Dietary long-chain PUFA in the form of TAG or phospholipids influence lymph lipoprotein size and composition in piglets

Polymorphism and expression level of the FADS3 gene and associated with the growth traits in Hu sheep

Growth traits are the economically important traits of sheep, and screening for genes related to growth and development is helpful for the genetic improvement of ovine growth traits. The fatty acid desaturase 3 (FADS3) is one of the important genes affecting the synthesis and accumulation of polyunsaturated fatty acids in animals. In this study, the expression levels of the FADS3 gene and polymorphism of the FADS3 gene associated with growth traits in Hu sheep were detected using quantitative real-time PCR (qRT-PCR), Sanger sequencing, and KAspar assay. The result showed that the expression levels of the FADS3 gene were widely expressed in all tissues, and the expression level of FADS3 in the lung was significantly higher than in other tissues (p < .05). Then, the polymorphism locus g. 2918 A > C was detected in intron 2 of the FADS3 gene, and associated analysis showed that the mutation in the FADS3 gene was associated significantly with growth traits (including body weight, body height, body length, and chest circumference, p < .05). Therefore, individuals with AA genotype showed significantly better growth traits than those with CC genotype, and FADS3 gene could be a candidate gene for improving growth traits in Hu sheep.

Towards an Optimized Fetal DHA Accretion: Differences on Maternal DHA Supplementation Using Phospholipids vs. Triglycerides during Pregnancy in Different Models

Docosahexaenoic acid (DHA) supplementation during pregnancy has been recommended by several health organizations due to its role in neural, visual, and cognitive development. There are several fat sources available on the market for the manufacture of these dietary supplements with DHA. These fat sources differ in the lipid structure in which DHA is esterified, mainly phospholipids (PL) and triglycerides (TG) molecules. The supplementation of DHA in the form of PL or TG during pregnancy can lead to controversial results depending on the animal model, physiological status and the fat sources utilized. The intestinal digestion, placental uptake, and fetal accretion of DHA may vary depending on the lipid source of DHA ingested by the mother. The form of DHA used in maternal supplementation that would provide an optimal DHA accretion for fetal brain development, based on the available data obtained most of them from different animal models, indicates no consistent differences in fetal accretion when DHA is provided as TG or PL. Other related lipid species are under evaluation, e.g., lyso-phospholipids, with promising results to improve DHA bioavailability although more studies are needed. In this review, the evidence on DHA bioavailability and accumulation in both maternal and fetal tissues after the administration of DHA supplementation during pregnancy in the form of PL or TG in different models is summarized.

Vegetable lecithins: A review of their compositional diversity, impact on lipid metabolism and potential in cardiometabolic disease prevention

Vegetable lecithins, widely used in the food industry as emulsifiers, are a mixture of naturally occurring lipids containing more than 50% of phospholipids (PL). PL exert numerous important physiological effects. Their amphiphilic nature notably enables them to stabilise endogenous lipid droplets, conferring them an important role in lipoprotein transport, functionality and metabolism. In addition, beneficial effects of dietary lecithin on metabolic disorders have been reported since the 1990s. This review attempts to summarize the effects of various vegetable lecithins on lipid and lipoprotein metabolism, as well as their potential application in the treatment of dyslipidemia associated with metabolic disorders. Despite controversial data concerning the impact of vegetable lecithins on lipid digestion and intestinal absorption, the beneficial effect of lecithin supplementation on plasma and hepatic lipoprotein and cholesterol levels is unequivocal. This is especially true in hyperlipidemic patients. Furthermore, the immense compositional diversity of vegetable lecithins endows them with a vast range of biochemical and biological properties, which remain to be explored in detail. Data on the effects of vegetable lecithins alternative to soybean, both as supplements and as ingredients in different foods, is undoubtedly lacking. Given the exponential demand for vegetable products alternative to those of animal origin, it is of primordial importance that future research is undertaken in order to elucidate the mechanisms by which individual fatty acids and PL from various vegetable lecithins modulate lipid metabolism. The extent to which they may influence parameters associated with metabolic disorders, such as intestinal integrity, low-grade inflammation and gut microbiota must also be assessed.

