King salmon (Oncorhynchus tschawytscha) in the water.

Immunity-linked peptides boosted by plant extracts in king salmon feed trial 

Editorial team Editorial team
Published

A proprietary phytobiotic feed ingredient has been shown to enhance the expression of antimicrobial peptides involved in the innate immune system of farmed Chinook salmon (Oncorhynchus tshawytscha) during a six-month commercial feeding trial.

The study was carried out by researchers from James Cook University (Australia), New Zealand’s Cawthron Institute, the University of Waikato, OptoScale, and the New Zealand King Salmon Company and involved the inclusion of the ingredient NatControl in feed. NatControl is produced by Florida-based HP Ingredients, which primarily supplies human health nutraceuticals made from patented botanical extracts.

Key findings

  • Upregulation of HAMP (hepcidin) across multiple immune-relevant tissues, including the head kidney, spleen, liver, gills, and skin.

  • Increased expression of LEAP2 paralogues in the liver, kidney, gills, and skin.

  • Enhanced molecular indicators of innate immune readiness.

  • No negative effects on growth performance or survival throughout the study.

In a press release, HP Ingredients said that Chinook salmon, also known as king salmon, are vulnerable to infectious diseases that have tendencies to spread rapidly under farming conditions. Conventional disease control strategies, including vaccines, antibiotics and chemotherapeutics, have had success but remain limited.

Increasing immune resilience through natural agents in king salmon may be a solution, added HP Ingredients.

First full characterisation

The new study, published in the Journal of Fish Biology, provides the first comprehensive characterisation of the HAMP (hepcidin) and LEAP2 antimicrobial peptide systems in Chinook salmon and demonstrates that these important immune biomarkers are significantly modulated through dietary supplementation with NatControl.

During the trial, salmon receiving diets supplemented with NatControl exhibited significant tissue-specific increases in expression of multiple antimicrobial peptide genes.

Although the fish were maintained under non-disease challenge conditions, the observed molecular responses indicate that NatControl effectively primes the innate immune system without compromising production performance, said HP Ingredients.

Pathogen trials needed

The researchers concluded that HAMP and LEAP2 represent valuable molecular biomarkers for evaluating functional feeds and that NatControl acts as an effective dietary immunostimulant capable of enhancing innate immune readiness. However, pathogen challenge trials are required to determine whether the observed upregulation of antimicrobial peptides translates into improved survival and reduced pathogen load.

HP Ingredients said the publication further expands the growing body of scientific evidence supporting phytobiotics as an important component of sustainable aquaculture nutrition.

“Modern aquaculture continues to seek sustainable alternatives that strengthen animal health while reducing reliance on antibiotics” said the company’s chief scientific officer, Dr Juan Hancke.

“This independent research demonstrates that NatControl can enhance the fish’s natural immune preparedness at the molecular level, providing producers with another science-based tool for supporting healthy stocks.”

phytobiotics news natcontrol innate immunity chinook salmon antimicrobial peptides