Changes In Fatty Acid Composition Research Articles

Production of Margarine Fat Containing Medium- and Long-Chain Triacylglycerols by Enzymatic Interesterification of Peony Seed Oil, Palm Stearin and Coconut Oil Blends.

This paper reports the preparation of margarine fat using Lipozyme TL IM as a catalyst and peony seed oil (PSO), palm stearin (PS) and coconut oil (CO) as raw materials. The results indicate that there were no significant changes in fatty acid composition before or after interesterification of the oil samples. However, the total amount of medium- and long-chain triglycerides (MLCTs) increased from 2.92% to 11.38% in sample E1 after interesterification, mainly including LaLaO, LaMO, LaPM, LaOO, LaPO and LaPP. Moreover, the slip melting point (SMP) of sample E1 decreased from 45.9 °C (B1) to 33.5 °C. The solid fat content (SFC) of all the samples at 20 °C was greater than 10%, indicating that they could effectively prevent oil exudation. After interesterification, the samples exhibited a β' crystal form and could be used to prepare functional margarine.

The Effect of Combined Exposure of Fusarium Mycotoxins on Lipid Peroxidation, Antioxidant Defense, Fatty Acid Profile, and Histopathology in Laying Hens' Liver.

Fumonisin B1, T-2 toxin, and deoxynivalenol are frequently detected in feed materials. The mycotoxins induce free radical formation and, thereby, lipid peroxidation. The effects of mycotoxin exposure at the EU recommended limit (T-2/HT-2 toxin: 0.25 mg/kg; DON = 3AcDON/15-AScDON: 5 mg/kg; fumonisin B1: 20 mg/kg) and double dose (T-2/HT-2 toxin: 0.5 mg/kg, DON/3-AcDON/15-AcDON: 10 mg, and FB1: 40 mg/kg feed) were investigated during short-term (3 days) per os exposure in the liver of laying hens. On day 1 higher while on day 3 lower MDA concentrations were found in the low-dose group compared to the control. Fatty acid composition also changed: the proportion of monounsaturated fatty acids increased (p < 0.05) and the proportion of polyunsaturated fatty acids decreased by day 3. These alterations resulted in a decrease in the index of unsaturation and average fatty acid chain length. Histopathological alterations suggested that the incidence and severity of liver lesions were higher in the mycotoxin-treated laying hens, and the symptoms correlated with the fatty acid profile of total phospholipids. Overall, the findings revealed that mycotoxin exposure, even at the EU-recommended limits, induced lipid peroxidation in the liver, which led to changes in fatty acid composition, matched with tissue damage.

Marine Fish Oil Replacement with Lard or Basa Fish (Pangasius bocourti) Offal Oil in the Diet of Tiger Puffer (Takifugu rubripes): Effects on Growth Performance, Body Composition, and Flesh Quality.

Lard (LD) and Basa fish offal oil (BFO) have similar fatty acid profiles, both containing high contents of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). The present study aimed to investigate the efficacy of partial or complete replacement of marine fish oil (MFO, herring oil) by LD or BFO in the diets of tiger puffer. The control diet contained 49.1% crude protein and 9.28% crude lipid content including 6% added MFO. In other diets, 1/3, 2/3, and 3/3 of the added MFO was replaced by LD or BFO, respectively. Each diet was fed to triplicate tanks of juvenile fish (initial body weight, 13.88 g). A 46-day feeding trial was conducted in a flow-through seawater system. Each diet was fed to triplicate 200-L rectangular polyethylene tanks, each of which was stocked with 30 fish. Fish were fed to satiation three times a day. The complete replacement of added MFO (replacing 65% of the total crude lipid) had no adverse effects on fish growth performance in terms of survival (>94%), weight gain (360-398%), feed intake (2.37-3.04%), feed conversion ratio (0.84-1.02), and somatic indices. The dietary LD or BFO supplementation also had marginal effects on fish body proximate composition, biochemical parameters, muscle texture, and water-holding ability, as well as the hepatic expression of lipid metabolism-related genes. Partial (2/3) replacement of added MFO by LD or BFO did not significantly reduce the muscle n-3 LC-PUFA content, indicating the n-3 LC-PUFA sparing effects of SFA and MUFA in LD and BFO. In general, dietary LD or BFO reduced the peroxidation level and led to significant changes in the muscle volatile flavor compound profile, which were probably attributed to the change in fatty acid composition. The results of this study evidenced that LD and BFO are good potential lipid sources for tiger puffer feeds.

