Dietary Unsaturated Fatty Acids Research Articles

PSII-8 Effects of Extruded-Expelled Soybean Meal and Benzoic Acid on Growth Performance, Carcass Characteristics, and Carcass Fat Iodine Value of Finishing Pigs

Abstract A total of 2,162 pigs (PIC 1050 × DNA 600; initially 31.4 ± 0.47 kg) were used in a 109-d finishing trial to evaluate the effects of extruded-expelled soybean meal (EESBM) and benzoic acid on growth performance, carcass characteristics, and carcass fat iodine value. Pigs were randomly allotted to 1 of 4 treatments with 27 to 28 pigs per pen and 20 pens per treatment. Dietary treatments were arranged in a 2 × 2 factorial with main effects of soybean meal source and benzoic acid. Diets contained either conventional soybean meal (SBM) or extruded-expelled soybean meal (EESBM; Lester Feed and Grain, Lester, IA) with or without 0.25% benzoic acid (VevoVitall, DSM Nutritional Products; Parsippany, NJ). The EESBM was analyzed to be 43.2% CP and 7.73% fat (acid hydrolysis). Experimental diets were not balanced for energy, but rather formulated to the same SID Lys:ME ratio and fed based on a feed budget from d 0 to 109 in 6 phases. Overall (d 0 to 109), there were no interactions between soybean meal source and benzoic acid (P > 0.10; Table 1). There was a main effect of soybean meal source where pigs fed EESBM had reduced (P = 0.010) ADFI compared with pigs fed conventional SBM without influencing ADG, resulting in increased (P < 0.001) G:F. Also, pigs fed diets with benzoic acid had reduced (P = 0.022) ADFI compared with pigs fed diets without benzoic acid without changes in ADG, resulting in pigs fed benzoic acid having increased (P = 0.006) G:F. When evaluating caloric efficiency, pigs fed diets containing benzoic acid had improved (P < 0.001) metabolizable energy (ME) caloric efficiency compared with pigs fed diets without benzoic acid, with soybean meal source not having any impact. For carcass belly fat IV, pigs fed EESBM had increased (P < 0.001) carcass belly fat iodine value compared with pigs fed conventional SBM. In summary, replacing conventional SBM with EESBM and the addition of benzoic acid improved feed efficiency. Also, as expected, pigs fed EESBM had a greater carcass belly fat iodine value compared with pigs fed conventional SBM, most likely due to the greater dietary unsaturated fatty acid contribution from EESBM.

Associations between Dietary Fatty Acid Profile and Milk Fat Production and Fatty Acid Composition in Dairy Cows: A Meta-Analysis.

This meta-analysis aimed to investigate the effect of dietary fatty acid (FA) profile on milk fat production and FA profile in dairy cows. The study also aimed to develop prediction models using a meta-regression approach. The database included 217 peer-reviewed articles on lactating dairy cows (n = 12,892), consisting of 515 treatment means. Effect size was assessed using the raw mean differences between diets with supplementary lipid sources and those without. Subgroup analyses were employed to assess heterogeneity. Diets rich in saturated FA (SFA) increased milk fat production and proportion, while reducing de novo FA in milk. Diets high in monounsaturated FA and polyunsaturated FA decreased mixed FA in milk. Most lipid-supplemented diets increase preformed FA in milk, except those rich in SFA. Prediction models were developed using meta-regression. Key predictors of milk fat production included neutral detergent fiber (NDF), dietary myristic acid, and milk production. Milk fat proportion was best predicted by dietary unsaturated FA, NDF, and forage. De novo FA in milk was predicted by dry matter intake (DMI) and dietary FA, while preformed FA was predicted by DMI, dietary oleic and linoleic acids. In conclusion, this study emphasizes the importance of the dietary FA profile in evaluating the effects of lipids on milk fat production and FA profile. Accurate and precise predictions of milk fat production, proportion, and FA profile can be achieved by considering cow production and dietary characteristics.

Associations of specific dietary unsaturated fatty acids with risk of overweight/obesity: population-based cohort study.

