COMPARISON BETWEEN TWO ARTIFICIAL INSEMINATION METHODS USING FROZEN SEMEN IN DOMESTIC CATS (Felis catus)

Abstract

The aim of this study was to compare the efficiency of the intravaginal and the intrauterine artificial insemination methods using domestic cat frozen/thawed semen by determining the pregnancy rate. The sperm was collected from two tom cats using an artificial vagina and the samples were assessed for motility (CASA), sperm morphology and plasma membrane integrity (propidium iodide and carboxyfluorescein diacetate). After dilution with TRIS/OEP (4% of glycerol), the sperm samples were put into 0.25 mL straws (25 x 106 of sperm presenting motility) which, after 20 minutes under 5oC, stayed 15 minutes in liquid nitrogen vapour, being afterwards immersed. For each AI, four straws from the same male were thawed during 12 seconds at 46oC and centrifuged at 250 x g for 8 minutes. The pellet was ressuspended in 100 μL of the extender and analyzed as described above. In queens, estrus and ovulation were induced using 100 UI of eCG and, after 84 hours, 100 UI of hCG. After 30 hours from the ovulation induction, the females were inseminated by the intrauterine (bilateral uterine horn insemination) (n=8) or by the intravaginal (n=8) method, using the semen obtained by male A (n=4 females for each AI method) or B (n=4 females for each AI method). For statistical analysis the Tukey test and the Wilcoxon test were used for the sperm quality results, while the Fisher test was used to compare the two AI methods, with p<0.05 taken as significant. Ovulation was triggered in 100% of the females after the hCG administration and occurred within 30 hours after the induction. A decrease (p<0,05) in plasma membrane integrity (88.9 ± 3.7% to 44.9 ± 3.7%), total motility (88.5 ± 1.8% to 52.8 ± 6.9%), progressive motility (66.5 ± 2.6% to 32.9 ± 5.6%), VAP (average path velocity) (134.4 ± 7.3 μm/s to 96.6 ± 4.0 μm/s), VSL (straight line velocity) (118.6 ± 5.8 μm/s to 83.4 ± 4.3 μm/s), VCL (curvilinear velocity) (168.9 ± 4.6 μm/s to 147.2 ± 5.0 μm/s), LIN (linearity) (70.2 ± 2.4% to 56.6 ± 2.5%) and percentage of normal acrosome (95.7 ± 2.2% to 54.9 ± 6.4%) and an increase (p<0,05) in ALH (amplitude of lateral head displacement) (4.4 ± 0.2 μm to 5.2 ± 0.4 μm) and percentage of morphologically abnormal spermatozoa (15.1 ± 3.2% to 62.3 ± 3.0%) were observed when comparing the sperm samples after and before frozen/thaw procedure from both tom cats. The average value of motility sperm quantity in each AI was 39.1 ± 5.5 x 106. Although a pronounced decrease in motility, acrosome integrity and plasma membrane integrity was observed for the sperm samples from both cats, a pregnancy rate of 75% was achieved when using the intrauterine AI method, against 0% with the intravaginal AI method. (poster)