
John P Giesy - One of the best experts on this subject based on the ideXlab platform.
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developmental and posthatch effects of in ovo exposure to 2 3 7 8 tcdd 2 3 4 7 8 pecdf and 2 3 7 8 tcdf in japanese quail coturnix japonica common pheasant phasianus colchicus and white Leghorn Chicken gallus gallus domesticus embryos
Environmental Toxicology and Chemistry, 2011Co-Authors: Andrew M Cohenbarnhouse, John P Giesy, Scott D Fitzgerald, Matthew J Zwiernik, Jane E Link, Sean W Kennedy, Steve Wiseman, Paul D JonesAbstract:An egg injection study was conducted to confirm a proposed model of relative sensitivity of three avian species to 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD)-like chemicals. It was previously reported that the order of species sensitivity to in ovo exposure to TCDD, 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), or 2,3,7,8-tetrachlorodibenzofuran (TCDF) at doses ranging from 0.044 to 37 picomoles (pmol)/g egg was the Chicken (Gallus gallus domesticus), common pheasant (Phasianus colchicus), and Japanese quail (Coturnix japonica) based on embryo mortality and hepatic enzyme induction. In the present study, the incidence of developmental deformities, changes in body and relative organ masses, and organ pathology of hatchlings as additional indicators of species sensitivity were assessed; in addition, embryo mortality in the three species was categorized by stage of development. Embryo mortality varied temporally with significant increases generally occurring after organogenesis and just prior to hatching. A significant increase in the percentage of developmental deformities was observed only in Japanese quail exposed to TCDF. Body and relative organ masses of quail, pheasants, and Chickens dosed in ovo with TCDD, PeCDF, or TCDF were not consistently affected. Chemical-related pathology occurred only in livers of quail at the greatest doses of each compound. These results indicated that the incidence of developmental deformities, changes in body and relative organ masses and organ pathology could not be used as indicators of species sensitivity or chemical potency. Environ. Toxicol. Chem. 2011;30:1659-1668. # 2011 SETAC
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sensitivity of japanese quail coturnix japonica common pheasant phasianus colchicus and white Leghorn Chicken gallus gallus domesticus embryos to in ovo exposure to tcdd pecdf and tcdf
Toxicological Sciences, 2011Co-Authors: Andrew M Cohenbarnhouse, John P Giesy, Scott D Fitzgerald, Matthew J Zwiernik, Jane E Link, Sean W Kennedy, Steve Wiseman, Jessica C Herve, Yinfei Yang, Paul D JonesAbstract:Egg injection studies were performed to confirm a proposed model of relative sensitivity of birds to 2,3,7,8-tetrachlorodibenzop-dioxin (TCDD). In this model, species are classified as belonging to one of three categories of sensitivity based on amino acid substitutions in the ligand-binding domain of the aryl hydrocarbon receptor. Embryo lethality and relative potencies of 2,3,7,8-tetrachlorodibenzofuran (TCDF) and 2,3,4,7, 8-pentachlorodibenzofuran (PeCDF) were compared with TCDD for Japanese quail (Coturnix japonica; least sensitive), Common pheasant (Phasianus colchicus; moderately sensitive), and White Leghorn Chicken (Gallus gallus domesticus; most sensitive). Doses ranging from 0.044 to 37 pmol/g egg (0.015‐12 ng/g egg) were injected into the air cell of eggs prior to incubation. LD50 (95% confidence intervals) values, based on rate of hatching for TCDD, PeCDF, and TCDF, were 30 (25‐36), 4.9 (2.3‐9.2), and 15 (11‐24) pmol/g egg for the quail, 3.5 (2.3‐6.3), 0.61 (0.28‐1.2), and 1.2 (0.62‐2.2) pmol/g egg for pheasant, and 0.66 (0.47‐0.90), 0.75 (0.64‐0.87), and 0.33 (0.23‐0.45) pmol/g egg for Chicken, respectively. LD50-based relative potencies of PeCDF and TCDF were 6.1 and 2.0 for quail, 5.7 and 2.9 for pheasant, and 0.88 and 2.0 for Chicken, respectively. TCDD was not the most potent compound among the species tested, with PeCDF and TCDF being more potent than TCDD in the quail and pheasant. TCDF was the most potent in Chicken. Species sensitivity was as expected for TCDD and TCDF, whereas for PeCDF, the Chicken and pheasant were similar in sensitivity and both were more sensitive than the quail. Results from companion in vitro studies are generally similar to those reported here with a few exceptions.