The role of specific unsaturated fatty acids (FAs) in the development of overweight/obesity remains unclear in the general population. Here, we aimed to explore the associations of different types of unsaturated FAs with overweight/obesity risk among the Chinese population. Eight thousand seven hundred forty-two subjects free of overweight/obesity at entry in the China Health and Nutrition Survey (CHNS) were followed up until 2015. Dietary unsaturated FAs were assessed by 3-day 24-h recalls with a weighing method in each wave. Cox regression models were used to obtain the hazard ratios (HRs) and 95% confidence intervals (CIs) for overweight/obesity risk associated with unsaturated FAs. During a median follow-up of 7 years, 2,753 subjects (1,350 males and 1,403 females) developed overweight/obesity. Consuming more monounsaturated FAs (MUFAs) was associated with a lower risk of overweight/obesity (highest vs. lowest quartile: HR 0.80, 95% CI 0.67-0.96; P-trend = 0.010). Similar inverse associations were observed for plant-MUFAs (HRQ4vsQ1 0.83, 95% CI: 0.73-0.94; P-trend = 0.003) and animal-MUFAs (HRQ4vsQ1 0.77, 95% CI: 0.64-0.94; P-trend = 0.004), total dietary oleic acid (OA) (HRQ4vsQ1 0.66, 95% CI: 0.55-0.79; P-trend <0.001), plant-OA (HRQ4vsQ1 0.73, 95% CI: 0.64-0.83; P-trend <0.001) and animal-OA (HRQ4vsQ1 0.68, 95% CI: 0.55-0.84; P-trend <0.001). In addition, the intakes of n-3 polyunsaturated FAs (PUFAs) (HRQ4vsQ1 1.24, 95% CI: 1.09-1.42; P-trend = 0.017) and α-linolenic acid (ALA) (HRQ4vsQ1 1.22, 95% CI: 1.07-1.39; P-trend = 0.039) but not marine n-3 PUFAs were positively linked to overweight/obesity risk. Consumption of n-6 PUFAs (HRQ4vsQ1 1.13, 95% CI: 0.99-1.28; P-trend = 0.014) and linoleic acid (LA) (HRQ4vsQ1 1.11, 95% CI: 0.98-1.26; P-trend = 0.020) had marginal and positive relationships with the incidence of overweight/obesity. N-6/n-3 PUFA ratio ranging from 5.7 to 12.6 was related to higher risk of overweight/obesity. Higher dietary intake of MUFAs was associated with lower overweight/obesity risk, which was mainly driven by dietary OA from either plant or animal sources. Intakes of ALA, n-6 PUFAs and LA were related to higher risk of overweight/obesity. These results support consuming more MUFAs for maintaining a healthy body weight among the Chinese population.

Integrating data from spontaneous and induced trans-10 shift of ruminal biohydrogenation reveals discriminant bacterial community changes at the OTU level.

Microbial digestion is of key importance for ruminants, and disturbances can affect efficiency and quality of products for human consumers. Ruminal biohydrogenation of dietary unsaturated fatty acids leads to a wide variety of specific fatty acids. Some dietary conditions can affect the pathways of this transformation, leading to trans-10 fatty acids rather than the more usual trans-11 fatty acids, this change resulting in milk fat depression in dairy cows. We combined data from an induced and spontaneous trans-10 shift of ruminal biohydrogenation, providing new insight on bacterial changes at different taxonomic levels. A trans-10 shift was induced using dietary addition of concentrate and/or unsaturated fat, and the spontaneous milk fat depression was observed in a commercial dairy herd. Most changes of microbial community related to bacteria that are not known to be involved in the biohydrogenation process, suggesting that the trans-10 shift may represent the biochemical marker of a wide change of bacterial community. At OTU level, sparse discriminant analysis revealed strong associations between this change of biohydrogenation pathway and some taxa, especially three taxa belonging to [Eubacterium] coprostanoligenes group, Muribaculaceae and Lachnospiraceae NK3A20 group, that could both be microbial markers of this disturbance and candidates for studies relative to their ability to produce trans-10 fatty acids.

Reprogrammed lipid metabolism protects inner nuclear membrane against unsaturated fat.

