TY JOUR TI THE EFFECT OF A SYMBIOTIC PREPARATION UNDER DIFFERENT SCHEMES OF THERAPEUTIC AND PREVENTIVE MEASURES IN BROILER CHICKEN REARING KW broilers KW synbiotic KW microbiome KW immunology KW productivity JO Bulletin of KSAU AU Astashev, I.V. AU Lescheva, N.A. AU Antonevskiy, I.V. AU Pleshakova, V.I. PY 2026 IS 0 PB Krasnoyarsk State Agrarian University