18-carbon Fatty Acids Research Articles

Modulation of the Plasma Lipidomic Profile in Piglets Fed Polar Lipid-Rich Diets

Background: Polar lipids from dairy are novel sources of energy that may replace other dietary lipids and impact plasma lipidomic profiles in piglets. This study evaluated the impact of feeding diets rich in polar lipids on the plasma lipidome of piglets during the weaning period. Material and Methods: Weaned male piglets (n = 240; 21 days of age; 6.3 ± 0.5 kg of BW) were blocked by initial weight and distributed into 48 pens of five animals each in a complete randomized block design with a 2 × 3 factorial arrangement of treatments as follows: a plant-based diet rich in neutral lipids from soybeans (24 pens; SD) or a polar lipid-rich diet by-product of cheese making (24 pens; PD) from weaning until the 21st day of the nursery phase. Within each diet group, animals received one of three milk replacers (MR; 0.5 L/d/animal) for the first 7 days after weaning: (1) commercial MR containing animal and coconut lipids (CO); (2) polar lipid-based MR (PO); or (3) soybean lipids-based MR (SO). Results: The PD diet group increased the plasma concentrations of sphingolipids, phospholipids, and cholesterol esters, but did not impact the concentrations of glycerolipids (GLs). Both the PO and CO milk replacers increased the plasma concentrations of ceramide, acyl-chain phosphatidyl choline, and cholesterol esters. The plasma concentrations of GLs containing 18-carbon fatty acids such as 18:0, 18:1, 18:2, and 18:3, were higher in SD, whereas GLs containing 16:0 and 20:3 were higher in PD. Conclusions: In summary, the diet lipid type significantly modulated the plasma lipid composition in piglets 7 days after weaning. The dietary inclusion of polar lipids in diets for growing pigs can modulate the plasma lipidomic profile, relative to plant-based diets rich in soybean lipids. Cost may be a major consideration when using these lipids in pig diets. Their health benefits need to be further characterized in other models of stress and inflammation.

Comparison of zooplankton assimilation of different carbon sources and fatty acids in a eutrophic lake and its restored basins

The ecological restoration of eutrophic lakes significantly influences the food composition of zooplankton. Zooplankton serve as the principal trophic link, transferring energy from phytoplankton to fish. Understanding the alterations in zooplankton carbon source compositions following ecological restoration and the seasonal variations in this relationship is crucial. This study employs stable carbon isotope (δ13C) and fatty acid (FA) analyses to investigate the seasonal changes in carbon source contributions to zooplankton between the restored and unrestored segments of Lake Xuanwu. Results from FA analysis reveal higher proportions of algal dietary markers in zooplankton FAs in both segments during spring and autumn. Summer exhibits a shift with zooplankton utilizing more bacterial FAs in the restored part and more algal FAs in the unrestored part. While approaching winter, zooplankton in the restored part consume more algal FAs but less in the unrestored part. Zooplankton FAs enriched in δ13C are associated with assimilation of more terrestrial carbon, contrasting with depleted δ13C when zooplankton relies more on phytoplankton. Isotope mixing models indicate a substantial contribution of terrestrial carbon to zooplankton carbon sources, especially in autumn (42.3% unrestored, 51.2% restored) and winter (41.4% unrestored, 36.8% restored), while phytoplankton has a higher contribution in summer (34.5% restored, 46.9% unrestored). These findings contribute to a comprehensive understanding of carbon cycling variations in food webs between eutrophic lakes and ecologically restored lakes.

Metagenomic analysis of a top-down enriched straw biodegradation synthetic bacterial consortium (StrBsyn) facilitates anaerobic rice straw degradation

Lignocellulose is a complex and recalcitrant component of plant biomass. Traditional sources of lignocellulose-degrading microorganisms are the rumen system of herbivores and soil microorganisms, with limited studies on marine sediments. In this study, we employed a "top-down" approach to construct a straw biodegradation synthetic bacterial consortium (StrBsyn) capable of degrading lignocellulose from offshore marine sediments. It achieved 66.74 % cellulose, 63.79 % hemicellulose, and 42.85 % lignin conversion within 30 days using 0.2 % rice straws. Additionally, the maximum concentrations of total organic carbon (TOC) and total volatile fatty acids (TVFA) reached 4.66 g/ml and 15.10 g/L, respectively, with a significant increase in pH. β-glucosidase, xylanase, laccase, and lignin peroxidase activities were detected in StrBsyn. Metagenomic sequencing revealed a dynamic shift in the community composition and functional genes. The taxonomic assignment of these functional genes suggested the genera Clostridium, Glomeromyces, and Sedimentobacter as major contributors to carbohydrate transport, metabolism, and lignin degradation processes. This study demonstrated the significant potential of harnessing the power of marine sediment microbial communities for sustainable and efficient anaerobic lignocellulose bioconversion.