SummaryThe cell nucleus is surrounded by a double membrane. The lipid packing and viscosity of membranes is critical for their function and is tightly controlled by lipid saturation. Circuits regulating the lipid saturation of the outer nuclear membrane (ONM) and contiguous endoplasmic reticulum (ER) are known. However, how lipid saturation is controlled in the inner nuclear membrane (INM) has remained enigmatic. Using INM biosensors and targeted genetic manipulations, we show that increased lipid unsaturation causes a reprogramming of lipid storage metabolism across the nuclear envelope (NE). Cells induce lipid droplet (LD) formation specifically from the distant ONM/ER, whereas LD formation at the INM is suppressed. In doing so, unsaturated fatty acids are shifted away from the INM. We identify the transcription circuits that topologically reprogram LD synthesis and identify seipin and phosphatidic acid as critical effectors. Our study suggests a detoxification mechanism protecting the INM from excess lipid unsaturation.

Metabolism of Dietary Polyunsaturated Fatty Acids Modulates Healthspan of C. elegans

Dietary omega-3 and omega-6 unsaturated fatty acids (UFAs) are essential for normal man physiological processes in multiple organisms. However, their mechanism(s) that drive these processes remain largely unknown. Recent studies showed that downstream metabolites of UFAs play a critical role in inflammation, blood pressure regulation, pain perception, carcinogenesis, wound healing, and tissue and neural repair. Here, we hypothesize that the metabolites of dietary UFAs affect both development and aging. To study the role and underlying mechanism of the effect of UFA metabolites on the healthspan of organisms, we used C. elegans as a model organism because 1) C. elegans has been wildly used for aging study; 2) The C. elegans genome is highly conserved; 3) genetic modifications are relatively easy; 4) vast community resources are available for minimum cost or free and 5) genetic tools are largely available. As a result, this model organism greatly facilitates the mechanistic investigation of the effects of UFA metabolites. In this specific presentation, we will present metabolomic data obtained from the state-of-the-art ultra-performance liquid chromatography coupled with tandem mass spectrometry to demonstrate that C. elegans produces similar classes of UFA metabolites comparable to humans and mammals, and the endogenous levels of cytochrome P450 (CYP) metabolites of UFA change with the age of C. elegans. We will also present the effect of treatment with CYP UFA metabolites or modulation of UFA CYP metabolism on aging (lifespan and thrashing assay), reproduction (egg laying and egg viability assay) and neurodevelopment (fluorescent imaging). In conclusion, our results indicate that UFA metabolites play important physiological roles in C. elegans, and future mechanistic studies will also be discussed.

Diet Content of Non-saturated Fatty Acids Decreases Plasma Adiponectin in Patientswith Metabolic Syndrome

Introduction: The metabolic syndrome (MS) has been related to the unbalance between pro and anti-inflammatory cytokines; where adiponectin, an anti-inflammatory adipokine, is considered to play a key metabolic role. The consumption of certain micronutrients has been claimed to modify pro and anti-inflammatory cytokines. Aim: To explore whether dietary micronutrients are related with plasma adiponectin in patients with MS. Methods: Cross-sectional analysis. Quartiles of dietary bioactive compounds were compared according to values of plasma adiponectin. Interquartile variation (IQV) and correlation analyses were performed. Results: There was a significant IQV of dietary unsaturated fatty acids (between 50%-66% of change, p25 vs p75, p<0.05), particularly for trans-fatty acids, poly-unsaturated fatty acids, mono-unsaturated fatty acids and ω-6 fatty acids, in relation to plasma adiponectin; as well as a negative correlation (rho=-0.53, -0.37, -0.29 and -0.34, respectively; p<0.05). Conclusion: Dietary amounts of unsaturated fatty acids inversely related to plasma adiponectin in patients with MS.

Chemical foot print of precomposted dung material of Elephus maximus and Bos taurus through GC–MS profile

