Impact of Arachidonic and Docosahexaenoic Acid Supplementation on Neural and Immune Development in the Young Pig

Omega-3 long-chain polyunsaturated fatty acids: Metabolism and health implications

Recently, omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) have gained substantial interest due to their specific structure and biological functions. Humans cannot naturally produce these fatty acids (FAs), making it crucial to obtain them from our diet. This comprehensive review details n-3 LC-PUFAs and their role in promoting and maintaining optimal health. The article thoroughly analyses several sources of n-3 LC-PUFAs and their respective bioavailability, covering marine, microbial and plant-based sources. Furthermore, we provide an in-depth analysis of the biological impacts of n-3 LC-PUFAs on health conditions, with particular emphasis on cardiovascular disease (CVD), gastrointestinal (GI) cancer, diabetes, depression, arthritis, and cognition. In addition, we highlight the significance of fortification and supplementation of n-3 LC-PUFAs in both functional foods and dietary supplements. Additionally, we conducted a detailed analysis of the several kinds of n-3 LC-PUFAs supplements currently available in the market, including an assessment of their recommended intake, safety, and effectiveness. The dietary guidelines associated with n-3 LC-PUFAs are also highlighted, focusing on the significance of maintaining a well-balanced intake of n-3 PUFAs to enhance health benefits. Lastly, we highlight future directions for further research in this area and their potential implications for public health.

In parenteral nutrition-fed piglets, fatty acids vary by lipid emulsion and tissue sampled

BACKGROUND

Children with intestinal failure without liver disease may be given soy-based lipid emulsion (SLE) or mixed lipid emulsion (MLE; containing soy, medium-chain triglyceride, olive, and/or fish oils). Both differ in essential fatty acid content: MLE has added arachidonic acid (AA) and docosahexaenoic acid (DHA). The aim of this study, in neonatal piglets, was to compare serum and tissue fatty acid composition when the emulsions were given at unrestricted doses.

METHODS

We compared SLE (n = 15) and MLE (n = 15) at doses of 10-15 g/kg/day in parenteral nutrition (PN). On day 14 we collected serum and tissues. Using gas-liquid chromatography, percentage fatty acids were measured in serum, brain, and liver phospholipid. Comparisons were made to reference values from litter-matched controls (n = 8).

RESULTS

Comparing median values, linoleic acid (LA) was lower for MLE vs SLE in serum (-27%), liver (-45%), and brain (-33%) (P < 0.001). AA was lower for MLE in serum (-25%), liver (-40%), and brain (-10%). DHA was higher for MLE in serum (+50%), liver (+200%), and brain (+10%). AA levels were lower for MLE vs control piglets in serum (-81%), liver (-63%), and brain (-9%). DHA levels were higher in serum (+41%), liver (+38%), and brain (+19%).

CONCLUSION

This study in piglets has shown that, at unrestricted doses, MLE treatment is associated with low serum and tissue AA compared with SLE and healthy litter-matched controls. Although not yet proven, low tissue AA levels may have functional consequences, and these data support current practice avoiding MLE dose restriction.

Efficient in vitro digestion of lipids and proteins in bovine milk fat globule membrane ingredient (MFGMi) and whey-casein infant formula with added MFGMi

The relative immaturity of the infant digestive system has the potential to affect the bioavailability of dietary lipids, proteins, and their digested products. We performed a lipidomic analysis of a commercial bovine milk fat globule membrane ingredient (MFGMi) and determined the profile of lipids and proteins in the bioaccessible fraction after in vitro digestion of both the ingredient and whey-casein-based infant formula without and with MFGMi. Test materials were digested using a static 2-phase in vitro model, with conditions simulating those in the infant gut. The extent of digestion and the bioaccessibility of various classes of neutral and polar lipids were monitored by measuring a wide targeted lipid profile using direct infusion-mass spectrometry. Digestion of abundant proteins in the ingredient and whey-casein infant formula containing the ingredient was determined by denaturing PAGE with imaging of Coomassie Brilliant Blue stained bands. Cholesterol esters, diacylglycerides, triacylglycerides, phosphatidylcholines, and phosphatidylethanolamines in MFGMi were hydrolyzed readily during in vitro digestion, which resulted in marked increases in the amounts of free fatty acids and lyso-phospholipids in the bioaccessible fraction. In contrast, sphingomyelins, ceramides, and gangliosides were largely resistant to simulated digestion. Proteins in MFGMi and the infant formulas also were hydrolyzed efficiently. The results suggest that neutral lipids, cholesterol esters, phospholipids, and proteins in MFGMi are digested efficiently during conditions that simulate the prandial lumen of the stomach and small intestine of infants. Also, supplementation of whey-casein-based infant formula with MFGMi did not appear to alter the profiles of lipids and proteins in the bioaccessible fraction after digestion.

