Long-chain polyunsaturated fatty acids and inflammation

Schizochytrium sp. and lactoferrin supplementation alleviates Escherichia coli K99-induced diarrhea in preweaning dairy calves

Calf diarrhea, a common disease mainly induced by Escherichia coli infection, is one of the main reasons for nonpredator losses. Hence, an effective nonantibacterial approach to prevent calf diarrhea has become an emerging requirement. This study evaluated the microalgae Schizochytrium sp. (SZ) and lactoferrin (LF) as a nutrient intervention approach against E. coli O101:K99-induced preweaning calve diarrhea. Fifty 1-d-old male Holstein calves were randomly divided into 5 groups (n = 10): (1) control, (2) blank (no supplement or challenge), (3) 1 g/d LF, (4) 20 g/d SZ, or (5) 1 g/d LF plus 20 g/d SZ (LFSZ). The experimental period lasted 14 d. On the morning of d 7, calves were challenged with 1 × 1011 cfu of E. coli O101:K99, and rectum feces were collected on 3, 12, 24, and 168 h postchallenge for the control, LF, SZ, and LFSZ groups. The rectal feces of the blank group were collected on d 14. Data were analyzed using the mixed procedure of SAS (version 9.4; SAS Institute Inc.). The E. coli K99 challenge decreased the average daily gain (ADG) and increased feed-to-gain ratio (F:G) and diarrhea frequency (control vs. blank). Compared with the control group, the LFSZ group had a higher ADG and lower F:G, and the LFSZ and SZ groups had lower diarrhea frequency compared with the control group. In addition, the LFSZ and SZ groups have no differences in diarrhea frequency compared with the blank group. Compared with the control group, the blank group had lower serum nitric oxide (NO), endothelin-1, d-lactic acid (D-LA), and lipopolysaccharide (LPS) concentrations, as well as serum IgG, IL-1β, IL-6, IL-10, and TNF-α levels on d 7 and 14. On d 7, compared with the control group, all treatment groups had lower serum NO level, the SZ group had a lower serum D-LA concentration, and the LF and LFSZ groups had lower serum LPS concentration. On d 14, compared with the control group, the fecal microbiota of the blank group had lower Shannon, Simpson, Chao1, and ACE indexes, the LFSZ group had lower Shannon and Simpson indexes, the SZ and LFSZ groups had a higher Chao1 index, and all treatment groups had a higher ACE index. In fecal microbiota, Bifidobacterium and Actinobacteria were negatively associated with IL-10 and d-lactate, while Akkermansia was negatively associated with endothelin-1 and positively correlated with LPS, fecal scores, and d-lactate levels. Our results indicated that LF and SZ supplements could alleviate E. coli O101:K99-induced calf diarrhea individually or in combination. Supplementing 1 g/d LF and 20 g/d SZ could be a potential nutrient intervention approach to prevent bacterial diarrhea in calves.

Omega-3 Fatty Acids and Balanced Gut Microbiota on Chronic Inflammatory Diseases: A Close Look at Ulcerative Colitis and Rheumatoid Arthritis Pathogenesis

The aim of this article was to review experimental and clinical studies regarding the use of omega-3 fatty acids on the prevention and control of chronic inflammatory diseases with autoimmune background through the gut microbiota modulation. For this, natural omega-3 sources are presented emphasizing the importance of a healthy diet for the body's homeostasis and the enzymatic processes that these fatty acids go through once inside the body. The pathogenesis of ulcerative colitis and rheumatoid arthritis are revisited under the light of the gut microbiota dysbiosis approach and how those fatty acids are able to prevent and control these two pathological conditions that are responsible for the global chronic burden and functional disability and life-threatening comorbidities if not treated properly. As a matter of reflection, as we are living a pandemic crisis owing to COVID-19 infection, we present the potential of omega-3 in preventing a poor prognosis once they contribute to balancing the immune system modulation the inflammatory process.

Effect of dietary n-3 polyunsaturated fatty acids on the composition of cecal microbiome of Lohmann hens