Absorption rate of krill oil and fish oil in blood and brain of rats

BACKGROUND

Krill (Euphausia superba) is a small marine crustacean with a lipid content. The mechanism of Krill oil function is not clear yet and research reports on the absorption rate of the phospholipids of krill oil in the blood and brain are very poor.

METHODS

We studied the effect of oral short-term and long-term administration of Krill oils (KOs) on bioavailability in the blood and brain of rats. For short-term testing of fish and KO bioavailability, rats were divided into four groups: normal, fish oil (FO), Krill oil 1 (KO), and Krill oil 2 (CKO). The blood and brain were collected at 2, 4, 8, 12, 24, and 48 h after oral administration (1000 mg/rat). Five hundred milligrams of FO, KO, and CKO were orally administered daily for 2 weeks for long-term administration, and then the brain and blood were collected.

RESULTS

Two types of KOs showed high content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the PL. The EPA content of CKO and KO were 41.13 and 32.49%, respectively. After short-term KO administration, KO showed a higher EPA content than CKO in the blood after 2 h. KO showed higher content of DHA than CKO even after 2 h. FO increased until 8 h, but then decreased rapidly until 12 h. Although the total unsaturated fatty acid (UFA) content of KOs was lower than the total UFS content in FO, the remaining UFS content in the brain was higher than that in FO over time. Following oral administration of FO, KO, and CKO for 1 and 2 weeks, triglycerides (TG) and PL contents in the blood for KOs were slightly higher than for FO. EPA and DHA levels in the brain were slightly higher in KOs following long-term administration, but the difference was not significant.

CONCLUSIONS

Base on these findings, KOs have functional potential for the brain and vascular diseases, and can be utilized as a multi-functional material composed mainly of functional ingredients.

Metabolomic Approaches to Explore Chemical Diversity of Human Breast-Milk, Formula Milk and Bovine Milk

Although many studies have been conducted on the components present in human breast milk (HM), research on the differences of chemical metabolites between HM, bovine milk (BM) and formula milk (FM) is limited. This study was to explore the chemical diversity of HM, BM and FM by metabolomic approaches. GC-TOFMS and UPLC-QTOFMS were applied to investigate the metabolic compositions in 30 HM samples, 20 FM samples and 20 BM samples. Metabolite profiling identified that most of the non-esterified fatty acids, which reflected the hydrolysis of triglycerides, were much more abundant in HM than those in FM and BM, except for palmitic acid and stearic acid. The levels of tricarboxylic acid (TCA) intermediates were much higher in FM and BM than those in HM. Each type of milk also showed its unique composition of free amino acids and free carbohydrates. In conclusion, higher levels of non-esterified saturated fatty acids with aliphatic tails <16 carbons, monounsaturated fatty acids and polyunsaturated fatty acids and lower levels of TCA intermediates are characteristic of HM, as compared with FM and BM. The content of non-esterified fatty acids may reflect the hydrolysis of triglycerides in different milk types.

Enhanced delivery of lipophilic nutrients to the infant brain via high density lipoprotein

Lipoproteins are the primary carriers of lipophilic cognitive nutrients such as docosahexaenoic acid, lutein, and α-tocopherol within circulation. The critical roles these nutrients play in growth and development are well established, and as such, their efficient delivery to the infant brain is crucial. Given the selectivity of the blood brain barrier, the lipoprotein fraction primarily responsible for brain delivery of these nutrients must be determined so that efforts aimed at increasing brain nutrient uptake, via lipoprotein profile manipulation, can be appropriately focused. Based on the preclinical and clinical data reviewed here, we hypothesize that high density lipoprotein is the fraction chiefly responsible for delivery of docosahexaenoic acid, lutein, and α-tocopherol to the infant brain. As high density lipoprotein levels tend to be lower in preterm, formula-fed infants as compared to their full-term, breast-fed counterparts, efforts aimed at increasing circulating high density lipoprotein levels, and subsequent delivery of cognitive lipophilic nutrients to the brain via manipulation of formula composition, may be most effective if targeted to this group. These efforts include (1) limiting the polyunsaturated: saturated fatty acid ratio; (2) increasing the casein: whey ratio; (3) altering the proportion of saturated fatty acids found in the sn-2 position of the parent triglyceride; (4) cholesterol supplementation; and (5) nucleotide supplementation.

