Blackburn H D, Silversides F, Purdy P H
National Animal Germplasm Program, National Center for Genetic Resources Preservation, Agricultural Research Service, USDA, 1111 S. Mason St., Fort Collins, CO 80521, USA.
Poult Sci. 2009 Oct;88(10):2192-8. doi: 10.3382/ps.2008-00403.
Developing gene bank germplasm collections for animal genetic resources requires establishing germplasm collection goals, that consider capturing the genetic diversity of the population in question and the amount of germplasm required for its reconstitution or other purposes, or both. Computing collection goals for chickens is complicated, compared with mammalian species, due to the multiple chances a single insemination of semen has to fertilize an egg. To address this issue, fertility data were used in conjunction with econometric procedures for determining production efficiency and diminishing returns. Experimental treatments consisted of inseminating fresh semen intravaginally (FIV), frozen-thawed semen inseminated intramagnally (FTIM), and frozen-thawed semen inseminated intravaginally (FTIV). Analysis revealed that the maximum efficiency for a single insemination was at postinsemination d 6, 8, and 3 for FIV, FTIM, and FTIV, respectively. But, additional benefit from a single insemination can be garnered by continuing to collect and incubate eggs to d 11, 17, and 11 for FIV, FTIM, and FTIV, respectively. By extending the insemination interval, the number of fertile eggs can be increased by 62 (FIV), 62 (FTIM), and 48% (FTIV). The ramifications of these results are profound when placed in the context of germplasm collection for gene banks. By using the FTIM treatment, the number of germplasm samples needed to secure a chicken breed, at the 150% level, can be reduced from the FAO projection of 2,454 to 386 straws (0.5 mL). Such a change represents a substantial reduction in collection, processing, and storage costs for gene banks. For industry, the results suggest that extending the time interval between inseminations will yield more fertile eggs and create opportunities to increase the number of hens mated to a rooster.
为动物遗传资源建立基因库种质收集体系，需要设定种质收集目标，该目标要考虑到获取相关群体的遗传多样性以及用于种群重建或其他目的所需的种质数量，或兼顾两者。与哺乳动物相比，计算鸡的收集目标更为复杂，这是因为单次精液授精有多次机会使卵子受精。为解决这一问题，结合计量经济学方法使用繁殖力数据来确定生产效率和收益递减情况。实验处理包括经阴道授精新鲜精液（FIV）、经子宫内授精冻融精液（FTIM）以及经阴道授精冻融精液（FTIV）。分析表明，单次授精的最大效率分别出现在授精后第6天（FIV）、第8天（FTIM）和第3天（FTIV）。但是，通过继续收集并孵化卵子至第11天（FIV）、第17天（FTIM）和第11天（FTIV），单次授精可获得额外收益。通过延长授精间隔，可使可育卵数量分别增加62%（FIV）、62%（FTIM）和48%（FTIV）。当将这些结果置于基因库种质收集的背景下时，其影响意义深远。采用FTIM处理方式，在150%的水平下，确保一个鸡品种所需的种质样本数量可从粮农组织预测的2454支细管（0.5毫升）减少至386支。这样的变化意味着基因库在收集、处理和储存成本方面大幅降低。对于家禽行业而言，结果表明延长授精间隔时间将产生更多可育卵，并创造机会增加与一只公鸡交配的母鸡数量。