Transcriptional activity and variation analysis of genes critical for long-chain fatty acid (C≥16) elongation and desaturation in Pekin ducks

To deepen our understanding of long-chain fatty acid carbon chain elongation and desaturation in ducks, this study systematically analyzed the transcriptional activities of key gene promoters, including ELOVLs, FADSs, and SCDs. Predictive modeling coupled with statistical analysis revealed a prevalence of binding motifs for transcription factors, particularly those associated with Sp1, NF-1, and C/EBPalpha. Moreover, variation analysis of resequencing data from both wild and domestic ducks, specifically mallards and Pekin ducks, informed targeted mutagenesis within the core promoter regions of ELOVL2, ELOVL5, and ELOVL6. Notably, mutations at positions -56 G>C in ELOVL2, -52 T>C in ELOVL5, and -513 T>C in ELOVL6 significantly diminished transcriptional activity. These findings substantially enhance our understanding of the molecular mechanisms regulating the biosynthesis of long-chain fatty acids in ducks and support future genetic selection initiatives aimed at developing Pekin duck breeds with enhanced nutritional value.

Palmitoylation regulates norepinephrine transporter uptake, surface localization, and total expression with pathogenic implications in postural orthostatic tachycardia syndrome.

Postural orthostatic tachycardia syndrome (POTS) is an adrenergic signaling disorder characterized by excessive plasma norepinephrine, postural tachycardia, and syncope. The norepinephrine transporter (NET) modulates adrenergic homeostasis via the reuptake of extracellular catecholamines and is implicated in the pathogenesis of adrenergic and neurological disorders. In this study, we reveal NET is palmitoylated in male Sprague-Dawley rats and Lilly Laboratory Cell Porcine Kidney (LLC-PK1) cells. S-palmitoylation, or the addition of a 16-carbon saturated fatty acid, is a reversible post-translational modification responsible for the regulation of numerous biological mechanisms. We found that LLC-PK1 NET is dynamically palmitoylated, and that inhibition with the palmitoyl acyltransferase (DHHC) inhibitor, 2-bromopalmitate (2BP) results in decreased NET palmitoylation within 90 min of treatment. This result was followed closely by a reduction in transport capacity, cell surface, and total cellular NET expression after 120 min of treatment. Increasing 2BP concentrations and treatment time revealed a nearly complete loss of total NET protein. Co-expression with individual DHHCs revealed a single DHHC enzyme, DHHC1, promoted wild-type (WT) hNET palmitoylation and elevated NET protein levels. The POTS-associated NET mutant, A457P, exhibits dramatically decreased transport capacity and cell surface levels which we have confirmed in the current study. In an attempt to recover A457P NET expression, we co-expressed the A457P variant with DHHC1 to drive expression as seen with the WT protein but instead saw an increase in NET N-terminal immuno-detectable forms and fragments. Elimination of a potential palmitoylation site at cysteine 44 in the N-terminal tail of hNET resulted in a low expression phenotype mimicking the A457P hNET variant. Further investigation of A457P NET palmitoylation and surface expression is necessary, but our preliminary novel findings reveal palmitoylation as a mechanism of NET regulation and suggest that dysregulation of this process may contribute to the pathogenesis of adrenergic disorders like POTS.

Quantification of Octadecanoids in Human Plasma Using Chiral Supercritical Fluid Chromatography-Tandem Mass Spectrometry.

Octadecanoids are a subset of oxylipins derived from 18-carbon fatty acids. These compounds have historically been understudied but have more recently attracted attention to their purported biological activity. One obstacle to the study of octadecanoids has been a lack of specific analytical methods for their measurement. A particular limitation has been the need for chiral-based methods that enable separation and quantification of individual stereoisomers. The use of chirality provides an additional dimension for distinguishing analytes produced enzymatically from those formed through autoxidation. In this chapter, we describe a comprehensive method using chiral supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) for the quantification of octadecanoids in human plasma. This method stands as an effective approach for quantifying octadecanoids and is applicable to diverse research applications including clinical research.

