Probiotic supplementation containing Bacillus velezensis enhances expression of immune regulatory genes against pigeon circovirus in pigeons (Columba livia)

• Published in: Journal of applied microbiology Vol. 130; no. 5; pp. 1695 - 1704
• Main Authors: Tsai, C.‐Y., Hu, S.‐Y., Santos, H.M., Catulin, G.E.M., Tayo, L.L., Chuang, K.P.
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01-05-2021
• Subjects: Animals; Antiviral Agents - pharmacology; Bacillus; Bacillus velezensis; Bird Diseases - immunology; Bird Diseases - virology; Birds; Circoviridae Infections - immunology; Circoviridae Infections - veterinary; Circovirus - drug effects; Circovirus - immunology; Columbidae - genetics; Columbidae - immunology; Columbidae - virology; Cytokines - genetics; Cytokines - metabolism; Dietary Supplements - microbiology; DNA, Viral; Feces; Feces - microbiology; Gene expression; Gene Expression Regulation; Genes; Immune response; Immune system; Immunity, Innate - genetics; indicator genes; Innate immunity; Interferon; Interferon-gamma; Interleukins; Myxovirus resistance proteins; Oral administration; pigeon circovirus; Pigeons; probiotic supplementation; Probiotics; Probiotics - pharmacology; Spleen; Stat1 protein; Supplements; TLR2 protein; TLR4 protein; Toll-like receptors; Transcription factors; Transducers; Viral Load; indicator genes; pigeons; pigeon circovirus; probiotic supplementation; Bacillus velezensis
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/jam.14893

Aims
In this study, we aimed to isolate and evaluate the efficacy of Bacillus velezensis as a probiotic and to assess its activity towards pigeons infected with pigeon circovirus (PiCV).
Methods and Results
Bacillus velezensis, isolated from pigeon faeces, was orally administered to pigeons for 60 days. After pigeons were challenged with PiCV, the PiCV viral load and expression of indicator genes for innate immunity were detected in spleen tissue and faeces of pigeons. Bacillus velezensis significantly reduced the PiCV viral load in the faeces and spleen of pigeons 5 days post‐challenge (dpc). The mRNA expression levels of treated pigeons showed that interferon‐gamma (IFN‐γ), myxovirus resistance 1 (Mx1), and signal transducers and activators of transcription 1 (STAT1) genes were upregulated, whereas no expression of interleukin‐4 (IL‐4) was detected. Moreover, toll‐like receptor 2 (TLR2) and 4 (TLR4) were significantly upregulated in probiotic‐treated pigeons (P < 0·05).
Conclusions
This is the first report showing that probiotic supplementation can effectively enhance the T‐helper type 1 immune response and decrease the PiCV viral loads in pigeons.
Significance and Impact of the Study
This study proposes that the administration of a probiotic strain, B. velezensis, to pigeons can protect against PiCV infection.