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Sensitivity of Embryos from Duck, Goose, Herring Gull, and Various Chicken Breeds to 3,3′,4,4′-Tetrachlorobiphenyl
ENVIRONMENT AND HEALTH Sensitivity of Embryos from Duck, Goose, Herring Gull, and Various Chicken Breeds to 3,3',4,4'-Tetrachlorobiphenyl BJORN BRUNSTROM Department of ZoOphysiology, Uppsala University, Box 560, S-751 22 Uppsala, Sweden (Received for publication May 12, 1987)
1988 Poultry Science 6 7 : 5 2 - 5 7 INTRODUCTION
Technical preparations of polychlorinated biphenyls (PCBs) are mixtures of biphenyls chlorinated to varying degrees and at various positions. Individual chlorobiphenyls differ considerably in toxicity and 3,3',4,4'-tetrachlorobiphenyl (TCB) is considered to be one of the most toxic (Yoshimura et al., 1979; McNulty et al., 1980; Silkworm and Grabstein, 1982; Safe, 1984). The compound TCB is structurally similar to 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD) and binds to the so-called Ah receptor (TCDD receptor). However, TCB is a less avid binder to this receptor than TCDD (Poland and Glover, 1977). The Ah receptor is thought to mediate the toxicity of TCDD and its congeners (Poland and Glover, 1980; Poland and Knutson, 1982). The compound TCB has proved to be very toxic in White Leghorn chick embryos (Brunstrom and Darnerud, 1983) and White Leghorn eggs are frequently used when testing the toxicity of various substances in chick embryos. Mouse strains vary in their sensitivity to TCDD and other compounds binding to the Ah receptor (Poland and Glover, 1980; Poland and Knutson, 1982). It is unknown whether similar intraspecific variation in the sensitivity to these substances exists in the chicken. Embryos of pheasant {Phasianus colchicus), mallard {Anas platyrhynchos), goldeneye (Bucephala clangula), and blackheaded gull (Larus ridibundus) have proved to be consider52
ably less sensitive to TCB than chick embryos (Brunstrom and Reutergardh, 1986). In the Canadian Great Lakes, reproductive problems in herring gull populations were noted in the early 1970s. Poor nesting success was suggested to be the result of high concentrations of TCDD in the eggs (Mineau et al., 1984). In the present study several breeds of chicken were compared regarding their sensitivity to TCB injected into embryonated eggs. The toxicity of this substance was also studied in embryos of duck, goose, and herring gull. MATERIALS AND METHODS
Animals and Chemicals. Fertilized eggs from Single Comb White Leghorn layers (Shaver strain) were obtained from Linkopings Kontrollhonseri, Linkoping, Sweden. Hens' eggs of other breeds were obtained from the Swedish University of Agricultural Sciences. Eggs of domestic goose (Anser anser) and Swedish duck (Anas platyrhynchos) were obtained from local suppliers. Herring gull (Larus argentatus) eggs were collected by the staff at Ottenby Bird Observatory, Sweden. The 3,3',4,4'-Tetrachlorobiphenyl (purity 98%) was prepared by Ake Bergman, Wallenberg Laboratory, University of Stockholm, Sweden. Experimental Protocol. Eggs were incubated at 37.5 to 38.0 C and 60% relative humidity and turned every 6 h. The TCB was injected into their yolks using the method previously de-
Downloaded from http://ps.oxfordjournals.org/ at NERL on May 28, 2015
ABSTRACT Yolks in embryonated eggs from duck, goose, herring gull, and various breeds of chicken were injected with 3,3',4,4'-tetrachlorobiphenyl (TCB). Hens' eggs were injected after 4 days of incubation and eggs from the other species were injected after 5 days of incubation. All breeds of chicken tested were very sensitive to TCB. At a dose of 20 fig/kg egg the death rate in chick embryos ranged from 70 to 100% at the end of the experiment by Day 18 of incubation. Liver lesions, hydropericardium, subcutaneous edema, shortened beak, and microphthalmia were found in both dead and living TCB-treated chick embryos. Embryos of the other species tested were considerably less sensitive than chick embryos to TCB. The highest dose administered to these species was 5,000 p.g/kg egg for ducks and 1,000 fxg/kg egg for geese and herring gulls. These doses did not affect the viability of the embryos and caused no gross abnormalities. (Key words: species differences; avian embryos; 3,3',4,4'-tetrachlorobiphenyl; polychlorinated biphenyl; toxicity; teratogenicity)