Impact of abiotic stressors on oleic acid accumulation in the leaves of young quinoa plants

Investigating the impact of not only individual stress factors but also their combined effect on plants becomes imperative in the context of natural and climatic fluctuations. 18-carbon unsaturated fatty acids such as oleic (18:1), linoleic (18:2) and α-linolenic (18:3) serve as vital non-enzymatic antioxidants, making significant contributions to plant defense. Moreover, they are indispensable in assessing the nutritional and biological value of plant lipids. Currently, Chenopodium quinoa L., a member of the Amaranth family, is increasingly recognized as a valuable source of antioxidant metabolites. Current study examined the fluctuation patterns in oleic acid ester content, serving as a non-enzymatic antioxidant, when plant exposed to varying intensities of osmotic, saline, and combined stress. A constant concentration of oleic acid esters was shown under different levels of saline stress. Osmotic stress did not affect the oleic acid content. Under salt stress, the oleic acid content increased compared to the control, varying at different NaCl concentrations. However, under combined stress, there was a significant increase in ester content, peaking at a stress level of 200NaCl/L+PEG, followed by a decrease as stress increased. It was noted that signs of stress for the photochemical quenching index of YII and ETR in photosystem II of young quinoa plants also occur with a combination of exposure to 300 mM/L NaCl + PEG. It was suggested that the level of combined stress at 200NaCl/P is transitional from eustress to distress. The results obtained could potentially become the basis for the targeted synthesis of valuable plant antioxidants for food and pharmaceutical purposes in the future.

A further understanding of changes of wheat bran functionality induced by different types of probiotics fermentation: From molecules to regulation mechanism

Wheat bran (WB) was solid-state fermented by either Lacticaseibacillus rhamnosus (LGG), Levilactobacillus brevis (LB) or Lactiplantibacillus plantarum (LP), respectively, and then their corresponding physicochemical and metabolic characteristics were investigated. Current study revealed fermentation of either Lacticaseibacillus rhamnosus or Lactiplantibacillus plantarum quickly generated lactic acid, but not for Levilactobacillus brevis. Importantly, all LAB fermentation promoted total phenolic acids contents, fermentation of LB-WB led to the greatest total phenolic content, followed by LGG-WB, with the least for LP-WB. Moreover, LGG fermentation significantly increased levels of oleic acid, stearic acid and phosphoenolpyruvic acid on carbon metabolism and fatty acid biosynthesis, while LB fermentation mainly increased levels of L-phenylalanine, cholecalciferol, D-gluconic acid and D-glucarate with the influence on the entire metabolic pathway. In contrast, LP fermentation significantly decreased levels of alpha-ketoglutaric acid, cis-aconitic acid on the citrate cycle (TCA cycle). This study revealed their corresponding metabolic characteristics, which might highlight potentially individual nutritional aspects.

Impact of thermal hydrolysis on VFA-based carbon source production from fermentation of sludge and digestate for denitrification: experimentation and upscaling implications

Stricter nutrient discharge limits at wastewater treatment plants (WWTPs) are increasing the demand for external carbon sources for denitrification, especially at cold temperatures. Production of carbon sources at WWTP by fermentation of sewage sludge often results in low yields of soluble carbon and volatile fatty acids (VFA) and high biogas losses, limiting its feasibility for full-scale application. This study investigated the overall impact of thermal hydrolysis pre-treatment (THP) on the production of VFA for denitrification through the fermentation of municipal sludge and digestate. Fermentation products and yields, denitrification efficiency and potential impacts on methane yield in the downstream process after carbon source separation were evaluated. Fermentation of THP substrates resulted in 37–70 % higher soluble chemical oxygen demand (sCOD) concentrations than fermentation of untreated substrates but did not significantly affect VFA yield after fermentation. Nevertheless, THP had a positive impact on the denitrification rates and on the methane yields of the residual solid fraction in all experiments. Among the different carbon sources tested, the one produced from the fermentation of THP-digestate showed an overall better potential as a carbon source than other substrates (e.g. sludge). It obtained a relatively high carbon solubilisation degree (39 %) and higher concentrations of sCOD (19 g sCOD/L) and VFA (9.8 g VFACOD/L), which resulted in a higher denitrification rate (8.77 mg NOx-N/g VSS∙h). After the separation of the carbon source, the solid phase from this sample produced a methane yield of 101 mL CH4/g VS. Furthermore, fermentation of a 50:50 mixture of THP-substrate and raw sludge produced also resulted in a high VFA yield (283 g VFACOD/kg VSin) and denitrification rate of 8.74 mg NOx-N/g VSS∙h, indicating a potential for reduced treatment volumes. Calculations based on a full-scale WWTP (Käppala, Stockholm) demonstrated that the carbon sources produced could replace fossil-based methanol and meet the nitrogen effluent limit (6 mg/L) despite their ammonium content. Fermentation of 50–63 % of the available sludge at Käppala WWTP in 2028 could produce enough carbon source to replace methanol, with only an 8–20 % reduction in methane production, depending on the production process. Additionally, digestate production would be sufficient to generate 81 % of the required carbon source while also increasing methane production by 5 % if a portion of the solid residues were recirculated to the digester.

