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Phosphatidylcholine is synthesized endogenously through the enzyme phosphatidylethanolamine-methyl transferase. As endogenous choline synthesis requires methyl groups from S-adenosylmethionine (SAM), the endogenous synthesis of choline may depend on SAM availability. SAM availability depends on methionine and ATP. SAM is also a precursor for cysteine and may affect taurine and glutathione concentrations. To investigate whether choline synthesis or transsulphuration is prioritized and the interactions between taurine and choline supplementation when methionine availability is low, juvenile Atlantic salmon were fed low methionine diets with and without taurine and choline supplementation. There were no differences in growth or protein accretion following treatments. Fish fed the low methionine diets did not develop a fatty liver, but choline supplementation increased the concentration of total phospholipids in liver and muscle. Taurine supplementation increased taurine concentrations in liver and muscle, but no interactions with choline were present. Liver SAM was unaffected by treatments. Two of three tanks fed the low methionine diet without choline and taurine supplementation had a higher gene expression of p38MAPK (mitogen activated phosphokinase). Choline supplementation to low methionine diets thus may have beneficial effect on the metabolic health and lipid transport to extra-hepatic tissues. Taurine supplementation had no effect on phospholipids status, but increased taurine concentration in tissues and as such may affect oxidation status when methionine availability is low. [ABSTRACT FROM AUTHOR]

The current study aimed to investigate the effect of surplus dietary arginine on polyamine and amino acid metabolism and accretion of proteins and lipids, as previous studies have demonstrated a lipid-reducing effect following surplus arginine supplementation in viscera as well as increased muscle growth. Four plant protein-based diets were given increasing concentrations of L-arginine, from 21.1 to 36.1 g kg-1 DM, and fed to quadruplicate tanks of adult Atlantic salmon (1.1 kg) for 12 weeks. No effects on growth or deposition of fat or protein were observed. Free amino acid concentrations and related metabolites were unaffected in the liver, except for urea, while concentrations in muscle and plasma reflected production of arginine metabolites. Polyamine concentrations were unaffected in liver, muscle and white adipose tissue ( WAT), as were the abundance and activity of spermidine/spermine N1-acetyltransferase ( SSAT), the rate-limiting enzyme in polyamine turnover. Gene expression demonstrated differential regulation of ornithine decarboxylase ( ODC) in liver and WAT, although overall little effects were observed on gene expression. Liver S-adenosylmethionine ( SAM) concentrations decreased with arginine supplementation. We suggest that adult Atlantic salmon have adapted to surplus arginine, and the main long-term effect appears to be increased concentrations of arginine metabolites. [ABSTRACT FROM AUTHOR]

Atlantic halibut juveniles, which have been fed Artemia during larval development, frequently demonstrate malpigmentation and impaired eye migration. This is in contrast to the high percentage of normally developed larvae fed copepods, reared under similar conditions. Nutrition is therefore an important component influencing larval development. Analyses of the nutrient composition of Artemia and copepods show that Atlantic halibut larvae fed Artemia probably receive sufficient amounts of vitamin A by converting canthaxanthin, while iodine may be deficient, possibly leading to interrupted thyroid hormone synthesis. An unbalanced fatty acid composition, such as high levels of arachidonic acid and low levels of docosahexaenoic acid, can be another limiting factor in Artemia. Vitamin A, fatty acids and thyroid hormones have all been shown to affect pigmentation in flatfish. They are ligands to nuclear receptors, thyroid hormone receptors, retinoic acid receptors, retinoic X receptors and peroxisomal proliferator-activated receptors, which are members of the superfamily of steroid hormone receptors. The receptors interact with each other to promote gene expression that modulates proliferation and differentiation of cells. Our hypothesis is that these interactions are important for development during flatfish metamorphosis. Very little data exist on the topic of impaired eye migration. However, energy limitation, iodine deficiency and an unbalanced fatty acid composition have been proposed as possible explanations. Here, we review the literature on development of pigment cells and the possible mechanisms behind the effects of vitamin A, fatty acids and thyroid hormone on pigmentation and eye migration during development of Atlantic halibut larvae. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The immune system is dependent on purines and pyrimidines as building blocks for DNA and RNA synthesis to enable rapid cell proliferation and protein synthesis. Emerging evidence suggests that dietary nucleotides optimize immune function. We investigated whether growth and function of human immune cells were affected by an exogenous source of nucleotides during specific antigen challenge. METHODS: Peripheral blood mononuclear cells from healthy individuals (n = 10) were stimulated with influenza virus antigen and DNA-Na(+) from fish soft roe, RNA from bakers yeast (Saccharomyces cerevisiae), 2'deoxyadenosine 5'-monophosphate sodium, 2'deoxycytidine 5'-monophosphate sodium, 2'deoxyguanosine 5'-monophosphate sodium, or 2'deoxyuridine 5'-monophosphate disodium. Growth effects were ascertained by measuring the amount of tritium-labeled Thymidine 5'-monophosphate sodium incorporated into cell DNA. Cell function was measured by detection of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha, and interleukin-10 production. RESULTS: Specific nucleotide derivatives alone did not affect the growth of healthy peripheral blood mononuclear cells. However, the nucleotide derivatives influenced immune cell growth and cytokine secretion when cocultured with specific antigen. DNA, RNA, deoxyadenosine monophosphate, deoxycytidine monophosphate, and deoxyuridine monophosphate increased influenza virus antigen-induced immune cell proliferation. In contrast, deoxyadenosine monophosphate and thymosine monophosphate inhibited the antigen-induced growth response. RNA and deoxyadenosine monophosphate cocultured with virus antigen significantly increased peripheral blood mononuclear cell secretion of IFN-gamma, interleukin-10, and tumor necrosis factor-alpha. DNA increased virus antigen-induced immune cell secretion of IFN-gamma only, whereas deoxyuridine monophosphate significantly increased secretion of interleukin-10 only. Deoxyguanosine monophosphate completely inhibited virus-triggered IFN-gamma secretion, whereas thymosine monophosphate did not change the secretion pattern of measured cytokines. CONCLUSION: Nucleotide derivatives affect growth and function of specific virus antigen-stimulated human immune cells in vitro. [ABSTRACT FROM AUTHOR]

