ORIGINAL RESEARCH article

Front. Genet.

Sec. Livestock Genomics

Volume 16 - 2025 | doi: 10.3389/fgene.2025.1633603

Sea lice (Lepeophtheirus salmonis) life stage impacts Atlantic salmon transcriptomic responses under different thermal profiles

Provisionally accepted
  • 1University of Prince Edward Island Department of Pathology & Microbiology, Charlottetown, Canada
  • 2City University of Hong Kong Jockey Club College of Veterinary Medicine and Life Sciences, Hong Kong, Hong Kong, SAR China

The final, formatted version of the article will be published soon.

Sea lice (Lepeophtheirus salmonis) infestation continues to pose a persistent and escalating challenge to the global salmon aquaculture industry. Given the complexity of host-parasite interactions, family-based transcriptomic studies provide crucial insights into genetic variation in host responses to sea lice, potentially guiding the development of selective breeding programs to manage parasite resistance in Atlantic salmon. This study investigated global gene expression (transcriptomic) responses of the skin and head kidney of Atlantic salmon (Salmo salar) from different families following infestation at two distinct stages of sea lice, chalimus II and adult, under varying temperature conditions (10 °C and 20 °C). RNA sequencing results revealed consistent expression of lice-responsive genes across different families under varying thermal conditions, which allowed the identification of potential biomarkers associated with adult-stage compared to chalimus-stage infestations. Our findings highlight critical physiological disruptions in salmon infested with advanced (adult) stages of lice, including uncontrolled and persistent inflammation, dampened/dysregulated immune responses, and impaired tissue repair at attachment sites. This study provides a comprehensive analysis of the transcriptomic responses of Atlantic salmon to different developmental stages of sea lice under specific temperature conditions (10 °C and 20 °C), and identifies several novel molecular markers from RNA-seq analysis that may be instrumental in developing targeted control strategies for this economically important parasite.

Keywords: Parasitic infestation, family-specific transcriptomics, genetic background, Infestation stage, selective breeding

Received: 23 May 2025; Accepted: 02 Jul 2025.

Copyright: © 2025 Ghanei-Motlagh, CAI, Poley, Whyte, Garber and Fast. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Reza Ghanei-Motlagh, University of Prince Edward Island Department of Pathology & Microbiology, Charlottetown, Canada
Mark D Fast, University of Prince Edward Island Department of Pathology & Microbiology, Charlottetown, Canada

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