Variation In Fatty Acid Composition Research Articles

Geographical variations in the fatty acids of Zanthoxylum seed oils: A chemometric classification based on the random forest algorithm

Some Zanthoxylum species have the potential to develop oil-oriented wood plants. But confusion of seed oils and low environmental adaptability of fatty acid lead to obstacles to their further development. In this work, a total of 99 seed samples of two widely distributed Zanthoxylum species (Zanthoxylum bungeanum and Zanthoxylum armatum) seeds were collected from 97 plantations located at 32 locations in China spread over a wide geographic area (a range of 17.2°longitude and 12.8°latitude) and fatty acid composition of seed oils extracted by supercritical CO2 extractor apparatus among individuals was determined. The random forest algorithm was employed to conduct a classification model to identity two species’ oils and the relationship between variation of fatty acid composition and environmental factors was analyzed. Two species seed oils contained C15-C20 fatty acids, of which palmitoleic acid was the most abundant in Z. armatum and oleic acid was the most abundant in Z. bungeanum. The built classification model showed 100% accuracy and explained proportions of total fatty acid composition’s variance by environmental factors between Z. armatum and Z. bungeanum were 83.15% and 67.43% respectively. Among all environmental factors, latitude had a significant contribution to variation of fatty acid composition in Z. armatum seed oil, while annual maximum precipitation greatly contributed to variation of fatty acid composition of Z. bungeanum seed oil.

Metabolomic and Lipidomic Signatures of Cold Tolerance in Bumble Bees

Thermal tolerance is a key physiological trait that often varies among populations and species, and can be a key determinant of current and future geographic distributions. The cellular basis for organismal differences in thermal tolerance is an active area of research, with chemical constituents of the cytosol and cell membrane likely playing important roles in maintaining cell function at low temperatures. For freeze‐avoiding organisms, the abundance and makeup of sugars and related molecules depress the freezing point, reducing the risk of ice formation. At less extreme temperatures, remodeling of membrane lipids can help maintain fluidity (and function) at cold temperatures. We have found striking differences in critical thermal minima (CTmin) of worker bumble bees reared in common‐garden conditions from queens collected at low and high latitudes. We compared metabolomic and lipidomic signatures of these bees to identify key molecules that likely underlie differences in cold tolerance. PCA analyses of GC‐MS data for aqueous abdominal extracts revealed clear separation of low and high latitude populations and reveal higher levels of several key molecules, including L‐proline, in the high latitude population. Lipid extractions and subsequent GC‐MS reveals variation in fatty acid composition of nutrients (triacylglycerols) and of cellular membranes, for which phospholipid composition is also critical for function at low temperatures. This broad spectrum approach to metabolomics and lipidomics allows us to compare a wide range of metabolites between bees differing in cold tolerance, facilitating ongoing research on the mechanistic basis for this physiological trait linked to the ecology of diverse organisms.Support or Funding InformationThis material is based upon work supported by the National Science Foundation under Grant Nos. DEB‐1457659 and RII Track 2‐1826834. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Two‐Step Direct Transesterification as a Rapid Method for the Analysis of Fatty Acids in Microalgae Biomass

A rapid and routine direct transesterification (DT) method for the evaluation of the relative fatty acid composition of microalgae biomass is presented in this paper. The method is optimized on Lake Superior Fish Tissue (SRM 1946), as standard reference material and then the proposed DT procedure is tested on various microalgae species, and the results are compared to a validated microwave assisted esterification (MAE) as a reference (R2 = 0.99). Total DT time is very fast (14 min), while the fatty acid compositions are virtually identical to those prepared by MAE for various species of microalgae as well as fish and krill biomasses.Practical Applications: Microalgae are known as a sustainable source of bioactive compounds such as fatty acids, and their implementation is growing. Application of microalgae biomass as a source of fatty acids requires fast and reliable methods of analysis of fatty acids. The DT method developed in this study can be used as a powerful tool for the monitoring of the variations in fatty acid composition during the cultivation, processing, formulation, and storage.The fatty acid composition of microalgae has been proven as a potential tool for the identification of microalgal taxa. Application of fatty acid composition as a fingerprinting tool requires fast, reliable, and precise methods. A rapid and routine direct transesterification method for the evaluation of the fatty acid composition of microalgae biomass is presented in this paper. The transesterification is being done in two steps as sonication assisting base‐catalyzed methanolysis followed by BF3 methylation reactions. Heating in boiling water bath for 2 min is required at both steps to improve the reactions.

