Effect of post-thaw dilution with caffeine, pentoxifylline, 2’-deoxyadenosine and prostatic fluid on motility of frozen-thawed dog semen

The aim of the experiment was to evaluate the motility pattern of frozen-thawed canine semen to which pentoxifyilline (PTX), caffeine (CAF), 2’-deoxyadenosine (DX), and prostatic fluid (PROST) were added after thawing. Semen evaluations were performed using computer-assisted sperm analysis (CASA) at thawing and during 120min of incubation at 37°C. Three experiments were conducted: 1) to establish which concentrations of stimulants work best; 2) to investigate the interaction between thawing rate and addition of CAF 5mM, PTX 2.5mM and PROST; 3) to evaluate the effect of PTX 7.5mM and DX 5mM on semen motility after thawing. In experiment 1, ALH and VCL were enhanced at thawing by CAF 7.5mM (CAF 7.5: 9.1±0.5μm; control: 6.7±0.4μm) and DX 5 and 7.5mM (DX 5: 199.1±12.8μm/s; DX 7.5: 197.3±13.9μm/s; control: 162.5±8.4μm/s), while PTX 2.5-5-7.5mM improved TOT after 120min of incubation. In experiment 2, PROST lowered ALH values throughout incubation (P<0.05) with respect to the other treatments, in particular when compared to CAF at Time=30 and at Time=60. In experiment 3, PTX 7.5mM improved VAP (PTX: 101.6±6.8μm/s; control: 81.9±10.5μm/s), VSL (PTX: 82.9±6.4μm/s; control: 65.9±9.8μm/s), VCL (PTX: 214.3±13.3μm/s; control:167±15.7μm/s), ALH (PTX: 10.5±0.3; control: 7.3±1.4μm), PM (PTX: 11.3±4.2%; control: 7.7±3.9%) and TOT (PTX: 20.1±5.3%; control:15.6±5.6%) at Time=120, while DX 5mM influenced VCL at Time=60 (DX: 218.3±14.3μm/s; control: 188.5±7.5μm/s, P<0.05). Motility stimulants may be useful for enhancing motility of canine frozen-thawed spermatozoa without affecting sperm longevity.