187 Single-layer centrifugation as a method for bacterial reduction in bull semen for assisted reproduction
A. Cojkic A , I. Hansson B and J. M. Morrell AA Department of Clinical Sciences, Division of Reproduction, Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
B Department of Biomedical Science and Veterinary Public Health, Division of Bacteriology and Food Safety, Swedish University of Agricultural Sciences, Uppsala, Sweden
Reproduction, Fertility and Development 35(2) 221-221 https://doi.org/10.1071/RDv35n2Ab187
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
The emerging problem of antimicrobial resistance increases the need to find alternatives to antibiotics for antimicrobial inhibition in semen extenders. Colloid centrifugation of semen, especially single-layer centrifugation (SLC), as a physical method for bacterial removal, was able to reduce bacterial counts in semen doses from boars, stallions, and dogs without having a detrimental effect on sperm quality. The aim of this study was to assess two densities of colloid for SLC density (high and low), evaluating their influence on bacterial reduction. Semen samples were collected from nine bulls, diluted 1:1 with antibiotic-free semen extender, and transported to the laboratory at the Swedish University of Agricultural Sciences overnight at 6°C. After arrival, sperm concentrations were extended to a concentration of 65 × 106 cells; each sample was split into three: control, and high and low density SLC. Aliquots of each sperm sample were cultured on Plate Count Agar and incubated for 72 h at 30°C before the efficiency of bacterial reduction was determined from bacterial counts (colony-forming units; CFU per mL). In total, two semen samples were collected from each bull; bacteriological analysis was performed in duplicate on each sample. Data analysis was performed by MANOVA and ANOVA, Tukey multiple comparison test, with P < 0.05 being defined as statistically significant. There were statistically significant differences in bacterial count reduction for both high (mean reduction = 100.83, P < 0.0001) and low (mean reduction 6, P = 0.003) SLC groups compared with control, but no significant difference between high and low density SLC (P = 0.07). Furthermore, there were no statistically significant differences in CFU between the two time points. Single-layer colloid centrifugation offers a feasible method for reducing bacterial contamination in bull semen.
Thanks to the barn and laboratory staff at VikingGenetics, Sweden for help with semen collection, and to FORMAS, Stockholm for funding (project number 2017-00957, awarded to JMM).
