<i>In vitro</i> fertilization of ovulated eggs from melamine fed mice.

(A) Representative images of fertilized eggs in control and melamine-treated mice. Most of eggs were not fertilized in high-dose treatment group. Scale bar, 40μm. (B) In vitro fertilization rates, control oocytes (n = 91), low group (n = 112), and high group (n = 124). Fertilization was determined by the presence of 2 pronuclei 12 hr after insemination. Data were presented as mean percentage (mean ± SEM) of at least three independent experiments. Asterisk denotes statistical difference at a P < 0.05 level of significance.