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effects of air cell injection of perfluorooctane sulfonate before incubation on development of the white Leghorn Chicken gallus domesticus embryo
Environmental Toxicology and Chemistry, 2006Co-Authors: Elizabeth D Molina, John P Giesy, R J Balander, Scott D Fitzgerald, R R Mitchell, Steven J BursianAbstract:Fifty white Leghorn Chicken (Gallus domesticus) eggs per group were injected with 0.1, 1.0, 10.0, or 20.0 μg perfluorooctane sulfonate (PFOS)/g egg before incubation to investigate the effects of PFOS on the developing embryo. Hatchlings were weighed, examined for gross developmental abnormalities, and transferred to a battery brooder, where they were raised for 7 d. Chicks were then weighed, and 20 birds per treatment were randomly chosen for necropsy. The brain, heart, kidneys, and liver were removed and weighed. Livers were processed further for determination of PFOS concentrations and histological assessment. Hatchability was reduced significantly in all treatment groups in a dose-dependent manner. The calculated median lethal dose was 4.9 μg PFOS/g egg. Perfluorooctane sulfonate did not affect posthatch body or organ weights. Exposure to PFOS caused pathological changes in the liver characterized by bile duct hyperplasia, periportal inflammation, and hepatic cell necrosis at doses as low as 1.0 μg PFOS/g egg. Perfluorooctane sulfonate concentrations in the liver increased in a dose-dependent manner. Based on reduced hatchability, the lowest-observed-adverse-effect level was 0.1 μg PFOS/g egg.
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mechanisms of tcdd induced abnormalities and embryo lethality in white Leghorn Chickens
Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2003Co-Authors: Alan L Blankenship, Steven J Bursian, Klara Hilscherova, Minghua Nie, Katherine K Coady, Sergio A Villalobos, Kurunthachalam Kannan, D C Powell, John P GiesyAbstract:The toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds in birds has been well-established in laboratory and field studies. Observed effects of TCDD and related chemicals in birds include developmental deformities, reproductive failure, liver damage, wasting syndrome and death. The mechanism of action of TCDD at the cellular level is primarily mediated through the aryl hydrocarbon receptor (AhR). However, the mechanism of toxic action at the organism level is poorly understood. In this study, the role of radical oxygen species and mixed function oxidize (MFO; cytochrome P4501A) in the mechanism of TCDD-induced abnormalities and lethality were examined by co-injecting radical scavengers and an MFO inhibitor (piperonyl butoxide). Egg injection studies were conducted to determine if in ovo TCDD exposure can cause oxidative stress in white Leghorn Chicken eggs. Test agents were injected into the yolk prior to incubation. Treatments included TCDD (150 ng/kg), triolein (vehicle control), and various co-treatments including MnTBAP (a mimetic of superoxide dismutase), piperonyl butoxide, piroxicam, vitamin A acetate, and vitamin E succinate. Phenytoin, which is known to cause teratogenesis through oxidative stress was used as a positive control. Eggs were incubated until hatch and then the following parameters were assessed: mortality, hatching success, abnormalities, weights for whole body, liver, heart and brain, and biochemical endpoints for oxidative stress. As a measure of exposure, concentrations of TCDD and ethoxyresorufin-O-deethylase (EROD) activities were measured in tissues of hatchlings. While greater mortality and abnormalities were observed in the TCDD treatment groups, the number of the replicates were not great enough to detect statistically significant differences in abnormality rates for the co-treatments. Some of the observed developmental abnormalities included edema, liver necrosis and bill, eye and limb deformities with TCDD treatments, bill and brain deformities with phenytoin treatments, eye abnormalities with Vitamin E treatments, and abnormal feather pigmentation with piperonyl butoxide treatments.
Paul D Jones - One of the best experts on this subject based on the ideXlab platform.
