In vitro storage of functional sperm at room temperature in zebrafish and medaka

Abstract

Abstract The longevity of sperm in teleost is short when isolated even in saline-balanced solution at a physiological temperature. In contrast, some internal fertilizers exhibit the long-term storage of sperm in the female reproductive tract. This evidence raises the question of whether sperm even from the external fertilizer possesses the ability to survive for a long time under appropriate conditions. Here, we show that the sperm of the external fertilizer, zebrafish, can survive and maintain fertility in L-15-based storage medium supplemented with bovine serum albumin, foetal bovine serum, glucose and lactic acid for 28 days at room temperature. The fertilized embryos developed to normal fertile adults. This storage medium was effective in another external fertilizer medaka sperm stored for 7 days at room temperature. These results reveal that sperm from external fertilizer teleost has the ability to survive in vitro for a long time. This sperm storage method allows to ship sperm in important lines by low-cost methods and to investigatekey factors for motility and fertile ability in teleost sperm.