New Antimicrobial Peptide Discovered in Seabream Fish Shows Dual Immune-Boosting Properties | Research

The takeaway

A novel piscidin peptide from gilthead seabream kills bacteria and stimulates immune responses, with a critical disulfide bridge for its activity.

22-residue dual-action peptide
Gb-piscidin both kills bacteria directly and stimulates immune responses in fish

What the researchers found

Gb-piscidin, a novel 22-residue class 1 piscidin from gilthead seabream, exhibits broad antimicrobial activity and immunostimulatory potential, with a Cys9-Cys16 disulfide bridge critical for function.

Why it matters

Aquaculture faces major disease challenges, and natural antimicrobial peptides from fish themselves could provide sustainable alternatives to antibiotics in fish farming.

How the study worked

Gene identification, tissue-specific expression analysis, recombinant production in E. coli, structural characterization, and biological evaluation of antimicrobial and immunomodulatory activity.

What this study cannot tell us

Single species study — applicability to other fish species or human use not established. Recombinant production in E. coli may differ from native peptide properties.

How to read the evidence

Basic research — gene identification through in vitro functional testing. No in vivo therapeutic testing reported.

When this study was published

Published in 2026; adds to the growing catalog of fish antimicrobial peptides.

The bigger picture

Fish antimicrobial peptides represent a vast, largely untapped reservoir of natural antibiotics that could benefit both aquaculture and potentially human medicine.

Questions still open

Could Gb-piscidin be used as a feed additive to prevent disease in aquaculture?
Does the disulfide bridge structure offer advantages for peptide stability in practical applications?

Common questions

What is a piscidin?

Piscidins are a family of antimicrobial peptides found naturally in fish. They are part of the fish's innate immune system and help protect against bacterial, viral, and fungal infections.

Could this help reduce antibiotic use in fish farming?

Potentially — natural antimicrobial peptides like Gb-piscidin could serve as sustainable alternatives to antibiotics in aquaculture, helping reduce the development of antibiotic-resistant bacteria.

Read the original research

Gb-piscidin: A novel antimicrobial and immunostimulant peptide from gilthead seabream (Sparus aurata) - Identification, tissue-specific expression, recombinant production, and biological evaluation.

Fish & shellfish immunology, 169, 111049

View on PubMed ↗Publisher’s paper ↗

Citation

Berenjkar, Najmeh; Kalbassi, Mohammad Reza; Hosseinkhani, Saman; Beemelmanns, Christine; Moghaddam, Jamshid Amiri. (2026). Gb-piscidin: A novel antimicrobial and immunostimulant peptide from gilthead seabream (Sparus aurata) - Identification, tissue-specific expression, recombinant production, and biological evaluation.. Fish & shellfish immunology, 169, 111049. https://doi.org/10.1016/j.fsi.2025.111049