The growth and reproductive potential of composting earthworm is influenced by the chemical composition of initial feed mixture. Thus the GC-MS technique is used to determine the biochemical foot prints of the vermibed substrate before composting process. The present study conducted to analyze the chemical composition of precomposted animal dung material of Elephus maximus and Bos taurus by GC-MS analysis. The dung materials were precomposted up to 14 days and used for the analysis. The GC-MS spectrogram of Elephus maximus and Bos taurus showed 20 and 15 different compounds respectively. Predominant levels of esters were observed in elephant dung, which were dominated by the esterified polyunsaturated fatty acids with maximum peak area for elaidinsaeure methyl ester (26.6%). In cow dung the maximum peak area was obtained for 1-Hydroxy-1-methyl) −2-Methyl tetrahydro −2 furanyl] − 4, 4, 14-Trimethylandrost- 9 (11) – ene −3, 6, 16 (17%) and alcohol were the dominant functional group followed by carboxylic acids and esters. Thus the results indicated that the presence of higher percentage of esterified poly unsaturated fatty acids in elephant dung reflects its higher quality suitable for vermicomposting, since the dietary unsaturated fatty acids have the positive impacts on the reproduction of earthworm by enhancing the functionality in sperm production.

Dietary unsaturated fatty acid metabolites modulate life span and health span of C. elegans

Dietary unsaturated fatty acids are essential to physiology in different organisms. However, their mechanism remains largely unknown. Recent studies showed that the downstream metabolites play a critical role in inflammation, blood pressure regulation, pain perception, carcinogenesis, wound healing, and tissue and neural repair. However, their role in lifespan and healthspan in mammals remain largely unknown. To study the role and associated mechanism on the effect of unsaturated fatty acid metabolites on lifespan and healthspan in organism, we use C. elegans as a model organism because of the following reasons: 1) It is genetically close to humans; 2) the genome is known; 3) genetic modification is relatively easy; 4) imaging C. elegans is relatively easy, and more importantly, 5) part of the unsaturated fatty acid metabolism is conserved between humans and C. elegans. In this presentation, we will present the effect of cytochrome P450 metabolites on lifespan and healthspan on C. elegans and will discuss the potential mechanism behind such effects.Support or Funding InformationThis work was supported by the National Institute of Environmental Health Sciences (NIEHS) R00 ES024806. This work was also supported by National Science Foundation DMS‐1761320.

Abstract P436: The Role of Free Fatty Acids in Patients With Obesity and Heart Failure With Preserved Ejection Fraction: A Post-hoc Analysis of the UFA-preserved Pilot Study

Background: Increased circulating free fatty acids (FFA) are associated with an increased risk for heart failure (HF). Interestingly, in the setting of established HF, the failing heart relies heavily on the use of FFA as energetic substrate, and therapeutics aimed at reducing FFA in HF have been found to worsen cardiac performance. A dietary intervention aimed at increasing unsaturated fatty acids (UFA) was associated with favorable changes in cardiorespiratory fitness (CRF) in patients with obesity and HF with preserved ejection fraction (HFpEF) in the UFA-Preserved Pilot Study, although the mechanism remains largely unknown. We hypothesized that dietary UFA supplementation is associated with an increase in circulating FFA and may improve determinants of CRF such as cardiac function and body composition. Methods: Eight subjects with obesity and HFpEF engaged in 12 weeks of UFA supplementation by increasing intake of foods rich in monounsaturated fatty acids (i.e., oleic acid) and polyunsaturated fatty acids (i.e., α-linolenic acid, linoleic acid) under instruction and monitoring of a research dietitian. Measures were performed at baseline and 12 weeks. Subjects underwent venipuncture to measure circulating FFA, plasma biomarkers of UFA consumption, and NT-proBNP.. Bioelectrical impedance analysis was used to estimate skeletal muscle mass (SMM). Maximal cardiopulmonary exercise testing was performed to measure CRF defined as peak oxygen consumption (VO 2 ). Data are presented as median and interquartile range. Within group changes were assessed using Wilcoxon rank test and correlations were performed using Spearman rank test. Results: Five subjects were female and median age was 53 [50-59] years. The dietary intervention resulted in a significant increase in FFA (from 0.29 [0.20-0.43] to 0.37 [0.32-0.73] μmol/L, p=0.012) and plasmatic UFA (from 1319 [1224-1477] to 1620 [1268-2110] μg/mL, p=0.05). Changes in FFA were positively associated with changes in plasmatic UFA (R=+0.74, p=0.035). Changes in FFA were associated with a trend toward improvement in peak VO 2 , although it did not reach statistical significance (R=+0.72, p=0.068). Changes in FFA were also positively and significantly associated with an increase in SMM expressed in kg (R=+0.99, p&lt;0.001) and % of body weight (R=+0.90, p=0.006) and inversely associated with changes in NT-proBNP (R=-0.85, p=0.007). Conclusion: In patients with obesity and HFpEF, dietary UFA supplementation increases FFA, which are associated with favorable changes in cardiac function and body composition. This supports a novel mechanism through which UFA may positively affect CRF. Ongoing randomized controlled trials (NCT03966755) are underway investigating UFA supplementation as a therapeutic strategy to improve CRF in obesity and HFpEF.

