Category: Conference lecture

Winter wounds are an increasing welfare and economic challenge in Norwegian Atlantic salmon farming. Low seawater temperatures may suppress drinking and water uptake, potentially disturbing osmotic balance and weakening skin integrity. This study examined how temperature affects drinking activity, osmoregulation, and osmolyte regulation in Atlantic salmon.
Seawater-acclimated smolts (~200 g) were reared for six weeks at 5, 8, 12, or 16 °C (32 ppt; four replicate tanks per treatment, 20 fish per tank). Growth, water flux, drinking rate, welfare indicators, and osmolyte profiles were assessed using UPLC, Conway analysis, and NMR. Correlation analysis and principal component analysis (PCA) were used to evaluate relationships among temperature, osmolality, and free amino acid (FAA) profiles.
Temperature significantly affected growth, increasing from 43.8 g at 5 °C to 183.8 g at 16 °C. Welfare was optimal at 8–12 °C, while fish at 5 °C showed poorer fin condition and reduced drinking rate. Osmolality increased positively with temperature. Muscle TMAO remained stable (~2 mg N 100 g⁻¹) across temperatures but was undetected in skin. Most FAAs accumulated at higher levels at 5 °C in both tissues, whereas hydroxyproline, glutamine, and arginine increased at 16 °C in muscle.
Spearman correlation analysis showed predominantly negative associations between skin FAAs and osmolality, particularly for glutamine, serine, glycine, glutamate, and hydroxyproline, while temperature was positively associated with osmolality. Muscle displayed fewer and weaker correlations. PCA identified a strong coordinated FAA response in skin (PC1 = 43.7% variance), whereas muscle showed a weaker and more heterogeneous pattern (PC1 = 26.9%).
These findings suggest that low temperature suppresses drinking and gastrointestinal water flux, increasing osmotic challenge in Atlantic salmon. Fish appeared to compensate through tissue-specific FAA accumulation consistent with osmotic adjustment. Ongoing metabolite and transporter expression analyses will further clarify temperature-related osmotic regulation.

In-field assessment of internal fruit quality is challenging under daylight conditions. We demonstrate non-contact NIR interaction spectroscopy for determining total soluble solids in on-the-plant strawberries, achieving robust measurements under strong and fluctuating ambient illumination.

Ongoing sea-ice decline and expanding industrial activity in the Arctic increase the risk of crude oil exposure in ecosystems where fish reproduction is tightly synchronized with seasonal environmental cues. We conducted in vivo experiments to examine how exposure to the water-soluble fraction (WSF) of crude oil during late vitellogenesis affects reproductive development, spawning phenology, and intergenerational outcomes in polar cod (Boreogadus saida) and Atlantic cod (Gadus morhua). Repeated experiments in these gadids consistently demonstrated advancement of spawning following exposure at advanced vitellogenesis, indicating reproducible effects. In polar cod, spawning was significantly and dose-dependently advanced without detectable effects on gonadal structure, gamete quality, fertilization success, or sperm performance. However, subtle alterations in plasma sex steroids and expression of genes involved in ovarian steroidogenesis suggested endocrine modulation of pathways regulating final oocyte maturation. Sustained PAH metabolite levels indicated prolonged internal exposure and possible complex mixture effects. To assess intergenerational consequences, offspring of exposed Atlantic cod were produced via controlled in vitro crosses. Maternal exposure resulted in a marked downregulation of genes involved in early development, and a complete embryo mortality before hatching. Paternal exposure caused minimal transcriptomic effects, but reduced early larval survival, suggesting delayed or epigenetic impacts. Together, these findings show that crude oil exposure affects sensitive life stages in adults and can compromise next-generation viability. Even modest phenological shifts may influence recruitment success, highlighting the need to integrate multigenerational endpoints into population-level risk assessments for Arctic fish.

Winter wounds are an increasing skin health challenge in Norwegian Atlantic salmon farming. Temperature is a key environmental factor influencing osmoregulation, metabolism, and welfare in seawater-acclimated Salmo salar smolts, and suboptimal temperature conditions are associated with increased susceptibility to winter-related skin lesions. This study investigated how four water temperatures (5, 8, 12, and 16 °C) affect growth, welfare, and physiological responses relevant to drinking activity and osmolyte regulation. Smolts of approximately 150 g were maintained for six weeks in seawater (32 ppt) with four replicate tanks per treatment (20 fish per tank⁻¹). A commercial diet containing yttrium oxide was used for later estimation of growth, welfare, and drinking rate, and magnesium was applied as a marker of gastrointestinal water flux. Feed intake, growth performance, and welfare indicators, including cataract, scale loss, fin erosion, deformities, and skin condition, were monitored. At the end of the experiment, skin and muscle samples were collected for profiling of compatible osmolytes using ultra-performance liquid chromatography (UPLC), Conway, and nuclear magnetic resonance (NMR), as well as for quantitative PCR analysis of aquaporins and osmolyte transporters. Temperature had a strong effect on feed intake and growth, which increased progressively with increasing temperature. Most welfare indicators remained low and stable at 8-12 °C, whereas fish held at 5 °C and 16 °C showed clear increases in cataract prevalence and severity, and poor fin condition. Gastrointestinal chyme analyses indicated temperature-dependent changes in water flux and relative drinking rate, with both decreasing under low-temperature conditions. Analyses of tissue osmolyte concentrations and the transcription of key membrane transporters are ongoing. Together, these results will provide further insight into how temperature affects water balance and osmotic regulation in seawater-acclimated Atlantic salmon and may help identify physiological mechanisms underlying temperature-related skin health challenges.

