Research of the influence of biologically active preparations of natural origin on zoological indices and quality of animal products was studied by the example of their application in broiler chicken diets in the conditions of the Republic of Belarus. On the basis of realized research it was established, that application of biologically active substances immunoamplifier Alveozan, probiotic Dialakt, probiotic Bifidoflorin liquid, prebiotic Biofon and prebiotic Biofon AIL (produced in the Republic of Belarus) did not render negative effect on quality of animal products (all studied meat samples had high quality). The received results testify to necessity of complex application of the above-stated preparations. Application of biologically active preparations made it possible to increase livability of growing birds on 100%, average live weight increase from 1,9 up to 5,1%, daily average weight gain - from 1,9 up to 5,1%, improvement of feed conversion ratio - from 18,3 up to 21%. All studied biologically active preparations made it possible to restore the physiological environment in poultry intestines, normal flora, to suppress the growth of pathogenic microorganisms. The above mentioned preparations could be applied both with preventive, and with the medical purposes

Development of diarrheal diseases of newborn animals has a miltifactorial character and it is very difficult to optimize the structure of microbial population in alimentary tract and to carry out the correction of the microbe status only by means medical preparations. Therefore, for regulation of standard structure of intestine microflora in a complex of medical and preventive measures for diarrhea diseases of young poultry an important role is played by application of probiotics, prebiotics, and immunoamplifiers. In course of study there were used biologically active preparations produced on the basis of ecologically pure products of a natural origin: immunostimulant Alveozan, probiotics Bifidoflorin liquid and Dialakt, and prebiotics Biofon АIL and Biofon. Research was realized on one-day-old broiler chickens of Kobb-500 cross. The obtained data on the positive influence of the studied preparations on microbiocenosis of an alimentary tract of broilers chickens correlated with the indexes of natural resistance (autarcesis).The analyzed preparations made it possible to increase the local protection, stimulation of hematopoiesis (increasing of hematoglobulin, erythrocytes and leukocytes); to increase the blood content of whole protein, albumens and globulins, bactericidal activity of blood serum. Complex introduction of the analysed preparations stimulated the natural disease resistance factors, normalized the metabolic function of poultry, promoted the increasing of chicken livability and productivity