Effects of CO2 on the physicochemical, microbial, and sensory properties of pork patties packaged under optimized O2 levels

The storage quality characteristics of fresh pork patties were investigated under 80% O2 modified atmosphere packaging (MAP80:20 = 80% O2/20% CO2) and 40% O2 MAP with various CO2 levels (MAP40:20 = 40% O2/20% CO2/40% N2; MAP40:40 = 40% O2/40% CO2/20% N2; MAP40:60 = 40% O2/60% CO2). Packaged patties were stored for 16 days at 4 °C to monitor their physicochemical (pH, instrumental color, oxidative stability, and fatty acid profile), microbial, and sensorial changes. Results suggested that decreasing O2 levels from 80% to 40% significantly inhibited the lipid oxidation of patties but led to a lower (P < 0.05) color stability. Elevating CO2 levels from 20% to 60% in combination with 40% O2 significantly suppressed bacterial growth and total volatile basic nitrogen production, and thus rendered patties with a better sensory quality and a similar meat color to 80% O2. However, increased CO2 levels promoted lipid oxidation through reducing the antioxidant capacity of patties, which was attributed to a CO2-induced reduction in superoxide dismutase and glutathione peroxidase activities during storage rather than a pH reduction or changes in fatty acid composition. Overall, 40% O2/40% CO2/20% N2 is a realistic alternative for pork patties to improve meat quality and extend the shelf-life to over 16 days.

Effects of feeding whole-cracked rapeseeds, nitrate, and 3-nitrooxypropanol on composition and functional properties of the milk fat fraction from Danish Holstein cows

The aim of this study was to determine the individual and combined effects of supplementing fat (FAT), nitrate (NITRATE) and 3-nitrooxypropanol (3-NOP) on compositional and functional properties of milk fat. An 8 × 8 incomplete Latin square design was conducted with 48 lactating Danish Holstein cows over 6 periods of 21 d each. Eight diets were 2 × 2 × 2 factorially arranged: FAT (30 or 63 g crude fat/kg DM), NITRATE (0 or 10 g nitrate/kg DM), and 3-NOP (0 or 80 mg 3-NOP/kg DM) and cows were fed ad libitum. Milk samples were analyzed for general composition, fatty acids (FA) and thermal properties of milk fat. Milk fat content was decreased by FAT and NITRATE and increased by 3-NOP. The changes in FA composition were mainly driven by the FAT × 3-NOP interaction. FAT shifted milk FA composition toward lower content of saturated FA (SFA) and greater contents of mono- and poly-unsaturated FA (MUFA and PUFA), whereas these effects of FAT were smaller in combination with 3-NOP. However, 3-NOP had no effects on SFA, MUFA and PUFA in low fat diets. FAT lowered solid fat content in milk fat because of decreased SFA content. The onset crystallization temperature of milk fat was decreased by 3-NOP when supplemented in low fat diets. According to the FAT × 3-NOP interaction, supplementation of fat without 3-NOP shifted peak temperature of low melting fraction of milk fat toward low temperature as a result of decreased proportion of C16:0, and increased proportions of C18:1 cis-9, C18:1 trans-11, C18:2 cis-9, and CLA cis-9,trans-11. In conclusion, no additive effects were observed among FAT, NITRATE and 3-NOP on chemical and thermal properties of milk fat and fat supplementation largely changed milk FA composition and in turn affected the thermal properties of milk fat.