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developmental and posthatch effects of in ovo exposure to 2 3 7 8 tcdd 2 3 4 7 8 pecdf and 2 3 7 8 tcdf in japanese quail coturnix japonica common pheasant phasianus colchicus and white Leghorn Chicken gallus gallus domesticus embryos
Environmental Toxicology and Chemistry, 2011Co-Authors: Andrew M Cohenbarnhouse, John P Giesy, Scott D Fitzgerald, Matthew J Zwiernik, Jane E Link, Sean W Kennedy, Steve Wiseman, Paul D JonesAbstract:An egg injection study was conducted to confirm a proposed model of relative sensitivity of three avian species to 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD)-like chemicals. It was previously reported that the order of species sensitivity to in ovo exposure to TCDD, 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), or 2,3,7,8-tetrachlorodibenzofuran (TCDF) at doses ranging from 0.044 to 37 picomoles (pmol)/g egg was the Chicken (Gallus gallus domesticus), common pheasant (Phasianus colchicus), and Japanese quail (Coturnix japonica) based on embryo mortality and hepatic enzyme induction. In the present study, the incidence of developmental deformities, changes in body and relative organ masses, and organ pathology of hatchlings as additional indicators of species sensitivity were assessed; in addition, embryo mortality in the three species was categorized by stage of development. Embryo mortality varied temporally with significant increases generally occurring after organogenesis and just prior to hatching. A significant increase in the percentage of developmental deformities was observed only in Japanese quail exposed to TCDF. Body and relative organ masses of quail, pheasants, and Chickens dosed in ovo with TCDD, PeCDF, or TCDF were not consistently affected. Chemical-related pathology occurred only in livers of quail at the greatest doses of each compound. These results indicated that the incidence of developmental deformities, changes in body and relative organ masses and organ pathology could not be used as indicators of species sensitivity or chemical potency. Environ. Toxicol. Chem. 2011;30:1659-1668. # 2011 SETAC
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sensitivity of japanese quail coturnix japonica common pheasant phasianus colchicus and white Leghorn Chicken gallus gallus domesticus embryos to in ovo exposure to tcdd pecdf and tcdf
Toxicological Sciences, 2011Co-Authors: Andrew M Cohenbarnhouse, John P Giesy, Scott D Fitzgerald, Matthew J Zwiernik, Jane E Link, Sean W Kennedy, Steve Wiseman, Jessica C Herve, Yinfei Yang, Paul D JonesAbstract:Egg injection studies were performed to confirm a proposed model of relative sensitivity of birds to 2,3,7,8-tetrachlorodibenzop-dioxin (TCDD). In this model, species are classified as belonging to one of three categories of sensitivity based on amino acid substitutions in the ligand-binding domain of the aryl hydrocarbon receptor. Embryo lethality and relative potencies of 2,3,7,8-tetrachlorodibenzofuran (TCDF) and 2,3,4,7, 8-pentachlorodibenzofuran (PeCDF) were compared with TCDD for Japanese quail (Coturnix japonica; least sensitive), Common pheasant (Phasianus colchicus; moderately sensitive), and White Leghorn Chicken (Gallus gallus domesticus; most sensitive). Doses ranging from 0.044 to 37 pmol/g egg (0.015‐12 ng/g egg) were injected into the air cell of eggs prior to incubation. LD50 (95% confidence intervals) values, based on rate of hatching for TCDD, PeCDF, and TCDF, were 30 (25‐36), 4.9 (2.3‐9.2), and 15 (11‐24) pmol/g egg for the quail, 3.5 (2.3‐6.3), 0.61 (0.28‐1.2), and 1.2 (0.62‐2.2) pmol/g egg for pheasant, and 0.66 (0.47‐0.90), 0.75 (0.64‐0.87), and 0.33 (0.23‐0.45) pmol/g egg for Chicken, respectively. LD50-based relative potencies of PeCDF and TCDF were 6.1 and 2.0 for quail, 5.7 and 2.9 for pheasant, and 0.88 and 2.0 for Chicken, respectively. TCDD was not the most potent compound among the species tested, with PeCDF and TCDF being more potent than TCDD in the quail and pheasant. TCDF was the most potent in Chicken. Species sensitivity was as expected for TCDD and TCDF, whereas for PeCDF, the Chicken and pheasant were similar in sensitivity and both were more sensitive than the quail. Results from companion in vitro studies are generally similar to those reported here with a few exceptions.
