Nofima

Moritella viscosa, responsible for winter ulcer disease, is one of the major health and welfare challenges in Atlantic salmon aquaculture. This study investigated whether pre-bath exposure to commensal skin bacteria influences Atlantic salmon susceptibility to M. viscosa, compared cohabitation and bath challenge models to evaluate infection routes, and examined host and tissue responses, including the bacterial binding capacity of skin mucins. Pre-exposure to Atlantic salmon skin commensals Pseudomonas, Psychrobacter and Aliivibrio, which was expected to stimulate the immune system, did not mitigate M. viscosa-induced damage. Both bath and cohabitant challenge models resulted in low mortalities (6.3% and 2.6%, respectively), although a subset of fish in each model developed severe skin ulcers. M. viscosa remained persistent across sample types. Ulcerated individuals in the cohabitation model formed a distinct subgroup showing reduced growth, elevated acute inflammation marker expression in skin and heart, decreased serum protein and albumin levels, diminished heterologous and M. viscosa-specific antibody titers, and reduced IL-22 and IFNγ concentrations. In non-ulcerated fish, the skin barrier was impaired and showed features associated with M. viscosa pathogenesis, as indicated by a numerical decrease in transepithelial resistance, disrupted tight junctions, compromised epidermal integrity, increased keratocyte gaps, and a shift from acidic to more neutral mucus. Additionally, skin mucus bound both the investigated commensal bacteria and the pathogens M. viscosa and Aeromonas salmonicida.

Understanding the long-term biological consequences of crude oil exposure on marine fish is essential for the sustainability of ecologically and economically important species such as Atlantic cod (Gadus morhua). While the direct effects of crude oil on early life stages are well documented, adult reproductive vulnerability and intergenerational consequences remain poorly understood, despite their pivotal role in spawning stock viability. Paternal contributions to next-generation outcomes are particularly underexplored. This study examined how parental exposure to a water-soluble fraction of crude oil affects transcriptomic profiles and survival outcomes in Atlantic cod offspring. Adult fish were exposed for 20days prior to spawning, and offspring were produced by in vitro cross-fertilization to generate four groups: control (unexposed parents), maternally exposed, paternally exposed and biparentally exposed. Embryos were reared under control conditions, and transcriptome profiles were analyzed from fertilization to hatching, alongside assessments of cardiac function and morphology post-hatch. Offspring from exposed females failed to survive to hatching. Eggs were smaller, and transcriptomic data revealed severe downregulation of genes involved in early developmental processes. Chemical analyses confirmed maternal transfer of a diverse range of petroleum aromatic hydrocarbons to oocytes. Our findings point to disrupted oocyte provisioning, likely linked to endocrine and epigenetic disturbances during oocyte maturation. Paternal exposure had minimal effect on RNA expression, and morphology at hatching. However, reduced survival in early larval stages suggests sublethal effects emerging later, possibly through epigenetic mechanisms, a hypothesis requiring further investigation.

The tongue of teleost fish is a mucosal organ whose role in immunity remains largely understudied. Here, we performed transcriptomic analyses of the Atlantic salmon (Salmo salar) smolt tongue to investigate its baseline gene expression profile and its immune response to a bacterial challenge with Yersinia ruckeri. In the unstimulated state, transcriptomic profiling revealed that the tongue is a highly metabolically active organ with enrichment of genes involved in cytoskeletal organisation, transport, and metabolism. Gene ontology (GO) analysis identified terms associated with immune system processes indicating that the tongue maintains a state of immune readiness even in the absence of infection or pathogenic stimulation. The transcriptional body map further revealed that the tongue shares gene expression features at the naïve state with both muscular and mucosal tissues including genes related to immunity. Following bacterial exposure both ex vivo and in vivo, an immune response was observed and was characterised by the upregulation of cytokines, chemokines, and antimicrobial effectors. GO and KEGG pathway enrichment analyses identified activation of immune- and metabolism-related pathways, including immune signalling, oxidative phosphorylation, lysosome, and phagosome pathways, thus reflecting the high energetic demand of the immune response to the bacterial pathogen. These findings collectively reveal that a transient bacterial challenge elicits a metabolically demanding immune response in the salmon tongue driven by coordinated regulation of immune signalling and cellular metabolic pathways. This study demonstrates that the Atlantic salmon tongue is an active component of the mucosal immune system and provides novel insights into the intersection of metabolism and immunity in fish mucosal organs, particularly in response to a transient bacterial challenge.

The development of miniaturized tunable laser sources for mid-infrared (MIR) spectroscopy has enabled portable, application-specific analytical devices. Recent advances in quantum cascade lasers (QCLs) and interband cascade lasers (ICLs) allow precise wavelength emission in narrow spectral regions, such as 1700–1600 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mtext>cm</mml:mtext> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> , which is critical for protein characterization. In this study, we evaluate machine learning techniques for selecting the most informative wavelengths to guide the design of tunable laser systems, and for their ability to account for specific constraints such as the possibility to do fine and coarse laser wavelength tuning. We focus on optimizing variable selection for a laser-based device targeting peptide analysis and protein quality assessment in hydrolysates as a case study. We compare sparse modelling techniques (SPLS), filter-based (SPA, CovSel, g-CovSel), and compression methods (PVS, PVR), and propose a new algorithm (w-CovSel) to assess their ability to reduce noise and isolate key spectral features. Our results highlight the potential of providing data-driven approaches to obtain laser design which enables high-performance MIR instrumentation tailored to specific analytical tasks.

