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Dietary trace mineral (Cu, Fe, Mn, Zn, and Se) source and levels on production parameters, fillet quality, mineralization, and skin morphology of 1+ and 0+ Atlantic salmon across regions in Norway
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Extending the Shelf-Life of Live Clams, Venerupis corrugata—Important Aspects of Current Packaging and Advances in Modified Atmosphere Packaging
Full text linkVenerupis corrugata (pullet carpet shell) is a premium native clam species in Portugal. This species is highly perishable, typically sold live within 3 or 4 days, posing a significant risk of loss. Therefore, efforts to extend its shelf-life are relevant. The impact of the storage temperature (3, 5, 8 and 12 °C) on clams in plastic net bags and the effect of modified atmosphere packaging (MAP) were investigated. The survival percentage and microbiological and chemical parameters were evaluated, as well as sensory characteristics. The survival percentage and sensory aspects results indicate that the longest time with 95% live clams was observed at 5 °C and 8 °C, but lower temperatures (3 and 5 °C) have lower death rates after the threshold. In the MAP tests, the clams were kept closed due to confinement in plastic trays applying a vacuum, before gas flushing that drew the lid film over the clams. However, a negative effect of CO2 was observed for clams, with lower survival when packaged in 30% CO2. The shelf-life increased by only 1–2 days under >70% O2 with no CO2. These results show that this species is very sensitive, and MAP is not commercially effective for this application.publishedVersio
Local inflammation at the salmon louse (Lepeophtheirus salmonis) attachment site contributes to copepodid rejection in coho salmon (Oncorhynchus kisutch)
Full text linkThe study investigates the susceptibility of Atlantic salmon (Salmo salar) and Pacific salmon species (pink salmon, Oncorhynchus gorbuscha; coho salmon, Oncorhynchus kisutch; and chum salmon, Oncorhynchus keta) to the parasitic salmon lice (Lepeophtheirus salmonis). The research had two main objectives: to characterize the morphology of the scaly skin in four salmonid species and to compare the cellular response at the louse attachment site in coho salmon and Atlantic salmon. Three consecutive challenge trials were conducted, with successful louse infestation only achieved across all four species in the third trial using mild anesthesia with tricaine methanesulfonate. Skin and fin samples were collected at 12, 24, 36, 48, 60, and 168 h post-infestation (hpi) for histological, proteomic, and spatial transcriptomic analyses. Results showed that chum salmon had significantly higher mucous cell coverage (30–40%) in the epithelium of scaly skin compared to Atlantic salmon (10%). At the louse attachment site in coho salmon, there was a greater influx of inflammatory cells at 36–48 hpi compared to Atlantic salmon. Proteomic analysis at 12 hpi and 36 hpi in coho salmon showed upregulation of neutrophil degranulation and formyl-methionyl-leucyl-phenylalanine signaling. Additionally, spatial transcriptomics at the attachment site showed local upregulation of inflammatory gene markers. These findings suggest that coho salmon mount a rapid and large-scale inflammatory response driven by neutrophils to louse attachment within the first 48 hpi. Overall, the study emphasizes the significance of local changes at the host-parasite interface for resistance mechanisms against salmon lice.Local inflammation at the salmon louse (Lepeophtheirus salmonis) attachment site contributes to copepodid rejection in coho salmon (Oncorhynchus kisutch)publishedVersio
Genetic analysis of individual feed intake and efficiency in Atlantic salmon smolts using X-ray imaging
Full text linkImproving feed efficiency (FE) is poised to become a primary focus of future aquaculture breeding programs, with ongoing research aiming to incorporate this trait to increase fish production, reduce feed costs and minimize environmental impact. Selection for improving FE requires a detailed understanding of its genetic parameters and association with growth traits under commercial conditions. However, scientific studies on FE at the individual level are missing in Atlantic salmon, likely due to the absence of accurate and efficient methods for measuring individual feed intake (IFI). Here we have used X-ray imaging on 700 salmon smolts, which have consumed feed containing radio-opaque beads, to