EMBRYO SENSITIVITY TO POLYCHLORINATED BIPHENYLS
53
TABLE 1. Embryonic mortality by Day 18 of incubatio n in eggs from various breeds of chicken injected on Day 4 with 3,3',4,4'-tetrachlorobiphenyl (TCB) Breed
Dose of TCB
Embryonic mortality
(Mg/kg egg)
(ratio)
White Leghorn
0 5 20
3/20 11/20 20/20
Brown Leghorn
0 5 20
1/15 7/15 14/15
7 47*
New Hampshire
0 1 5 20
6/20 1/20 14/20 20/20
30 5 70*
Rhode Island Red
0 1 5 20
3/20 3/20 8/20 14/20
15 15 40
0 1 5 20
2/17 1/17 6/17 14/17
12 6 35
0 5 20
3/15 3/15 13/15
Light Sussex
15 55*
100***
93***
100***
70**
82*** 20 20
87***
•Significantly different from control (P<.05). *'Significantly different from control (P<.01). **'Significantly different from control (P-C001).
scribed (Brunstrom and Orberg, 1982; Brunstrom and Darnerud, 1983). Hens' eggs were incubated for 4 days whereas goose, duck, and herring gull eggs were incubated for 5 days before injections were made. At injection time, embryos of the various species had all reached about the same developmental stage. Injection
volumes were 100 \xL for the chicken, 150 JJLL for the duck and the herring gull, and 300 |xL for the goose. Eggs were candled every 2nd or 3rd day throughout the incubation period. Eggs containing dead embryos were opened and the embryos inspected for gross malformations. The experiment was terminated and the remaining
TABLE 2. Embryonic mortality by Days 24, 25, and 24 of incubation in eggs from duck, goose, and herring gull, respectively. Eggs were injected on Day 5 with 3,3 ,4,4'-tetrachlorobiphenyl (TCB) Species
Dose of TCB
Embryonic mortality
(Mg/kg egg)
(ratio)
(%)
Duck
0 1,000 5,000
0/9 1/9 0/9
0 11 0
Goose
0 100 1,000
1/14 0/14 0/14
7 0 0
Herring gull
0 1,000
2/14 2/15
14 13
Downloaded from http://ps.oxfordjournals.org/ at NERL on May 28, 2015
Australorp
(%)
BRUNSTROM
54
eggs opened after 18, 24, 24, and 25 days of incubation for the chicken, duck, herring gull, and goose, respectively. Frequencies of mortality and abnormalities after treatment with different doses of TCB were compared with control values using the Chi square test of heterogeneity. However, when the smallest expected frequency was less than five, the Fisher exact probability test (Fisher, 1934) was used.
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The proportion of eggs containing dead embryos for each dose and breed of chicken at termination of the experiment is given in Table 1. A dose of 20 |xg TCB/kg egg significantly reduced survival in all breeds. The frequency of embryonic mortality was 70 to 100% at this dose. A lower dose, 5 jig/kg, also significantly reduced the survival of chick embryos in certain of the breeds. In embryos of duck, goose, and herring gull no increase in mortality was observed at any of the doses used (Table 2). A high frequency of abnormalities was noted in living chick embryos in the groups given 5 and 20 (xg TCB/kg egg (Table 3). The most frequent abnormalities were liver lesions and hydropericardium. Liver lesions varied in severity from small, discrete areas of pale tissue to extensive areas of damage affecting the main part of the liver. In controls, liver lesions were rarely observed except in Brown Leghorns, where small, discrete areas of pale tissue occurred in six birds. No further characterization of the liver lesions was made. Severity of pericardial edema also varied and a subjective estimation had to be made to distinguish excessive amounts of pericardial fluid accumulated in the pericardium from the extremes expected as a result of normal variation. In addition, subcutaneous edema, microphthalmia, and shortened beak (most frequently the upper) were found in the living embryos. These abnormalities were, however, more frequent in the dead embryos, where 23, 13, and 5 embryos were found with subcutaneous edema, microphthalmia, and shortened beak, respectively. However, many of the embryos died so early during development that abnormalities, if any, were not detectable. In Figure 1, some of the most frequent abnormalities in the chick embryos are shown. In the duck and the herring gull no abnormalities were noted. A few of the goose embryos had edema but this was not related to the TCB dose.
