RETINOIDS IN EGGS AND EMBRYOS OF BIRDS FED FISH FROM THE GREAT-LAKES

Retinoids were analyzed in 11-day chick embryos and eggs from white Le ghorn hens (Gallus domesticus) fed environmentally-derived polychlorin ated biphenyls (PCB) in carp (Cyprinus carpio) from Saginaw Bay. The y olks and the embryos contained all-trans-retinol, 3,4-didehydroretinol and retinyl esters. There was no significant difference in the total retinoid content in the yolks of 11-day incubated eggs among hens fed for 7 weeks diets containing 0.5-6.6 mg PCB/kg diet. However, the prop ortional amount of retinols in the high (6.6 mg) PCB group was signifi cantly less than that in low (0.5 mg) PCB controls, while the amount o f retinyl palmitate in the high PCB group was significantly greater th an that in the controls. Retinoids in the embryos were not affected by any of the PCB levels fed to hens for 7 weeks prior to laying the egg s. The 50% reduction in the molar ratio of retinols to retinyl palmita te in the yolks of eggs as the result of the high PCB level fed to hen s for 7 weeks can serve as an indicator for chronic exposure to PCB co ntamination at the level of 6.6 mg or higher PCB/kg diet. (C) 1997 Els evier Science B.V.