The effect of disodium cromoglycate (DSCG) on in vitro proliferation of CD4+ and CD8+ T cells and CD19+ B cells, positively selected by immunomagnetic separation, was investigated. The cells were obtained from allergic patients with moderate serum IgE levels and mild to moderate atopic dermatitis, and healthy controls. The different cell subfractions were stimulated with mitogens or specific allergens, as well as cell supernatants from the lymphoblastoid B- (RPMI 8866) and T-hybridoma (166 A2) cell lines. Proliferative responses of T- and B-cell subsets stimulated with mitogens together with recombinant interleukin-2 (rIL4-2) or accessory cells (AC) could be inhibited by DSCG. In allergic individuals, significant allergen-specific stimulation could be observed in the CD8-depleted peripheral blood mononuclear cell (PBMC) fractions. Isolated CD4+ T cells, without AC or IL-2, could also be stimulated with specific allergen. but the responses were rather low. DSCG inhibited, concentration dependently, all allergen-induced responses. Interestingly, only atopic derived CD4+ and CD8+ T cells were stimulated by soluble low-affinity IgE receptor (Fc∊RII/sCD23) and lgE binding factor (IgEBF), including IgE enhancing factor, present in culture supernatants from RPMI 8866 and 166 A2, respectively. These responses were also inhibited by DSCG. This was in contrast to the amplifying effect of DSCG on spontaneously proliferating RPMI 8866 and 166 A2, cells, cultured in fresh cRPMI 1640 medium without sCD23 and IgE enhancing factor. Our results show that DSCG delivers an inhibitory signal or signals to PBMC subpopulations expressing Fc∊RlI/ sC D23, either upregulated by phytohemagglutinin in normal and atopic cells, or by allergens or sCD23 in atopic cells. The findings suggest that sCD23 in supernatants or in serum may reverse the general inhibitory mode of DSCG. [ABSTRACT FROM AUTHOR]

The decapeptide 1–10 of hen's egg ovalbumin (OA), deduced from the known amino acid sequence (Gly-Ser-Ile-Gly-Ala-Ala-Ser-Met-Glu-The), was synthesized by Merrifield solid phase peptide synthesis with a yield of >70%. The completeness of the insertion of amino acids during synthesis was monitored by the amino acid compositions of the peptide-resin, prior to coupling of the preceding residue. The linearity of the synthesis was supported by dansyl Edman degradation and detection of three NH: terminal residues 5-dimethylaminonaphthcline- 1-sulphonyl (DNS)-Gly, -Ser, -Ile, respectively. The peptide was purified by gel filtration chromatography and analytical reversed-phase high-performance liquid chromatography (HPLC). The homogeneity of the preparation was calculated both from the amino acid analysis and by integrating the peaks of HPLC to be >83%. The antigenicity of the purified (P2) peptide could be detected by precipitation inhibition with the nephelometric technique. The decapeptide could also specifically react with functional structures on reaginic IgE molecule from the sera of individuals allergic to eggs, inhibiting its further binding to ovalbumin. An in-vivo experiment using direct skin test on two patients allergic to eggs showed no activity, rendering further testing unnecessary. The results suggest that the decapeptide of the NH2 terminal segment of OA encompasses an Ig-binding haptenic epitope. [ABSTRACT FROM AUTHOR]

