Effect of bull, diluter and LDL-cholesterol concentration on spermatozoa resistance against cold shock

Abstract

The objectives of this study were to determine and evaluate the effect of bull, diluter and addition of LDL in different concentration on the percentage rate of spermatozoa survival after cold shock. In total, four bulls were collected during a period of eight weeks. A total of 8 samples of fresh semen with required quality were processed. Three extenders were used for dilution of each sample; AndroMed®, Bioxcell® and Triladyl®, each in standard and LDL enriched variants. In the case of AndroMed® and Bioxcell®, 4, 6 and 8% of LDL were simply added. In Triladyl®, 6, 8 and 10% of LDL replaced the standard egg yolk component. Resistance of spermatozoa against cold shock (0 °C, 10 minutes) was evaluated by the percentage rate of live sperm using Eosin-Nigrosine staining immediately and 2 hours after heat incubation (37 °C). The results showed the influence of bull individuality as an important factor. Among diluters used it is possible to recommend AndroMed® and Bioxcell® due to significantly (P < 0.01) lower decline of live sperm proportion during the cold shock test than Triladyl® (-9.19, respectively -4.95%). The optimal LDL concentration increasing resistance of spermatozoa against cold shock was not determined, therefore subsequent research is necessary.

Keywords

• bull semen
• sperm survival
• cold shock
• extender
• LDL cholesterol