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effects of in ovo exposure of white Leghorn Chicken common pheasant and japanese quail to 2 3 7 8 tetrachlorodibenzo p dioxin and two chlorinated dibenzofurans on cyp1a induction
Environmental Toxicology and Chemistry, 2010Co-Authors: Yinfei Yang, Andrew M Cohenbarnhouse, Matthew J Zwiernik, Sean W Kennedy, Steve Wiseman, Paul D Jones, Yi Wan, John L Newsted, Denise P Kay, Steven J BursianAbstract:In birds, activation of the aryl hydrocarbon receptor (AhR) by some polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) results in induction of cytochrome P4501A (CYP1A) expression. This response has been useful for predicting relative sensitivity of birds to dioxin-like compounds. To further investigate species-sensitivity to dioxins and dioxin-like compounds induction of cytochrome P450 1A4 and 1A5 (CYP1A4 and CYP1A5) mRNA and ethoxyresorufin O-deethylase (EROD) activity were quantified in liver of posthatch white Leghorn Chicken, common pheasant, and Japanese quail exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), or 2,3,7,8-tetrachlorodibenzofuran (TCDF) via air cell injection. The rank-order of sensitivity of TCDD- and TCDF-exposed birds, based on CYP1A, was Chicken > pheasant > quail. Based on CYP1A5 mRNA expression and EROD induction, the order of sensitivity of PeCDF-exposed birds was identical to that for TCDD and TCDF. However, based on CYP1A4 mRNA expression the rank-order was pheasant > Chicken > quail. When comparing the potency of the three compounds in each species, based on CYP1A4 mRNA expression, TCDD was the most potent compound in Chicken. However, PeCDF was equally potent to TCDD in quail and was more potent than TCDD in pheasant. These results suggest that quantitative real-time polymerase chain reaction (Q-PCR) analysis of CYP1A expression, particularly CYP1A4 mRNA expression, may be a more sensitive biomarker of exposure than analysis of EROD induction, especially in less responsive avian species. Based on these findings future risk assessments should consider the sensitivity of the species inhabiting a site and the congeners of concern that are present. Environ. Toxicol. Chem. 2010;29:1490–1502. © 2010 SETAC
Ulrich Wernery - One of the best experts on this subject based on the ideXlab platform.
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primordial germ cell mediated chimera technology produces viable pure line houbara bustard offspring potential for repopulating an endangered species
PLOS ONE, 2010Co-Authors: Ulrich Wernery, Vijay Baskar, Zhor Guerineche, Shazia Saleem, Darren K Griffin, Kamal Khazanehdari, Jorg Kinne, Renate Wernery, Ilkuk ChangAbstract:Background The Houbara bustard (Chlamydotis undulata) is a wild seasonal breeding bird populating arid sandy semi-desert habitats in North Africa and the Middle East. Its population has declined drastically during the last two decades and it is classified as vulnerable. Captive breeding programmes have, hitherto, been unsuccessful in reviving population numbers and thus radical technological solutions are essential for the long term survival of this species. The purpose of this study was to investigate the use of primordial germ cell-mediated chimera technology to produce viable Houbara bustard offspring. Methodology/Principal Findings Embryonic gonadal tissue was dissected from Houbara bustard embryos at eight days post-incubation. Subsequently, Houbara tissue containing gonadal primordial germ cells (gPGCs) was injected into White Leghorn Chicken (Gallus gallus domesticus) embryos, producing 83/138 surviving male chimeric embryos, of which 35 chimeric roosters reached sexual maturity after 5 months. The incorporation and differentiation of Houbara gPGCs in chimeric Chicken testis were assessed by PCR with Houbara-specific primers and 31.3% (5/16) gonads collected from the injected Chicken embryos showed the presence of donor Houbara cells. A total of 302 semen samples from 34 chimeric roosters were analyzed and eight were confirmed as germline chimeras. Semen samples from these eight roosters were used to artificially inseminate three female Houbara bustards. Subsequently, 45 Houbara eggs were obtained and incubated, two of which were fertile. One egg hatched as a male live born Houbara; the other was female but died before hatching. Genotyping confirmed that the male chick was a pure-line Houbara derived from a chimeric rooster. Conclusion This study demonstrates for the first time that Houbara gPGCs can migrate, differentiate and eventually give rise to functional sperm in the chimeric Chicken testis. This approach may provide a promising tool for propagation and conservation of endangered avian species that cannot breed in captivity.