Higher efficacy of dietary DHA provided as a phospholipid than as a triglyceride for brain DHA accretion in neonatal piglets

Long-chain PUFAs (LCPUFAs) occur in foods primarily in the natural lipid classes, triacylglycerols (TAGs) or phospholipids (PLs). We studied the relative efficacy of the neural omega-3 DHA provided in formula to growing piglets as a dose of (13)C-DHA bound to either TAG or phosphatidylcholine (PC). Piglets were assigned to identical formula-based diets from early life and provided with TAG-(13)C-DHA or PC-(13)C-DHA orally at 16 days. Days later, piglet organs were analyzed for (13)C-DHA and other FA metabolites. PC-(13)C-DHA was 1.9-fold more efficacious for brain gray matter DHA accretion than TAG-(13)C-DHA, and was similarly more efficacious in gray matter synaptosomes, retina, liver, and red blood cells (RBCs). Liver labeling was greatest, implying initial processing in that organ followed by export to other organs, and suggesting that transfer from gut to bloodstream to liver in part drove the difference in relative efficacy for tissue accretion. Apparent retroconversion to 22:5n-3 was more than double for PC-(13)C-DHA and was more prominent in neural tissue than in liver or RBCs. These data directly support greater efficacy for PC as a carrier for LCPUFAs compared with TAG, consistent with previous studies of arachidonic acid and DHA measured in other species.

Multiscale structures of lipids in foods as parameters affecting fatty acid bioavailability and lipid metabolism

On a nutritional standpoint, lipids are now being studied beyond their energy content and fatty acid (FA) profiles. Dietary FA are building blocks of a huge diversity of more complex molecules such as triacylglycerols (TAG) and phospholipids (PL), themselves organised in supramolecular structures presenting different thermal behaviours. They are generally embedded in complex food matrixes. Recent reports have revealed that molecular and supramolecular structures of lipids and their liquid or solid state at the body temperature influence both the digestibility and metabolism of dietary FA. The aim of the present review is to highlight recent knowledge on the impact on FA digestion, absorption and metabolism of: (i) the intramolecular structure of TAG; (ii) the nature of the lipid molecules carrying FA; (iii) the supramolecular organization and physical state of lipids in native and formulated food products and (iv) the food matrix. Further work should be accomplished now to obtain a more reliable body of evidence and integrate these data in future dietary recommendations. Additionally, innovative lipid formulations in which the health beneficial effects of either native or recomposed structures of lipids will be taken into account can be foreseen.

Chemical properties of ω-3 fortified gels made of protein isolate recovered with isoelectric solubilisation/precipitation from whole fish

Protein isolate was recovered from whole gutted fish using isoelectric solubilisation/precipitation (ISP). The objective was to determine chemical properties of heat-set gels made of the ISP protein isolate fortified with ω-3 polyunsaturated fatty acids (PUFAs)-rich oils (flaxseed, fish, algae, krill, and blend). The extent of the PUFAs increase, ω-6/ω-3 FAs and unsaturated/saturated FAs ratios, and the indices of thrombogenicity and atherogenicity depended on specific ω-3 PUFAs-rich oil used to fortify protein isolate gels. Lipid oxidation in ω-3 PUFAs fortified gels was minimal, although greater (P<0.05) than control gels (without ω-3 PUFAs fortification). However, all gels were in the slightly rancid, but acceptable range. The commonly used thiobarbituric-acid-reactive-substances (TBARS) assay to determine lipid oxidation in seafood may be inaccurate for samples containing krill oil due to its red pigment, astaxanthin. Protein degradation (total-volatile-basic-nitrogen) was greater (P<0.05) in ω-3 PUFAs fortified gels than control gels. However, all gels were considerably below the acceptability threshold for protein degradation. The shear stress of ω-3 PUFAs fortified gels was generally greater than the control gels and the shear strain was generally unchanged. This study demonstrates that ω-3 PUFAs fortification of protein isolates recovered with ISP from fish processing by-products or whole fish has potential application in the development of functional foods.

