INFLUENCE OF SOLUTIONS OF DIFFERENT OSMOLARITY ON MORPHOMETRIC PARAMETERS OF 15-32-CELLS BOVINE EMBRYOS

Abstract

The illustrative material was obtained that allows to observe clearly the effect of different tonicity solutions on the morphology of bovine 5-days pre-compacted 15-17-cells embryos and 6-days early morulae obtained in vivo, depending on their technological state. The average values and rates of variation of the following morphometric parameters were determined in embryos at the stages of the developmental study: outer and inner zona pellucida (ZP) diameters, ZP thickness, embryonic cell mass (CM) diameter and individual embryonic cell diameters. The mentioned parameters were determined in each of the embryos consistently in intact, denuded and deblastomerised states in isotonic (0.29 Osm), hypertonic (1.5 Osm) and hypotonic (0.2 Osm) conditions. Manipulations with embryos were carried out in such a way that during consistent transfer through solutions of different osmolarity, it was possible to identify the dynamics of changes in the morphology and parameters of each of the embryos (in the intact state and after denudation) and of each of the individual embryonic cells (after deblastomerisation of the embryo). A decrease or increase in the size of the CM of embryos of the studied developmental stages during their successive transfer through solutions with different osmolarity occurred with the preservation of the approximate proportionality of their shape. After partial dehydration in hypertonia, the denuded embryos recovered their sizes mostly not fully relative to their initial sizes in the intact state in solutions of the appropriate osmolarity. Similar osmotic behavior was also observed in individual cells of deblastomerised embryos. The experimental data presented in the article make it possible to predict the behavior of embryos during micromanipulations, to determine the sequence, technique and conditions of operations with them, as well as the types, shape and sizes of microtools necessary for this.