Effect of heating time on changes in physicochemical properties and fatty acid composition of red palm oil

Crude Palm Oil (CPO) contains approximately 50% saturated fatty acids and approximately 40% unsaturated fatty acids. Unsaturated fatty acid content is known to be effective in lowering blood cholesterol levels. Palm oil also contains -carotene which is very beneficial for health. Palm oil processing is defined by three stages, namely degumming, bleaching and deodorization. The bleaching process is carried out at 90–105oC using 1-2% bleaching earth and deodorization at 240-270oC. The high concentration of bleaching earth and deodorization temperature causes carotene to be degraded leading to low carotene content in the final product. The effort to maintain the carotene content is to process CPO into red palm oil (RPO). The content of carotene and fatty acids contained therein will be damaged in the presence of high heat, ascertain this, a study was conducted on the effect of heating time on the chemical properties of red palm oil. The study was conducted using a completely randomized block design with prolonged heating treatment (0, 2, 4, 6, 8 and 10 hours) at 180oC and repeated 3 times and then the fatty acid content, peroxide value, iodine number and functional groups formed in bulk red palm oil purchased online were observed. The results showed that increasing the heating time can decrease the iodine number but increase the acid number and peroxide value. Heating at 180oC for 10 hours produced iodine, acid and peroxide value of 57.72, 9.56 and 12.55, respectively. The results of the analysis using Fourier Transform Infra-Red (FTIR) showed the presence of free fatty acids at wave number 722 cm-1 and peroxide numbers at wave number 2.854 cm-1. The test results using gas chromatography showed that linoleic acid decreased by about 3.23% during heating for up to 10 hours, while saturated fatty acids increased by about 0.32%. Key words: Cooking oil, Free fatty acid, Iodine number, Peroxide number, polymerization

Comparison of miR-106b, miR-191, and miR-30d expression dynamics in milk with regard to its composition in Holstein and Ayrshire cows.

Milk composition varies considerably and depends on paratypical, genetic, and epigenetic factors. MiRNAs belong to the class of small non-coding RNAs; they are one of the key tools of epigenetic control because of their ability to regulate gene expression at the post-transcriptional level. We compared the relative expression levels of miR-106b, miR-191, and miR-30d in milk to demonstrate the relationship between the content of these miRNAs with protein and fat components of milk in Holstein and Ayrshire cattle. Milk fat, protein, and casein contents were determined in the obtained samples, as well as the content of the main fatty acids (g/100 g milk), including: saturated acids, such as myristic (C14:0), palmitic (C16:0), and stearic (C18:0) acids; monounsaturated acids, including oleic (C18:1) acid; as well as long-, medium- and short-chain, polyunsaturated, and trans fatty acids. Real-time stem-loop one-tube reverse transcription polymerase chain reaction with TaqMan probes was used to measure the miRNA expression levels. The miRNA expression levels in milk samples were found to be decreased in the first two months in Holstein breed, and in the first four months in Ayrshire breed. Correlation analysis did not reveal any dependence between changes in the expression level of miRNA and milk fat content, but showed a multidirectional relationship with individual milk fatty acids. Positive associations between the expression levels of miR-106b and miR-30d and protein and casein content were found in the Ayrshire breed. Receiver operating characteristic curve analysis showed that miR-106b and miR-30d expression levels can cause changes in fatty acid and protein composition of milk in Ayrshire cows, whereas miR-106b expression level determines the fatty acid composition in Holsteins. The data obtained in this study showed that miR-106b, miR-191, and miR-30d expression levels in milk samples have peculiarities associated with breed affiliation and the lactation period.

Effects of nitrogen starvation on growth and biochemical composition of some microalgae species.

