The most feasible biotechnologies for ex situ conservation of genetic resources in avian species is semen cryopreservation. However, research on turkey semen cryopreservation is not yet satisfactory to facilitate a turkey semen cryobank. Therefore, there is a clear need to standardise the freezing process to improve the post-thaw quality of turkey spermatozoa. The most important factor that may affect the success of cryopreservation is the choice of the cryoprotectant (CPA). Recently, bee honey has been used as a non-permeable (NP) CPA with satisfactory results for sperm cryopreservation in some mammals. Thus, the goal of this study was to investigate the effect of different concentration of bee honey as NP-CPA on the cryosurvival of turkey semen. Pool of semen (8–10 ejaculates/pool) were collected from toms (BUT) (Amadori group). Each pool was pre-extended (1:1; v/v) with Tselutin extender (TE) and cooled at 4 °C for 25 min. The semen was split into four aliquots and diluted (1:1; v/v) with four different freezing extenders composed of TE, containing 20% dimethylsulphoxide (DMSO) and 0, 1, 2 or 5% of honey. The diluted semen was packaged in 0.25 mL plastic straws and equilibrated at 4 °C for 20 min, then the straws were frozen by exposure at 10 cm above the liquid nitrogen level for 10 min. Lastly, the straws were dipped in liquid nitrogen at −196 °C. Semen samples were thawed at 50 °C for 10 s. Sperm motility (CASA system), DNA integrity (Acridine Orange), sperm viability and osmotic resistance (SYBR-PI) were assessed. The freezing/thawing process caused a significant reduction of semen quality compared to fresh semen (p<.05). However, the post-thawing semen quality was affected differently in relation to the honey concentration used. Higher value (p<.05) of sperm viability (43.5 ± 1.3), total and progressive motility (35.6 ± 2.3, 3.9 ± 0.4 respectively) were found in semen frozen with the 1% of honey in respect to that with only DMSO and 5% of honey. In conclusion, these data show that the use of 1% honey improves the cryosurvival of turkey spermatozoa. The benefits of the honey on sperm cryopreservation is due to the capacity to minimise the ice crystals formation inside the cytoplasm of sperm responsible for cryodamage. The development of an effective freezing protocol will lead to the take-off of a turkey sperm cryobank and preserve the genetic resources of autochthonous poultry breeds in Italy.
How can the honey improve the post-thaw quality of turkey spermatozoa
DI IORIO M.;RUSCO G.;MANCHISI A.;IAFFALDANO N.
2019-01-01
Abstract
The most feasible biotechnologies for ex situ conservation of genetic resources in avian species is semen cryopreservation. However, research on turkey semen cryopreservation is not yet satisfactory to facilitate a turkey semen cryobank. Therefore, there is a clear need to standardise the freezing process to improve the post-thaw quality of turkey spermatozoa. The most important factor that may affect the success of cryopreservation is the choice of the cryoprotectant (CPA). Recently, bee honey has been used as a non-permeable (NP) CPA with satisfactory results for sperm cryopreservation in some mammals. Thus, the goal of this study was to investigate the effect of different concentration of bee honey as NP-CPA on the cryosurvival of turkey semen. Pool of semen (8–10 ejaculates/pool) were collected from toms (BUT) (Amadori group). Each pool was pre-extended (1:1; v/v) with Tselutin extender (TE) and cooled at 4 °C for 25 min. The semen was split into four aliquots and diluted (1:1; v/v) with four different freezing extenders composed of TE, containing 20% dimethylsulphoxide (DMSO) and 0, 1, 2 or 5% of honey. The diluted semen was packaged in 0.25 mL plastic straws and equilibrated at 4 °C for 20 min, then the straws were frozen by exposure at 10 cm above the liquid nitrogen level for 10 min. Lastly, the straws were dipped in liquid nitrogen at −196 °C. Semen samples were thawed at 50 °C for 10 s. Sperm motility (CASA system), DNA integrity (Acridine Orange), sperm viability and osmotic resistance (SYBR-PI) were assessed. The freezing/thawing process caused a significant reduction of semen quality compared to fresh semen (p<.05). However, the post-thawing semen quality was affected differently in relation to the honey concentration used. Higher value (p<.05) of sperm viability (43.5 ± 1.3), total and progressive motility (35.6 ± 2.3, 3.9 ± 0.4 respectively) were found in semen frozen with the 1% of honey in respect to that with only DMSO and 5% of honey. In conclusion, these data show that the use of 1% honey improves the cryosurvival of turkey spermatozoa. The benefits of the honey on sperm cryopreservation is due to the capacity to minimise the ice crystals formation inside the cytoplasm of sperm responsible for cryodamage. The development of an effective freezing protocol will lead to the take-off of a turkey sperm cryobank and preserve the genetic resources of autochthonous poultry breeds in Italy.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
