Effects of persistent organic contaminants on the developing reproductive organs of fish-eating birds and the domestic chicken

Reproductive abnormalities are associated with contaminants in wildlife, including Great Lakes birds. This project investigated chemical effects on the developing reproductive systems of wild herring gulls (Larus argentatus ) and black guillemots (Cepphus grylle) and captive chickens (Gallus domesticus). Reproductive tracts were assessed on day 20 of incubation or days 14 and 42 post-hatch following injection with PCBs (congeners 77 or 126) or Aroclor 1254, estradiol (E2), tamoxifen (TAM, an E2 antagonist), E2 + TAM, or carrier (sunflower oil) on day 0 of incubation. The frequency of seminiferous tubules protruding through the cortex of the testes increased in embryos exposed to PCB 77, 126 and Aroclor 1254. PCBs 77 and 126 increased the size and number of nodules (primordial germ cells or Sertoli cells in the testicular cortex) in embryos. Nodules persisted in PCB 77 and 126 chickens at days 14 and 42 post-hatch. Sertoli density increased in PCB 77 embryos. PCB 126 increased oocyte density in embryos while PCB 77 increased oocytes with lipids at day 14. E2 produced flattened testes with protruding tubules in embryonic males, an effect antagonized by TAM. E2 induced residual right ovaries and increased ovarian cortical area, and TAM decreased the later effect. Saglek Bay, Labrador was a relatively uncontaminated environment until an Aroclor 1260 spill at a military radar site. Medullar tissue outside the testicular cortex and protruding seminiferous tubules were observed in 4-week old guillemots exposed to PCBs. Nodules increased in size and frequency with PCB exposure. In the moderate exposure group, Sertoli density was decreased and oocytes with lipids increased compared to reference and high exposure groups. Gonads of herring gull embryos (N = 252) and chicks (N = 198) were collected (1997 and 2001) from the Great Lakes and Atlantic reference colony (Kent). In embryos and chicks from polluted Great Lakes sites, nodules increased in frequency and size. Nonylphenol and PCBs correlated with multiple histological endpoints in both sexes (nodule area, tubule diameter, oocyte density, oocytes with lipids, PGC/oocyte ratio). Gonadal alterations in three bird species were associated with nonylphenol and organochlorine exposure and thus support the hypothesis that contaminants alter the development of the avian reproductive system.