Quantitative variation of fatty acid composition in seed oil from baobab (Adansonia digitata L.) wild populations in sub-Sahara Africa

Baobab (Adansonia digitata L., Malvaceae) seed oil contains Fatty Acids (FAs) with commercial and cosmeceutical value. The influence of provenance and geographical region on FAs profile and content of seed oil from baobab wild populations in sub-Saharan Africa (SSA) was assessed in this study. The FA profiles were determined as fatty acid methyl esters (FAME) by Gas Chromatography (GC). Generally, the seed oil contained 17–22% saturated fatty acids (SFA), 32–38% monounsaturated fatty acids (MUFA) and 22–26% polyunsaturated fatty acids (PUFA). Palmitic acid (C16:0) was the most abundant SFA, while oleic (C18:1) and linoleic acid (C18:2, LA) were the dominant MUFA and PUFA, respectively. There existed significant (p < .05) variations in FAs concentration within and between the baobab provenances. Principal component analysis (PCA) was conducted to determine relationships between FAs, provenances and countries. The variation in FAs content can be attributed to genetic, edaphic and climatic factors due to geographical locations.

Association Genetics Identifies Single Nucleotide Polymorphisms Related to Kernel Oil Content and Quality in Camellia oleifera.

Camellia oleifera, as an important nonwood tree species for seed oil in China, has received enormous attention owing to its high unsaturated fatty acid contents benefited to human health. It is necessary to examine allelic diversity of key genes that are associated with oil production in C. oleifera cultivars with a large variation of fatty acid compositions. In this study, we performed the association analysis between four key genes (two CoSAD and two Cofad2) coding fatty acid desaturases and traits including oil content and fatty acid composition. We identified two single nucleotide insertion-deletion (InDel) and 362 single-nucleotide polymorphisms (SNPs) within the four candidate genes by sequencing an association population (216 accessions). Single-marker (or haplotype) and traits association tests were conducted by linkage disequilibrium (LD) approaches to detect significant marker-trait associations. Validation population (279 hybrid individuals from six full-sibs families) studies were performed to validate the function of allelic variations significantly associated. In all, 90 single marker-trait and one haplotype-trait associations were significant in association population, and these loci explained 1.87-17.93% proportion of the corresponding phenotypic variance. Further, six SNP marker-trait associations ( Q < 0.10) from Cofad2-A, CoSAD1, and CoSAD2 were successfully validated in the validation population. The SNP markers identified in this study can potentially be applied for future marker-assisted selection to improve oil content and quality in C. oleifera.

Temporal and spatial variation in fatty acid composition in Acropora tenuis corals along water quality gradients on the Great Barrier Reef, Australia

Fatty acids (FA) play a vital role in coral physiology, metabolism and stress resistance. Optimal health requires a balance of fatty acids, and more specifically essential polyunsaturated fatty acids (PUFA), for efficient biochemical and physiological functioning. Therefore, it is necessary to fully assess and evaluate the viability of FA as biomarkers for monitoring the health of coral populations. This study explores seasonal and spatial variation in the abundance of 17 FA in the coral Acropora tenuis, along two water quality gradients on the central Great Barrier Reef. Ratios of key FA varied similarly along the two water quality gradients and were highest in corals from comparatively good water quality conditions. Strong differences in PUFA composition were found between wet and dry seasons, with high percentage n-3 PUFA defining the dry seasons (June 2013 and October 2013) and high percentage n-6 PUFA defining the wet seasons (February 2013 and 2014). Saturated FA and monounsaturated FA concentrations varied with season, positively correlated with Symbiodinium density, and had highest concentrations in corals exposed to relatively poor water quality. Overall, results demonstrate that essential FA and their derived ratios support FA as a potential indicator of coral holobiont health; however, strong seasonal variation may negate FA and their derived ratios as water quality indicators.

