IP03 Avian Endocrine Test Protocols
B113 & B114
1:20 PM - 4:40 PM, Monday
(IP022) Evaluation of Low Dose E2 Effects in Enhanced One-generation Reproduction Test Using Japanese Quail.
Shibuya, K.1, Wada, M.2, Satou, K.1, Itabashi, M.1, Sakamoto, T.3, Nunoya, T.1, 1 Nippon Institute for Biological Science, Tokyo, Japan, Japan2 Tokyo Medical and Dental University, Chiba, Japan, Japan3 Trans Genic Inc., Kumamoto, Japan, Japan
ABSTRACT- We have developed so-called avian enhanced one-generation reproduction test using the Japanese quail (Coturnix coturnix japonica) to detect endocrine disruption, based on the testing guidelines of avian reproduction toxicity test (OECD TG206 and ARTT2000). In the previous testing protocols, endpoints such as blood levels of test substance and vitellogenin (Vg), histopathology in parent birds, egg weight and eggshell strength, size of gonad, gross pathology, and histopathology in 14-day-old offspring were not included. Therefore, those endpoints were newly added. Moreover, offspring from the treatment week-2 eggs were maintained up to 10 weeks of age, and their viability, clinical signs, body weights, sizes of cloacal gland in males, age of the first egg laying, numbers of eggs laid and eggs with abnormalities, gross pathology, organ weights and body weight ratios, and histopathology were examined. Using this new testing protocol, low dose effects of 17 beta-estradiol (E2) were assessed. After the 2-week pre-treatment period, pairs of 10-week-old birds were fed a phytoestrogen-deficient diet containing E2 at 0 (control), 0.3, 3, and 30 ppm for 6 weeks. Blood Vg level, histopathology of the gonad and cloacal gland in parent birds, number of eggs with abnormalities, egg weight, fertility, hatchability, body weight, gross pathology and histopathology of the gonad in 14-day-old offspring, and body weight, gross pathology and histopathology of the gonad in offspring maintained up to 10 weeks of age revealed significant or meaningful changes in the low dose E2 groups. Furthermore, decreased weights of cloacal gland and delay of the first egg laying day were observed in offspring maintained up to 10 weeks of age in the E2 groups. Consequently, the enhanced one-generation reproduction test seems to be sensitive enough to detect low dose effects of estrogenic endocrine disrupting chemicals (The present study was supported by Ministry of the Environment, Japan).
Key words: Japanese quail, Avian reproduction test, endpoints, estradiol