The competitiveness and sustainability of modern processing industries increasingly depend on their ability to transform rich process data into actionable insight and robust control strategies. While Near-Infrared (NIR) spectroscopy is already a well-established PAT tool, many industrial applications remain constrained by surface-sensitivity, contact requirements, and limited robustness under real-world process conditions.

In this plenary lecture, I will present SenseInside, a novel non-contact, subsurface NIR sensing instrument developed in collaboration between SINTEF and Nofima, Norway, for demanding food products- it also has relevance beyond the food sector. SenseInside enables chemical and structural measurements beneath the surface (up to ~2cm) of heterogeneous materials at stand-off distances of up to ~20 cm, allowing true in-line and at-line deployment without physical contact. This capability opens new possibilities for continuous quality monitoring and process control in applications where conventional reflectance or contact-based NIR solutions fall short.

A key element of the presentation is our method of working, where sensor development is driven by real industrial challenges. We tightly integrate fundamental understanding of light–matter interaction, advanced instrumentation, and data analytics. This approach means SenseInside is scientifically sound, aligned with industrial needs, and ready for the commercialisation scaling that we have currently underway.

Advancing spectroscopic sensing technologies for real world applications, such as robot mounted, in-field quality assessment of complex food products, requires improving instrument robustness and enabling measurements under challenging conditions. Maintaining sufficient spectrometer performance within practical constraints demands balancing sensor size and cost, tolerance to environmental influences, and sample complexity. A key to success lies in a holistic understanding of the entire measurement solution, from instrumentation to sample properties and data analysis.

SINTEF and Nofima have extensive experience in pushing sensor performance through the development of novel near-infrared (NIR) interactance-based spectroscopic instruments for non-contact, non-invasive, sub-surface measurements of complex food products. Interactance measurements penetrate deeper into the product than reflectance, providing more representative sample information and enabling more robust calibration models. This advantage, however, comes at the expense of signal strength, placing higher demands on instrument performance.

Here, we demonstrate that a first-principles, physics-based approach enables successful in-field sensing under highly demanding conditions. Using a portable instrument designed for robotic operation, this approach realised accurate prediction of total soluble solids (sugar content) in on-the-plant strawberries under daylight conditions, as illustrated in Figure 1. We present our methodology for quantifying the effects of challenging environments and non-optimal instrument properties, and for understanding how the physical and chemical characteristics of complex, highly scattering food products impact measurement quality. Finally, we describe how these insights inform instrument design and strengthen multivariate calibration models, highlighting the importance of physics-based design choices for achieving robust spectroscopic sensing in real-world environments.

Near-infrared (NIR) interaction spectroscopy enables non-contact, non-destructive, subsurface sensing of layered, structurally evolving samples. Achieving robust calibration behaviour requires a better understanding of the underlying light–matter interactions governing the signal. In this work, we investigate how absorption, scattering, structural changes, and measurement geometry influence NIR interactance spectra, using water content assessment of dried salt-cured cod (clipfish) as a case study. Bulk optical properties of the fish muscle at different drying stages, previously obtained from double integrating sphere (DIS) measurements and inverse adding-doubling (IAD) analysis, were used as input for Monte Carlo simulations of the NIR interactance signal. Comparison with measured signals shows that the spectral variation during drying is primarily governed by the formation of a surface salt layer, rather than by changes in the optical properties of the muscle. This leads to distinct photon transport regimes, which explain limitations in chemometric model robustness and define requirements for robust sampling. These results demonstrate how a physics-based understanding of NIR interaction spectroscopy can improve signal interpretation, geometry selection, and calibration robustness in complex turbid media.

Food waste reduction calls for systematic change and collaboration across the value chain. Researchers have suggested an “outside the box” Life Cycle Thinking (LCT) approach to address the challenge. Studies have shown that food value chain actors tend to focus on their own food waste and rarely apply an LCT-perspective when addressing food waste. This paper seeks to shed light on how LCT can play a role in solving the food waste challenge using the bread value chain in Norway as a case study.
The hypothesis is that actors across the bread value chain have different perspectives on how to reduce bread waste, and that bread waste reduction requires an LCT-approach using insights from the whole value chain to avoid sub-optimal solutions and problem shifting. Our study adds to the state of the art by providing empirical insights to this issue within the context of bread waste.

