Nordskog A W, Cheng S
Department of Animal Science, Iowa State University, Ames 50011.
Poult Sci. 1988 Jun;67(6):859-64. doi: 10.3382/ps.0670859.
The deleterious effect of inbreeding on fertility and hatchability was studied in a population of Leghorns developed primarily for immunogenetics studies. The 1983 population averaged 42% inbreeding and traced back to only two sires and five dams of the 1965 base population. Up to 1975 (Period 1), the population was maintained as a single-unit closed flock, during which time inbreeding increased an average of 1.44% per year. After 1975 (Period 2), the population was split into five sublines. Inbreeding then increased at the average rate of 2.7% per year. The regression of fertility on inbreeding was -.31 +/- .04 in Period 1 and -.17 +/- .06 in Period 2. Corresponding values for hatchability of fertile eggs were +.08 +/- .05 in Period 1 and -.24 +/- .07 in Period 2. The regression of hatchability of total eggs set was -.15 +/- .04 in Period 1 and -.35 +/- .10 in Period 2. The evidence implies that both fertility and hatchability have a heritable basis. As expected, the deleterious effects of inbreeding on reproduction was more severe in Period 2, with sublining.
在主要为免疫遗传学研究培育的来航鸡群体中，研究了近亲繁殖对繁殖力和孵化率的有害影响。1983年的群体平均近亲繁殖率为42%，其谱系可追溯到1965年基础群体中的仅两只公鸡和五只母鸡。到1975年（第1阶段），该群体作为一个单一单元的封闭鸡群进行维持，在此期间近亲繁殖率平均每年增加1.44%。1975年之后（第2阶段），该群体被分成五个亚系。此后近亲繁殖率以每年2.7%的平均速度增加。在第1阶段，繁殖力对近亲繁殖的回归系数为-.31±.04，在第2阶段为-.17±.06。第1阶段受精蛋孵化率的相应值为+.08±.05，第2阶段为-.24±.07。第1阶段总入孵蛋孵化率的回归系数为-.15±.04，第2阶段为-.35±.10。证据表明繁殖力和孵化率都有遗传基础。正如预期的那样，在第2阶段亚系形成时，近亲繁殖对繁殖的有害影响更为严重。