Chemical properties of surimi seafood nutrified with ω-3 rich oils

Surimi-based seafood products are widely accepted and enjoyed worldwide. The US consumption increased in 1980s; however, it leveled thereafter. Food products nutrified with ω-3 polyunsaturated fatty acids (PUFAs) are in increasing demand due to demonstrated health benefits. Currently, surimi seafood is not nutrified with ω-3 PUFAs. In the present study, surimi seafood was nutritionally-enhanced with ω-3 PUFAs-rich oils (flaxseed, algae, menhaden, krill, and blend). The objectives were (1) chemical characterization of FA composition and oxidation, and (2) determination of physicochemical properties (colour and texture) of the nutritionally-enhanced surimi seafood. Oil addition resulted in increased (P<0.05) concentration of total ω-3 FAs in surimi seafood; however, the concentration of α-linolenic (ALA, 18:3ω-3), eicosapentaenoic (EPA, 20:5ω-3) and docosahexaenoic (DHA, 22:6ω-3) acids depended on which oil was added. Although the ω-3 PUFAs nutrification resulted in increased (P<0.05) susceptibility of surimi seafood to lipid oxidation, it was within ranges acceptable to consumers. Texture analysis (texture profile analysis, Kramer shear and torsion test) showed that ω-3 PUFAs nutrification did not affect texture. Colour properties of ω-3 PUFAs nutrified surimi seafood were generally improved except when krill oil or blend was added. This study demonstrates that nutritional value of surimi seafood can be enhanced with concurrent improvement of colour and without affecting texture.

Lymphatic chylomicron size is inversely related to biliary phospholipid secretion in mice

Biliary phospholipids (PL) stimulate dietary fat absorption by facilitating intraluminal lipid solubilization and by providing surface components for chylomicron (CM) assembly. Impaired hepatic PL availability induces secretion of large very-low-density lipoproteins, but it is unclear whether CM size depends on biliary PL availability. Biliary PL secretion is absent in multidrug resistance protein 2-deficient (Mdr2(-/-)) mice, whereas it is strongly increased in essential fatty acid (EFA)-deficient mice. We investigated lymphatic CM size and composition in mice with absent (Mdr2(-/-)) or enhanced (EFA deficient) biliary PL secretion and in their respective controls under basal conditions and during enteral lipid administration. EFA deficiency was induced by feeding mice a high-fat, EFA-deficient diet for 8 wk. Lymph was collected by mesenteric lymph duct cannulation with or without intraduodenal lipid administration. Lymph was collected in 30-min fractions for up to 4 h, and lymphatic lipoprotein size was determined by dynamic light-scattering techniques. Lymph lipoprotein subfractions were isolated by ultracentrifugation, and lipid composition was measured. Lymphatic CMs were significantly larger in Mdr2(-/-) mice than in Mdr2(+/+) controls either without (+50%) or with (+25%) enteral lipid administration, and molar core-surface ratios were increased [triglyceride (TG)-to-PL ratio: 4.4 +/- 1.4 in Mdr2(-/-) mice vs. 2.7 +/- 0.8 in Mdr2(+/+) mice, P < 0.001]. In contrast, EFA-deficient mice secreted lipoproteins into lymph that were significantly smaller than in EFA-sufficient controls (173 +/- 32 vs. 236 +/- 47 nm), with correspondingly decreased core-surface ratios (TG-to-PL ratio: 3.0 +/- 1.0 in EFA-deficient mice vs. 6.0 +/- 1.9 in EFA-sufficient mice, P < 0.001). CM size increased during fat absorption in both EFA-deficient and EFA-sufficient mice, but the difference between the groups persisted. In conclusion, the present results strongly suggest that the availability of biliary PL is a major determinant of the size of intestinally produced lipoproteins both under basal conditions and during lipid absorption. Altered CM size may have physiological consequences for postprandial CM processing.