Combined Supplementation with Arachidonic and Docosahexaenoic Acids in T Helper Type-2 Skewed Brown Norway Rat Offspring is Beneficial in the Induction of Oral Tolerance toward Ovalbumin and Immune System Development

BACKGROUND

A T helper type-2 (Th2) skewed immune response is associated with food allergies. DHA and arachidonic acid (ARA) have been shown to promote oral tolerance (OT) in healthy rodents.

OBJECTIVES

We studied the effect of combined ARA + DHA supplementation during the suckling and weaning periods on OT and immune system development in Th2-skewed Brown Norway rat offspring.

METHODS

Dams were fed ARA + DHA (0.45% ARA, 0.8% DHA wt/wt of total fat; n = 10) as a suckling period diet (SPD) or control SPD (0% ARA, 0% DHA, n = 8). At 3 wk, offspring from each SPD group received ARA + DHA (0.5% ARA, 0.5% DHA wt/wt of total fat) weaning diet (WD), or control until 8 wk. For OT, offspring were orally exposed to either ovalbumin (OVA) or placebo between 21 and 25 d, followed by systemic immunization with OVA + adjuvant at 7 wk. Primary outcomes, ex vivo cytokine production by splenocytes and plasma OVA-specific Igs, were analyzed using a 3-way ANOVA.

RESULTS

At 8 wk, despite no lasting effect of SPD on splenocytes fatty acids, ARA + DHA WD resulted in 2× higher DHA in splenocyte phospholipid compositions without affecting ARA. OT development was observed in OVA-exposed groups with 15% lower plasma OVA-IgE (P = 0.04) and 35% lower OVA-IgG1 (P = 0.01) than placebo. ARA + DHA SPD resulted in 35% lower OVA-IgG1 and iIL-6 (P = 0.04) when stimulated with LPS, and a higher proportion of mature B cells (OX12+, P = 0.0004, and IgG+, P = 0.008). ARA + DHA WD resulted in 20% higher Th1 cytokines (TNF-α and IFN-γ) production to lymphocyte stimulant and higher splenocyte proportion of CD45RA+ (pan-B cells) and OX6+ (dendritic cells) than control WD (P values < 0.05).

CONCLUSIONS

Combined supplementation of ARA and DHA is beneficial for OT development, especially in the suckling period. Further, ARA + DHA supplementation can also counteract the Th2-skewed immunity of Brown Norway rat offspring through higher Th1 cytokine production by lymphocytes.

Joint analyses of human milk fatty acids, phospholipids, and choline in association with cognition and temperament traits during the first 6 months of life

Early dietary exposure via human milk nutrients offers a window of opportunity to support cognitive and temperament development. While several studies have focused on associations of few pre-selected human milk nutrients with cognition and temperament, it is highly plausible that human milk nutrients synergistically and jointly support cognitive and behavioral development in early life. We aimed to discern the combined associations of three major classes of human milk nutrients with cognition and temperament during the first 6 months of life when human milk is the primary source of an infant’s nutrition and explore whether there were persistent effects up to 18 months old. The Mullen Scales of Early Learning and Infant Behavior Questionnaires—Revised were used to assess cognition and temperament, respectively, of 54 exclusively/predominantly breastfed infants in the first 6 months of life, whose follow-ups were conducted at 6–9, 9–12, and 12–18 months old. Human milk samples were obtained from the mothers of the participants at less than 6 months of age and analyzed for fatty acids [total monounsaturated fatty acids, polyunsaturated fatty acid, total saturated fatty acid (TSFA), arachidonic acid (ARA), docosahexaenoic acid (DHA), ARA/DHA, omega-6/omega-3 polyunsaturated fatty acids ratio (n-6/n-3)], phospholipids [phosphatidylcholine, phosphatidylethanolamine (PE), phosphatidylinositol (PI), sphingomyelin], and choline [free choline, phosphocholine (PCho), glycerophosphocholine]. Feature selection was performed to select nutrients associated with cognition and temperament. The combined effects of selected nutrients were analyzed using multiple regression. A positive association between the arachidonic acid (ARA) and surgency was observed (p = 0.024). A significant effect of DHA, n-6/n-3, PE, and TSFA concentrations on receptive language (R² = 0.39, p = 0.025) and the elevated ARA, PCho, and PI with increased surgency (R² = 0.43, p = 0.003) was identified, suggesting that DHA and ARA may have distinct roles for temperament and language functions. Furthermore, the exploratory association analyses suggest that the effects of human milk nutrients on R.L. and surgency may persist beyond the first 6 months of life, particularly surgency at 12–18 months (p = 0.002). Our study highlighted that various human milk nutrients work together to support the development of cognition and temperament traits during early infancy.

