In vitro storage of functional sperm at room temperature in zebrafish and medaka
Takemoto K, Nishimura T, Kawasaki T, Imai Y, Levy K, Hart N, Olaya I, Burgess SM, Elkouby YM, Tanaka M, Sakai N,
Zebrafish (2023) 20, 229-235 DOI:10.1089/zeb.2023.0054 A PDF of this paper can be downloaded from here.
The longevity of sperm in teleost such as zebrafish and medaka is short when isolated even in saline-balanced solution at a physiological temperature. However, we thought that under suitable conditions sperm could be survived for a longer period of time, and we investigated these conditions. Here, we show that the sperm of zebrafish can survive and maintain fertility in L-15-based storage medium supplemented with 50 Units/ml penicillin, 50 µg/ml streptomycin, 0.5% (w/v) bovine serum albumin, 3% foetal bovine serum, 25 mM glucose, 0.1 mM lactic acid, 10 mM Hepes (pH 7.9), and 22% water for 28 days at room temperature. The fertilized embryos developed to normal fertile adults. This storage medium with increasing lactic acid two-fold was effective in medaka sperm stored for 7 days at room temperature. These results suggest that sperm from external fertilizer zebrafish and medaka has the ability to survive for at least 4 weeks and 1 week, respectively, in the body fluid-like medium at a physiological temperature. This sperm storage method allows researchers to ship sperm by low-cost methods and to investigate key factors for motility and fertile ability in those sperm.
Figure: Zebrafish cover featuring zebrafish and medaka sperm
