Photoacceleration of embryonic development in depigmented Japanese quail eggs

Pigmented and depigmented Japanese quail eggs were incubated either in the presence of a light source for one week or in the dark. Acceleration of embryonic development was apparent by the first day of incubation in the depigmented eggs exposed to light. Embryonic weights of eggs exposed to light were significantly (P less than .05) greater than eggs incubated in the dark by the fourth day of incubation. Air cell temperatures of depigmented eggs were significantly (P less than .05) lower than pigmented eggs by the fourth day of incubation when both groups of eggs were exposed to a light source. Thus photoacceleration appeared to be a real effect, and great enough to overcome the lower egg temperature at which these embryos developed. Embryos developing in lighted depigmented eggs can decrease the hatching time of other groups incubated with them.