Changes In Plasma Hormone In New YangZhou Hens Laying On Consecutive Days Under Different Photoperiods

The objective was to determine the changes in plasma concentrations of Luteinizing hormone (LH), Estradiol (E2) and testosterone (T) in New YangZhou Hens laying on consecutive days under different photoperiods, and to study the relationship between surges of reproductive hormones and egg production. The results indicated:1. Under constant lighting (14L: 10D), plasma concentrations of LH of hens laying on 2 or 3 consecutive days was higher than the hens laying on normal days(the hens without consecutive laying days). The plasma concentrations of E2 after laying on 3 consecutive days was higher than the hens laying on 2 consecutive days and normal days. Plasma concentrations of T of hens laying on 2 or 3 consecutive days was significantly higher than the hens laying on normal days (P<0.05). Under this photoperiod, plasma concentrations of LH, E2 and T of hens laying on consecutive days was higher than the hens laying on normal days.2. Under diurnal lighting (24L:OD), plasma concentrations of LH of hens before laying on 3 consecutive days was higher than the hens laying on 2 consecutive days and normal days . Plasma concentrations of E2 after laying on 3 consecutive days was significantly higher than the hens laying on normal days (P<0.05); and plasma concentrations of E2 before laying was higher than the hens laying on normal days. Plasma concentrations of T of hens before laying on 2 or 3 consecutive days was higher than the hens laying on normal days. Under this photoperiod, plasma concentrations of LH, E2 and T of hens before ( or after) laying on consecutive days was higher than the hens laying on normal days.3. Under natural lighting, plasma concentrations of LH of hens after laying on 2 and 3consecutive days was higher than the hens laying on normal days. Plasma concentrations of E2 before laying on 2 consecutive days was higher than the hens laying on normal days; plasma concentrations of E2 before laying on 3 consecutive days was significantly higher than the hens laying on normal days (P<0.05) ; and plasma concentrations of E2 of hens after laying on 3 consecutive days was significantly higher than the hens laying on 2 consecutive days and normal days (P<0.05).4. For the hens laying on normal days, plasma concentrations of LH after laying in Group C (the natural lighting group) was higher than which in Group A (the constant lighting group) and Group B (the diurnal lighting group), and plasma concentrations of LH before laying in Group A and C was higher than in Group B. Plasma concentrations of E2 before laying in Group A and C was higher than in Group B ;and plasma concentrations of E2 after laying in Group C was much, higher than in Group A and B( P<0.05). Plasma concentrations of T before laying in Group C was higher than in Group A and B, and after laying ,the plasma concentrations of T in Group A was significantly higher than in Group B (P<0.05) .5. For the hens laying on 2 consecutive days , plasma concentrations of LH before laying in Group A was much higher than Group B (P<0.05). Plasma concentrations of LH after laying in Group C was higher than in Group A and B.Plasma concentrations of T in Group C was much higher than in Group A and B (P<0.05 ).6. For the hens laying on 3 consecutive days , plasma concentrations of LH before laying in Group C was much higher than Group A (P<0.05) ;and was also higher than Group B. Plasma concentrations of E2 after laying in Group C was much higher than in Group A and B . Plasma concentrations of T in Group A was much higher than in Group B (P<0.05) .7. Under different lighting photoperiods in the experiment, plasma concentrations of LH, E2 and T of hens laying on consecutive days were higher than hens laying on normal days. For the hens with different consecutive laying days, plasma concentrations of LH, E2 and T in Group A and C were higher than which in Group B.