Comprehensive lipidomics and flavoromics analysis reveals the formation mechanism of the unique flavor in quail egg yolks during thermal treatment

After thermal treatment, quail eggs pruduce an attractive flavor that is favored by consumers. In this study, the key aroma volatiles and their lipid precursors during thermal treatment were investigated by the electronic nose, GC-MS, GC-O-MS and UPLC-Q-Exactive HF-X. The results exhibited that the raw and fresh flavor of raw egg yolks came from 1-Octen-3-ol, 2-Ethyl-1-hexanol, 1-Decene, and 1-Undecene. 2-Methyl-3-octanone, Toluene, and some aromatic compounds worked synergistically to contribute to the aroma profile of boiled eggs. (+)-2-Bornanone, Octanal, 2-Methyl-butanal, Nonanal, (.+Dihydro-3-hydroxy-4,4-dimethyl-2(3 H)-furanone, 6,7-Dihydro-2,5-dimethyl-5 H-cyclopentapyrazine, (E)-2-methyl-6-(1-propenyl)-pyrazine, 2-Ethyl-3,5-dimethyl-pyrazine, 3,5-Diethyl-2-methyl-pyrazine, 2,5-Dimethyl-pyrazine were the key flavor compounds in the fried egg and gave it the popcorn and roasted flavors. The statistical analysis of the lipid profile revealed that brief, high-temperature heating (100 or 200 °C for 10 min) in typical boiled and fried quail eggs had minor effects on the lipid nutritional value. PE-related lipids, particularly those containing 18-carbon fatty acids, contributed to the aroma formation of fried quail eggs.Graphical

S-acylation of Ca2+ transport proteins in cancer.

Alterations in cellular calcium (Ca2+) signals have been causally associated with the development and progression of human cancers. Cellular Ca2+ signals are generated by channels, pumps, and exchangers that move Ca2+ ions across membranes and are decoded by effector proteins in the cytosol or in organelles. S-acylation, the reversible addition of 16-carbon fatty acids to proteins, modulates the activity of Ca2+ transporters by altering their affinity for lipids, and enzymes mediating this reversible post-translational modification have also been linked to several types of cancers. Here, we compile studies reporting an association between Ca2+ transporters or S-acylation enzymes with specific cancers, as well as studies reporting or predicting the S-acylation of Ca2+ transporters. We then discuss the potential role of S-acylation in the oncogenic potential of a subset of Ca2+ transport proteins involved in cancer.

Arcobacteraceae are ubiquitous mixotrophic bacteria playing important roles in carbon, nitrogen, and sulfur cycling in global oceans.

