Impaired social behavior in chicks exposed to sodium valproate during the last week of embryogenesis

Hideo Nishigori, Keisuke Kagami, Ai Takahashi, Yu Tezuka, Atsushi Sanbe, Hidekazu Nishigori

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


Rationale and objectives: To evaluate direct exposure to sodium valproate (VPA) during embryogenesis, we administered VPA to chick embryos and examined their social behaviors after hatching. Methods and results: Embryos treated with VPA (35 μmol/egg) on day 14 were similar to controls for hatching date (day 21) and hatchlings' abilities, such as motor, imprinting, and surface righting. However, these VPA chicks on posthatching day 3 scored significantly low in the chick's social separation stress (SSS) test as follows. Aggregation test evaluated the speed of four chicks, individually isolated by a cardboard in a box, to aggregate upon removal of the cardboards. Belongingness test evaluated the speed of a chick isolated at a corner to join the group of three chicks placed at the opposite corner. Vocalization test for each chick was performed in an isolated corner by using a sound level meter. The results demonstrated that compared with controls, VPA chicks were significantly slow in aggregation (12.7 ± 2.5 s vs. 2.9 ± 0.9 s, p = 0.006) and belongingness (3.6 ± 0.28 s/40 cm vs. 2.6 ± 0.14 s/40 cm, P = 0.003) and weak in vocalization (13.4 ± 2.8 dB/30 s vs. 26.7 ± 1.3 dB/30 s, P = 0.001), respectively. Weight of cerebellum of VAP chick was 15 % lighter than controls (P = 0.004). Conclusions: Chick embryos exposed to VPA during the last week of embryogenesis had impaired social behaviors in spite of normal mortar and imprinting ability. The present method will be a useful animal model for assessing the effects of environment during embryogenesis on social behaviors in later life.

Original languageEnglish
Pages (from-to)393-402
Number of pages10
Issue number3
Publication statusPublished - 2013 Jun
Externally publishedYes


  • Aggregation
  • Belongingness
  • Cerebellum
  • Chick
  • Embryo
  • Hatching
  • Imprinting
  • Social behaviors
  • Valproic acid
  • Vocalization

ASJC Scopus subject areas

  • Pharmacology


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