Supplementation of n-3 fatty acids to poultry diets is widely acknowledged for its role in enhancing poultry products, however, little is known about the compositional responses of gut microbial communities to type and dosage of these supplements.  Here, we compared the effects of n-3 polyunsaturated fatty acids (PUFA), supplied as alpha-linolenic acid (ALA) or docosahexaenoic acid (DHA), on the composition of bacterial communities in ceca of laying hens.  Corn-soybean basal diets were supplemented with either flaxseed oil (FO, ALA-rich) or marine algal biomass (MA, DHA-rich), and each supplied 0.20 and 0.60% of total n-3 PUFA in the diet.  Lohmann LSL-Classic laying hens (n = 10/treatment) were randomly allocated to one of the 4 diets.  After 8 weeks of feeding, blood, liver and cecal digesta samples were obtained for plasma glucose, fatty acids, and short chain fatty acids analyses, respectively.  The gut bacterial communities were characterized using genomic DNA extracted from cecal contents, whereby the V3-V4 hypervariable region of the 16S rRNA gene was sequenced using the Illumina Miseq® platform.  Firmicutes and Bacteroidetes were the predominant phyla in both the FO- and MA-fed groups.  The relative abundance of Tenericutes, often associated with immunomodulation, was relatively higher (P<0.0001) in the FO than MA group.  Although the relative abundance of Bacteroides was greater for the FO- than the MA-fed group, this genus was negatively correlated (P<0.05) with total n-3 PUFA in the liver at higher dosages of both FO- and MA-fed hens.  Higher dose of FO (0.60%) and both dosages of MA (0.20 and 0.60%) substantially enriched several members of Firmicutes (e.g., Faecalibacterium, Clostridium and Ruminococcus) which are known to produce butyrate.  Moreover, co-occurrence network analysis revealed that, in the FO 0.60- and MA 0.20-fed hens, Ruminococcaceae was the most influential taxon accounting for about 31% of the network complexity.  These findings demonstrate that supplementation of different type and level of n-3 PUFA in hens' diets could enrich microbial communities with potential role in lipid metabolism and health.

The effect of docosahexaenoic acid-rich algae supplementation in milk replacer on performance and selected immune system functions in calves

The aim of this study was to determine the effect of docosahexaenoic acid-rich algae (DHA-RA) supplementation in milk replacer (MR) on performance, selected cytokine expression in lymphocytes, and blood immunoglobulin concentration in newborn dairy calves. Forty female Holstein-Friesian calves (8.6 ± 0.8 d old and 41.1 ± 4.3 kg; mean ± standard deviation) were blocked by date of birth and allocated into 4 experimental groups (10 animals/group): (1) not supplemented with DHA-RA, (2) supplemented with 9 g of DHA-RA/d in MR, (3) supplemented with 18 g of DHA-RA/d in MR, and (4) supplemented with 27 g of DHA-RA/d in MR. Milk replacer was fed in an amount equal to 900 g of MR powder/d (as fed), 2 times a d, for 49 d. Starter mixture (SM) was fed ad libitum beginning on d 15 of the study. Each calf was in the study over a period of 49 d. The MR and SM intake and fecal score were recorded daily and body weight was recorded weekly. Blood samples were collected before the morning feeding, at the beginning of the study, every consecutive week, and at the end of the study for morphology and smear analysis, serum immunoglobulin level (IgG, IgA, and IgM), and lymphocyte isolation. The mRNA isolated from lymphocytes was checked for TNFα, IL-1β, IL-6, and p65 expression. Average daily gain between d 1 to 14 of the study increased quadratically with increasing dose of DHA-RA. However, average daily gain between d 15 to 49 of the study tended to linearly decrease and over the whole study linearly decreased with increasing dose of DHA-RA. The MR intake decreased linearly between d 1 to 14 of the study and over the whole study, and mean SM intake decreased quadratically with increasing dose of DHA-RA. Feed efficiency increased quadratically and fecal score decreased quadratically during the first 14 d of the study. Increasing dose of DHA-RA led to cubic changes in feed efficiency and fecal score between d 15 and 49 of the study. Overall, over the whole study period a tendency was observed for lower fecal score for the DHA-RA supplemented groups. Interleukin-1β mRNA expression decreased linearly, whereas the mRNA expression of p65 and TNFα as well as serum IgG concentration tended to decrease linearly with increasing dose of supplemental DHA-RA. No effect of group was found on IgA and IgM serum level and the majority of blood parameters. Altogether, treatment worsened production variables but seemed to have a beneficial effect on the immune system of calves.

Dietary Supplementation With ω6 LC-PUFA-Rich Algae Modulates Zebrafish Immune Function and Improves Resistance to Streptococcal Infection