Nitrogen is one of the most important nutrient sources for the growth of microalgae. We studied the effects of nitrogen starvation on the growth responses, biochemical composition, and fatty acid profile of Dunaliella tertiolecta, Phaeodactylum tricornutum, and Nannochloropsis oculata. The lack of nitrogen caused changes in carbohydrate, protein, lipid, and fatty acid composition in all examined microalgae. The carbohydrate content increased 59% in D. tertiolecta, while the lipid level increased 139% in P. tricornutum under nitrogen stress conditions compared to the control groups. Nitrogen starvation increased the oligosaccharide and polysaccharide contents of D. tertiolecta 4.1-fold and 3.6-fold, respectively. Furthermore, triacylglycerol (TAG) levels in N. oculata and P. tricornutum increased 2.3-fold and 7.4-fold, respectively. The dramatic increase in the amount of TAG is important for the use of these microalgae as raw materials in biodiesel. Nitrogen starvation increased the amounts of oligosaccharides and polysaccharides of D. tertiolecta, while increased eicosapentaenoic acid (EPA) in N. oculata and docosahexaenoic acid (DHA) content in P. tricornutum. The amount of polyunsaturated fatty acids (PUFAs), EPA, DHA, oligosaccharides, and polysaccharides in microalgal species can be increased without using the too costly nitrogen source in the culture conditions, which can reduce the most costly of living feeding.

Understanding the changes in millable oil content and fatty acid composition of infrared radiation treated mustard (Brassica juncea) seeds using Vis-NIR-SWIR hyperspectral imaging

Enhancing the recovery of edible oil during mechanical oil expression offers a potential solution to mitigate the gap between the supply and demand. Infrared (IR) pre-treatment has demonstrated an enhanced availability of mechanically extractable oil from mustard seeds. In this study, hyperspectral imaging (HSI) techniques were employed to investigate the spatial distribution of oil in mustard seeds subjected to IR treatment under varying voltage and time of exposure. Both visible near-infrared (Vis-NIR, 399–1003 nm) and short-wave infrared (SWIR, 895–1712 nm) HSI systems were utilized to acquire spectral data followed by chemometric analysis, including partial least square discriminant analysis (PLS-DA) and regression (PLSR), to develop prediction models. The PLS-DA model exhibited robust classification capabilities for the differentiating mustard seeds based on various IR treatments from control samples. Notably, the accuracy levels achieved were 94.7 % for Vis-NIR-HSI and 99.2 % for SWIR-HSI. The prediction of oil content and fatty acid components, such as erucic acid, oleic acid, saturated fatty acids and mono fatty acids (MUFAs) could be carried out by the PLSR model developed using SWIR-HSI spectral data (R2 > 0.80). These predictions closely aligned with the outcomes obtained from analytical techniques. However, when utilizing Vis-NIR spectral data, the predictions (R2 > 0.65) were comparatively less accurate.

Investigation of chemical properties and bioactive compounds of oils from different pumpkin seeds (Cucurbita pepo L.) during maturation

AbstractIn this study, seed and oil yields, protein, and moisture ratios of seeds of four different types of pumpkin seed varieties, namely Palancı population, VD1sn8, and VD1sn6 hybrid varieties and commercial variety grown in Edirne conditions in 2014 and 2015. Also, this study aimed to determine the change of fatty acid, tocopherol, and sterol composition of mentioned pumpkin seed varieties in three different periods from seed formation to final harvest time. During the ripening period, it was obtained that the oil yield increased, the moisture content of pumpkin seeds decreased. In the last harvest period, the oil yield of pumpkin seed varieties was determined to be between 37.21% and 42.07%. Protein ratios of all pumpkin seed species were found to be very close to each other (37.94%–39.28%) and statistically similar (p &gt; 0.05). In 2014 and 2015, the dominant fatty acids for all pumpkin seed varieties are 18:1 (39.49%–46.95%) and 18:2 (32.57%–39.26%). Except for these fatty acids, 16:0 varies between 10.65% and 13.60% in all varieties; 18:0 varies at a ratio of 5.70%–6.38%. It is seen that the dominant tocopherol isomer is γ‐tocopherol for all pumpkin seed species in all harvest periods. In the last harvest period in 2014 and 2015, the amounts of γ‐tocopherol constitute 99.98%–84.95% and 86.91%–89.86% of the total tocopherol, respectively. It was observed that the tocopherol composition changed during the ripening period in all pumpkin seed species (p &lt; 0.05). In general, the amount of sterols decreased during the ripening period for all cultivars in 2014 and 2015. In order from the highest to the least, β‐sitosterol, 5,24‐stigmastadienol, campesterol, Δ‐5 avenasterol, and stigmasterol were determined as phytosterols in pumpkin seed oils. Generally, β‐sitosterol ratios in all varieties were high in the 1st harvest period, decreased slightly in the 2nd harvest period, increased again until the 3rd harvest period and reached the values in the 1st harvest period in both 2014 and 2015.

