Abstract:

In order to further know the mechanism in the effect of light on egg-laying in hen, the response of hen brain on different light intensity was investigated using c-fos method. The right eyes of 150 days old hens were weared a blinder for 7 days, and received the different intensity light stimulation for 1.5 hours and dark adaptation 1.5 hours. After perfusion with fixative, their brains were removed from the skulls and were made into continuous paraffin sections. Using immunohistochemical method, expression of c-fos gene in mesencephalon and diencephalons was examined. The result showed that a number of Fos-like immunoreactive positive neurons were observed in hen mesencephalon and diencephalons after a light stimulation, being mainly present in left stratum griseum centrale (SGC) of tectum, nucleus rotundus (ROT), nucleus geniculatus lateralis pars ventralis (GLV), nucleus semilunaris (SLu), isthmi pars principais (Imc, Ipc), paraventricular nucleus (PVN), arcuate nucleus (ARC), and nucleus nervi oculomotorii (OMv). The expression of c-fos gene was varied with the different intensity light stimulation in hen, the immunoreactive intensity was the highest in 20Lux and 30Lux group, secondary in 40Lux, the lowest in 10Lux group within SGC, ROT, SLu, Glv, Imc and Ipc. That was highest in 20Lux group, gradually weakened in 30Lux and 40Lux group within PVN and ARC. The immunoreactive intensity was increased with the intensity of light within OMc. It indicated that the responses in central nervous system to the light stimulation vary with their intensity.