Partitioning of fatty acids into tissues and fluids from reproductive organs of ewes as affected by dietary phenolic extracts

Evaluation of dietary interventions with regard to fertility problems often observed in ruminant livestock is of global interest. Though the effects of polyphenol supplementation in ruminants on digestion and food quality are well described, the impact on reproductive tissues and fluids remains scarcely investigated. These compounds protect dietary unsaturated fatty acids (FA) from oxidation and biohydrogenation and thus saturation. In addition, modification of the expression of genes associated with FA metabolism may occur. Therefore, we characterized for the first time the FA profiles of reproductive tissues and fluids and investigated their potential modification by dietary polyphenols in 22 cyclic ewes. The animals were randomly divided into four groups and fed a basal diet of meadow hay and one of four concentrate types either non-supplemented (control) or supplemented with grape seed extract, Acacia mearnsii bark extract (13 g/kg dry matter (DM) each) or a combination of both (26 g/kg DM). After 10 weeks of feeding, the animals were slaughtered. Samples of reproductive (oviduct, uterus) and metabolically differently active tissues (liver, muscle, adipose) as well as of plasma and fluids from oviduct and uterus were analysed for their FA composition. In addition, the expression of lipid metabolic and antioxidant genes was analysed in all tissues except the adipose tissue. Fatty acid profiles in tissues and fluids as well as gene expression in tissues significantly differed between the different fluids and tissues. In contrast, only a few diet and matrix (fluid or tissue) × diet interactions were observed. Still, the FA profile of the uterus was the only one not at all affected by the diet. The mRNA expression was not affected by the diet for most of the genes investigated, which might in part be explained by the similar plasma polyphenol concentrations found at slaughter. Overall, our findings contribute to an improved understanding of the characteristic FA composition of reproductive tissues and fluids in sheep. In addition, the effect of polyphenols on different tissues, fluids and tissue gene expression has been confirmed as described in other animal species.

Effect of 2-hydroxy-4-(methylthio) butanoate (HMTBa) supplementation on rumen bacterial populations in dairy cows when exposed to diets with risk for milk fat depression

Diet-induced milk fat depression (MFD) is a condition marked by a reduction in milk fat yield experimentally achieved by increasing dietary unsaturated fatty acids and fermentable carbohydrates. 2-Hydroxy-4-(methylthio) butanoate (HMTBa) is a methionine analog observed to reduce diet-induced MFD in dairy cows. We hypothesize that the reduction in diet-induced MFD by HMTBa is due to changes in the rumen microbiota. To test this, 22 high-producing cannulated Holstein dairy cows were placed into 2 groups using a randomized block design and assigned to either control or HMTBa supplementation (0.1% of diet dry matter). All cows were then exposed to 3 different diets with a low risk (32% neutral detergent fiber, no added oil; fed d 1 to 7), a moderate risk (29% neutral detergent fiber and 0.75% soybean oil; fed d 8 to 24), or a high risk (29% neutral detergent fiber and 1.5% soybean oil; fed d 25 to 28) for diet-induced MFD. Rumen samples were collected on d 0, 14, 24, and 28, extracted for DNA, PCR-amplified for the V1-V2 region of the 16S rRNA gene, sequenced on an Illumina MiSeq (Illumina, San Diego, CA), and subjected to bacterial diversity analysis using the QIIME pipeline. The α diversity estimates (species richness and Shannon diversity) were decreased in the control group compared with the HMTBa group. Bacterial community composition also differed between control and HMTBa groups based on both weighted UniFrac (relative abundance of commonly detected bacteria) and unweighted UniFrac (presence/absence) distances. Within the HMTBa group, no differences were observed in bacterial community composition between d 0 and d 14, 24, and 28; however, in the control group, d 0 samples were different from d 14, 24, and 28. Certain bacterial genera including Dialister, Megasphaera, Lachnospira, and Sharpea were increased in the control group compared with the HMTBa group. Interestingly, these genera were positively correlated with milk fat trans-10,cis-12 conjugated linoleic acid and trans-10 C18:1, fatty acid isomers associated with biohydrogenation-induced MFD. It can be concluded that diet-induced MFD is accompanied by significant alterations in the rumen bacterial community and that HMTBa supplementation reduces these microbial perturbations.

