Improved flow cytometric sorting of X- and Y-chromosome bearing sperm: substantial increase in yield of sexed semen.

摘要

A new elliptical nozzle designed to improve sperm orientation during passage through the sorter was tested under flow cytometric sorting conditions. The degree of orientation improvement was determined with different sample rates using live and deadspermatozoa of several species (cattle, pigs and rabbits). There was a minimum of a 2-fold increase in the proportion of oriented spermatozoa compared with the currently used modified flow cytometer/cell sorter employing a bevelled needle. More than 60%of intact bull and boar spermatozoa were correctly oriented compared with 25-30% using the bevelled needle system. The proportion of oriented spermatozoa was independent of sample rate and sperm motility. The accuracy of DNA measurement and high-puritysorting was tested using the nozzle. The accuracy of measurement and sorting performance were not affected. Samples of 88% purity of sorted viable bull and boar X- and Y-spermatozoa were obtained. The yield of sorted X- and Y-chromosome-bearing spermatozoa using the nozzle was, on average, twice that of the bevelled needle system used in conjunction with a standard equipment nozzle for orientation. The possibility of higher sample rates and greater increases in sorting efficiency are discussed.