A Microbial Feed Additive Abates Intestinal Inflammation in Atlantic Salmon

Area of Science:

• Aquaculture
• Fish immunology
• Microbial ecology

Background:

• Intestinal inflammation poses a significant challenge in Atlantic salmon aquaculture.
• Maintaining gut health is crucial for fish growth and welfare.
• Microbial feed additives are explored as a strategy to enhance fish gut health.

Purpose of the Study:

• To evaluate the efficacy of a microbial feed additive (Bactocell®) in mitigating experimentally induced intestinal inflammation in Atlantic salmon.
• To investigate the impact of the probiotic on intestinal micromorphology, gene expression, and proteomic profiles during inflammation.

Main Methods:

• Atlantic salmon were fed either a probiotic-coated feed (Bactocell®) or a control feed for 6 weeks.
• Intestinal inflammation was induced via oxazolone intubation at week 3.
• Intestinal tissues were collected at 4 hours, 24 hours, and 3 weeks post-induction for analysis.
• Analyses included intestinal micromorphology, quantitative PCR for inflammatory genes, and proteomic profiling.

Main Results:

• Oxazolone induced significant inflammatory responses in both groups at 24 hours, characterized by edema, villi widening, and immune cell infiltration.
• The control group exhibited higher expression of inflammatory genes (mul1b, il1b, tnfa, ifng) compared to the probiotic group.
• Proteomic analysis in the probiotic group revealed five differentially regulated proteins (Calr, Psma5, Trp1, Ctsb, Naga) at 24 hours post-induction.
• Inflammatory responses subsided by 3 weeks in the probiotic-treated group.

Conclusions:

• The microbial feed additive Bactocell® demonstrates efficacy in counteracting intestinal inflammation in Atlantic salmon.
• Bactocell® supports the restoration of intestinal homeostasis following inflammatory challenges.
• This study provides evidence for the beneficial role of microbial additives in salmon aquaculture for improved gut health.