Influence of wastewater discharge from dredging mariculture pond sediments on the food sources of two intertidal crab species

The present study δ13C, δ15N and fatty acid compositions of two dominant mangrove crabs, Tubuca arcuata and Parasesarma plicatum were compared between a mangrove site frequently receiving dredged wastewater from mariculture ponds and an adjacent reference site, to investigate the impact of wastewater discharge on their diets. A laboratory experiment was also conducted to further test how their diets changed with the wastewater input. The result showed no significant change in the δ13C while clear 15N enrichment of crabs in association with the wastewater discharge. Changes in 15N signature and fatty acid composition of the crabs due to the wastewater discharge indicated that the impact of wastewater discharge was related to crab species, being more apparent on the deposit feeder (T. arcuata) than the herbivorous P. plicatum. The results suggested that the discharge of dredged wastewater into mangroves resulted in the uptake of wastewater-derived materials and nutrients by mangrove crabs.

Neuroprotective Effects of Metformin Through AMPK Activation in a Neurotoxin-Based Model of Cerebellar Ataxia.

Cerebellar ataxia is a heterogeneous group of neural disorders clinically characterized by cerebellar dysfunction. The diagnosis of patients with progressive cerebellar ataxia is complex due to the direct correlation with other neuron diseases. Although there is still no cure for this pathological condition, some metabolic, hereditary, inflammatory, and immunological factors affecting cerebellar ataxia are being studied and may become therapeutic targets. Advances in studying the neuroanatomy, pathophysiology, and molecular biology of the cerebellum (CE) contribute to a better understanding of the mechanisms behind the development of this disorder. In this study, Wistar rats aged 30 to 35 days were injected intraperitoneally with 3-acetylpyridine (3-AP) and/or metformin (for AMP-activated protein kinase (AMPK) enzyme activation) and euthanized in 24 hours and 4 days after injection. We analyzed the neuromodulatory role of the AMPK on cerebellar ataxia induced by the neurotoxin 3-AP in the brain stem (BS) and CE, after pre-treatment for 7 and 15 days with metformin, a pharmacological indirect activator of AMPK. The results shown here suggest that AMPK activation in the BS and CE leads to a significant reduction in neuroinflammation in these regions. AMPK was able to restore the changes in fatty acid composition and pro-inflammatory cytokines caused by 3-AP, suggesting that the action of AMPK seems to result in a possible neuroprotection on the cerebellar ataxia model.

Stem Cells Derived from Human Exfoliated Deciduous Teeth Functional Assessment: Exploring the Changes of Free Fatty Acids Composition during Cultivation.

The metabolic regulation of stemness is widely recognized as a crucial factor in determining the fate of stem cells. When transferred to a stimulating and nutrient-rich environment, mesenchymal stem cells (MSCs) undergo rapid proliferation, accompanied by a change in protein expression and a significant reconfiguration of central energy metabolism. This metabolic shift, from quiescence to metabolically active cells, can lead to an increase in the proportion of senescent cells and limit their regenerative potential. In this study, MSCs from human exfoliated deciduous teeth (SHEDs) were isolated and expanded in vitro for up to 10 passages. Immunophenotypic analysis, growth kinetics, in vitro plasticity, fatty acid content, and autophagic capacity were assessed throughout cultivation to evaluate the functional characteristics of SHEDs. Our findings revealed that SHEDs exhibit distinctive patterns of cell surface marker expression, possess high self-renewal capacity, and have a unique potential for neurogenic differentiation. Aged SHEDs exhibited lower proliferation rates, reduced potential for chondrogenic and osteogenic differentiation, an increasing capacity for adipogenic differentiation, and decreased autophagic potential. Prolonged cultivation of SHEDs resulted in changes in fatty acid composition, signaling a transition from anti-inflammatory to proinflammatory pathways. This underscores the intricate connection between metabolic regulation, stemness, and aging, crucial for optimizing therapeutic applications.