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EMBRYO SENSITIVITY TO POLYCHLORINATED BIPHENYLS
DISCUSSION
No great intraspecific variation in sensitivity to TCB was found in chicken embryos. In mice, certain inbred strains, typified by C57BL/6, are sensitive to TCDD and its congeners, whereas other inbred strains, typified by DBA/2J, are considerably less sensitive (Poland and Glover, 1980; Dencker el al., 1985). The less sensitive
55
strains have a lower concentration of the Ah receptor or a receptor with a lower affinity for TCDD than the more sensitive strains. All breeds of chicken tested showed about equal sensitivity to TCB and their embryos also exhibited a fairly similar pattern of abnormalities. Liver lesions, edema, and eye and beak deformities were found in embryos from all breeds used.
Downloaded from http://ps.oxfordjournals.org/ at NERL on May 28, 2015 FIGURE 1. Some abnormalities seen in 18-day-old chick embryos from eggs injected with 3,3',4,4'-tetrachlorobiphenyl (20 (jcg/kg) on Day 4 of incubation: a) Large subcutaneous edema on the rump of a Rhode Island Red embryo; b) Severe hydropericardium (arrows) in an Australorp embryo; c) A Sussex embryo with shortened upper beak and microphthalmia.
BRUNSTROM
56
ACKNOWLEDGMENTS
Thanks are due to Ake Bergman for providing 3,3',4,4'-tetrachlorobiphenyl. Anna-Britta Carlgren, Lena Charpentier, and Martin Wilhelmsson are thanked for supplying hens' eggs. The staff at Ottenby Bird Observatory supplied the herring gull eggs. This study was supported by a grant (Number 85/57) from the Bank of Sweden Tercentenary Foundation. REFERENCES Brunstrom, B., and P. O. Darnerud, 1983. Toxicity and distribution in chick embryos of 3,3',4,4'-tetrachlorobiphenyl injected into eggs. Toxicology 27:103-110.
Brunstrom, B., and J. Orberg, 1982. A method for studying embryotoxicity of lipophilic substances experimentally introduced into hens' eggs.Ambio 11:209-211. Brunstrom, B., and L. Reutergardh, 1986. Differences in sensitivity of some avian species to the embryotoxicity of a PCB, 3,3',4,4'-tetrachlorobiphenyl, injected into the eggs. Environ. Pollut. 42:37-45. Cantrell, J. S., N. C. Webb, and A. J. Mabis, 1969. The identification and crystal structure of a hydropericardium-producing factor: 1,2,3,7,8,9-Hexachlorodibenzo-p-dioxin. Acta Crystallogr. Sect. B Struct. Crystallogr. Cryst. Chem. 25:150-156. Cecil, H. C , J. Bitman, R. J. Lillie, G. F. Fries, and J. Verrett, 1974. Embryotoxic and teratogenic effects in unhatched fertile eggs from hens fed polychlorinated biphenyls (PCBs). Bull. Environ. Contam. Toxicol. 11:489-495. Dencker, L., E. Hassoun, R. d'Argy, and G. Aim, 1985. Fetal thymus organ culture as an in vitro model for the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin and its congeners. Mol. Pharmacol. 27:133-140. Firestone, D., 1973. Etiology of chick edema disease. Environ. Health Perspect. 5:59-66. Fisher, R. A., 1934. Statistical methods for research workers. Oliver and Boyd, Ltd., Edinburgh, UK. McLaughlin, J., Jr., J. P. Marliac, M. J. Verrett, M. K. Mutchler, and O. G. Fitzhugh, 1963. The injection of chemicals into the yolk sac of fertile eggs prior to incubation as a toxicity test. Toxicol. Appl. Pharmacol. 5:760-771. McNulty, W. P., G. M. Becker, and H. T. Cory, 1980. Chronic toxicity of 3,4,3',4'- and 2,5,2',5'-tetrachlorobiphenyls in Rhesus macaques. Toxicol. Appl. Pharmacol. 