Rumen bacterial community responses to DPA, EPA and DHA in cattle and sheep: A comparative in vitro study

The role of marine lipids as modulators of ruminal biohydrogenation of dietary unsaturated fatty acids may be explained by the effects of their n-3 polyunsaturated fatty acids (PUFA) on the bacterial community. However, the impact of individual PUFA has barely been examined, and it is uncertain which bacteria are truly involved in biohydrogenation. In addition, despite interspecies differences in rumen bacterial composition, we are not aware of any direct comparison of bovine and ovine responses to dietary PUFA. Therefore, rumen fluid from cannulated cattle and sheep were used as inocula to examine in vitro the effect of 20:5n-3 (EPA), 22:5n-3 (DPA), and 22:6n-3 (DHA) on the bacterial community. Amplicon 16 S rRNA sequencing suggested that EPA and DHA had a greater contribution to the action of marine lipids than DPA both in cattle and sheep. Certain effects were exclusive to each ruminant species, which underlines the complexity of rumen microbial responses to dietary fatty acids. Based on changes in bacterial abundance, Barnesiella, Prevotella, Paraprevotella, Hallela, Anaerovorax, Succiniclasticum, Ruminococcus and Ruminobacter may be involved in the ruminal response in biohydrogenation to the addition of marine lipids, but further research is necessary to confirm their actual role in ruminal lipid metabolism.

Partitioning of Rumen-Protected n-3 and n-6 Fatty Acids is Organ-Specific in Growing Angus Heifers.

Dietary polyunsaturated fatty acids (PUFA), especially n-3 and n-6 fatty acids (FA), play an important role in the regulation of FA metabolism in all mammals. However, FA metabolism differs between different organs, suggesting a distinct partitioning of highly relevant FA. For the present study in cattle, a novel technology was applied to overcome rumen biohydrogenation of dietary unsaturated FA. Angus heifers were fed a straw-based diet supplemented for 8 weeks with 450 g/day of rumen-protected oil, either from fish (FO) or sunflower (SO). The FA composition in blood and five important organs, namely heart, kidney, liver, lung, and spleen, was examined. In blood, proportions of polyunsaturated FA were increased by supplementing FO compared to SO. The largest increase of eicosapentaenoic acid (EPA) proportion was found with FO instead of SO in the kidney, the lowest in the lung. Docosahexaenoic acid (DHA) was increased more in the liver than in kidney, lung, and spleen. The heart incorporated seven times more EPA than DHA, which is more than all other organs and described here for the first time in ruminants. In addition, the heart had the highest proportions of α-linolenic acid (18:3n-3) and linoleic acid (18:2n-6) of all organs. The proportions of polyunsaturated FA in the lung and spleen were exceptionally low compared to heart, liver, and kidney. In conclusion, it was shown that the response to FO in the distribution of dietary n-3 FA was organ-specific while proportions of n-6 FA were quite inert with respect to the type of oil supplemented.

Central role of obesity in endothelial cell dysfunction and cardiovascular risk.

Atherosclerosis is the leading cause of mortality in the contemporary world. The critical role of the endothelial cells (EC) in vascular homeostasis, the metabolic changes that take place when the cell is activated, and the elements involved in these processes have been widely explored over the past years. Obesity and its impact, promoting a rise in blood levels of free fatty acids (FAs) are often associated with atherosclerosis and cardiovascular mortality. However, the mechanisms that promote cardiovascular structural changes and adaptive changes in the ECs, particularly in the context of obesity, are little known. Here, we reviewed studies that assessed the metabolic adaptations of healthy and dysfunctional ECs during exposure to FAs, as well as the epidemiological perspectives of cardiovascular structural changes in obesity. Finally, we explored the role of new agents - sphingolipids, dietary unsaturated fatty acids and sodium-glucose cotransporter-2 inhibitors (iSGLT2) - in atherosclerosis and their relationship with obesity.