phenotype the IFI at multiple time points. The study aims to I) train and validate a deep learning image based “YOLO-XBeads” model for accurate estimation of IFI from X-ray images, II) estimate the genetic parameters of IFI and different FE metrics such as feed conversion ratio (FCR), phenotypic residual feed intake (pRFI), genetic residual feed intake (gRFI), and growth traits such as Body weight (BW), average daily gain (ADG) and whole-body fat (WBF), and III) quantify the phenotypic and genetic relationships among these traits in Atlantic salmon. The YOLO-XBeads model performed well on X-ray images, with a high correlation to the true value (R2 = 0.99) and mean absolute percentage error of 2.60 – 5.94 %. The time efficiency (two orders of magnitude faster than available software) of our model significantly reduces the analysis time, labour and cost compared to conventional image software and manual human counting. We found significant heritability estimates for IFI (0.20 ± 0.05 – 0.50 ± 0.07), ADG (0.44 ± 0.06 – 0.55 ± 0.06), BW (0.50 ± 0.06 – 0.55 ± 0.06), pRFI (0.11 ± 0.05 – 0.16 ± 0.07), gRFI (0.06 ± 0.03 – 0.18 ± 0.06), FCR (0.09 ± 0.04 – 0.23 ± 0.06) and WBF (0.61 ± 0.06), indicating potential for genetic improvement. Additionally, the strong genetic correlations (rg = 0.71 ± 0.07 – 0.98 ± 0.01) between different point estimates of the primary traits (IFI, ADG and BW) over time demonstrated the stability of these traits over the studied growth period. Averaging the FE and related traits over the whole growth period (50 – 300 g) of salmon showed variable rg between traits. The highest rg values (0.86 ± 0.05 – 0.99 ± 0.01) were observed among different FE metrics, indicating similar genetic regulation. Following this, a strong rg (0.95 ± 0.02) was found between IFI and ADG, indicating that ADG can explain a significant proportion of the genetic variation in IFI. However, we found low but significant genetic variation for pRFI and gRFI, which shows heritable variation remains after accounting for the relationships of BW and ADG with the IFI. In addition, WBF showed moderate rg (0.52 ± 0.09 – 0.64 ± 0.07) with IFI, BW and ADG traits. Conversely, FE metrics showed weak rg with ADG (0.00 ± 0.21 – 0.38 ± 0.17) as well as with WBF (−0.03 ± 0.18 – - 0.21 ± 0.19), indicating little or no indirect genetic improvement in FE through selection for growth or WBF in freshwater smolts. Overall, the FE and related traits were found to be measurable and heritable at the individual level in Atlantic salmon smolts, signifying the potential for improving economic gain and minimizing environmental impact. However, further studies are needed at the sea phase.publishedVersio
Protein hydrolysates from Italian sea bream and sea bass aquaculture side streams – chemical, biological, and techno-functional characterization
Full text linkWith the increasing demand for food and sustainable food processes, using side streams from food production has gained increased attention. After fish filleting, a significant amount of the biomass, such as heads, viscera, backbones, and skins, is left unused or utilized for low-value purposes. This biomass has high contents of valuable proteins and lipids that can be used for higher-value products, such as for human consumption or feed. This study used residual biomass from Italian sea bream and sea bass aquaculture to produce protein hydrolysates. Before hydrolysis, the biomass was pre-processed using an industrial patented dehydration process. Both pre-processed and un-processed biomasses were hydrolyzed, testing four different commercial proteases. The proximate composition of the starting materials was assessed. After hydrolysis, the yield, proximate composition, total amino acid content, and peptide size distribution of the hydrolysates were determined, showing high protein contents above 87% for all hydrolysates. The oil samples obtained after hydrolysis were analyzed for oxidation products. The protein hydrolysates were analyzed for different biological activities including antioxidant activity, anti-diabetes activity, and effect on cell growth and glucose uptake. In addition, the emulsifying properties of the hydrolysates were evaluated. The results indicate variations in chemical composition and biological activity between the hydrolysates. The most prominent differences were yield (on a dry matter basis), which was higher for the hydrolysates produced from un-processed biomass, and molecular weight distribution, which showed that the hydrolysates produced from pre-processed biomass were less hydrolyzed (AMW above 3000 g/mol) compared to hydrolysates from un-processed biomass (AMW below 2600 g/mol). In addition, the antioxidant activity was higher for the hydrolysates from un-processed biomass (22-25 µM TEAC) compared to the hydrolysates from pre-processed biomass (around 15 µM TEAC), assayed at 100 µg/mL. The results of this study are highly relevant for further evaluation and development of pre-processing technology and its effect on the final protein hydrolysate products.publishedVersio