The efficacy of beeswax in extending frying life of sunflower oil and storage stability of fried potato chips

AbstractThis study was performed to investigate the impact of adding beeswax to sunflower oil on its frying life and the oxidative stability of the fried potato chips during storage. In this study, sunflower oil and its oleogels containing 2, 4, and 6/100 g(w/w) of beeswax were used in order to fry potato chips for 4 h each day for 4 days consecutively. Samples fried in sunflower oil absorbed the highest amount (37.0%) of oil compared to the lowest (32.9%) in 2% oleogel. The addition of beeswax did not negatively affect the color, texture, and sensory quality of potato chips. Based on the analysis of total polar components, changes in fatty acid composition, and p‐anisidine evaluation, the findings of this study indicate that the utilization of beeswax‐sunflower oil oleogel, particularly the 6% oleogel, may offer enhanced frying stability compared to sunflower oil. Moreover, chemical analyses of the potato chips stored for 30 days revealed that the control sample contained highest level of secondary oxidation products compared to the oleogels, indicating that fried potato chips in oleogels were more resistant to oxidation during storage. Therefore, beeswax can be considered as a natural preservative that improves the shelf life of fried potato chips as well as the frying stability of sunflower oil.

Oxidation Stability of Hazelnut Oil Supplemented with β-Carotene During Light Exposure Using Xenon Test Instrument

Objective: The inhibition of lipid oxidation is important for the application of edible fats and oils in food processing. High oleic oils exhibit high stability during oxidation. Hazelnut oil, naturally rich in oleic acid, has recently become widely used in the food industry due to its high oxidation stability. Antioxidants are added to oils to make them more resistant to oxidation. β-carotene is a natural antioxidant and leads to increased resistance to photooxidation. The aim of this work was to investigate the effect of a natural antioxidant β-carotene on light-induced lipid stability of hazelnut oils.&#x0D; Materials and Methods: The hazelnut oil was supplemented with β-carotene in 25 ppm. Not-supplemented hazelnut oil (HO) and the beta-carotene added hazelnut oil (HO with β-car.) were irradiated in a xenon test instrument by different light intensities at 275 and 765 W/m2 for 2, 4, 6, 8, 10, 12, 18, 24, 30, 36, 42 and 48 hours. Fatty acids from the hazelnut oil samples were determined as fatty acid methyl esters (FAMEs) using GC-FID method. To investigate the degree of oxidation of the hazelnut oil samples, the induction time with an accelerated aging test using a Rancimat, peroxide value, volatile lipid oxidation compounds using SPME-GC-FID and antioxidative capacity using DPPH-radical scavenging assay were measured.&#x0D; Results: The results indicated that the change in fatty acid composition with irradiation intensity and duration of irradiation is not so strong. Among the fatty acids, a significant change was detected only in the linoleic acid content between the HO and the HO with β-car. after light exposure. The amounts of hexanal, heptenal, E-2,4-heptadienel, nonenal, and nonanoic acid increased after photooxidation. The antioxidant capacity of the hazelnut oil samples decreased during light exposure. After light exposure, HO with β-car. showed a higher induction time and lower peroxide value compared to HO.&#x0D; Conclusion: These results confirm that the β-carotene supplemented hazelnut oil showed higher oxidative stability than hazelnut oil without additional β-carotene. In conclusion, the results suggest that β-carotene could slow down the photooxidation of hazelnut oil.

Implication of Mn-cofactored superoxide dismutase in the tolerance of swarmer Pseudomonas aeruginosa to polymixin, ciprofloxacin and meropenem antibiotics.