Conditions Associated with Marine Lipid-Induced Milk Fat Depression in Sheep Cause Shifts in the In Vitro Ruminal Metabolism of 1-13C Oleic Acid.

Simple SummaryDairy ewes, just like cows, suffer from the low-fat milk syndrome, also known as milk fat depression (MFD), when marine lipids are added to their diet to modulate milk fatty acid (FA) profile. Alterations in the ruminal metabolism of dietary unsaturated FA seem to be at the core of this MFD but its causative agent has not yet been confirmed. Although some alterations may derive from shifts in oleic acid metabolism, methodological constraints represent a major challenge: the fact that oleic and other dietary FA (e.g., linoleic and linolenic acids) have common intermediates hampers the identification of those metabolites deriving specifically from each one. Thus, we conducted an in vitro trial combining an isotopic tracer approach with the use of rumen inoculum from ewes fed a diet supplemented or not with fish oil (which is known to cause MFD in dairy animals), to provide new insights into shifts in oleic acid metabolism. Fish oil altered the relative contribution of specific pathways, with relevant increments in oxygenated FA, including a major candidate milk fat inhibitor (10-oxo-18:0). Changes in the concentration of trans 18:1 intermediates were also observed. Results are discussed in the context of their potential association with milk fat depression.Shifts in ruminal oleic acid (OA) metabolism have received little research attention but recent studies have suggested their association with marine lipid-induced milk fat depression (MFD) in ewes and cows. Measurement of specific products of OA within the complex mixture of digesta lipids is however challenging. Therefore, this in vitro trial combined the isotopic labelling technique with the use of rumen inoculum from cannulated sheep fed a diet supplemented or not with 2% of fish oil (which has been demonstrated to cause MFD in dairy ruminants) to characterize the metabolism of OA in response to ruminal alterations associated with MFD. The products of 13C-OA after 24 h of incubation were analysed by gas chromatography-combustion isotope ratio mass spectrometry (GC-C-IRMS). Numerous 13C-labeled 18:1 intermediates and oxygenated FA were detected and no elongation or desaturation of 13OA occurred. Diet supplementation with fish oil (i.e., MFD conditions) resulted in no unique metabolites of 13OA but in relevant changes in the relative contribution of specific metabolic pathways. The inhibition of 18:0 saturation caused by this treatment appeared largely attributable to increased oxygenated FA proportion, in particular the candidate milk fat inhibitor 10-oxo-18:0, and warrants further research on the association between MFD and oxygenated FA. Changes in the concentration of 13C-labeled trans 18:1 intermediates but not in cis 18:1, were also observed.

Growth and metabolomic responses of Pacific white shrimp (Litopenaeus vannamei) to different dietary fatty acid sources and salinity levels

The outstanding benefits of and strong interest in the inland low-salinity culture of penaeid shrimp have led to the growth of this industry worldwide. This study aimed to explore the effects of dietary fatty acids on shrimp in low-salinity culture. Individuals of the marine white shrimp Litopenaeus vannamei were fed one of three diets (coconut oil, fish oil, or an equal mixture of both) of differing fatty acid profiles for eight weeks while being maintained at two different salinities (3 or 30 psu). Then, a GC-TOF/MS-based metabolomics analysis was performed to reveal the regulatory roles of fatty acids in shrimp growth, survival and osmoregulation at two salinities. The shrimp fed the mixed oil diet had higher weight gain and survival, and those fed the diet with only fish oil added exhibited higher unsaturated fatty acid levels in the gills and hepatopancreas irrespective of salinity. Na+/K+-ATPase and total ATPase activities were lowest in the shrimp fed the mixed oil diet at both salinities. When coconut oil was the only lipid source, shrimp tissues contained higher tyrosine, lysine and serine levels at 3 psu than at 30 psu. In contrast, the shrimp fed fish oil as the sole lipid source had higher glucose at 3 psu than at 30 psu. This study indicates that appropriate supplementation of dietary unsaturated and saturated fatty acids can improve shrimp osmoregulation capacity and thus promote shrimp growth and survival in low-salinity water.