56:182-190. Mineau, P., G. A. Fox, R. J. Norstrom, D. V. Weseloh, D. J. Hallett, and J. A. Ellenton, 1984. Using the herring gull to monitor levels and effects of organochlorine contamination in the Canadian Great Lakes. Adv. Environ. Sci. Technol. 14:425^52. Poland, A., and E. Glover, 1977. Chlorinated biphenyl induction of aryl hydrocarbon hydroxylase activity: A study of the structure-activity relationship. Mol. Pharmacol. 13:924-938. Poland, A., and E. Glover, 1980. 2,3,7,8-Tetrachlorodibenzo-p-dioxin: Segregation of toxicity with the Ah locus. Mol. Pharmacol. 17:86-94. Poland, A., and J. C. Knutson, 1982. 2,3,7,8-Tetrachlorodibenzo-p-dioxin and related halogenated aromatic hydrocarbons: Examination of the mechanism of toxicity. Annu. Rev. Pharmacol. Toxicol. 22:517-554. Rifkind, A. B., and H. Muschick, 1983. Benoxaprofen suppression of polychlorinated biphenyl toxicity without alteration of mixed function oxidase function. Nature 303:524-526. Safe, S., 1984. Polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs): Biochemistry, toxicology, and mechanism of action. CRC Crit. Rev. Toxicol. 13:319-395. Schmittle, S. C , H. M. Edwards, and D. Morris, 1958. A disorder of chickens probably due to a toxic feedPreliminary report. J. Am. Vet. Med. Ass. 132:216— 219. Schrankel, K. R., B. L. Kreamer, and M.T.S. Hsia, 1982. Embryotoxicity of 3,3',4,4'-tetrachloroazobenzene and 3,3',4,4'-tetrachloroazoxybenzene in the chick
Downloaded from http://ps.oxfordjournals.org/ at NERL on May 28, 2015
In the United States, an outbreak of chick edema disease in the late 1950s that led to the death of millions of broiler chicks resulted from the ingestion of toxic compounds in certain feed fats (Schmittle et al, 1958; Firestone, 1973). Among other symptoms, these chicks had excessive fluid in the pericardium and abdominal cavity. Later, chick edema disease was attributed to contamination of feeds by chlorinated dibenzodioxins (Cantrell et al., 1969; Firestone, 1973). Edema has been reported in chick embryos after treatment with 3,3',4,4'-tetrachloroazobenzene, 3,3',4,4'-tetrachloroazoxybenzene (Schrankel etal, 1982), technical PCB (McLaughlin et al., 1963; Cecil et al., 1974; Brunstrom and Orberg, 1982), and TCB (Brunstrom and Darnerud, 1983; Rifkind and Muschick, 1983). In the present study, embryos of all chicken breeds used exhibited edema after treatment with TCB. Embryos of duck, goose, and herring gull proved to be considerably less sensitive than chick embryos to TCB. The same was true for embryos of certain other avian species (Brunstrom and Reutergardh, 1986). This marked interspecific variability emphasizes the dangers of using toxicity data from one species of bird to predict toxic effects in another species. The mechanism through which toxicity is induced by TCB is probably the same as for TCDD. As herring gull embryos are much less sensitive to TCB than are chick embryos, they are probably also less sensitive to TCDD. However, the concentration of TCDD found in herring gull eggs in the Great Lakes was fairly high (Mineau et al., 1984). Thus, the possibility that TCDD contributed to the observed reproductive disturbances should not be excluded.
EMBRYO SENSITIVITY TO POLYCHLORINATED BIPHENYLS embryo. Arch. Environ. Contam. Toxicol. 11:195202. Silkworth, J. B., and E. M. Grabstein, 1982. Polychlorinated biphenyl immunotoxicity: Dependence on isomer planarity and the Ah gene complex. Toxicol.
