光照对马岗鹅季节性繁殖活动和内分泌的调控

研究了光照对马岗鹅季节性繁殖活动和内分泌的调控。在整个试验期（2004.01.13-12.18）对照组接受自然光照,处理组接受人工控制的长短光照处理。在非繁殖期（4-7月份）,对照组公母鹅血浆PRL浓度升高,LH浓度和公鹅睾酮水平降低,鹅换羽;在繁殖期（8-3月份）,公母鹅血浆PRL水平下降,LH浓度和公鹅睾酮水平则上升。在处理组,延长光照均使公母鹅PRL浓度升高,LH浓度和公鹅睾酮水平降低,鹅群进入休产期并换羽;缩短光照则降低PRL水平,促进LH分泌和公鹅睾酮水平上升,鹅群进入繁殖期。整个试验阶段,两组中公鹅甲状腺素T3水平均无明显季节性变化,处理组和对照组母鹅平均产蛋48.8和26.3枚,前者比后者高85.6%。试验结果表明,长光照抑制,短光照促进马岗鹅繁殖活动,光照通过调节PRL和LH的分泌调控马岗鹅繁殖活动的季节性变化。

Regulation of Photoperiod on Seasonal Reproductive Activities and Endocrine in Magang Geese

To study the regulation of photoperiod on seasonal reproduction and the associated endocrine mechanisms in Magang geese,adult breeding geese and ganders were exposed to natural photoperiod(controls),or subjected to an artificial program of long and short photoperiods(experimental birds).In both groups,egg laying ceased after photoperiod increased,and onset and continued when photoperiod decreased or remained for 11 h.Treatment with the artificial photo-program also increased the eggs laid by 85.6%,from the 26.3 eggs per control goose to 48.8 eggs on average in the experimental goose.In both control and experimental ganders,plasma LH concentrations were high in reproduction season from August to March or under short photoperiod,but decreased to low levels in non-reproduction season from April to July or under long photoperiod.A similar but much less marked seasonal pattern of plasma LH concentrations was observed in geese.In all geese and ganders,seasonal patterns of PRL concentrations were opposite to those of LH,in relation to changes of photoperiod.Plasma testosterone concentrations in ganders followed the seasonal secretion pattern of LH throughout experimental period.In addition,plasma T3 concentrations in both control and experimental ganders fluctuated throughout the experiment,but by no means correlated to changes of photoperiod or season.These results demonstrated that long photoperiod directly inhibited while short photoperiod directly stimulated reproductive activities in Magang geese and ganders.The photoperiodic effect was mediated via the secretions of PRL and LH,whose seasonal secretions coordinated the reproductive seasonality of Magang geese.