A Temperature-Dependent Switch in Feeding Preference Improves Drosophila Development and Survival in the Cold

How cold-blooded animals acclimate to temperature and what determines the limits of their viable temperature range are not understood. Here, we show that Drosophila alter their dietary preference from yeast to plants when temperatures drop below 15°C and that the different lipids present in plants improve survival at low temperatures. We show that Drosophila require dietary unsaturated fatty acids present in plants to adjust membrane fluidity and maintain motor coordination. Feeding on plants extends lifespan and survival for many months at temperatures consistent with overwintering in temperate climates. Thus, physiological alterations caused by a temperature-dependent dietary shift could help Drosophila survive seasonal temperature changes.

Dietary Unsaturated Fatty Acids Modulate Maternal Dyslipidemia-Induced DNA Methylation and Histone Acetylation in Placenta and Fetal Liver in Rats.

The present study assessed the role of dietary unsaturated fatty acids in maternal dyslipidemia-induced DNA methylation and histone acetylation in placenta and fetal liver and accumulation of lipids in the fetal liver. Weanling female Wistar rats were fed control and experimental diets for 2 months, mated, and continued on their diets during pregnancy. At gestation days of 18-20, rats were euthanized to isolate placenta and fetal liver. DNA methylation, DNA methyl transferase-1 (DNMT1) activity, acetylation of histones (H2A and H2B), and histone acyl transferase (HAT) activity were evaluated in placenta and fetal liver. Fetal liver lipid accumulation and activation of peroxisome proliferator-activated receptor-α (PPAR-α) were assessed. Maternal dyslipidemia caused significant epigenetic changes in placenta and fetal liver. In the placenta, (1) global DNA methylation increased by 37% and DNMT1 activity by 86%, (2) acetylated H2A and H2B levels decreased by 46% and 24% respectively, and (3) HAT activity decreased by 39%. In fetal liver, (1) global DNA methylation increased by 52% and DNMT1 activity by 78%, (2) acetylated H2A and H2B levels decreased by 28% and 26% respectively, and (3) HAT activity decreased by 37%. Maternal dyslipidemia caused a 4.75-fold increase in fetal liver triacylglycerol accumulation with a 78% decrease in DNA-binding ability of PPAR-α. Incorporation of dietary unsaturated fatty acids in the maternal high-fat diet significantly (p < 0.05) modulated dyslipidemia-induced effects in placenta and fetal liver. Eicosapentaenoic acid (EPA, 20:5n-3) + docosahexaenoic acid (DHA, 22:6n-3) exhibited a profound effect followed by alpha-linolenic acid (ALA, 18:3n-3) than linoleic acid (LNA, 18:2n-6) in modulating the epigenetic parameters in placenta and fetal liver.

Effects of nutrient limitations on three species of zooplankton

Nutrient imbalance—a mismatch in nutrient ratios between the available food supply and the demands of consumers—has the potential to be transported up food chains, exposing zooplankton to nutrient limitations. In this study, the response of Calanus sinicus (copepod), Moina mongolica (cladocera), and Brachionus plicatilis (rotifer) to nutrient-limited (no-limited, P-limited, and N-limited) food were evaluated from the perspective of growth, reproduction, and stoichiometric homoeostasis. The results indicated that the growth of three species was suppressed under nutrient-limited (especially P-limited) conditions. However, the effect of nutrient limitations on their reproduction was species-specific. For C. sinicus, the dietary UFA (unsaturated fatty acid) as a major phospholipid component affected their egg production and total FA supporting energy promoted the hatchability of eggs. Furthermore, excess carbon in the diet promoted egg production but reduced hatching success. For M. mongolica, nutritional (P and UFA) and energy (total FA) support affected their fecundity. B. plicatilis fecundity exhibited the same pattern of growth (no-limited>N-limited>P-limited). In terms of stoichiometric homeostasis, B. plicatilis’s elemental compositions were less likely to be affected by nutrient limitations than M. mongolica. We suggest that the effects of nutrient imbalances could potentially become an evolutionary force affecting ecosystem structure and stability in eutrophic waters.