The protective role of superoxide dismutase (Sod) against oxidative stress, resulting from the common antibiotic pathway of action, has been studied in the wild type and mutant strains of swarmer Pseudomonas aeruginosa, lacking Cytosolic Mn-Sod (sodM), Fe-Sod (sodB) or both Sods (sodMB).Our results showed that inactivation of sodB genes leads to significant motility defects and tolerance to meropenem. This resistance is correlated with a greater membrane unsaturation as well as an effective intervention of Mn-Sod isoform, in antibiotic tolerance.Moreover, loss of Mn-Sod in sodM mutant, leads to polymixin intolerance and is correlated with membrane unsaturation. Effectivelty, sodM mutant showed an enhanced swarming motility and a conserved rhamnolipid production. Whereas, in the double mutant sodMB, ciprofloxacin tolerance would be linked to an increase in the percentage of saturated fatty acids in the membrane, even in the absence of superoxide dismutase activity.The overall results showed that Mn-Sod has a protective role in the tolerance to antibiotics, in swarmer P.aeruginosa strain. It has been further shown that Sod intervention in antibiotic tolerance is through change in membrane fatty acid composition.

Changes in nutrient composition and gene expression in growing mealworms (Tenebrio molitor)

Abstract Insects are of high interest as a sustainable source of nutrients to be included in the food production system. The larvae of Tenebrio molitor, commonly known as yellow mealworms (MW), have a high protein content, which means potential applications in the animal feed and human food sectors. However, previous reports have shown considerable variability in the nutrient composition of mealworms, which may in part, be due to harvesting at different developmental stages. A better understanding of the regulation of composition during development would potentially facilitate future attempts to manipulate nutrient content, perhaps through gene editing, to maximize commercial value. In the present study, mealworms were harvested at various time points within a 24 day period leading up to the start of pupation. At the earliest time points (between days −24 and −17), a 44% increase in fat content was seen, which was maintained throughout the rest of development. By day −12, protein content fell by 12%, a change that was also maintained. Throughout development there was a change in fatty acid composition, with a shift from oleic acid being the major fatty acid at day −24, to linoleic acid being predominant at later time points. In an attempt to better understand the genetic basis of these changes, an analysis of the transcriptome was undertaken. In the absence of a specific annotated genome for the mealworm, an Affymetrix GeneChip microarray for Drosophila was utilized. The hybridisation of RNA extracted from five developmental stages (larvae and pupae) showed differential gene expression; and some potential orthologs were identified which may be involved in regulating nutrient composition during development. However, we were unable to identify a significant proportion of the most highly regulated genes, highlighting the need for a fully annotated mealworm genome.

Seasonal effect on fatty acid composition in phospholipid classes and triacylglycerols of male Capoeta umbla

The seasonal changes in muscle tissue, total lipids and fatty acid composition of phospholipids (PL), triacylglycerol (TAG), and phospholipid classes of male Capoeta umbla were investigated in this study. Phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS) were identified as the major phospholipids (PLs) in the muscle tissue (PS). Triacylglycerols showed high contents of MUFA, 14:0, 16:1n-7, 18:1n-9, 18:2n-6, and 18:3n-3; while phospholipids presented high contents of AA, DHA, and 18:0. Myristic acid, 16:1n-7, 18:1n-9, monounsaturated fatty acids (MUFA), linoleic acid (18:2n-6), and linolenic acid (18:3n-3) were shown to be present in larger concentrations in TAG than in PL classes. In PL classes, 16:0, 18:0, arachidonic acid (20:4n-6) (AA), eicosapentaenoic acid (EPA) (20:5n-3), docosahexaenoic acid (DHA) (22:6n-3) and polyunsaturated fatty acid (ΣPUFA) were higher than the TAG fraction. The fatty acid composition of total lipid and lipid classes (TAG and PL) were affected by the seasonal variations and lipid fraction.

Associations between subclinical intramammary infection and milk fatty acid profile at the quarter level in Holstein cattle.