A simple and rapid method for the extraction of D-series resolvins (RvD1, RvD2, RvD3, RvD4, RvD5) released into Leibovitz's L-15 complete medium by head kidney cells from Atlantic salmon and the further determination of liquid chromatography triple quadrupole mass spectrometry is proposed. A three-level factorial design was proposed to select the optimal concentrations of internal standards that were used in the evaluation of the performance parameters, such as linear range (0.1-50 ng mL -1 ), limits of detection and quantification (0.05 and 0.1 ng mL -1 , respectively), and recovery values ranging from 96.9 to 99.8%. The optimized method was used to determine the stimulated production of resolvins by head kidney cells exposed to docosahexaenoic acid, and the results indicated that it is possible that the production was controlled by circadian responses.

Introduction: Fluid overload in patients in the intensive care unit (ICU) is associated with higher mortality. There are few randomized controlled trials to guide physicians in treating patients with fluid overload in the ICU, and no guidelines exist. We aimed to elucidate how ICU physicians from Nordic countries define, assess, and treat fluid overload in the ICU., Materials and Methods: We developed an online questionnaire with 18 questions. The questions were pre-tested and revised by specialists in intensive care medicine. Through a network of national coordinators. The survey was distributed to a wide range of Nordic ICU physicians. The distribution started on January 5th, 2022 and ended on May 6th, 2022., Results: We received a total of 1,066 responses from Denmark, Norway, Finland, Sweden, and Iceland. When assessing fluid status, respondents applied clinical parameters such as clinical examination findings, cumulative fluid balance, body weight, and urine output more frequently than cardiac/lung ultrasound, radiological appearances, and cardiac output monitoring. A large proportion of the respondents agreed that a 5% increase or more in body weight from baseline supported the diagnosis of fluid overload. The preferred de-resuscitation strategy was diuretics (91%), followed by minimization of maintenance (76%) and resuscitation fluids (71%). The majority declared that despite mild hypotension, mild hypernatremia, and ongoing vasopressor, they would not withhold treatment of fluid overload and would continue diuretics. The respondents were divided when it came to treating fluid overload with loop diuretics in patients receiving noradrenaline. Around 1% would not administer noradrenaline and diuretics simultaneously and 35% did not have a fixed upper limit for the dosage. The remaining respondents 63% reported different upper limits of noradrenaline infusion (0.05-0.50 mcg/kg/min) when administering loop diuretics., Conclusion: Self-reported practices among Nordic ICU physicians when assessing, diagnosing, and treating fluid overload reveals variability in the practice. A 5% increase in body weight was considered a minimum to support the diagnosis of fluid overload. Clinical examination findings were preferred for assessing, diagnosing and treating fluid overload, and diuretics were the preferred treatment modality., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The Department of Anesthesia and Intensive Care had received funding for other research projects from Novo Nordisk Foundation, Merchant Jakob Ehrenreich and wife Grete Ehrenreich’s Foundation, Health Insurance Denmark, and Svend Andersen’s foundation., (Copyright © 2022 Zeuthen, Wichmann, Schønemann-Lund, Järvisalo, Rubenson-Wahlin, Sigurðsson, Holen and Bestle.)