Mixotrophy is an important trophic strategy for bacterial survival in the ocean. However, the global relevance and identity of the major mixotrophic taxa remain largely elusive. Here, we combined phylogenetic, metagenomic, and metatranscriptomic analyses to characterize ubiquitous Arcobacteraceae based on our deep-sea in situ incubations and the global data. The phylogenomic tree of Arcobacteraceae is divided into three large clades, among which members of clades A and B are almost all from terrestrial environments, while those of clade C are widely distributed in various marine habitats in addition to some terrestrial origins. All clades harbor genes putatively involved in chitin degradation, sulfide oxidation, hydrogen oxidation, thiosulfate oxidation, denitrification, dissimilatory nitrate reduction to ammonium, microaerophilic respiration, and metal (iron/manganese) reduction. Additionally, in clade C, more unique pathways were retrieved, including thiosulfate disproportionation, ethanol fermentation, methane oxidation, fatty acid oxidation, cobalamin synthesis, and dissimilatory reductions of sulfate, perchlorate, and arsenate. Within this clade, two mixotrophic Candidatus genera represented by UBA6211 and CAIJNA01 harbor genes putatively involved in the reverse tricarboxylic acid pathway for carbon fixation. Moreover, the metatranscriptomic data in deep-sea in situ incubations indicated that the latter genus is a mixotroph that conducts carbon fixation by coupling sulfur oxidation and denitrification and metabolizing organic matter. Furthermore, global metatranscriptomic data confirmed the ubiquitous distribution and global relevance of Arcobacteraceae in the expression of those corresponding genes across all oceanic regions and depths. Overall, these results highlight the contribution of previously unrecognized Arcobacteraceae to carbon, nitrogen, and sulfur cycling in global oceans.IMPORTANCEMarine microorganisms exert a profound influence on global carbon cycling and ecological relationships. Mixotrophy, characterized by the simultaneous utilization of both autotrophic and heterotrophic nutrition, has a significant impact on the global carbon cycling. This report characterizes a group of uncultivated bacteria Arcobacteraceae that thrived on the "hot time" of bulky particulate organic matter and exhibited mixotrophic strategy during the in situ organic mineralization. Compared with clades A and B, more unique metabolic pathways were retrieved in clade C, including the reverse tricarboxylic acid pathway for carbon fixation, thiosulfate disproportionation, methane oxidation, and fatty acid oxidation. Global metatranscriptomic data from the Tara Oceans expeditions confirmed the ubiquitous distribution and extensive transcriptional activity of Arcobacteraceae with the expression of genes putatively involved in carbon fixation, methane oxidation, multiple sulfur compound oxidation, and denitrification across all oceanic regions and depths.

Valorization of citrus peel industrial wastes for facile extraction of extractives, pectin, and cellulose nanocrystals through ultrasonication: An in-depth investigation

In this work we developed an eco-friendly valorisation of Citrus wastes (CWs), through a solvent-assisted ultrasonication extraction technique, thus having access to a wide range of bio-active compounds and polysaccharides, extremely useful in different industrial sectors (food, cosmetics, nutraceutical). Water-based low-amplitude ultrasonication was examined as a potential method for pectin extraction as well as polar and non-polar citrus extractives (CEs), among which hesperidin and triglycerides of 18 carbon fatty acids were found to be the most representative ones. In addition, citric acid:glycerol (1:4)-based deep eutectic solvent (DES) in combination with ultrasonic extraction was utilized to extract microcellulose (CMC), from which stable cellulose nanocrystals (CNCs) with glycerol-assisted high amplitude ultrasonication were obtained. The physical and chemical properties of the extracted polysaccharides (pectin, micro and nanocellulose) were analysed through DLS, ζ-potential, XRD, HP-SEC, SEM, AFM, TGA-DSC, FTIR, NMR, and PMP-HPLC analyses. The putative structure of the extracted citrus pectin (CP) was analysed and elucidated through enzyme-assisted hydrolysis in correlation with ESI-MS and monosaccharide composition. The developed extraction methods are expected to influence the industrial process for the valorisation of CWs and implement the circular bio-economy.

Influence of different fatty acids on the wettability, self-cleaning and anti-corrosion behavior of superhydrophobic surfaces obtained with LDH on aluminum

The present study aims to evaluate the influence of different fatty acids on the wettability, self-cleaning, and anti-corrosion properties of aluminum alloy 5052 (AA5052). Superhydrophobic surfaces are developed through acid etching with HCl solution, in-situ growth of zinc layered double hydroxides (ZnAl LDH), and chemical modification with three different fatty acids: lauric (LA), myristic (MA), and stearic (STA). SEM images show the formation of micro-nanometric binary structures of flowers and petals covered by a thin film, which is associated with ZnAl LDH formation and fatty acid deposition through EDS. The contact angle (CA) values indicate the change in the wettability of the surfaces after chemical modification, ranging from CA = 0° to CA > 160°. Visual tests reveal notable disparities in buoyancy and self-cleaning behaviors, liquid adhesion, and the formation of plastrons between the coated and uncoated samples. The results demonstrate the influence of the fatty acid carbon chain size on the CA and corrosion resistance efficiency (IE) in saline environment (NaCl 0.6 mol/l), with the STA sample exhibiting the best performance (CASTA = 164°; IESTA = 99.98 %) followed by MA (CAMA = 162°; IEMA = 99.27 %) and LA (CALA = 160°; IELA = 81.24 %). Future researchs will focus on obtaining self-healing properties and the durability of the coatings will be evaluated using accelerated testing methods.

