光照对鸡生长、产蛋及血浆雌二醇、黄体生成素、甲状腺素的影响

70日龄星杂“579”小母鸡120只,随机分成A、B、C三组。C组为对照组。A、B两组分别以32和8Lx的强度补充光照,使其每天的光照时间达14h。从70日龄起,每10天称重一次;从开产日龄起,对每只鸡的产蛋分别按日龄称重、登记。结果表明,光照强度与鸡的生长速度和平均蛋重相关不显著,而与鸡的性成熟和产蛋量显著相关。用放射免疫分析法测定了三组鸡100～180日龄间外周血浆E_2、LH和T_4含量,B组鸡LH峰值最高,其峰值(149日龄)与基础值(100日龄)对比,增长率为231.4％;A组鸡血浆T_4水平增加明显,但其产蛋量相对较低;补充光照组能促使血浆E_2峰值的出现早于自然光照组,但各组鸡E_2峰值无显著差异。

THE EFFECT OF LIGHT ILLUMINATION ON GROWTH, EGG PRODUCTION, PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE, ESTRADIOL AND THYROXINE IN PULLETS

One hundred and twenty 70-day-old pullets were randomly divided into 3 equal groups A, B and C.C, which was used as control group, lived in the sunshine.A and B lived with artificial light at an intensity of 32 and 8 lx, respectively. The illuminating time was 14 hours everyday. The results indicated that light intensity does not obviously influence the gain of body weight and egg weight but apparenly affect the number of production. The level of plasma luteinizing hormone in group B was significantly higher than the basal level ( P<0.01 ) and this group had highest egg production. The plasma concentration of thyroxine ( T4 ) increased markedly in group A, but the egg production of this group was lowest. The time on which estradiol ( E2) reached to peak level in group A and B was 135-day-old and was earlier than that in control group ( 142 day-old ) . It seems that light may accelerate sex maturation of pullets.