Inclusion of new environmental toxicants increase with the amount of plant ingredients substituting marine proteins and oils in feed for farmed Atlantic salmon (Salma salar). Agricultural pesticides like chlorpyrifos-methyl, present in commercial salmon feeds, may affect salmon immune and detoxification responses. Atlantic cod (Gadus morhua), surrounding the net pens, grazing on feces and uneaten pellets may be affected accordingly. The aim of this study was to analyze transcription responses in Atlantic cod head kidney tissue and isolated leukocytes following dietary chlorpyrifos-methyl inclusions and possible interactions with proinflammatory signals. Head kidney tissues and leukocytes were isolated from cod fed diets contaminated with chlorpyrifos-methyl (0.5 mg/kg, 2.4 mg/kg, 23.2 mg/kg) for 30 days. The isolated leukocytes were further challenged with bacteria (lipopolysaccharide (LPS), virus (polyinosinic acid:polycytidylic acid (PIC) mimic and l-arginine, an immuno-modulating amino acid, in vitro. The LPS-induced transcription of the interleukin genes il-1β, il-6, il-8 increased in leukocytes isolated from cod fed chlorpyrifos-methyl 23.2 mg/kg, compared to cod fed the control diet, indicating increased inflammation. Transcriptional levels of carnitine palmitoyl transferase (cpt1a), aryl hydrogen receptor (ahr) and catalase (cat) were all reduced by dietary inclusions of chlorpyrifos-methyl in the leukocytes. The findings suggests that dietary chlorpyrifos-methyl exposure impair inflammation, detoxification and redox signaling in cod leukocytes., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The objective of this study was to evaluate if the intestinal RTgutGC cell line could be suitable for research on dietary ingredients and their function as modulators of inflammation during lipopolysaccharide (LPS) induced stress. The RTgutGC cells cultured together with RNA from baker's yeast, reached confluency after 72 h. The cells were grown in either compete L-15 (CM) or nutrient deprived L-15 (DM). Then, the RTgutGC cells were exposed to LPS or RNA from baker's yeast, either alone, or in combination, in CM or DM. All cultures were harvested following LPS challenge for 48 h and 72 h. LPS induced transcription of Interleukin 1β (IL-1β), Interleukin -8 (IL-8), Toll like receptor 3 (TLR3), interferon regulating factor 3 (irf3), Nuclear factor ĸβ (NFĸβ), one of the multidrug transporters, ABCC2, and glutamine synthase 1 (GLS01) in RTgutGC cells at one or both sampling points (48 h and/or 72 h post LPS challenge). RNA from baker's yeast in culture alone, (cultured 120 h and 144 h with RTgutGC cells and harvested at the respective LPS sampling points) induced transcription of INF1, TNFα and ticam/trif, not induced by LPS. In addition, RNA from baker's yeast affected IL-1β, TLR3, irf3 and NFĸβ, comparable to the responses triggered by LPS. RNA from baker's yeast alone did not affect ABCC2 or GLS01 transcriptions in this set up. So, LPS and RNA from baker's yeast affects distinct but also common gene transcripts in this intestinal cell line. Culturing RTgutGC cells in DM, adding a combination of LPS and RNA from baker's yeast, reduced IL-1β transcription compared to cells grown in CM, 48 h and 72 h post LPS challenge. Also, in RTgutGC cells, grown in DM, the LPS induced transcription of ABCC2 declined, measured 48 h post LPS challenge. Possibly indicating that optimal transcription of IL-1β and ABBC2 in RTgutGC cells, cultured over time, requires access of adequate nutrients under stressful condition. RNA from baker's yeast induced INF1 transcription in the RTgutGC cells, regardless if the medium was complete or deprived of nutrients. However, culturing RTgutGC cells in DM enriched with RNA from baker's yeast for a longer period of time (120 h, 144 h), seemed beneficial for INF1 transcription., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Polyunsaturated fatty acids such as arachidonic and eicosapentaenoic acids are the precursors of eicosanoid metabolites (e.g prostaglandins and prostacyclins) which regulate inflammatory and immune response processes in fish organs. The present research studies the differential production of PGI 2 , PGI 3 , PGE 2 and PGE 3 by primary liver and head kidney cells isolated from salmon and challenged with single or combined ARA and/or EPA. There was a significant increase in the production of PGE 2 and PGI 3 in both types of cells after exposure to single and combined fatty acids. Increased production of PGE 3 was only detected in liver cells after exposure to ARA+EPA. The levels of PGI 2 in liver cells were significantly increased after exposure to all the tested fatty acid systems, while the production levels in head kidney cells were only significant after exposure to ARA or ARA+EPA, but not to EPA, where the production was non-significantly decreased compared to the control cells. In general, liver cells synthetized higher prostaglandin levels than prostacyclins, and the opposite was observed in head kidney cells, which synthetized highly remarkable amounts of prostacyclin compared to liver cells. The overall production for both types of cells and various fatty acid systems were characterized by a high proportion of the omega-3 fatty acid metabolites (PGE 3 +PGI 3 ) compared to the omega-6 counterpart (PGE 2 +PGI 2 ). Some potential production mechanisms are proposed and comprehensively discussed. The results of the present research are the first to deliver the differential production of prostacyclins and prostaglandins by liver and head kidney cells from salmon, thereby paving the way for understanding the significance of these prostanoids in fish physiology and disease., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Author(s). Published by Elsevier Ltd.)