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primordial germ cell mediated chimera technology produces viable pure line houbara bustard offspring potential for repopulating an endangered species
PLOS ONE, 2010Co-Authors: Ulrich Wernery, Vijay Baskar, Zhor Guerineche, Shazia Saleem, Darren K Griffin, Kamal Khazanehdari, Jorg Kinne, Renate Wernery, Chunhai Liu, Ilkuk ChangAbstract:Background The Houbara bustard (Chlamydotis undulata) is a wild seasonal breeding bird populating arid sandy semi-desert habitats in North Afric population has declined drastically during the last two decades and it is classified as vulnerable. Captive breeding programmes have, h reviving population numbers and thus radical technological solutions are essential for the long term survival of this species. The purpo investigate the use of primordial germ cell-mediated chimera technology to produce viable Houbara bustard offspring. Methodology/Principal Findings Embryonic gonadal tissue was dissected from Houbara bustard embryos at eight days post-incubation. Subsequently, Houbara tissue germ cells (gPGCs) was injected into White Leghorn Chicken (Gallus gallus domesticus) embryos, producing 83/138 surviving male ch chimeric roosters reached sexual maturity after 5 months. The incorporation and differentiation of Houbara gPGCs in chimeric Chicken with Houbara-specific primers and 31.3% (5/16) gonads collected from the injected Chicken embryos showed the presence of donor H semen samples from 34 chimeric roosters were analyzed and eight were confirmed as germline chimeras. Semen samples from these artificially inseminate three female Houbara bustards. Subsequently, 45 Houbara eggs were obtained and incubated, two of which wer male live born Houbara; the other was female but died before hatching. Genotyping confirmed that the male chick was a pure-line Hou rooster.
Andrew M Cohenbarnhouse - One of the best experts on this subject based on the ideXlab platform.
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developmental and posthatch effects of in ovo exposure to 2 3 7 8 tcdd 2 3 4 7 8 pecdf and 2 3 7 8 tcdf in japanese quail coturnix japonica common pheasant phasianus colchicus and white Leghorn Chicken gallus gallus domesticus embryos
Environmental Toxicology and Chemistry, 2011Co-Authors: Andrew M Cohenbarnhouse, John P Giesy, Scott D Fitzgerald, Matthew J Zwiernik, Jane E Link, Sean W Kennedy, Steve Wiseman, Paul D JonesAbstract:An egg injection study was conducted to confirm a proposed model of relative sensitivity of three avian species to 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD)-like chemicals. It was previously reported that the order of species sensitivity to in ovo exposure to TCDD, 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), or 2,3,7,8-tetrachlorodibenzofuran (TCDF) at doses ranging from 0.044 to 37 picomoles (pmol)/g egg was the Chicken (Gallus gallus domesticus), common pheasant (Phasianus colchicus), and Japanese quail (Coturnix japonica) based on embryo mortality and hepatic enzyme induction. In the present study, the incidence of developmental deformities, changes in body and relative organ masses, and organ pathology of hatchlings as additional indicators of species sensitivity were assessed; in addition, embryo mortality in the three species was categorized by stage of development. Embryo mortality varied temporally with significant increases generally occurring after organogenesis and just prior to hatching. A significant increase in the percentage of developmental deformities was observed only in Japanese quail exposed to TCDF. Body and relative organ masses of quail, pheasants, and Chickens dosed in ovo with TCDD, PeCDF, or TCDF were not consistently affected. Chemical-related pathology occurred only in livers of quail at the greatest doses of each compound. These results indicated that the incidence of developmental deformities, changes in body and relative organ masses and organ pathology could not be used as indicators of species sensitivity or chemical potency. Environ. Toxicol. Chem. 2011;30:1659-1668. # 2011 SETAC
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sensitivity of japanese quail coturnix japonica common pheasant phasianus colchicus and white Leghorn Chicken gallus gallus domesticus embryos to in ovo exposure to tcdd pecdf and tcdf