57
Appl. Pharmacol. 65:109-115. Yoshimura, H., S. Yoshihara, N. Ozawa, and M. Miki, 1979. Possible correlation between induction modes of hepatic enzymes by PCBs and their toxicity in rats. Ann. N. Y. Acad. Sci. 320:179-192.
Downloaded from http://ps.oxfordjournals.org/ at NERL on May 28, 2015
1988 Poultry Science 6 7 : 5 2 - 5 7 INTRODUCTION
Technical preparations of polychlorinated biphenyls (PCBs) are mixtures of biphenyls chlorinated to varying degrees and at various positions. Individual chlorobiphenyls differ considerably in toxicity and 3,3',4,4'-tetrachlorobiphenyl (TCB) is considered to be one of the most toxic (Yoshimura et al., 1979; McNulty et al., 1980; Silkworm and Grabstein, 1982; Safe, 1984). The compound TCB is structurally similar to 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD) and binds to the so-called Ah receptor (TCDD receptor). However, TCB is a less avid binder to this receptor than TCDD (Poland and Glover, 1977). The Ah receptor is thought to mediate the toxicity of TCDD and its congeners (Poland and Glover, 1980; Poland and Knutson, 1982). The compound TCB has proved to be very toxic in White Leghorn chick embryos (Brunstrom and Darnerud, 1983) and White Leghorn eggs are frequently used when testing the toxicity of various substances in chick embryos. Mouse strains vary in their sensitivity to TCDD and other compounds binding to the Ah receptor (Poland and Glover, 1980; Poland and Knutson, 1982). It is unknown whether similar intraspecific variation in the sensitivity to these substances exists in the chicken. Embryos of pheasant {Phasianus colchicus), mallard {Anas platyrhynchos), goldeneye (Bucephala clangula), and blackheaded gull (Larus ridibundus) have proved to be consider52
ably less sensitive to TCB than chick embryos (Brunstrom and Reutergardh, 1986). In the Canadian Great Lakes, reproductive problems in herring gull populations were noted in the early 1970s. Poor nesting success was suggested to be the result of high concentrations of TCDD in the eggs (Mineau et al., 1984). In the present study several breeds of chicken were compared regarding their sensitivity to TCB injected into embryonated eggs. The toxicity of this substance was also studied in embryos of duck, goose, and herring gull. MATERIALS AND METHODS
Animals and Chemicals. Fertilized eggs from Single Comb White Leghorn layers (Shaver strain) were obtained from Linkopings Kontrollhonseri, Linkoping, Sweden. Hens' eggs of other breeds were obtained from the Swedish University of Agricultural Sciences. Eggs of domestic goose (Anser anser) and Swedish duck (Anas platyrhynchos) were obtained from local suppliers. Herring gull (Larus argentatus) eggs were collected by the staff at Ottenby Bird Observatory, Sweden. The 3,3',4,4'-Tetrachlorobiphenyl (purity 98%) was prepared by Ake Bergman, Wallenberg Laboratory, University of Stockholm, Sweden. Experimental Protocol. Eggs were incubated at 37.5 to 38.0 C and 60% relative humidity and turned every 6 h. The TCB was injected into their yolks using the method previously de-
Downloaded from http://ps.oxfordjournals.org/ at NERL on May 28, 2015
ABSTRACT Yolks in embryonated eggs from duck, goose, herring gull, and various breeds of chicken were injected with 3,3',4,4'-tetrachlorobiphenyl (TCB). Hens' eggs were injected after 4 days of incubation and eggs from the other species were injected after 5 days of incubation. All breeds of chicken tested were very sensitive to TCB. At a dose of 20 fig/kg egg the death rate in chick embryos ranged from 70 to 100% at the end of the experiment by Day 18 of incubation. Liver lesions, hydropericardium, subcutaneous edema, shortened beak, and microphthalmia were found in both dead and living TCB-treated chick embryos. Embryos of the other species tested were considerably less sensitive than chick embryos to TCB. The highest dose administered to these species was 5,000 p.g/kg egg for ducks and 1,000 fxg/kg egg for geese and herring gulls. These doses did not affect the viability of the embryos and caused no gross abnormalities. (Key words: species differences; avian embryos; 3,3',4,4'-tetrachlorobiphenyl; polychlorinated biphenyl; toxicity; teratogenicity)
EMBRYO SENSITIVITY TO POLYCHLORINATED BIPHENYLS
53
TABLE 1. Embryonic mortality by Day 18 of incubatio n in eggs from various breeds of chicken injected on Day 4 with 3,3',4,4'-tetrachlorobiphenyl (TCB) Breed
Dose of TCB
Embryonic mortality
(Mg/kg egg)
(ratio)
White Leghorn
0 5 20
3/20 11/20 20/20
Brown Leghorn
0 5 20
1/15 7/15 14/15
7 47*
New Hampshire
0 1 5 20
6/20 1/20 14/20 20/20
30 5 70*
Rhode Island Red
0 1 5 20
3/20 3/20 8/20 14/20
15 15 40
0 1 5 20
2/17 1/17 6/17 14/17
12 6 35
0 5 20
3/15 3/15 13/15
Light Sussex
15 55*
100***
93***
100***
70**
82*** 20 20
87***
•Significantly different from control (P<.05). *'Significantly different from control (P<.01). **'Significantly different from control (P-C001).
