Changes in kinetic parameters and cytological characteristics of rooster spermatozoa under the influence of technological factors

Abstract

The problems of fertility reducing of rooster semen in the cycle «native sperm-equilibration-short-term and long-term storage (cryopreservation)» are urgent. The purpose of this study was to determine the effect of different methods of preparation (centrifugation or filtration) of rooster semen on its quality characteristics, depending on the method of removing possible pollutions; to evaluate the change in the composition of the cytosol of spermatozoa of native sperm under the influence of dilution and during short-term storage. Materials and methods. Semen of roosters (n=22) of the Russian white breed was used. Experiment 1: semen was divided into 3 aliquots: I - diluted with synthetic cryoprotective medium LCM in a ratio of 1:1, II - filtered semen diluted with medium (membrane pore diameter 0.2 μm), III - centrifuged (at 3000 rpm in for 10 minutes). Native and frozen/thawed sperm were evaluated in terms of damage to spermatozoa membranes, chromatin, and acrosomes. The composition of carbohydrates and polyols of native spermatozoa was assessed under the influence of dilution and after storage (3 h). The advantage of filtration as a method of technological preparation of semen compared to centrifugation in terms of progressive motility (with rectilinear-translational movement) of sperm (41.0 % versus 27.0 %) and chromatin damage (43.4 % versus 66.4 %) has been shown. The same advantage was observed in frozen/thawed sperm filtered before freezing in terms of progressive motility (25.5 % vs. 5.5 %) and chromatin damage - 16.5 % vs. 33.6 %, respectively. Semen filtration, as a method of technological processing of rooster semen, can be an effective additional step in the preparation of semen for artificial insemination and/or short-term storage. The main component in the composition of the cytosol of native spermatozoa, according to the content of carbohydrates and polyols, was inositol - 73.7 % of ∑ carbohydrates and polyols. The level of inositol decreased during storage by 6.5 times (from 0.030 mg/ml to 0.007 mg/ml). The data obtained let us suppose the role of inositol as the main antioxidant in the cytosol of spermatozoa. Technological factors of storing rooster semen in various modes (short-term at a temperature of 5ºC and long-term at a temperature of -196ºC) have a significant impact on the ratio of sperm cytosol components (carbohydrates and polyols). A significant, 2.5-fold decrease in the relative content of inositol in the cytosol of frozen/thawed spermatozoa, compared with the indicators of native semen, allows us to recommend the introduction of the antioxidant inositol into the composition of cryoprotective media for rooster semen.