Lactic Acid Bacteria in Finfish-An Update

Area of Science:

• Aquaculture
• Microbiology
• Immunology

Background:

• Lactic acid bacteria (LAB) are key microorganisms in the fish gastrointestinal tract, offering benefits like improved digestion and immunity.
• Traditional culture-dependent methods have limitations; culture-independent techniques now reveal diverse indigenous LAB species including Lactobacillus and Lactococcus.
• Many LAB strains produce antibacterial substances, positioning them as promising probiotics for aquaculture.

Purpose of the Study:

• To review recent findings on the isolation, detection, and probiotic use of LAB in aquaculture.
• To examine the impact of LAB on finfish immune responses, including innate immunity.
• To discuss pathogenic LAB in finfish and potential treatment strategies.

Main Methods:

• Literature review focusing on culture-independent techniques for LAB identification.
• Analysis of studies evaluating LAB administration as probiotics in finfish.
• Examination of research on LAB's effects on fish innate and adaptive immunity.

Main Results:

• LAB administration generally shows beneficial effects on finfish growth, reproduction, immune response, and disease resistance.
• LAB enhance innate immunity through increased neutrophil activity, lysozyme secretion, phagocytosis, and cytokine production (e.g., IL-1β, IL-6, TNF-α).
• Some LAB strains can induce anti-inflammatory cytokines like IL-10, indicating varied immunological effects based on host and strain.

Conclusions:

• LAB are valuable probiotics in aquaculture, improving fish health and disease resistance.
• Further research is needed to understand LAB's role in modulating adaptive immunity in finfish.
• Understanding LAB-fish immune interactions is crucial for optimizing probiotic applications in aquaculture.