Mastitis, especially the subclinical form, is the most common economic and health problem in dairy cows. Little is known about changes in milk fatty acid (FA) composition according to infection/inflammation status of the mammary gland. The aim of this study was to investigate the associations between naturally occurring subclinical intramammary infection (IMI) from different pathogens, i.e. Streptococcus agalactiae, Staphylococcus aureus, Streptococcus uberis and Prototheca spp., and the detailed milk FA profile assessed at quarter level in Holstein cows. After an initial bacteriological screening (T0) on 450 Holstein cows reared in three dairy herds, we identified 78 cows positive at the bacteriological examination. These animals were followed up at the quarter level two weeks (T1) and six weeks (T2) after T0. In total, 600 single-quarter samples were obtained at T1 and T2. Individual FAs were determined using the gas chromatography analytical method. Investigated traits were 70 individual FAs, 12 FA groups, and six desaturation indices. The associations between subclinical IMI combined with somatic cell count (SCC) and milk FA profile were investigated using a hierarchical linear mixed model (i.e., observational unit was quarter within cow) with the following fixed effects: days in milk (DIM), parity, herd, SCC, bacteriological status (BACT, positive and negative), and the SCC × BACT interaction. The random effect of individual cow nested within herd, DIM and parity was used as the error term for the latter effects. The most significant associations were detected at T2. Notably, IMI reduced the proportions of individual short-chain FA, especially 4:0 and 6:0 (-14%), but increased the proportion of the most abundant medium-chain FA (MCFA), 16:0 (+4%). A reduction in the desaturation indices was observed mostly for 14:1 index (-9%), in line with the reduction in 14:1 (-10%). Somatic cell count significantly affected 14 individual FAs. In particular, samples with high SCC (≥200 000) had significantly lower proportions of 8:0, 10:0, 11:0, 12:0, and 13:0 compared with samples with low SCC (<200 000). Increasing SCC in animals positive at the bacteriological examination were associated with a reduction in total MCFA at T2 (while in negative animals, they remained constant across SCC classes), possible evidence that elongation of the FA chain from 11 to 16 carbons is affected by a combination of infection and SCC. This study showed that subclinical IMI and SCC are mainly associated with reductions in the synthesis of FA and the desaturation process in the mammary gland.

Fatty-acid based assessment of benthic food-web responses to multiple stressors in a large river system

Rivers are often exposed to multiple stressors, such as nutrients and contaminants, whose impacts on the river food webs may not be distinguished by sole assessment of biological community structures. We examined the benthic algal assemblages and the fatty acids (FA) of benthic macroinvertebrates in the lower Athabasca River in Canada, aiming to assess the changes in algal support and nutritional quality of the benthic food web in response to cumulative exposure to natural bitumen, municipal sewage discharge (hereafter, “sewage”), and oil sands mining (“mining”). Data show that the decline in water quality (increases in nutrient concentrations and total suspended solids) was associated with decreases in benthic diatom abundance, and was driven mainly by sewage-induced nutrient enrichment. Responses in nutritional quality of benthic macroinvertebrates, indicated by their polyunsaturated FA (PUFA) concentrations, were taxon- and stressor-specific. Nutritional quality of the larval dragonfly predator, Ophiogomphus, decreased nonlinearly with decreasing benthic diatom abundance and was lowest at the sewage-affected sites, although exposure to natural bitumen also resulted in reduced Ophiogomphus PUFA concentrations. In contrast, the PUFA concentrations of mayfly grazers/collector-gatherers were not affected by natural bitumen exposure, and were higher at the sewage and sewage+mining sites. The PUFA concentrations of the shredder Pteronarcys larvae did not change with cumulative exposure to the stressors. Sediment metal and polycyclic aromatic compound concentrations were not associated with the macroinvertebrate FA changes. Overall, we provide evidence that sewage induced reduction in trophic support by PUFA-rich diatoms, and was the predominant driver of the observed changes in FA composition and nutritional quality of the benthic macroinvertebrates. Fatty-acid metrics are useful to untangle effects of concurrent stressors, but the assessment outcomes depend on the functional feeding guilds used. A food-web perspective using multiple trophic levels and feeding guilds supports a more holistic assessment of the stressor impacts.