scribed (Brunstrom and Orberg, 1982; Brunstrom and Darnerud, 1983). Hens' eggs were incubated for 4 days whereas goose, duck, and herring gull eggs were incubated for 5 days before injections were made. At injection time, embryos of the various species had all reached about the same developmental stage. Injection
volumes were 100 \xL for the chicken, 150 JJLL for the duck and the herring gull, and 300 |xL for the goose. Eggs were candled every 2nd or 3rd day throughout the incubation period. Eggs containing dead embryos were opened and the embryos inspected for gross malformations. The experiment was terminated and the remaining
TABLE 2. Embryonic mortality by Days 24, 25, and 24 of incubation in eggs from duck, goose, and herring gull, respectively. Eggs were injected on Day 5 with 3,3 ,4,4'-tetrachlorobiphenyl (TCB) Species
Dose of TCB
Embryonic mortality
(Mg/kg egg)
(ratio)
(%)
Duck
0 1,000 5,000
0/9 1/9 0/9
0 11 0
Goose
0 100 1,000
1/14 0/14 0/14
7 0 0
Herring gull
0 1,000
2/14 2/15
14 13
Downloaded from http://ps.oxfordjournals.org/ at NERL on May 28, 2015
Australorp
(%)
BRUNSTROM
54
eggs opened after 18, 24, 24, and 25 days of incubation for the chicken, duck, herring gull, and goose, respectively. Frequencies of mortality and abnormalities after treatment with different doses of TCB were compared with control values using the Chi square test of heterogeneity. However, when the smallest expected frequency was less than five, the Fisher exact probability test (Fisher, 1934) was used.
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The proportion of eggs containing dead embryos for each dose and breed of chicken at termination of the experiment is given in Table 1. A dose of 20 |xg TCB/kg egg significantly reduced survival in all breeds. The frequency of embryonic mortality was 70 to 100% at this dose. A lower dose, 5 jig/kg, also significantly reduced the survival of chick embryos in certain of the breeds. In embryos of duck, goose, and herring gull no increase in mortality was observed at any of the doses used (Table 2). A high frequency of abnormalities was noted in living chick embryos in the groups given 5 and 20 (xg TCB/kg egg (Table 3). The most frequent abnormalities were liver lesions and hydropericardium. Liver lesions varied in severity from small, discrete areas of pale tissue to extensive areas of damage affecting the main part of the liver. In controls, liver lesions were rarely observed except in Brown Leghorns, where small, discrete areas of pale tissue occurred in six birds. No further characterization of the liver lesions was made. Severity of pericardial edema also varied and a subjective estimation had to be made to distinguish excessive amounts of pericardial fluid accumulated in the pericardium from the extremes expected as a result of normal variation. In addition, subcutaneous edema, microphthalmia, and shortened beak (most frequently the upper) were found in the living embryos. These abnormalities were, however, more frequent in the dead embryos, where 23, 13, and 5 embryos were found with subcutaneous edema, microphthalmia, and shortened beak, respectively. However, many of the embryos died so early during development that abnormalities, if any, were not detectable. In Figure 1, some of the most frequent abnormalities in the chick embryos are shown. In the duck and the herring gull no abnormalities were noted. A few of the goose embryos had edema but this was not related to the TCB dose.
