Ameliorative Role of Some Herbal Powders and Vitamins in Enhancing the Effectiveness of Antibacterial Agents and Performance of Broiler Chicken's

Bacterial infections significantly cause illness and death in humans and animals. The overuse of traditional antibiotics has led to antimicrobial resistance. The study aimed to evaluate polyherbal mixture (PHM) and trace elements as an alternative to antibiotics in poultry production, which focused on performance, carcass composition, blood profiles, serum biochemistry, liver enzymes, mortality rates, and intestinal morphology under heat stress. The experiment spanned 40 days, using a 2 x 3 factorial design, with first-factor trace elements at 0 and 5 g/kg and the second-factor PHM at 0, 25, and 50 g/kg. The study found that dietary inclusion of varying levels of PHM significantly increased the relative weight of the Bursa of Fabricius, particularly at the level of 5% (P < 0.05), but had no effect on other organs, small intestine length, ceca, average weight gain (AWG), or average feed intake (AFI) (P > 0.05). However, PHM-treated groups showed numerically lower mortality in heat-stressed chickens. Also, incorporating PHM and trace elements at different levels into broilers' diets did not significantly alter liver enzyme levels, glucose, uric acid, and lipid profiles compared to the control group (P > 0.05). However, the group receiving 5% trace elements showed a notable reduction in triglyceride and very low-density lipoprotein levels (P < 0.05). Salmonella sp. and E. coli O157:H7 were detected in the control and trace elements experimental groups. At the same time, they were not found in the cecal digesta at varying levels in the PHM experimental groups. Additionally, the PHM extract demonstrated significant antibacterial effects against Salmonella sp. and E. coli O157:H7 and E. coli ATCC at 20 mg, with maximum inhibition zones compared to other antibiotics. In conclusion, several potent bioactive components in the PHM provide antibacterial properties against E. coli and Salmonella sp. It reduces both pathogens in the cecal content of chickens reared under chronic heat stress conditions. Also, incorporating varying levels of PHM notably enhanced the feed intake and was associated with slightly lower mortality rates in heat-stressed chickens. Therefore, PHM could be used as an antibacterial agent against both Salmonella sp. and E. coli species in chickens to reduce microbial resistance.