  The hypothesis of antigravitational interaction of elementary particles and
antiparticles is considered on the basis of the simple two-component
hydrodynamic model with gravitational repulsion and attraction. It is shown
increasing of the Jeans instability rate, the presence of antiscreening and the
dominative role of the gravitational repulsion as a possible mechanism for
spatial separation of matter and antimatter in Universe, as well as the
observable acceleration of the far galaxies. The sound wave is found for the
two-component gravitational-antigravitational system, which starts for k = 0 in
the case of annihilation neglecting. The suggested approach permits to
reestablish the idea about baryon symmetry of Universe, causing its steady
flatness of the large scale and accelerated Universe expansion.
