The
inability to preserve rabbit semen for more than 36 hours post-collection is a
major limitation for artificial insemination programs in the rabbit meat
industry. This study aimed to evaluate the effect of temperature and diluent on
sperm motility and viability during liquid storage of rabbit semen over 96
hours. Semen was collected by artificial vagina from five rabbit bucks (three
ejaculates/buck). Each ejaculate was initially evaluated for volume, a minimum
sperm concentration of 300 x 106 spermatozoa/mL and at least 70% motile
spermatozoa. Each of three equal aliquots was diluted 1:10 with a different
extender: Extender A (313.79 mM TRIS, 103.07 mM citric acid.H20,
33.3 mM glucose and 80 mg/L kanamycin), Extender B (313.79 mM TRIS, 103.07 mM
citric acid.H20, 33.3 mM glucose, 80 mg/L kanamycin and 14% gelatin)
or Extender C (250.04 mM TRIS, 79.76 mM citric acid.H20, 69.38 mM
glucose, 75.0 IU streptomycin and 166.2 IU G-Penicillin). The diluted semen was
divided into two subsamples and stored at 5⁰C or 15⁰C. Sperm motility was evaluated by the CASA System (CASA: HTM IVOS v. 12)
at 0, 24, 48, 72 and 96 hours of storage. The best two performing extenders
were then assessed for viability using FITC-PNA/PI dual staining by the flow
cytometer. Data were analyzed using a Linear
Mixed Model (Genstat: VSN International.). After 96 hours, spermatozoa diluted
in Extender C at 15⁰C displayed the highest percentage (±SEM) motility (62±1.3%, P<0.001).
Extender B performed worst independent of storage temperature. There were no
differences between the acrosome or membrane integrities for diluted semen
regardless of extender or storage temperature. In conclusion, Extender C is the
best diluent for the preservation of rabbit sperm motility when storing at 15⁰C for up to 96 hours. Further research will
investigate the fecundity of the stored semen in rabbit artificial insemination
programs.