Arachidonic acid (ARA, 20:4n-6) and dihomo-γ-linolenic acid (DGLA, 20:3n-6) are omega-6 long-chain polyunsaturated fatty acids (LC-PUFA), which are key precursors for lipid mediators of the immune system and inflammatory response. The microalga Lobosphaera incisa (WT) and its Δ5-desaturase mutant P127 (MUT) are unique photosynthetic sources for ARA and DGLA, respectively. This study explores the effect of dietary supplementation with L. incisa and P127 biomass on tissue fatty acid composition, immune function, and disease resistance in zebrafish (Danio rerio). The broken microalgal biomass was added to commercial fish feed at 7.5 and 15% (w/w), providing 21.8 mg/g feed ARA for the WT-supplemented group and 13.6 mg/g feed DGLA for the MUT-supplemented group at the 15% inclusion levels. An unsupplemented group was used as the control. After 1 month of feeding, fish were challenged with Streptococcus iniae. Fish were sampled before the challenge and 1 week after the challenge for various analyses. Tissue ARA and DGLA levels significantly increased in the liver, corresponding to microalgal supplementation levels. The elevated expression of specific immune-related genes was evident in the kidneys in all treatment groups after 1 month of feeding, including genes related to eicosanoid synthesis, lysozyme, and NF-κB. In the liver, microalgal supplementation led to the upregulation of genes related to immune function and antioxidant defense while the expression of examined genes involved in ARA metabolism was downregulated. Importantly, fish fed with 15% of both WT- and MUT-supplemented feed showed significantly (p < 0.05) higher survival percentages (78 and 68%, respectively, as compared to only 46% in the control group). The elevated expression of genes related to inflammatory and immune responses was evident post-challenge. Collectively, the results of the current study demonstrate the potential of microalgae-derived dietary ARA and DGLA in improving immune competence and resistance to bacterial infection in zebrafish as a model organism.

MFSD2A Promotes Endothelial Generation of Inflammation-Resolving Lipid Mediators and Reduces Colitis in Mice

BACKGROUND & AIMS

Alterations in signaling pathways that regulate resolution of inflammation (resolving pathways) contribute to pathogenesis of ulcerative colitis (UC). The resolution process is regulated by lipid mediators, such as those derived from the ω-3 docosahexaenoic acid (DHA), whose esterified form is transported by the major facilitator superfamily domain containing 2A (MFSD2A) through the endothelium of brain, retina, and placenta. We investigated if and how MFSD2A regulates lipid metabolism of gut endothelial cells to promote resolution of intestinal inflammation.

METHODS

We performed lipidomic and functional analyses of MFSD2A in mucosal biopsies and primary human intestinal microvascular endothelial cells (HIMECs) isolated from surgical specimens from patients with active, resolving UC and healthy individuals without UC (controls). MFSD2A was knocked down in HIMECs with small hairpin RNAs or overexpressed from a lentiviral vector. Human circulating endothelial progenitor cells that overexpress MFSD2A were transferred to CD1 nude mice with dextran sodium sulfate-induced colitis, with or without oral administration of DHA.

RESULTS

Colonic biopsies from patients with UC had reduced levels of inflammation-resolving DHA-derived epoxy metabolites compared to healthy colon tissues or tissues with resolution of inflammation. Production of these metabolites by HIMECs required MFSD2A, which is required for DHA retention and metabolism in the gut vasculature. In mice with colitis, transplanted endothelial progenitor cells that overexpressed MFSD2A not only localized to the inflamed mucosa but also restored the ability of the endothelium to resolve intestinal inflammation, compared with mice with colitis that did not receive MFSD2A-overexpressing endothelial progenitors.

CONCLUSIONS

Levels of DHA-derived epoxides are lower in colon tissues from patients with UC than healthy and resolving mucosa. Production of these metabolites by gut endothelium requires MFSD2A; endothelial progenitor cells that overexpress MFSD2A reduce colitis in mice. This pathway might be induced to resolve intestinal inflammation in patients with colitis.

Stearoyl-CoA Desaturase 1 Is a Key Determinant of Membrane Lipid Composition in 3T3-L1 Adipocytes

Stearoyl-CoA desaturase 1 (SCD1) is a lipogenic enzyme important for the regulation of membrane lipid homeostasis; dysregulation likely contributes to obesity associated metabolic disturbances. SCD1 catalyses the Δ9 desaturation of 12-19 carbon saturated fatty acids to monounsaturated fatty acids. To understand its influence in cellular lipid composition we investigated the effect of genetic ablation of SCD1 in 3T3-L1 adipocytes on membrane microdomain lipid composition at the species-specific level. Using liquid chromatography/electrospray ionisation-tandem mass spectrometry, we quantified 70 species of ceramide, mono-, di- and trihexosylceramide, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, bis(monoacylglycero)phosphate, phosphatidylinositol and cholesterol in 3T3-L1 adipocytes in which a 90% reduction in scd1 mRNA expression was achieved with siRNA. Cholesterol content was unchanged although decreases in other lipids resulted in cholesterol accounting for a higher proportion of lipid in the membranes. This was associated with decreased membrane lateral diffusion. An increased ratio of 24:0 to 24:1 in ceramide, mono- and dihexosylceramide, and sphingomyelin likely also contributed to this decrease in lateral diffusion. Of particular interest, we observed a decrease in phospholipids containing arachidonic acid. Given the high degree of structural flexibility of this acyl chain this will influence membrane lateral diffusion, and is likely responsible for the transcriptional activation of Lands' cycle enzymes lpcat3 and mboat7. Of relevance these profound changes in the lipidome were not accompanied by dramatic changes in gene expression in mature differentiated adipocytes, suggesting that adaptive homeostatic mechanisms to ensure partial maintenance of the biophysical properties of membranes likely occur at a post-transcriptional level.

