17 EFFECT OF LOCAL TREATMENT OF SEMINAL VESICULITIS ON THE QUALITY OF EQUINE FRESH SEMEN

Abstract

Stallions affected by seminal vesiculitis present history of infertility or subfertility, ejaculatory disturbance, spread of sexually transmitted pathogens, and changes in semen characteristics, leading to reduced semen quality and longevity. The aim of this study was to evaluate the semen quality of stallions with seminal vesiculitis before and after local treatment. Five stallions with a mean age of 12.4 years diagnosed with seminal vesiculitis were used. The identification of the microorganism involved in the pathogenesis of seminal vesiculitis of each animal was performed by bacterial culture of the seminal vesicles flush with Ringer Lactate solution, performed in duplicate at 1-week intervals. After identification of bacteria was performed, there was susceptibility testing to antibiotic (antibiogram) and the appropriate antibiotic was chosen. The local treatment was performed by endoscopy for 10 consecutive days, and this consisted of flushing with Ringer Lactate solution, followed by infusion of the antibiotic selected. The semen analyses were performed before starting the local treatment for seminal vesiculitis (M0), after a week (M1), and after a month (M2) of therapy. Sperm kinetics were performed by computerized method – CASA for the following parameters: percentage of sperm with total motility, progressive motility, and rapid sperm. Analysis of plasma membrane integrity was performed by epi-fluorescence microscopy, using the combination of fluorescent probes carboxyfluorescein diacetate and propidium iodide. Percentage of leukocytes was assessed through evaluation in light optical microscopy of semen smears stained with DiffQuick. The content of nitric oxide (NO) was determined by colourimetric Griess reaction by a spectrophotometer through the concentrations of nitrate (NO₃^–) and nitrite (NO₂^–). To perform the count of colony forming units per millilitre (CFU mL^–1), an aliquot of 0.1 mL of semen was diluted in 9.9 mL of saline. A 0.1-mL aliquot of this sample was plated on Mueller-Hinton agar. The seeded plates were incubated, and the bacterial colonies were counted after 24 h. According to the performed dilution, total colonies identified corresponds to ×10 000 CFU mL^–1. The data were analysed by two-way ANOVA followed by Tukey's test (P < 0.05). The values (mean ± standard error) of seminal parameters on M0, M1, and M2 were the following, respectively: sperm kinetics (total motility: 46.5 ± 5.13^a; 75.1 ± 3.42^b; 42.8 ± 5.28^a; progressive motility: 19.3 ± 3.86^a; 33.4 ± 2.39^b; 16.5 ± 2.40^a; rapid sperm: 22.2 ± 1.82^a; 52.2 ± 5.65^b; 22.1 ± 2.62^a); plasma membrane integrity (47.5 ± 4.65^a; 62.9 ± 5.41^b; 39.1 ± 4.32^a); percentage of leukocytes (35.2 ± 2.36^a; 15.1 ± 2.55^b; 36.1 ± 4.04^a); CFU (119 980 × 10³ ± 19 528.0 × 10^3a; 5375 × 10³ ± 2453.7 × 10^3b; 65 850 × 10³ ± 19 701.0 × 10^3ab) on fresh semen; and NO content (0.645 ± 0.172^a, 0.117 ± 0.023^b, 0.364 ± 0.110^ab) on seminal plasma. The results demonstrate that local treatment after a week leads to an improvement in sperm quality; however, this was not maintained after 1 month of therapy, since the seminal parameters at this time are similar to pretreatment, which can be justified by recurrent disease.