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EMBRYO SENSITIVITY TO POLYCHLORINATED BIPHENYLS
DISCUSSION
No great intraspecific variation in sensitivity to TCB was found in chicken embryos. In mice, certain inbred strains, typified by C57BL/6, are sensitive to TCDD and its congeners, whereas other inbred strains, typified by DBA/2J, are considerably less sensitive (Poland and Glover, 1980; Dencker el al., 1985). The less sensitive
55
strains have a lower concentration of the Ah receptor or a receptor with a lower affinity for TCDD than the more sensitive strains. All breeds of chicken tested showed about equal sensitivity to TCB and their embryos also exhibited a fairly similar pattern of abnormalities. Liver lesions, edema, and eye and beak deformities were found in embryos from all breeds used.
Downloaded from http://ps.oxfordjournals.org/ at NERL on May 28, 2015 FIGURE 1. Some abnormalities seen in 18-day-old chick embryos from eggs injected with 3,3',4,4'-tetrachlorobiphenyl (20 (jcg/kg) on Day 4 of incubation: a) Large subcutaneous edema on the rump of a Rhode Island Red embryo; b) Severe hydropericardium (arrows) in an Australorp embryo; c) A Sussex embryo with shortened upper beak and microphthalmia.
BRUNSTROM
56
ACKNOWLEDGMENTS
Thanks are due to Ake Bergman for providing 3,3',4,4'-tetrachlorobiphenyl. Anna-Britta Carlgren, Lena Charpentier, and Martin Wilhelmsson are thanked for supplying hens' eggs. The staff at Ottenby Bird Observatory supplied the herring gull eggs. This study was supported by a grant (Number 85/57) from the Bank of Sweden Tercentenary Foundation. REFERENCES Brunstrom, B., and P. O. Darnerud, 1983. Toxicity and distribution in chick embryos of 3,3',4,4'-tetrachlorobiphenyl injected into eggs. Toxicology 27:103-110.
Brunstrom, B., and J. Orberg, 1982. A method for studying embryotoxicity of lipophilic substances experimentally introduced into hens' eggs.Ambio 11:209-211. Brunstrom, B., and L. Reutergardh, 1986. Differences in sensitivity of some avian species to the embryotoxicity of a PCB, 3,3',4,4'-tetrachlorobiphenyl, injected into the eggs. Environ. Pollut. 42:37-45. Cantrell, J. S., N. C. Webb, and A. J. Mabis, 1969. The identification and crystal structure of a hydropericardium-producing factor: 1,2,3,7,8,9-Hexachlorodibenzo-p-dioxin. Acta Crystallogr. Sect. B Struct. Crystallogr. Cryst. Chem. 25:150-156. Cecil, H. C , J. Bitman, R. J. Lillie, G. F. Fries, and J. Verrett, 1974. Embryotoxic and teratogenic effects in unhatched fertile eggs from hens fed polychlorinated biphenyls (PCBs). Bull. Environ. Contam. Toxicol. 11:489-495. Dencker, L., E. Hassoun, R. d'Argy, and G. Aim, 1985. Fetal thymus organ culture as an in vitro model for the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin and its congeners. Mol. Pharmacol. 27:133-140. Firestone, D., 1973. Etiology of chick edema disease. Environ. Health Perspect. 5:59-66. Fisher, R. A., 1934. Statistical methods for research workers. Oliver and Boyd, Ltd., Edinburgh, UK. McLaughlin, J., Jr., J. P. Marliac, M. J. Verrett, M. K. Mutchler, and O. G. Fitzhugh, 1963. The injection of chemicals into the yolk sac of fertile eggs prior to incubation as a toxicity test. Toxicol. Appl. Pharmacol. 5:760-771. McNulty, W. P., G. M. Becker, and H. T. Cory, 1980. Chronic toxicity of 3,4,3',4'- and 2,5,2',5'-tetrachlorobiphenyls in Rhesus macaques. Toxicol. Appl. Pharmacol. 56:182-190. Mineau, P., G. A. Fox, R. J. Norstrom, D. V. Weseloh, D. J. Hallett, and J. A. Ellenton, 1984. Using the herring gull to monitor levels and effects of organochlorine contamination in the Canadian Great Lakes. Adv. Environ. Sci. Technol. 