The effect of probiotic additives and Bacillus licheniformis inclusion in the diet on broiler growth

Abstract

Withdrawal of antibiotic growth stimulants has forced the search for alternative solutions for improving the health and productivity of poultry. One of these is the administration of probiotic strains. These additives can occur in the form of monocultures, as well as mixtures of various strains (18). Live cultures of microorganisms in the diet stimulate the activity of intestinal enzymes, the secretion of bacteriocins with antibacterial properties, acidification of the intestinal contents and local immunity within the gastrointestinal mucosa (13, 16). Probiotics induce the effects of stimulating the intestinal immune response by activating Toll-like receptors (TLRs) in the intestinal epithelium and modulating cytokine production in response to NF-κB pathway signaling (23, 31). The addition of probiotic bacteria to poultry feed causes the phenomenon of competitive displacement (33) of enteropathogens by adhesins of non-pathogenic bacteria, which after binding to TLR receptors of epithelial cells induce a non-pathogenic immune response in the small intestine (26). The beneficial effect of probiotic strains has been confirmed in many studies using various animal species (11, 25, 28). Studies on poultry confirm that the feed additive in the form of Bacillus subtilis bacteria increases bird resistance to colonization of the gastrointestinal tract by E. coli and reduces the presence of pathogenic microorganisms E. coli, Salmonella enteritidis and Clostridium perfingens in the spleen, caecum and liver in young animals (19, 20). The addition of Bacillus subtilis and The effect of probiotic additives and Bacillus licheniformis inclusion in the diet on broiler growth