1. Paraprobiotic supplementation to fish feed: effects on the immune support system and control of Aeromonas hydrophila infection in Labeo rohita.
- Author
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Barui, Kallol, Choudhury, Tanmoy Gon, Kamilya, Dibyendu, Devi, Arambam Ashwini, Monsang, Shongsir Joy, Rathore, Gaurav, Devi, W. Malemnganbi, and Kumar, Monalisha
- Subjects
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ROHU , *AEROMONAS hydrophila , *BACILLUS amyloliquefaciens , *ALKALINE phosphatase , *SCANNING electron microscopy - Abstract
Paraprobiotics, non-viable versions of probiotic microorganisms, offer a promising prophylactic strategy in aquaculture, addressing concerns about the safety and functionality of probiotics while harnessing similar health benefits for fish and shellfish. This study determined the dietary effects of paraprobiotic preparation from Bacillus amyloliquefaciens COFCAU_P1 to support the immune system and control Aeromonas hydrophila infection in Labeo rohita fingerlings. Paraprobiotic was prepared by heat and formalin inactivation of the probiotic B. amyloliquefaciens and subsequently analyzed by scanning electron microscopy. The cellular immunological responses viz. superoxide anion, myeloperoxidase activity, nitric oxide production, and leucocyte proliferation of rohu head-kidney (HK) leucocytes increased significantly with different doses (106, 107, and 108 cells ml−1) of both heat and formalin-inactivated preparations in vitro. Both preparations significantly enhanced the in vitro immune gene (IL-1β and IFN-γ) expression, indicating their immunostimulatory response at the molecular level. As the formalin-inactivated preparation showed a better immune response, it was selected for the subsequent in vivo experiment. Dietary administration of formalin-inactivated B. amyloliquefaciens at different doses (106, 107, and 108 cells g−1 feed) showed significantly higher responses in innate immune (respiratory burst, myeloperoxidase, and anti-protease activity) and biochemical parameters (total protein, albumin, globulin alkaline phosphatase activity, and glucose content). Resistance against experimental A. hydrophila infection was increased significantly after 30 days of feeding of the formalin-inactivated B. amyloliquefaciens. At the paraprobiotic dose of 1 × 108 cells g−1 feed, the maximum immune response and survivability against A. hydrophila infection were observed. It can be inferred from the results that formalin-inactivated B. amyloliquefaciens paraprobiotic can be used as a promising immunostimulant in aquaculture. The potency of B. amyloliquefaciens paraprobiotic to enhance immunity and survivability of rohu against experimental A. hydrophila infection is worth mentioning. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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