20 semi-structured interviews with experts across the bread value chain were conducted, aiming to explore bread waste reduction using an LCT-perspective. Each expert was first asked general questions about bread waste, and then presented future scenarios for bread waste reduction.

Experts have different views regarding bread waste prevention, that vary based on their position in the value chain and what they are exposed to on a daily basis. Other contributions in the bread waste literature point to packaging optimization, nudges, tools and balancing economic incentives and the power-relationship between the various supply-chain actors as key solutions to reduce bread waste. We will discuss our results in light of this literature.

The study shed new light on how the perspectives of the actors in the bread value chain are positioned by their roles and whether or how this is related to LCT. The results can be used to inform industry and/or policymakers on how to ensure a holistic approach to bread waste reduction using a life cycle perspective.

Carotenoid pigments such as astaxanthin and canthaxanthin are responsible for the characteristic pinkred coloration of salmonid flesh, with additional pigments like adonirubin, 3-hydroxyechinenone, adonixanthin, asteroidenone, and echinenone playing roles as metabolic intermediates or minor
contributors. These pigments are not synthesised de novo by salmonids but are absorbed from the diet, metabolised in the liver, and deposited in muscle tissue. Synthetic astaxanthin is commonly used in
industry, with organic alternatives of microalgal and bacterial origin occupying a limited place in this space
with no available documentation on their pigmentation efficiency in trout. Triplicate groups of rainbow trout
(Onchorynchus mykiss) were reared from 25 g to 125 g body weight during 8 weeks in tanks, fed one of
four diets, containing no (control), or approx. 30 ppm astaxanthin (free and astaxanthin esters), synthetic– CAROPHYLL
®Pink–SA, from dried Haematococcus pluvialis–AA, or the bacterial biomass Panaferd
©–PA). CAROPHYLL
®Pink contained nearly only free astaxanthin (approx. 100,000 ppm), Haematococcus
pluvialis biomass contained mainly astaxanthin esters (97%) and less free astaxanthin (3% of 6,900 ppm
total astaxanthin), while Panaferd
© of approx. 36,000 ppm total astaxanthin contained 67% free
astaxanthin, 33% astaxanthin esters, it contained 9,640 ppm adonirubin, and lower amounts of
canthaxanthin (2,010 ppm). No treatment differences were observed on growth, biometrics, or feed
efficiency. The sum of fillet pigments was double as high in SA and PA (total carotenoid apparent
digestibility coefficient –ADC– 77 and 75%, respectively) as compared to AA (48% total carotenoid ADC).
Irrespective of pigment source, it was mostly free astaxanthin detected in the fillets. Much lower amounts
of canthaxanthin and adonirubin were identified in fillets of fish in the AA and PA treatments, in addition to
low levels of 3-hydroxyechinenon, adonixanthin, asteroidenon and echinenone detected in PA. The main
pigment analysed in the liver was again free astaxanthin, but significant amounts of adonirubin were also
found both in AA and PA, and smaller amounts of canthaxanthin were SA, AA and PA. Significant
amounts of pigment metabolites (94ppm β-caroten and 92ppm 3-hydroksyechinenon) were found in fish
faeces in AA, and PA (89ppm adonixanthin), unlike SA and control treatments.

Enhanced resistance to sea lice infestation remains one of the most important goals to
ensure sustainable Atlantic salmon farming in the marine environment. Some Pacific
salmon, notably Coho salmon, exhibit natural resistance to both Caligus rogercresseyi
(Chile) and Lepeophtheirus salmonis (Northern Hemisphere). Previous RNA-seq data
identified several Coho salmon genes that could be responsible for this difference.
To determine whether certain genes played a functional role in sea lice resistance,
CRISPR-Cas9 was used to knockout three different regions (R1 – R3) in each one of four
selected immune genes (GE1 – GE4) alongside a phenotypic marker gene (slc45a) that
produces an albino phenotype in successful knockouts. Coho salmon embryos (n=5633)
were injected with one of the four CRISPR constructs alongside slc45a, resulting in 9.3-
13.8% of alevins presenting an albino/mosaic phenotype. For wildtype (WT) controls, a
subset of embryos did not receive injections. Following development into smolts (~15
g), fish received a lice infestation challenge (100 copepodids/fish) to assess the impact
of each gene disruption on parasite susceptibility. Significantly higher lice infestations
were observed in fish with GE2 and GE4 knockouts compared to WT controls, suggesting
these genes contribute to resistance. Fin tissue from challenged fish was sequenced
(Illumina NextSeq), confirming high editing efficiency in the GE4 target, particularly at R2.
R3 edits were strongly associated with the pigment marker. Ongoing RNA-seq analysis will
evaluate how these gene disruptions affect broader expression patterns. Uncovering the
genetic basis of sea lice resistance could help develop sustainable strategies to improve
Atlantic salmon aquaculture.