Effect of increasing dietary inclusion of whole cottonseed on nutrient digestibility and milk production of high-producing dairy cows

We determined the effects increasing dietary inclusion of whole cottonseed (WCS) on nutrient digestibility and milk production responses of high-producing dairy cows. Twenty-four multiparous Holstein cows (mean ± SD; 52.7 ± 2.63 kg/d of milk; 104 ± 23 DIM) were randomly assigned to treatment sequences in a replicated 4 × 4 Latin square design with 21-d periods. Treatments were increasing doses of WCS at 0, 8, 16, and 24% DM, with WCS replacing soybean meal and hulls to maintain similar diet nutrient composition (%DM) of NDF (32%), forage NDF (21%), starch (27%), and CP (17%). Total fatty acid (FA) content of each treatment was 1.70, 2.96, 4.20, and 5.40%DM, respectively. Three preplanned contrasts were used to test the linear, quadratic, and cubic effects of increasing dietary WCS. Increasing dietary WCS from 0 to 24% DM quadratically influenced intakes of DM and NDF, with the highest value being for the 8% WCS, and intakes of 16- and 18-carbon, and total FA, with maximum values obtained up to 24% WCS. Increasing dietary WCS affected digestibility of DM (cubic) and NDF (quadratic), with the lowest values being for the 8% WCS. Increasing WCS increased 16-carbon digestibility (quadratic) but decreased digestibility of 18-carbon and total FA (both quadratic), with highest and lowest values for the 24% WCS, respectively. Increasing dietary WCS quadratically increased absorbed 16- and 18-carbon, and total FA, with maximum values obtained for 24% WCS. Increasing dietary WCS quadratically increased yields of milk, milk fat, milk protein, milk lactose, 3.5% fat corrected milk, and energy corrected milk, and linearly increased body weight gain. The source of milk FA was affected by dietary WCS, with a quadratic decrease in the yield of de novo and mixed milk FA and a quadratic increase in preformed milk FA. Increasing dietary WCS linearly increased trans-10 C18:1 milk FA content. As dietary WCS increased, plasma insulin linearly decreased, and plasma gossypol levels linearly increased. Despite the decrease in total FA digestibility, increasing dietary WCS from 0 to 24% DM increased FA absorption. Increasing dietary inclusion of WCS up to 16% DM increased milk production responses and DM intake. Under the current dietary conditions, high-producing dairy cows benefited best from a diet containing 8-16% DM inclusion of WCS.

Effects of abomasal infusion of soybean or sunflower lecithin on nutrient digestibility and milk production in lactating dairy cows

The fatty acid (FA) and phospholipid composition of dietary lecithin may influence FA digestibility and milk production in cattle. Eight multiparous Holstein cows (99.4 ± 9.2 DIM; 48.9 ± 3.8 kg of milk/d) were enrolled in a 3 × 3 incomplete Latin square design with 3 treatments provided as continuous abomasal infusates spanning 14-d experimental periods: water (CON), soybean lecithin (SBL; 74.5 g of deoiled soy lecithin), or sunflower lecithin (SFL; 133.5 g of hydrolyzed sunflower lecithin). Cows were fed the same diet, which contained (% DM) 27.0% NDF, 15.6% CP, 26.2% starch, and 5.87% FA. Treatments did not modify BW, milk fat, protein, or lactose contents, or the efficiency of producing ECM. Cows infused with SFL had greater milk yields than those receiving SBL or CON treatments. Cows infused with SFL had higher total solids, protein, and lactose yields than cows receiving the SBL or CON treatments. Sunflower lecithin enhanced feed efficiency (milk yield/DMI) relative to SBL or CON. Treatment did not affect intakes or apparent total-tract digestibilities for NDF, CP, starch, or 16-carbon (16C) FA. Cows receiving SFL had greater total FA and 18-carbon (18C) FA intakes than SBL or CON, but treatments did not affect their digestibility. Milk FA composition was modified by treatment. Cows receiving SFL had a greater concentration of PUFA and lower concentrations of SFA and MUFA in milk relative to SBL or CON. In conclusion, the abomasal infusion of SFL improved milk production and milk FA composition, indicating potential benefits for dairy cow nutrition and milk quality.