Toxicological Sciences, 2011Co-Authors: Andrew M Cohenbarnhouse, John P Giesy, Scott D Fitzgerald, Matthew J Zwiernik, Jane E Link, Sean W Kennedy, Steve Wiseman, Jessica C Herve, Yinfei Yang, Paul D JonesAbstract:Egg injection studies were performed to confirm a proposed model of relative sensitivity of birds to 2,3,7,8-tetrachlorodibenzop-dioxin (TCDD). In this model, species are classified as belonging to one of three categories of sensitivity based on amino acid substitutions in the ligand-binding domain of the aryl hydrocarbon receptor. Embryo lethality and relative potencies of 2,3,7,8-tetrachlorodibenzofuran (TCDF) and 2,3,4,7, 8-pentachlorodibenzofuran (PeCDF) were compared with TCDD for Japanese quail (Coturnix japonica; least sensitive), Common pheasant (Phasianus colchicus; moderately sensitive), and White Leghorn Chicken (Gallus gallus domesticus; most sensitive). Doses ranging from 0.044 to 37 pmol/g egg (0.015‐12 ng/g egg) were injected into the air cell of eggs prior to incubation. LD50 (95% confidence intervals) values, based on rate of hatching for TCDD, PeCDF, and TCDF, were 30 (25‐36), 4.9 (2.3‐9.2), and 15 (11‐24) pmol/g egg for the quail, 3.5 (2.3‐6.3), 0.61 (0.28‐1.2), and 1.2 (0.62‐2.2) pmol/g egg for pheasant, and 0.66 (0.47‐0.90), 0.75 (0.64‐0.87), and 0.33 (0.23‐0.45) pmol/g egg for Chicken, respectively. LD50-based relative potencies of PeCDF and TCDF were 6.1 and 2.0 for quail, 5.7 and 2.9 for pheasant, and 0.88 and 2.0 for Chicken, respectively. TCDD was not the most potent compound among the species tested, with PeCDF and TCDF being more potent than TCDD in the quail and pheasant. TCDF was the most potent in Chicken. Species sensitivity was as expected for TCDD and TCDF, whereas for PeCDF, the Chicken and pheasant were similar in sensitivity and both were more sensitive than the quail. Results from companion in vitro studies are generally similar to those reported here with a few exceptions.
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effects of in ovo exposure of white Leghorn Chicken common pheasant and japanese quail to 2 3 7 8 tetrachlorodibenzo p dioxin and two chlorinated dibenzofurans on cyp1a induction
Environmental Toxicology and Chemistry, 2010Co-Authors: Yinfei Yang, Andrew M Cohenbarnhouse, Matthew J Zwiernik, Sean W Kennedy, Steve Wiseman, Paul D Jones, Yi Wan, John L Newsted, Denise P Kay, Steven J BursianAbstract:In birds, activation of the aryl hydrocarbon receptor (AhR) by some polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) results in induction of cytochrome P4501A (CYP1A) expression. This response has been useful for predicting relative sensitivity of birds to dioxin-like compounds. To further investigate species-sensitivity to dioxins and dioxin-like compounds induction of cytochrome P450 1A4 and 1A5 (CYP1A4 and CYP1A5) mRNA and ethoxyresorufin O-deethylase (EROD) activity were quantified in liver of posthatch white Leghorn Chicken, common pheasant, and Japanese quail exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), or 2,3,7,8-tetrachlorodibenzofuran (TCDF) via air cell injection. The rank-order of sensitivity of TCDD- and TCDF-exposed birds, based on CYP1A, was Chicken > pheasant > quail. Based on CYP1A5 mRNA expression and EROD induction, the order of sensitivity of PeCDF-exposed birds was identical to that for TCDD and TCDF. However, based on CYP1A4 mRNA expression the rank-order was pheasant > Chicken > quail. When comparing the potency of the three compounds in each species, based on CYP1A4 mRNA expression, TCDD was the most potent compound in Chicken. However, PeCDF was equally potent to TCDD in quail and was more potent than TCDD in pheasant. These results suggest that quantitative real-time polymerase chain reaction (Q-PCR) analysis of CYP1A expression, particularly CYP1A4 mRNA expression, may be a more sensitive biomarker of exposure than analysis of EROD induction, especially in less responsive avian species. Based on these findings future risk assessments should consider the sensitivity of the species inhabiting a site and the congeners of concern that are present. Environ. Toxicol. Chem. 2010;29:1490–1502. © 2010 SETAC