Veterinary Research Forum

Abstract Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne’s disease and a potential contributor to Crohn’s disease, presents a significant challenge due to its resistance to conventional antibiotics. This necessitates the development of innovative strategies for prevention and treatment. This study aimed to evaluate the anti-bacterial activity of pathogen-specific antibodies derived from chicken egg yolks (immunoglobulin Y [IgY]) and the postbiotics from lactic acid bacteria against MAP. Immunoglobulin Y antibodies were produced by immunizing hens with formalin-killed MAP strain antigens. The IgY was extracted and purified, and the anti-MAP titers were quantified by indirect enzyme-linked immunosorbent assay. The minimum inhibitory concentration of different concentrations of specific anti-MAP IgY and the mixture of postbiotics (from four different probiotic strains, including Lactobacillus reuteri, Lactobacillus rhamnosus, Lactobacillus acidophilus, and Pediococcus acidilactici) individually and in combination against MAP was determined at various time intervals. Anti-MAP IgY titers in egg yolks increased within 2 weeks of immunization, reaching peak levels at 6 weeks. Growth inhibition assays revealed that postbiotics concentration as low as 6.25 mg mL^-1 effectively inhibited MAP growth. Anti-MAP IgY demonstrated anti-bacterial activity with a minimum inhibitory concentration of 50.00 mg mL^-1, while the combined IgY-posbiotics treatment achieved MAP growth inhibition at a minimum inhibitory concentration of 3.125 mg mL^-1. The findings of the study suggest that combination therapy with specific IgY and postbiotics may be a promising preventive strategy for controlling MAP infections. Further in vivo studies are needed to elucidate the underlying mechanisms and optimize the application of this approach for broader use in veterinary and human medicine.

Abstract American foulbrood (AFB) and European foulbrood (EFB) diseases caused by Paenibacillus larvae and Meliscococcus plutonius are prevalent honeybee brood diseases that pose significant economic challenges to the apiculture industry globally. Antibiotic treatment has led to the emergence of antibiotic-resistant strains, encouraging the search for alternative and safe measures to effectively control these diseases. Honeybee gut microbiomes have proven effects on all spectra of honeybee health by enhancing resistance to several diseases via immune modulation and the production of different antimicrobial metabolites. The major part of the gut microbiota is identified as probiotic bacteria, which are live microorganisms that, when administered in adequate amounts, confer health benefits to the host. Probiotics have shown promising health benefits for honeybees. Honeybee gut probiotics provide protection via the production of different metabolites (postbiotics), such as hydrogen peroxide, vitamins, organic acids, free fatty acids, bacteriocins, neurotransmitters, secreted bio-surfactants, and reactive oxygen species. Vast numbers of these gut bacteria and their postbiotics have wide-spectrum antibacterial effects on AFB and EFB. This review highlights the significance of the honeybee gut microbial community, its probiotic potency, and the role of postbiotic metabolites as safe prophylactic measures for preventing AFB and EFB diseases in honeybees.