IP03 Avian Endocrine Test Protocols
B113 & B114
1:20 PM - 4:40 PM, Monday
(IP024) Findings from Two-Generation Tests in Japanese and Northern Bobwhite Quail.
Ottinger, M1, Hazelton, J1, Quinn, Jr, M1, Thompson, N1, Mann, L1, Barton, A1, Abdelnabi, M1, Lavoie, E1, Beavers, J2, Jaber, M2, 1 University of Maryland, College Park, Maryland, USA2 Wildlife International, Ltd., Easton, Maryland, USA
ABSTRACT- Two-generation dietary testing paradigms provide a method for determining the effects of endocrine disrupting chemicals (EDCs) on avian species. The Japanese quail has been developed as a model for precocial avian species; however, northern bobwhite quail have been the standard for toxicological testing. Our purpose was to compare relevant end points in these species, using a two-generation dietary study. Japanese and northern bobwhite quail (parents; P) were raised under short photoperiod and then photostimulated and placed on diet containing methoxychlor (MXC; 0, 5ppm, and 10ppm). Feed intake, egg production, fertility, offspring viability were monitored; chicks (F1) were raised on the same diet as their parents, paired as adults, and monitored for sexual maturation, reproductive behavior and endocrine measures. F2 chicks were raised on control feed and assessed for the same end points as the F1 birds. There were some fundamental species differences in that bobwhite quail matured more slowly and had lower productivity. Little effect of 5ppm MXC was observed on egg production, fertility, and chick growth. Both species showed delayed sexual maturation with treatment, with significant (p<0.05) reduction in the number of birds achieving optimal reproductive performance at 10ppm MXC. Sexual behavior was significantly (p<0.05) impaired by MXC exposure in both F1 and F2 Japanese quail males; behavioral assessment was not conducted in bobwhite males. Although variable, plasma and fecal steroid hormones showed significant (p<0.05) differences with treatment. In the low MXC treatment, there was an apparent bimodal response, suggesting that variability is also an important index of EDC exposure. The relationship between reproductive status and steroid hormones was weaker in bobwhite quail. MXC exposure was associated with delayed sexual maturation in both species. Hypothalamic neurotransmitters and GnRH-I appear to be sensitive indicators of endocrine disruption. In summary, Japanese quail offer a fast maturing precocial avian model for evaluating EDCs and reliable measurement end points are emerging for regulatory testing. Supported by EPA R-82877801
Key words: endocrine disrupting chemicals, Japanese quail, reproductive performance, neuroendocrine measures