Transcriptomic characterisation of a common skin lesion in farmed chinook salmon.

Little is known about host responses of farmed Chinook salmon with skin lesions, despite the lesions being associated with increased water temperatures and elevated mortality rates. To address this shortfall, a transcriptomic approach was used to characterise the molecular landscape of spot lesions, the most commonly reported lesion type in New Zealand Chinook salmon, versus healthy appearing skin in fish with and without spot lesions. Many biological (gene ontology) pathways were enriched in lesion adjacent tissue, relative to control skin tissue, including proteolysis, fin regeneration, calcium ion binding, mitochondrial transport, actin cytoskeleton organisation, epithelium development, and tissue development.

A highly sensitive, non-invasive qPCR-based strategy for direct quantification of Yersinia ruckeri in fish faeces.

Finfish with asymptomatic Yersinia ruckeri infections pose a major risk as they can transmit the pathogen and cause clinical outbreaks in stock populations. Current tools have insufficient quantitative ability for accurately detecting the trace levels of Y. ruckeri typically associated with asymptomatic infection, necessitate invasive or lethal sampling, or require long processing times.

Oral vaccination of first-feeding Atlantic salmon, Salmo salar L., confers greater protection against yersiniosis than immersion vaccination.

Yersinia ruckeri is a ubiquitous pathogen of finfish capable of causing major mortalities in farmed fish stocks. It can be transmitted vertically from parent to progeny as well as horizontally in the water column from both clinically infected fish and asymptomatic carriers, and is consequently capable of infecting fish at early stages of development. Immunisation strategies that can protect small fry are therefore critical for the effective management of fish health, as is the ability to detect covertly infected fish.

Alginate Microencapsulation for Oral Immunisation of Finfish: Release Characteristics, Ex Vivo Intestinal Uptake and In Vivo Administration in Atlantic Salmon, Salmo salar L.

This study examined the feasibility of alginate microcapsules manufactured using a low-impact technology and reagents to protect orally delivered immunogens for use as immunoprophylactics for fish. Physical characteristics and protein release kinetics of the microcapsules were examined at different pH and temperature levels using a microencapsulated model protein, bovine serum albumin (BSA). Impact of the microencapsulation process on contents was determined by analysing change in bioactivity of microencapsulated lysozyme.