Are flame retardants also growth retardants?

To investigate the effects of two emerging polychlorinated flame retardants on hatching success and growth in birds, an in ovo exposure experiment on Japanese quail (Coturnix coturnix japonica) was performed. In total 392 eggs were injected with Dechlorane Plus (DP; syn- and anti-isomer), Tris(1,3-dichloro-2-propyl)phosphate (TDCIPP) and a mixture of both chemicals (MIX). Eggs were injected in the yolk sac, right before incubation (at embryonic day zero) and were administered a low (10 ng/g egg), medium (100 ng/g egg) or high (1000 ng/g egg) dose of the compound or mixture. Two control groups were also included: one group was only injected with a ‘vehiculum’ containing peanut oil and lecithin, while the other group did not receive any injection. Eggs were incubated for 17-18 days and chicks (n=101) were kept in cages per three individuals. Food and water was provided ad libitum. Everyday body weight, head length and tarsus length were measured to examine effects of the contaminants on growth. At day 14, the birds were killed by decapitation and samples were taken for analysis of the compounds in the tissues. It was hypothesized that growth would be negatively affected by the injected compounds and that there would be an effect of mixture toxicity. Also hatching success was expected to be lower in exposed eggs and behave in a dose-related manner. The overall hatching success of the birds in this experiment was 47.2%. Preliminary results indicate that hatchability was decreased in all exposed eggs compared to the control eggs (58.5%). Hatching success of the different exposure groups followed the decreasing order of TDCIPP (49.2%) > DP (46.0%) > MIX (41.5%). Interestingly, in contrast to DP and TDCIPP, hatching success in MIX increased with dose. Furthermore, the growth data are currently under investigation and these results will also be presented at the conference.