Abstract
Introduction: Salmonella enterica serovar Typhimurium is one of the most common nontyphoidal Salmonella serovars affecting poultry production worldwide. Moreover, its increasing resistance to antibiotics has made treatment extremely challenging. Leech saliva contains compounds that confer natural antibacterial and immunomodulatory properties.
Objectives: This study aimed to examine whether treatment with leech saliva alone or in combination with gentamicin reduces the severity of infection in chickens experimentally infected with Salmonella Typhimurium.
Methods: A total of 60 Ross 308 chicks were randomly and equally allocated to four groups: a control group, a gentamicin-treated group, a leech saliva-treated group, and a dual therapy group receiving both leech saliva and gentamicin. Bacterial load, gross pathology changes, and histopathological alterations in the spleen, liver, and intestine were examined over five days.
Results: Monotherapy with leech saliva moderately reduced the microbial load and infection-associated tissue damage caused by S. Typhimurium, whereas gentamicin monotherapy showed greater efficiency. Compared with either monotherapy, combination therapy yielded the most favorable outcomes, demonstrating significantly enhanced bacterial clearance and a greater reduction in pathological changes (P<0.05). Histopathological scores further demonstrated that combination therapy markedly decreased enteritis as well as hepatic and splenic necrosis compared with both monotherapy groups.
Conclusion: The findings indicate that leech saliva exerts a beneficial antimicrobial adjunctive effect. This natural compound may be used as a valuable adjunct in treatments and represents a promising strategy for combating the multidrug resistance of S. Typhimurium in poultry.