Effects of the palmitic-to-oleic ratio in the form of calcium salts of fatty acids on the production and digestibility in high-yielding dairy cows

The form of fat supplements, degree of saturation, and the fatty acid (FA) profile influence cows' production response. The objective was to determine the effects of supplemental fats in the form of calcium salts (CS) of FA (CSFA) with different ratios between palmitic (PA) and oleic (OA) acids on nutrient digestibility and cow performance. Forty-two dairy cows were assigned to 3 groups and fed (for 13 wk) rations that contained 2.2% CSFA (on a DM basis) with increasing PA-to-OA ratios as follows: (1) CS45:35, 45% PA and 35% OA; (2) CS60:30, 60% PA and 30% OA; and (3) CS70:20, 70% PA and 20% OA. Rumen and fecal samples were taken for VFA and digestibility measurements, respectively. Increasing the PA-to-OA ratio linearly decreased the milk and ECM yields, whereas a quadratic effect was observed for milk fat concentration (3.55%, 3.94%, and 3.87% in the CS45:35, CS60:30, and CS70:20 groups, respectively) and fat yield. Dry matter intake was highest in the CS60:30 group (33.7 kg/d) and lowest in the CS70:20 group (31.6 kg/d), and a tendency of quadratic effect was observed for calculated energy balance with no difference in BW gain among the groups. The milk-to-DMI ratio was decreased, and the ratio of ECM-to-DMI tended to decrease when the PA-to-OA ratio increased. The highest apparent total-tract digestibilities of DM, OM, and protein were observed in the CS60:30 cows, and NDF tended to decrease with increasing PA-to-OA ratio; however, digestibility of the total FA and FA subgroups (16- and 18-carbon FA) were not different among groups. Across treatments, the 18-carbon FA digestibility was higher than the 16-carbon FA digestibility. Under the current study conditions, the CS60:30 cows had the highest fat concentration and fat yield; energy output in milk; DMI; and digestibility of DM, OM, and protein. However, further research is required to fine tune the optimal FA ratio in supplemental fat sources to maximize production and efficiency under various conditions, such as production level, stage of lactation, and diet composition.

NADPH Oxidase 4 Knockout in Dahl Salt-Sensitive Rats Impacts Kidney O2 Consumption and UCP2 Responses to a High Salt Diet

Rationale: The effects of a high salt (HS) diet upon renal metabolism and O2 utilization have not been extensively studied and there is a significant gap in our understanding of the role of oxidative stress in the effciency of energy production and substrate metabolism. The present study compared the effects of a HS diet (4% NaCl) on changes in O2 consumption and transcriptomic profiles in Dahl salt-sensitive (SS) rats to SS rats with a global knockout of NADPH oxidase 4 (NOX4) gene (SS Nox4−/−). Methods: Male SS (n=9) and SS Nox4−/− (n=10) rats were fed a 0.4% NaCl (LS) diet. At 7-8 weeks of age, the rats were implanted with a renal artery ultrasonic flow probe (Transonic) together with a femoral arterial catheter and a renal venous catheter. Renal blood flow (RBF) and mean arterial pressure (MAP) were measured continuously (24/7) and arterial (A) and renal venous (Vr) blood was sampled intermittently when rats were fed the LS and on days 7, 14, and 21 after switching to the HS diet. A and Vr blood O2 content was immediately measured by radiometer. From separate groups of rats subjected to the same protocol, the renal cortical tissue (Cx) and outer medulla (OM) were removed for mRNAseq analysis (Novogene, Inc). Results: When switching to the HS diet, the average 24-hour MAP of SS rats rose from 122 ± 2 to 140 ± 2 on HS7 to 164 ± 5 mmHg by HS21. In contrast, MAP in SS Nox4−/− rats increased from 121 ± 2 at LS to 132 ± 1 at HS7 to 152 ± 3 mmHg at HS21 (p<0.05, compared to SS). RBF, normalized by changes of kidney weights obtained in another group of SS and SS Nox4−/− rats fed the same HS diet, SS rats exhibited a significant reduction of RBF over the 3 weeks of the HS diet averaging LS 7.2 ± 0.6, HS7 5.1 ± 0.5 and HS21 4.6 ± 0.7 mL/min/g kidney weight (gkw). This reduction of RBF was not observed in SS Nox4−/− rats (LS 6.8 ± 0.8, HS7 6.6 ± 0.6, HS21 6.0 ± 0.6 mL/min/gkw). The kidney O2 extraction ratio at LS tended to be lower in SS Nox4−/− (11.2 ± 1.7%) compared to SS (14.0 ± 1.1%) (p=0.10). When switched to the HS diet, O2 extraction was significantly reduced in the SS Nox4−/− rats reaching 8.3 ± 1.0% at HS21 (p<0.05), while it did not change significantly in SS (12.7 ± 1.4%) at HS21. Notably, as determined by RNAseq analysis, Ucp2 expression in cortical tissue was significantly greater in SS fed HS than in SS Nox4−/−rats at HS21 . A gene enrichment analysis of the mRNAseq cortical tissue data (GSEA-KEGG pathways) focused on metabolic pathways indicated that knockout of Nox4 resulted in reduced expression of linoleic acid, lysine, and histidine metabolism pathways at LS when compared to SS. Those differences were not observed after HS feeding. However, upregulation of oxidative phosphorylation pathway was observed at HS21 in SS Nox4−/− when compared to SS rats. In the OM, a greater expression of genes associated with fatty acid degradation and carbon metabolism was observed in SS Nox4−/− rats when fed LS which was observed also at HS21. Conclusion: The preliminary results of this study suggest that reduced extraction of O2 in the SS Nox4−/− rats compared to SS rats may be partially explained by the differential response of Ucp2 to salt. Further studies are needed to determine whether the effciency of ATP production is enhanced in SS Nox4−/− as consequence of reduction of reactive oxygen species (e.g., H2O2) and the related downstream pathways such as phosphorylation of mTORC1. R01 HL151587, AHA 23POST1008714. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Exploring the Metatranscriptome of Bacterial Communities of Two Moss Species Thriving in Different Environments-Terrestrial and Aquatic.