Impacts of Formula Supplemented with Milk Fat Globule Membrane on the Neurolipidome of Brain Regions of Piglets

The milk fat globule membrane (MFGM) appears to play an important role in infant neurocognitive development; however, its mechanism(s) of action remains unclear. This study aimed to investigate the role of a dietary MFGM supplement on the lipid profiles of different neonatal brain regions. Ten-day-old male piglets (4−5 kg) were fed unsupplemented infant formula (control, n = 7) or an infant formula supplemented with low (4%) or high (8%) levels of MFGM (n = 8 each) daily for 21 days. Piglets were then euthanized, and brain tissues were sectioned. Untargeted liquid chromatography-mass spectrometry lipidomics was performed on the cerebellum, hippocampus, prefrontal cortex, and the rest of the brain. The analyses identified 271 and 171 lipids using positive and negative ionization modes, respectively, spanning 16 different lipid classes. MFGM consumption did not significantly alter the lipidome in most brain regions, regardless of dose, compared to the control infant formula. However, 16 triacylglyceride species were increased in the hippocampus (t-test, p-value < 0.05) of the high-supplemented piglets. Most lipids (262 (96.7%) and 160 (93.6%), respectively) differed significantly between different brain regions (ANOVA, false discovery rate corrected p-value < 0.05) independent of diet. Thus, this study highlighted that dietary MFGM altered lipid abundance in the hippocampus and detected large differences in lipid profiles between neonatal piglet brain regions.

Cumulative Metabolic and Epigenetic Effects of Paternal and/or Maternal Supplementation with Arachidonic Acid across Three Consecutive Generations in Mice

Apart from the known associations between arachidonic acid (AA), weight gain, and neurological and immune function, AA exposure leads to alterations in global and gene-specific DNA methylation (DNAm) and fatty acid (FA) content in human cultured cells. However, it is unknown as to whether the latter effects occur in vivo and are maintained over extended periods of time and across generations. To address this issue, we asked whether AA supplementation for three consecutive generations (prior to coitus in sires or in utero in dams) affected offspring growth phenotypes, in addition to liver DNAm and FA profiles in mice. Twelve-week-old BALB/c mice were exposed daily to AA dissolved in soybean oil (vehicle, VH), or VH only, for 10 days prior to mating or during the entire pregnancy (20 days). On average, 15 mice were supplemented per generation, followed by analysis of offspring body weight and liver traits (x average = 36 and 10 per generation, respectively). Body weight cumulatively increased in F2 and F3 offspring generations and positively correlated with milligrams of paternal or maternal offspring AA exposure. A concomitant increase in liver weight was observed. Notably, akin to AA-challenged cultured cells, global DNAm and cis-7-hexadecenoic acid (16:1n-9), an anti-inflammatory FA that is dependent on stearoyl-CoA desaturase 1 (SCD1) activity, increased with milligrams of AA exposure. In accordance, liver Scd1 promoter methylation decreased with milligrams of germline AA exposure and was negatively correlated with liver weight. Our results show that mice retain cellular memories of AA exposure across generations that could potentially be beneficial to the innate immune system.

Safety and Efficacy of Sodium and Potassium Arachidonic Acid Salts in the Young Pig

Arachidonic acid (ARA; 20:4n6) and docosahexaenoic acid (DHA; 22:6n3) are polyunsaturated fatty acids (FA) naturally present in breast milk and added to most North American infant formulas (IF). We investigated the safety and efficacy of novel sodium and potassium salts of arachidonic acid as bioequivalent to support tissue levels of ARA comparable to the parent oil; M. alpina oil (Na-ARA and K-ARA) and including a Na-DHA group. Pigs of both sexes were randomized to one of five dietary treatments (n = 16 per treatment; 8 male and 8 female) from postnatal day 2 to 23. ARA and DHA were included as either triglyceride (TG) or salt. Target dietary ARA/DHA concentrations as percent of total FA by weight were as follows: TT (0.47 TG/0.32 TG), NaT (0.47 Na-salt/0.32 TG), KT (0.47 K-salt/0.32 TG), and Na0 (0.47 Na-salt/0.00), NaNa (0.47 Na-salt/0.32 Na-salt). The primary outcome in this study was bioequivalence of ARA brain accretion. Growth performance; blood and tissue fatty acid levels; liver histology; complete blood cell counts; and serum chemistries were all evaluated. Overall, diets containing test sources of ARA and DHA did not affect growth performance; liver histology; or substantially influence hematological outcomes as compared with TT. The results confirm that the use of Na and K salt forms of ARA yield bioequivalent ARA accretion in the cerebral cortex and retinal tissue compared to TG-ARA. These findings confirm that use of Na-ARA and K-ARA salts in the young pig was safe and nutritionally bioequivalent to TG-ARA for critical neural tissues.