Variations in fatty acid composition and oxidative stability of hazelnut (&lt;em&gt;Corylus avellana&lt;/em&gt; L.) varieties stored by traditional method

In this study, the changes in fatty acid composition, peroxide number, free fatty acids, oleic acid/ linoleic acid (O/L) and iodine value (IV) were investigated during the traditional storage of hazelnuts. The samples were selected from Giresun Quality Tombul, Kara and Sivri hazelnut varieties with economical prescription. Samples were stored according to the conventional methods in external interference-free warehouses until the next harvest time. At the end of storage, the amount of oleic acid in all varieties increased while the amount of linoleic acid decreased. Even though an increase in the free fatty acids and peroxide number in all types of hazelnuts during storage was determined, the values were considerably lower than the rancidity limits at the end of the storage period. As a result of the study it was observed that the hazelnut shell is an important preservative during storage and that hazelnuts can be preserved until the next harvest period under simple storage conditions.

Geographic variation in fatty acid composition and food source of the commercial clam (&lt;em&gt;Venerupis decussata&lt;/em&gt;, Linnaeus, 1758), from the Tunisian Coast: Trophic links

Lake and coastal Tunisian areas are rich biodiversity habitats, although little information is available about the distribution of food sources for the inhabitant species. In this study, a fatty acid analysis was used to study the trophic ecology of Venerupis decussatac ommunities from 10 sites located along the Tunisian Coast. The richest population in fatty acids was found in S4 followed by S5 and S8, while that of S1, S3 and S10 were the least rich. Results from multivariate analysis confirmed the ecological position of the studied population based on their fatty acid composition. Our results divided the ten studied populations into three similar groups according to their ecological and geographical positions in relation to environmental parameters and food and trophic links. A principal component analysis revealed that diatoms and dinoflagellates were the predominate diets in all the sampling stations. Bacteria and urban discharge dominated the dietary source of clams from S10 and S9. Zooplankton were the preferred diet of V. decussata harvested from the two S2 and S3 lakes; although green algae, phytoplankton and detritus were absent from the dietary source of the two previous populations. Despite spatial differences, clams from the north and the south could be easily distinguished from each other, which indicates the utility of this method in the dietary analysis of different food chain links. This study proves that geographic, ecologic and abiotic factors as well as their mutual interaction should be properly investigated in studies focusing on the trophic chains of aquatic ecosystems.

Fatty Acid Composition of New Zealand Forage Finished Beef Compared to US Grain Fed Beef