Abstract Bread is among the most discarded foods globally. The objective of this study was to investigate incorporating bread crumbles into baked goods as a strategy for bread waste reduction. Three bread types (white (W), whole-grain (WG), and whole-grain with seeds (S)) were converted into crumbles. These were used in bread and muffins by replacing 10–30% (bread) or 10–50% (muffins) of wheat flour. W-type crumbles had high starch, WG crumbles had high arabinoxylan, and S-type crumbles had high protein and lipid content. Dough properties were evaluated via the Farinograph and Extensograph. Crumble addition increased water absorption and development time of bread dough but decreased dough stability, extensibility, and maximum resistance to extension in a dose-dependent manner. Above 10%, crumbles reduced specific volumes (30–44% for bread, 8–9% and 14–17% at 30% and 50% in muffins, respectively), increased firmness, and made bread loaves and muffins darker. In contrast, bread with 10% and muffins with 10% and 30% crumbles possessed similar properties, including sensory attributes, to controls. Bread with S-type crumbles had a different flavor profile than other breads, particularly at higher substitution levels. Ten percent of any crumble type could be incorporated without significantly impairing quality, highlighting industrial feasibility. Above 10%, the crumble type, i.e., the ingredients for the bread used to make the crumbles, became a critical factor. This study was the first to compare crumbles from different bread types. Results showed that incorporating bread crumbles into bread and muffin recipes is a suitable strategy to recycle surplus bread and contribute to waste reduction.

In many cooperatively breeding species non-breeding individuals help to rear the offspring of breeders. The physiological mechanisms that regulate such cooperative helping behavior are poorly understood, but may have been co-opted, during the evolution of cooperative breeding, from pre-existing mechanisms that regulated parental care. Key among these may be a role for prolactin. Here we investigate whether natural variation in circulating prolactin levels predicts both parental and helper contributions to nestling provisioning in wild cooperatively breeding white-browed sparrow weavers, Plocepasser mahali. In sparrow weaver groups, a dominant pair monopolize reproduction and non-breeding subordinates help with nestling feeding. We show that: (i) among parents, females feed their nestlings at higher rates, make longer provisioning visits, and have higher prolactin levels than males; and (ii) among subordinates, engaged in cooperative helping behavior, those within their natal groups feed nestlings at higher rates and have higher prolactin levels than immigrants. Accordingly, continuous variation in prolactin levels positively predicts nestling provisioning rates and provisioning visit durations when all bird classes are combined. These relationships are principally driven by differences among bird classes; the more limited within-class variation in prolactin and provisioning traits were not evidently correlated, for which a range of potential explanations exist. While these correlative findings are broadly consistent with the hypothesis that parental care and cooperative helping behavior are regulated by a shared mechanism, experiments are now needed to establish whether prolactin plays a causal role, and if so, whether it regulates continuous variation in provisioning rate or simply activates provisioning behavior.

This study investigated immune responses to Yersinia ruckeri in the olfactory organ and brain of Atlantic salmon parr and the influence of embryonic temperature history on immunity and disease resistance. Atlantic salmon were reared at 4°C or 8°C from fertilisation to the eyed stage of embryogenesis and maintained under standard rearing conditions until the parr stage (∼20g). Fish were bath-exposed to Y. ruckeri, and immune responses were assessed at 1, 3, and 14 days post-infection (dpi). At 14 dpi, cumulative mortality in the 8°C group (∼35%) was significantly higher than in the 4°C group (∼22%). Low bacteria levels were detected in the olfactory organ and brain. Y. ruckeri antigens were present in the lamina propria of the olfactory lamellae and the optic tectum, including the meninges and nucleus of the vagus nerve. Mild histological changes, such as congestion and leukocyte infiltration were observed in the olfactory organ, although mucosal morphometric parameters were unaffected by infection or embryonic temperature history. Y. ruckeri modulated the expression of cytokines, antibacterial defence genes, and immunoglobulins in the olfactory organ. The most significant changes occurred at 3 and 14 dpi. Embryonic temperature history did not broadly alter immune gene expression, but interleukin-1β (il1b) and tumour necrosis factor-α (tnfa) had higher expression in the 8°C group. In the brain, microglial markers including aif1 and cd45 were significantly upregulated at 14 dpi, particularly in the 8°C group. This study provides insights into the nasal immune responses of Atlantic salmon to Y. ruckeri. Our findings suggest that lower embryonic temperature history influenced disease resistance against Y. ruckeri in Atlantic salmon parr, but only minimally shaped immune responses in the olfactory organ and brain following infection.

Crowding is a common aquacultural procedure and its monitoring and management is key to limiting its potential detrimental effects upon the fish. Crowding intensity in Atlantic salmon aquaculture is typically assessed manually using surface-based observations, such as changes in surface activity, or the numbers of dorsal fins or white sides that are visible during inspections of the crowd. However, surface observations, whilst having utility in many settings, do not always equate with the sub-surface behaviours of fish and the potential welfare risks that occur underwater. Here we suggest an underwater crowding risk scale for Atlantic salmon held in net pens based on underwater observations for crowd monitoring using a Remotely Operated Vehicle (ROV). The scale is based on a survey of fish farm professionals, fish welfare researchers and fish health students. A crowding event will typically fluctuate between different intensity levels over time and intensity and risk level can change in an instant. The scale is therefore based on what an ROV operator can see within a 10 s time frame, so that the ROV operator can help guide the staff managing the crowd in their corrective actions to lower the risk. This is a first attempt to make such an ROV-scale and to introduce stakeholders to the concept. It is therefore labelled v0.1. Given the importance of crowding for fish welfare, this study should be quickly followed up by work to improve and enhance the scale. • An underwater risk scale for crowding Atlantic salmon in net pens is presented. • The scale is based on a survey of fish farm professionals, fish welfare researchers and fish health students. • The scale is based on what an ROV operator can see within a 10 s time frame. • It aims to assist ROV operators in detecting potential risks so that they can guide the staff managing the crowd. • This is a first attempt to make such an ROV-scale and it is therefore labelled v0.1.