Effect of seminal plasma infused at the time of frozen semen artificial insemination on jennies (equus asinus) uterine cytology evaluated 24 hours later

Fertility rates obtained by frozen semen artificial insemination (AI) in the donkey species are often disappointing (0-36%) (1). In the horse, seminal plasma (SP) modulates polymorphonuclear cells (PMN) activity in vitro and post mating induced endometritis in vivo (2, 3). In jennies SP did not decrease uterine PMN 6-10 hours post frozen semen AI (1). The aim of this study was to evaluate uterine cytology in donkeys 24 hours after frozen semen AI with or without post-thaw addition of seminal plasma. Two cycles of 5 Amiata jennies were assigned in random order to either frozen semen AI (AI) or frozen semen AI with post-thaw addition of 70% v/V seminal plasma (AI+SP). Ovulation was induced (h0) by a GnRH analogue (Suprefact®, Sanofi Aventis, IT; 0.1mg SC) and a single AI was performed 30 hours later with 500x106 spermatozoa (pooled semen of two jacks). Low volume uterine lavage (LVL) (4) was performed at h0, to exclude jennies with PMN, and 24 hours after AI. Amount of recovered fluid, adsorbance (Accucel, IMV, FR) and cell concentration by hemocytometer were evaluated. The proportion of PMN was assessed on a smear stained with Diff Quik® (Microptic, ES) on 200 cells. Concentration and total number of PMN were determined as well. Eight days after ovulation the uterus was flushed to evaluate embryo recovery rate. Statistics: Paired T-test (P<0.05 significant). Amount of recovered fluid (42.4±7.1% and 42.0±8.9%), adsorbance (0.222±0.12 and 0.171±0.13), cell concentration (0.284±0.01 and 0.233±0.16), %PMN (53.7±39.3 and 47.7±24.3), PMN concentration (0.221±0.2 and 0.266±0.2), total PMN number (8.5±8.4 and 10.4±8.3) and embryo recovery rate (1/5 and 1/5, 20%) did not differ between AI and AI + SP. Post-thaw addition of SP did not reduce the number of PMN into the uterus 24 hours after AI, thus suggesting that uterine clearance was not improved.