Sperm motility and cryopreservation of spermatozoa in freshwater gobies

Abstract

Testicular sperm motility and methods for the cryopreservation of spermatozoa in the freshwater goby Rhinogobius sp. CB (Cross Band type) were examined. Spermatozoa were almost immotile upon dilution with 300 mOsm kg À1 of NaCl, KCl and mannitol solutions but began to swim in solutions with concentrations <200 mOsm kg À1 . The highest percentage and longest duration of motility was obtained in the 0 and 100-200 mOsm kg À1 solutions, respectively. The highest post-thaw motility, c. 50% of motility before cryopreservation, was obtained when spermatozoa were diluted with an extender of 10% methanol and 90% artificial seminal plasma, cooled at À10Á0 AE 1Á1°C min À1 (mean AE S.E.) to À50°C and plunged into liquid nitrogen. Spermatozoa were cryopreserved in a 50 ml acrylic haematocrit tube to store the small amount of milt. As the cryopreservation method described above was applicable to the endangered Rhinogobius sp. BI (Bonin Island type), it is probable that this method can be used for other species of freshwater gobies.

Mate Choice for Nonadditive Genetic Benefits Correlate With MHC Dissimilarity in the Rose Bitterling (Rhodeus Ocellatus)

“…The eggs were gently squeezed from the female and divided into approximately four equal groups in separate 70‐mm‐diameter Petri dishes containing freshwater (mean = 8.0 ± 3.10 SD eggs per group). Sperm was stripped from the four experimental males by gently pressing their abdomens and mixed in 9 mL of teleost saline (Yokoi et al 2008). A 1‐mL subsample of this sperm solution was diluted with a further 9 mL of saline.…”

Cognitive ability is heritable and predicts the success of an alternative mating tactic

“…eggs per group). Sperm was stripped from the two experimental males by gently pressing their abdomens and mixed in 9 ml of teleost saline [31]. A 1 ml subsample of this sperm solution was diluted with a further 9 ml of saline.…”

Long‐term fitness consequences for offspring of female oviposition decisions in the rose bitterling (Rhodeus ocellatus)

“…Sperm was stripped from the male and mixed with 9 mL of teleost saline (Yokoi et al 2008). Experimental R. ocellatus were from the River Yangtze Basin, China, and were the first-generation bred in captivity.…”

“…Once the female had ovulated a batch of eggs, evident from her extended ovipositor, the eggs were gently squeezed from the female. Sperm was stripped from the male and mixed with 9 mL of teleost saline (Yokoi et al 2008). A 1 mL subsample of sperm solution was pipetted over the eggs and the Petri dishes left on the laboratory bench for 30 min.…”