Effects of centrifugation on equine spermatozoa immediately and after cooling for 24 hours
Len, Jose Augusto, MVZ, Universidad de Guadalajara, 1994 Master of Science, Summer Commencement, 2008 Major: Veterinary Medical Sciences Effects of Centrifugation on Equine Spermatozoa Immediately and After Cooling for 24 Hours Thesis directed by Professor Bruce Eilts Pages in thesis, 60. Words in abstract, 245. ABSTRACT The objectives of this study were to determine the effects of centrifugation on equine sperm progressive motility, plasma membrane integrity (viability), and acrosome integrity. We hypothesized that high centrifugation forces would be detrimental to equine sperm, yet recovery rates would increase. Ejaculates from six stallions were collected, extended (INRA96) to a concentration of 25 x 106 cells/mL, and subjected for 10 min to 1) no centrifugation (NC); 2) 400 x g (400); 3) 900 x g (900); and 4) 4500 x g (4500). Before and after centrifugation (Day 0), and after 24 h of cooling (Day 1), sperm motility was assessed by computer assisted semen analysis, and samples were stained with SYBR-14/propidium iodide (PI) for viability, and with PI/fluorescent isothiocynate-PNA (Arachis Hypogaea) for acrosome integrity and assessed by flow cytometry. Data were analyzed using Shapiro-Wilk’s statistics; using a mixed linear model, effects of treatment and day were assessed. Compared with the other treatment groups the 4500 treatment group showed reduced motility, viability, and intact acrosomes (P<0.05). The 400 and 900 treatment groups yielded lower recovery rates than the 4500 treatment group (NC= 100.0 ± 0.0%, 400 = 54.4 ± 8.6%, 900 = 75.0 ± 7.1% and 4500 = 97.9 ± 2.8%) (P<0.05). Centrifugation at 400 or 900 x g did not damage equine sperm. Further studies of centrifugal forces between 900 and 4500 x g are warranted to find optimal forces that maximize recovery rate, minimize sperm damage, and do not affect fertility.