Fatty acid profile of British Columbia suckler beef

In this study, the influence of feeding system on the fatty acid (FA) profile of suckler beef (SB), moderate grain-fed (MG), and grass-fed (GF) beef was compared. It was found that total saturated FA content was not affected; however, greater 14:0, total polyunsaturated FA content, and lower n-6/n-3 ratio suggest some transmittance of milk FA in SB calves (P < 0.001).

Effect of PUFA-rich plant oil on risk factors of STZ-induced diabetes in Wistar rats

OBJECTIVE

This study has been focused on the effect of an n-6 polyunsaturated fatty acid (PUFA) rich plant oil on oxidation and glycooxidation stress markers as well as on antioxidant enzyme activities in male Wistar rats with streptozotocin-induced diabetes.

METHODS

The non-diabetic and diabetic groups of Wistar rats were administered plant oil at concentrations of 100 and 500 mg/kg body weight and controls without plant oil. The parameters of glycaemic control, lipid profile, total antioxidant status, antioxidant enzyme activities, together with oxidative and glycooxidative stress markers were measured in the blood.

RESULTS

The intake of the plant oil did not significantly influence the parameters of glycaemic control and significantly increased the levels of all lipid profile parameters in the diabetic rats. Plant oil administration significantly decreased the total antioxidant status and glutathione peroxidase activity and the activity of Cu/Zn superoxide dismutase was significantly increased. The plant oil also increased the levels of lipoperoxides and advanced the glycation end products.

DISCUSSION

These results suggest that the plant oil with high concentrations of n-6 PUFA - linoleic acid, acts prooxidatively when administered to the rats.

The relationship between the fatty acid composition of immune cells and their function

The immune system, including its inflammatory components, is fundamental to host defence against pathogenic invaders. It is a complex system involving interactions amongst many different cell types dispersed throughout the body. Central to its actions are phagocytosis of bacteria, processing of antigens derived from intracellular and extracellular pathogens, activation of T cells with clonal expansion (proliferation) and production of cytokines that elicit effector cell functions such as antibody production and killing cell activity. Inappropriate immunologic activity, including inflammation, is a characteristic of many common human disorders. Eicosanoids produced from arachidonic acid have roles in inflammation and regulation of T and B lymphocyte functions. Eicosapentaenoic acid (EPA) also gives rise to eicosanoids and these may have differing properties from those of arachidonic acid-derived eicosanoids. EPA and docosahexaenoic acid (DHA) give rise to newly discovered resolvins which are anti-inflammatory and inflammation resolving. Human immune cells are typically rich in arachidonic acid, but arachidonic acid, EPA and DHA contents can be altered through oral administration of EPA and DHA. This results in a changed pattern of production of eicosanoids and probably also of resolvins, although the latter are not well examined in the human context. Changing the fatty acid composition of immune cells also affects phagocytosis, T cell signaling and antigen presentation capability. These effects appear to mediated at the membrane level suggesting important roles of fatty acids in membrane order, lipid raft structure and function, and membrane trafficking. Thus, the fatty acid composition of human immune cells influences their function and the cell membrane contents of arachidonic acid, EPA and DHA are important. Fatty acids influence immune cell function through a variety of complex mechanisms and these mechanisms are now beginning to be unraveled.

Anti-inflammatory and proresolving lipid mediators

The popular view that all lipid mediators are pro-inflammatory arises largely from the finding that nonsteroidal anti-inflammatory drugs block the biosynthesis of prostaglandins. The resolution of inflammation was widely held as a passive event until recently, with the characterization of novel biochemical pathways and lipid-derived mediators that are actively turned on in resolution and that possess potent anti-inflammatory and proresolving actions. A lipid-mediator informatics approach was employed to systematically identify new families of endogenous local-acting mediators from omega-3 polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid) in resolving exudates, which also contain lipoxins and aspirin-triggered lipoxins generated from arachidonic acid. Given their potent bioactions, these new chemical mediator families were termed resolvins and protectins. Here, we review the recent advances in our understanding of the biosynthesis and stereospecific actions of these new proresolving mediators, which have also proven to be organ protective and antifibrotic.