Mosses host diverse bacterial communities essential for their fitness, nutrient acquisition, stress tolerance, and pathogen defense. Understanding the microbiome's taxonomic composition is the first step, but unraveling their functional capabilities is crucial for grasping their ecological significance. Metagenomics characterizes microbial communities by composition, while metatranscriptomics explores gene expression, providing insights into microbiome functionality beyond the structure. Here, we present for the first time a metatranscriptomic study of two moss species, Hypnum cupressiforme (Hedw.) and Platyhypnidium riparioides (Hedw.) Dixon., renowned as key biomonitors of atmospheric and water pollution. Our investigation extends beyond taxonomic profiling and offers a profound exploration of moss bacterial communities. Pseudomonadota and Actinobacteria are the dominant bacterial phyla in both moss species, but their proportions differ. In H. cupressiforme, Actinobacteria make up 62.45% and Pseudomonadota 32.48%, while in P. riparioides, Actinobacteria account for only 25.67% and Pseudomonadota 69.08%. This phylum-level contrast is reflected in genus-level differences. Our study also shows the expression of most genes related to nitrogen cycling across both microbiomes. Additionally, functional annotation highlights disparities in pathway prevalence, including carbon dioxide fixation, photosynthesis, and fatty acid biosynthesis, among others. These findings hint at potential metabolic distinctions between microbial communities associated with different moss species, influenced by their specific genotypes and habitats. The integration of metatranscriptomic data holds promise for enhancing our understanding of bryophyte-microbe partnerships, opening avenues for novel applications in conservation, bioremediation, and sustainable agriculture.

Transcriptome and metabolome analysis reveals the salt stress-response mechanism in desert isolated Chlorella sp. DT025

Understanding salt stress-response mechanisms is beneficial for biodiesel production using microalgae. Herein, using physiological and multi-omics analyses, we revealed substance changes and the salt-stress response of Chlorella sp. DT025, isolated from a desert salt marsh. Using 15–30 g/L NaCl, high biomass (4.1–2.6 g/L) and high lipid content (45–65 %) were obtained. Under salt stress, the levels of chlorophyll synthesis-, photosynthesis-, Calvin cycle-, and starch synthesis-related differentially expressed genes (DEGs) were downregulated, while the contents of chlorophyll, most amino acids and nucleotides were decreased. Moreover, the levels of TCA cycle-, fatty acid (FA) synthesis and degradation-, glycerophospholipid metabolism-, nitrogen metabolism-, proline synthesis-, and antioxidant metabolism-related DEGs were upregulated, increasing FAs (major 16- and 18- carbon FAs), phosphatidylglycerol, lysophosphatidylglycerol, digalactosyldiacylglycerol, proline, catalase, and superoxide. These results reveal the molecular basis of salt tolerance in DT025 and suggest that it exhibits active metabolism using lipids as substances for energy storage and release under salt stress.