Simple and Effective Methods of Freezing Capercaillie (Tetrao urogallus L.) Semen

Abstract

A continuous decline in the number and range of capercaillie (Tetrao urogallus L.) in many European countries can be observed, mostly due to habitat destruction by human activity, unecological forestry management, and increased density of natural predators. Ex situ in vitro gene banks provide a unique opportunity to preserve the genetic material for future generations. Simple and effective cryopreservation methods for capercaillie semen are discussed. Semen was collected from seven males kept in the Capercaillie Breeding Centre at Forestry Wisła in Poland. Within five minutes after collection, ejaculates were diluted with EK diluent, then divided into two parts, and subjected to two freezing procedures: in pellets and in straws. In fresh semen, ejaculate clearness, viscosity, color and volume, as well as sperm concentration, motility and morphology, were evaluated, while in frozen-thawed semen only motility and morphology of sperm were determined. Fertilizing ability of thawed semen was examined for samples frozen in straws. Significant (P<0.05) differences between individual males were found in relation to the majority of fresh semen traits: ejaculate volume averaged 102.1 µL (varying from 49.0 to 205.0); average sperm concentration was 632.5 x106 mL-1 (178.8–1257.1); percentage of live normal cells varied from 39.2 to 70.3% (58.7% on an average); percentage of motile cells ranged from 76.0 to 85.7%) and motility parameters were male dependent, as well. Both cryopreservation methods had a negative effect on morphology and motility of frozen-thawed semen; however, the straw method yielded 60.7% and the pellet method 42.5% of live cells in total in thawed semen (P<0.05), while the number of live normal (intact) cells was similar (22.4 and 22.2%, respectively). Egg fertility varied between 77.8 and 91.7% (average 84.4%). Both freezing procedures seem to be effective in obtaining acceptable viability and high fertilizing potency of thawed sperm and can be used to create a gene bank of capercaillie semen.

Effect of selenium and vitamin E addition to the extender on liquid stored capercaillie (Tetrao urogallus) semen quality

“…In the presented experiment, one male (no 72) of four examined had a low SQF (8.6 on average), mainly due to low number of live normal sperm (33.3%). The ejaculates produced by the remained males were at a high level (SQF from 40.4 to 74.3), comparable to those presented in our previous publications (Kowalczyk & Łukaszewicz, ; Kowalczyk et al., ).…”

“…It is worth emphasizing that similar as in our previous study, where significant individual differences between capercaillie in resistance to cryoinjury stress were indicated (Kowalczyk & Łukaszewicz, ), in this experiment, such differences were also stated in relation to short‐term liquid storage. It was particularly evident in case of male no 72, whose fresh semen had the lowest motility.…”

“…We documented that in case of capercaillie, for successful AI purposes, the ejaculate quality has to be at minimum 10 SQF. Males whose ejaculates are scored at 10 SQF and more can be recognized as sufficiently good semen donors (Kowalczyk & Łukaszewicz, ; Kowalczyk et al., ; Łukaszewicz & Kowalczyk, ). In the presented experiment, one male (no 72) of four examined had a low SQF (8.6 on average), mainly due to low number of live normal sperm (33.3%).…”

“…By the Decree of Polish Ministry of the Environment (“The protection of animal species,” October 12, 2011), the capercaillie ex situ in vivo breeding centres and reintroduction programmes were established (Merta, Kobielski, Krzywiński, & Rzońca, ; Rzońca, Łukaszewicz, & Kowalczyk, ; Strzała, Kowalczyk, & Łukaszewicz, ). An increasing the reproductive efficiency of captive kept capercaillie by the use of biotechnological methods contributes significantly to the achievement of this goal (Ciereszko, Dietrich, Liszewska, Krzywiński, & Kobus, ; Kowalczyk & Łukaszewicz, ; Kowalczyk, Łukaszewicz, & Rzońca, ; Łukaszewicz & Kowalczyk, ; Łukaszewicz, Kowalczyk, & Rzońca, ). The possibility of short‐term semen storage will expand the applicability of assisted reproduction technology in capercaillie breeding centres.…”

Effect of cryoprotectants and thawing temperatures on chicken sperm quality

“…To date, semen cryopreservation is the only effective method of storing reproductive cells for the ex situ management of genetic diversity in birds ensuring the creation of semen cryobanks (Iaffaldano, Di Iorio, Miranda, et al., ; Kowalczyk & Łukaszewicz, ). In this regard, following the international agreements on animal biodiversity, the need to improve and standardize germplasm cryopreservation technology has been emphasized by the demand of ex situ in vitro conservation programs.…”