Low density lipoproteins at 2% concentration can replace whole egg yolk in tes-tris-milk extender for freezing buffalo sperm cells

Background: Over the years, the most commonly used extenders for semen cryopreservation contain egg yolk as cryoprotectant. However, more recent studies have used the low density lipoproteins, extract of hen egg yolk which is responsible for the cryoprotective effect. Nevertheless, little was known about its required minimum concentration as well as its interaction with other extra cellular cryoprotectants, like skimmed milk. The present study aimed at investigating the effect of replacing whole egg yolk by adding low density lipoproteins at low concentrations, in TES-Tris-skim milk based extender, on the post-thaw quality of buffalo bull sperm.Materials, Methods & Results: Eighteen ejaculates were collected from six buffalo bulls and diluted with TES-Tris-skim milk based extender containing LDL, extracted from hen egg yolks, at the concentrations of 2%, 4%, 8% and 14%, against a control extender containing 20% fresh egg yolk. After semen collection, analyses of subjective motility, vigor, force tourbillon, sperm concentration (Neubauer chamber) and sperm morphology (phase contrast microscopy) were performed. The diluted semen was packaged in 0.25 mL straws, and cooling was performed on computerized machine (TK 4000®), using a cooling rate of -0.25°C/min to 5°C. Semen was kept in balance at 5°C for 4 h. The straws were frozen in an ice chest, kept at 5 cm from the surface of liquid nitrogen for 20 min and then immersed in liquid nitrogen. The samples were kept in cryogenic container until thawing. Post-thaw kinetic parameters during incubation at 37°C (CASA), sperm membrane integrity (SYBR-14/PI), membrane functionality (hypo-osmotic swelling test) and DNA fragmentation (%DFI - SCSA) were evaluated after thawing. Immediately post-thaw, total motility was higher in the control (56.53 ± 9.73) than in the tested extenders; however, after 30 min the difference was no longer detected.[…]

Low density lipoproteins at 2% concentration can replace whole egg yolk in tes-tris-milk extender for freezing buffalo sperm cells

Background: Over the years, the most commonly used extenders for semen cryopreservation contain egg yolk as cryoprotectant. However, more recent studies have used the low density lipoproteins, extract of hen egg yolk which is responsible for the cryoprotective effect. Nevertheless, little was known about its required minimum concentration as well as its interaction with other extra cellular cryoprotectants, like skimmed milk. The present study aimed at investigating the effect of replacing whole egg yolk by adding low density lipoproteins at low concentrations, in TES-Tris-skim milk based extender, on the post-thaw quality of buffalo bull sperm.Materials, Methods & Results: Eighteen ejaculates were collected from six buffalo bulls and diluted with TES-Tris-skim milk based extender containing LDL, extracted from hen egg yolks, at the concentrations of 2%, 4%, 8% and 14%, against a control extender containing 20% fresh egg yolk. After semen collection, analyses of subjective motility, vigor, force tourbillon, sperm concentration (Neubauer chamber) and sperm morphology (phase contrast microscopy) were performed. The diluted semen was packaged in 0.25 mL straws, and cooling was performed on computerized machine (TK 4000®), using a cooling rate of -0.25°C/min to 5°C. Semen was kept in balance at 5°C for 4 h. The straws were frozen in an ice chest, kept at 5 cm from the surface of liquid nitrogen for 20 min and then immersed in liquid nitrogen. The samples were kept in cryogenic container until thawing. Post-thaw kinetic parameters during incubation at 37°C (CASA), sperm membrane integrity (SYBR-14/PI), membrane functionality (hypo-osmotic swelling test) and DNA fragmentation (%DFI - SCSA) were evaluated after thawing. Immediately post-thaw, total motility was higher in the control (56.53 ± 9.73) than in the tested extenders; however, after 30 min the difference was no longer detected.[…](AU)

as / Sperm subpopulations

A biotecnologia da reprodução é importante para melhorar a eficiência reprodutiva desenvolvendométodos que identifiquem os melhores reprodutores. Embora a motilidade espermática seja a variável maisavaliada, é necessária a avaliação das características da cinética espermática, as quais se alteram conformeespécie, indivíduos, ejaculados e desafios a que são submetidos. Atualmente sabe-se que o ejaculado não écomposto de um grupo homogêneo de espermatozoides, e sim por subpopulações espermáticas heterogêneas, asquais apresentam respostas variadas quanto aos padrões de motilidade, e a identificação dessas subpopulaçõespode auxiliar na escolha do reprodutor mais eficiente.

Reproductive biotechnology is important for improving reproductive efficiency by developing methodsthat identify the best breeding. Although sperm motility is the most evaluated variable, it is necessary to evaluatethe characteristics of sperm kinetics, which change according to species, individuals, ejaculates and thechallenges that are submitted. It is known that ejaculate is not composed of a homogeneous group ofspermatozoids, but by heterogeneous sperm subpopulations, such as varied kiosks for motility patterns, and asubpopulation identifier may aid in the selection of most efficient breeders.

as / Sperm subpopulations

A biotecnologia da reprodução é importante para melhorar a eficiência reprodutiva desenvolvendométodos que identifiquem os melhores reprodutores. Embora a motilidade espermática seja a variável maisavaliada, é necessária a avaliação das características da cinética espermática, as quais se alteram conformeespécie, indivíduos, ejaculados e desafios a que são submetidos. Atualmente sabe-se que o ejaculado não écomposto de um grupo homogêneo de espermatozoides, e sim por subpopulações espermáticas heterogêneas, asquais apresentam respostas variadas quanto aos padrões de motilidade, e a identificação dessas subpopulaçõespode auxiliar na escolha do reprodutor mais eficiente.(AU)

Reproductive biotechnology is important for improving reproductive efficiency by developing methodsthat identify the best breeding. Although sperm motility is the most evaluated variable, it is necessary to evaluatethe characteristics of sperm kinetics, which change according to species, individuals, ejaculates and thechallenges that are submitted. It is known that ejaculate is not composed of a homogeneous group ofspermatozoids, but by heterogeneous sperm subpopulations, such as varied kiosks for motility patterns, and asubpopulation identifier may aid in the selection of most efficient breeders.(AU)