Effekt av rigor-status før innfrysing for råstoff av torsk og hyse
Full text linkDette prosjektet har dokumentert utfordringer knyttet til innfrysning av veldig fersk torsk og hyse. Tidligere har det vært kjent at frosset pre-rigor råstoff kan medføre et større væskeslipp når det tines, men at denne effekten opphører om råstoffet fryselagres mer enn 2 måneder. Tidligere (upubliserte) forsøk har vist at fileter som fryses inn raskt etter avlivning, over tid kan utvikle en markert gulfarge gjennom fryselagring. Vi har i dette prosjektet fokusert på å dokumentere og forstå væsketap og fargeforandring for hvitfisk (torsk og hyse) som fryses inn på ulike stadier post-mortem. For å belyse dette ble både rund fisk og filet frosset inn og dette ble lagret ved ulike fryselagringstemperatur og utsatt for ulike lysregimer. Hypotesen var at fryselagringstemperatur kan påvirke væsketap og at lys er en katalysator for guling av muskelen. Resultatene viser at ved å fryse inn pre-rigor råstoff vil dette føre til et markert høyere væskeslipp ved tining. Dette gjelder for både hyse og torsk, men i vårt forsøk så opphørte denne effekten for hyse etter 8 ukers fryselagring. For torsk var væsketapet forhøyet gjennom et helt års fryselagring. På grunn av måten hyse ble fanget er det usikkert hvorvidt man kan forvente at utfordringen er begrenset til en kort periode etter innfrysing. For torsk, derimot, er utfordringen vedvarende og nærmest uavhengig av fryselagringstemperatur. Forklaringen kan være at energi i muskulaturen, som vanligvis brukes opp gjennom rigorforløpet (fisken blir stiv en periode), også kan forårsake bevegelse av iskrystaller. I praksis medfører det at iskrystallene i større grad skjærer seg gjennom cellestrukturer, noe som gir økt væsketap når cellevæske forlater muskelcellene. Siden denne væsken er næringsrik og inneholder mye proteiner og mineraler, så medfører slikt tap både et svinn av råstoff og et tap av kvalitet. Å utsette innfrysingen er en løsning for å unngå denne effekten, men samtidig vil andre nedbrytende effekter gjøre seg gjeldende om perioden blir lang (via enzymer). Fra kvalitetsmessige og praktiske årsaker vil det være viktig å finne det optimale tidspunktet for innfrysing. Resultatene våre antyder at i-rigor råstoff er lite nedbrutt av enzymer og at rigor-energien er tilstrekkelig redusert slik at væsketapet ikke blir forhøyet. Gul farge på hvitfisk er en utfordring og assosieres ofte med dårlig og gammel fisk. Dette kan komme fra gradvis oksidering av fett og blod og gjør fisken mindre hvit over tid. Den gulfargen som vi har observert for frosset pre-rigor hyse blir synlig etter relativt kort fryselagringsperiode (20 uker) og blir mer tydelig over tid. Vi så ingen guling av torsk i dette prosjektet, men tidligere forsøk (upublisert) viser at også torsk kan bli gul om den fryses raskt etter avliving. Vi hadde en hypotese om at gulfargen kunne være katalysert av lys, men all data i dette prosjektet peker mot at lys ikke har noen betydning for denne gulingen. Både frosset filet og frosset hel hyse var synlig gul etter 20 ukers fryselagring. Gulfargen er ikke en overflateeffekt, da den er gjennomgående i hele muskelen. Torsken, som i dette forsøket ikke ble gul, hadde vesentlig dårligere kondisjon enn hysa som ble brukt i tilsvarende forsøk. Siden torsken, som i tidligere forsøk var blitt gul, var i god kondisjon, er det nærliggende å anta at fiskens kondisjon kan spille en rolle for utvikling av slik farge under fryselagring. Både væsketap og misfarging er lite gunstig sett fra forbrukernes perspektiv, og slike avvik vil føre til et vesentlig økonomisk tap for bransjen. Utfordringen er på en måte dobbel siden det er stort fokus på kvalitet (fryse så tidlig som mulig) som også her gir de største utfordringene (økt væsketap og misfarging). Derfor er det viktig at næringen er klar over problemstillingen og på sikt finner de beste løsningene for å minimere slike effekter.Effekt av rigor-status før innfrysing for råstoff av torsk og hysepublishedVersio