14:425^52. Poland, A., and E. Glover, 1977. Chlorinated biphenyl induction of aryl hydrocarbon hydroxylase activity: A study of the structure-activity relationship. Mol. Pharmacol. 13:924-938. Poland, A., and E. Glover, 1980. 2,3,7,8-Tetrachlorodibenzo-p-dioxin: Segregation of toxicity with the Ah locus. Mol. Pharmacol. 17:86-94. Poland, A., and J. C. Knutson, 1982. 2,3,7,8-Tetrachlorodibenzo-p-dioxin and related halogenated aromatic hydrocarbons: Examination of the mechanism of toxicity. Annu. Rev. Pharmacol. Toxicol. 22:517-554. Rifkind, A. B., and H. Muschick, 1983. Benoxaprofen suppression of polychlorinated biphenyl toxicity without alteration of mixed function oxidase function. Nature 303:524-526. Safe, S., 1984. Polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs): Biochemistry, toxicology, and mechanism of action. CRC Crit. Rev. Toxicol. 13:319-395. Schmittle, S. C , H. M. Edwards, and D. Morris, 1958. A disorder of chickens probably due to a toxic feedPreliminary report. J. Am. Vet. Med. Ass. 132:216— 219. Schrankel, K. R., B. L. Kreamer, and M.T.S. Hsia, 1982. Embryotoxicity of 3,3',4,4'-tetrachloroazobenzene and 3,3',4,4'-tetrachloroazoxybenzene in the chick
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In the United States, an outbreak of chick edema disease in the late 1950s that led to the death of millions of broiler chicks resulted from the ingestion of toxic compounds in certain feed fats (Schmittle et al, 1958; Firestone, 1973). Among other symptoms, these chicks had excessive fluid in the pericardium and abdominal cavity. Later, chick edema disease was attributed to contamination of feeds by chlorinated dibenzodioxins (Cantrell et al., 1969; Firestone, 1973). Edema has been reported in chick embryos after treatment with 3,3',4,4'-tetrachloroazobenzene, 3,3',4,4'-tetrachloroazoxybenzene (Schrankel etal, 1982), technical PCB (McLaughlin et al., 1963; Cecil et al., 1974; Brunstrom and Orberg, 1982), and TCB (Brunstrom and Darnerud, 1983; Rifkind and Muschick, 1983). In the present study, embryos of all chicken breeds used exhibited edema after treatment with TCB. Embryos of duck, goose, and herring gull proved to be considerably less sensitive than chick embryos to TCB. The same was true for embryos of certain other avian species (Brunstrom and Reutergardh, 1986). This marked interspecific variability emphasizes the dangers of using toxicity data from one species of bird to predict toxic effects in another species. The mechanism through which toxicity is induced by TCB is probably the same as for TCDD. As herring gull embryos are much less sensitive to TCB than are chick embryos, they are probably also less sensitive to TCDD. However, the concentration of TCDD found in herring gull eggs in the Great Lakes was fairly high (Mineau et al., 1984). Thus, the possibility that TCDD contributed to the observed reproductive disturbances should not be excluded.
EMBRYO SENSITIVITY TO POLYCHLORINATED BIPHENYLS embryo. Arch. Environ. Contam. Toxicol. 11:195202. Silkworth, J. B., and E. M. Grabstein, 1982. Polychlorinated biphenyl immunotoxicity: Dependence on isomer planarity and the Ah gene complex. Toxicol.
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Appl. Pharmacol. 65:109-115. Yoshimura, H., S. Yoshihara, N. Ozawa, and M. Miki, 1979. Possible correlation between induction modes of hepatic enzymes by PCBs and their toxicity in rats. Ann. N. Y. Acad. Sci. 320:179-192.
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