Metabolic changes in the organism of laying hens when using antibiotics and phytobiotics

Abstract. The use of medicinal plant extracts in animal production has recently increased due to the discovery of previously unreported side effects of antibiotics, including the cumulation of their toxic metabolites in food, as well as the increased occurrence of antibiotic resistance of microorganisms. Non-therapeutic use of antimicrobials is also associated with the spread of multiple drug resistance, including resistance to antimicrobials that have never been used in animal agriculture. It has long been known that components of plant substances have the ability to inhibit bacterial growth. It is becoming common practice to use plant essential oils to improve feed utilization by ruminants, and essential oils have long been known for their antimicrobial properties. The purpose of this work was to evaluate the metabolic effects of phytobiotic and joint use with antibiotic in controlling microbial load. According to the results obtained, it is clear that phytobiotic in addition to antimicrobial effects has other positive effects expressed in membrane stabilizing and antioxidant properties, but there are some negative effects associated with difficulty of digestion and absorption of lipid nutrients. At the same time, the combined use of phytobiotic and antibiotic showed itself as optimal, due to the good antimicrobial effect, while mitigating or eliminating the negative effects identified when using phytobiotic and enrofloxacin separately, namely, eliminating immunosuppressive and depressive effects, as well as the absence of manifestations of impaired digestion and absorption of fat-soluble nutrients. Scientific novelty. The data obtained will expand the range of antimicrobial agents used in poultry farming, as well as allow the use of more flexible schemes to control the microbial load on the body of birds.