Staphylococcus spp. eradication from surfaces by the engineered bacteriolytic enzymes
Full text linkStaphylococcus spp. are Gram-positive bacteria that can be opportunistic pathogens capable of causing life-threatening infections. Staphylococcus aureus, the most harmful species among them produces heat-resistant endotoxins, which cause food intoxications. Staphylococci may form biofilms on food-processing surfaces and become more resistant to routinely used antimicrobials. The bacteriolytic enzymes Auresine and AuresinePlus, both derived from S. aureus LytM autolysin engineered catalytic domain, were tested for their specificity and activity against various staphylococcal species and other bacteria. Both enzymes exhibited lytic activity against all tested staphylococcal species except S. pasteuri. The specificity of staphylococcal strains to these enzymes depended on the composition of their peptidoglycan cross-bridges. The bacteriolytic effect of the enzymes depended on the growth phase, initial cell number of target bacteria and the enzyme concentration applied. Bacterial elimination and bactericidal effects of both Auresine and AuresinePlus against S. aureus biofilms were confirmed by live/dead staining, with AuresinePlus showing a more pronounced effect. Additionally, Auresine and AuresinePlus presented increased effectiveness in eliminating staphylococcal cells adhered to surfaces, when combined with a detergent or the enzymes - amylase and cellulase. Importantly, cells recovered from biofilms after enzyme treatment did not display decreased susceptibility to applied enzymes, indicating the sustained efficacy of Auresine and AuresinePlus. In conclusion, Auresine and AuresinePlus demonstrate promising bactericidal activity against various staphylococcal species, highlighting their potential as antibacterial agents.publishedVersio
CRISPR-Cas9/Cas12a-based genome editing in Atlantic cod (Gadus morhua)
Full text linkAquaculture is the fastest-growing food sector worldwide but faces sustainability challenges that need to be addressed in many ways, including genetic enhancement. Atlantic cod has re-emerged as an aquaculture species and tools for genetic manipulation are needed. Thus, we compared five formats of CRISPR to determine which was most efficient to generate knock outs in Atlantic cod. Cas9 protein was presented in preformed ribonucleoprotein (RNP) complexes with single guide or with duplex guide RNAs or an mRNA encoding Cas9 was used with the same two formats of guide RNAs. Cas12a was tested as RNP complexes with single guide RNAs. We found Cas9 mRNA with single guide RNA to be the most efficient format to knock out both alleles of the slc45a2 gene, which resulted in an albino-like phenotype in up to 75% of surviving larvae. DNA analysis of individual larvae revealed mosaic genotypes with variable indel mutations. The mortality of injected eggs was high, resulting in low overall efficiency. Nevertheless, this study lays the foundation for further genetic and functional research using the CRISPR/Cas9 genome editing system in Atlantic cod.publishedVersio
Veileder: Bruk av helgenomsekvensering for forebygging og kontroll av Listeria monocytogenes i matindustrien
Full text linkDenne veilederen er utarbeidet av forskerne Solveig Langsrud, Annette Fagerlund, Trond Møretrø, Even Heir og Birgitte i Moen i prosjektet PathoSeq og er basert på både praktisk kunnskap og forskning. Det er matprodusenter som har ansvar for at maten er trygg, sammen med senere ledd i kjeden som dagligvare, restauranter og forbrukere. PathoSeq er et prosjekt med mål om økt mattrygghet gjennom å avklare potensialet til – og redusere barrierer for – bruk av helgenomsekvensering i matindustrien. Prosjektet er ledet av Annette Fagerlund ved matforskningsinstituttet Nofima og samler en tverrfaglig gruppe av aktører fra akademia, industri og interesseorganisasjoner. PathoSeq er finansiert av Bionær-programmet i Forskningsrådet (prosjekt nr 294910). Veilederen bygger i tillegg på forskning i Nofimas strategiske program, Future Food Control (Fondet for forskningsavgift på landbruksprodukter, Prosjekt 314743) og tidligere forsknings- og innovasjonsprosjekter (Forskningsmidlene for jordbruk og matindustri (prosjekt 207765) og Fiskeri- og havbruksnæringens forskningsfinansiering (prosjekt 900521)Veileder: Bruk av helgenomsekvensering for forebygging og kontroll av Listeria monocytogenes i matindustrienpublishedVersio