ObjectivesThe objective of this study was to evaluate differences in fatty acid (FA) composition of NZ beef finished on fodder beet (Beta vulgaris subsp. vulgaris L.; FB) or traditional grass diets and US grain-finished beef.Materials and MethodsStrip loins (n = 240) were selected from a commercial abattoir in NZ representing two feeding treatments (FB, non-FB) and expected low and high eating quality (primarily based on marbling) following a nationwide feeding trial to finish beef steers using FB. Selection resulted in four treatments: FB low quality (FBL), FB high quality (FBH), non-FB low quality (NFBL), and non-FB high quality (NFBH). Additionally, sides of beef (n = 120) representing USDA Top Choice (TCH) and Select (SEL) were sourced from a commercial abattoir in the US. Loins were fabricated prior to 21 d postmortem to isolate the longissimus lumborum (LL); these were sliced into 2.5 cm steaks, vacuum packaged, and stored at 2–4°C until 21 d or 35 d postmortem and frozen on the appropriate day. Lipids were extracted from a subset of samples via chloroform: methanol extraction then separated into polar and neutral fractions. Fatty acid methyl esters were evaluated using GC-FID. Data were analyzed with a 2-way ANOVA at a significance level of α = 0.05 and treatment, aging, and the respective interaction as fixed effects.ResultsAging influenced percent saturated FA (%SFA; P < 0.01), monounsaturated FA (%MUFA; P < 0.01), and polyunsaturated FA (%PUFA; P = 0.01). An increase in %MUFA and %PUFA at 35 d compared with 21 d (P < 0.01) corresponded with a decrease in %SFA at 35 d (P < 0.01). Treatment also influenced %PUFA (P < 0.01). NFBL contained the greatest %PUFA (P < 0.05). TCH and FBH contained less %PUFA than all treatments except SEL (P > 0.05). Treatment and aging also affected palmitic and stearic acids (P < 0.01), which make up the greatest portion of SFA. The proportion of palmitic acid was least in SEL (P < 0.05) and greater in FBH than NFBH and TC (P < 0.05). The US treatments had lower proportions of stearic acid than NZ treatments (P < 0.05). Both palmitic and stearic acids were of greater proportions in 35 d samples than 21 d samples (P < 0.05). Oleic acid contributes largely to total FA and was affected by the interaction of treatment and aging (P = 0.04). At 35 d, NZ treatments had greater proportions of oleic acid than at 21 d (P < 0.05). The proportion of oleic acid was least in SEL at both aging times. Of the PUFA, linoleic was affected by treatment (P < 0.05) and was greatest in SEL and TC (P < 0.05); FB treatments had the lowest proportion of linoleic acid (P < 0.05). Treatment and aging affected α-linolenic acid (P < 0.01). NFBL and NFBH had a greater proportion than both FB and US treatments (P < 0.05); both FB treatments had greater proportions of α-linolenic than US treatments (P < 0.05). Proportion of α-linolenic acid was elevated with 35 d aging (P < 0.05). Treatment affected proportions of long chain PUFA (P < 0.05) with TCH and SEL having lower proportions than NZ treatments (P < 0.05). Low quality NZ treatments had the greatest proportions of long chain PUFA (P < 0.05).ConclusionWhile finishing diet does affect fatty acid composition of beef strip steaks, finishing on FB produces a similar FA composition to non-FB grass. Total lipid content is also responsible for variation in FA composition. As lipids oxidize during aging, a shift toward more unsaturated FA occurs, leading to a decrease in %SFA.

Seasonal variation in fatty acid composition of wild boar in Lithuania

The aim of the present study was to investigate the fatty acid composition of wild boar meat hunted in Lithuania during different seasons of the year. Twenty four wild boars hunted during winter (January) and summer (June) hunting seasons were used in the experiment. Each sex (10 females and 10 entire males) was represented by first and second year sub-adult youngsters. Neither the hunting season nor the sex affected the intramuscular fat content in the meat of wild boar. The meat from wild boar hunted during winter season presented lower proportions of saturated (SFA) and higher proportions of polyunsaturated (PUFA) fatty acids, higher PUFA/SFA and n-6/n-3 PUFA ratios.HighlightsThe fatty acid composition in the meat of wild boar was determined during the two most distinctive periods of the year (January and June).The effect of hunting season on the proportions of fatty acids and lipid quality indices was evaluated.

Variation of fatty acid composition in seed oil in the collection of induced oil flax (Linum humile Mill.) mutants

A wide variety of application fields for flax seeds requires for breeders to develop new varieties with different characteristics, corresponding to the intended final product. The method of experimental mutagenesis is one of the ways to solve this problem. This method allows mutant lines with an array of morphometric and biochemical traits to be created from a single species and within a relatively short period of time. The article demonstrates that treatment of Linum humile Mill. seeds of the cultivars Iceberg and Solnech-ny with the new chemical mutagens DG-2, DG-6, DG-7, DG-9 (derivatives of dimethyl sulfate (DMS)) as well as with the mutagens DMS and EMS resulted in the production of mutant lines and accessions with altered morphometric and biochemical parameters. Seeds of the initial cultivars were treated with 0.5 and 0.05 % aqueous solutions of the above mentioned substances and planted in the field to raise M1, M2, and M3generations. Ultimately, 27 types of mutations were identified and subdivided into five groups by morphometric characteristics. The fatty acid composition of seed oil for the isolated mutant specimens was studied: the content of palmitic, stearic, oleic, linoleic (w6) and lino-lenic (w3) acids, as well as the w6/w3 ratio. The statistical analysis showed significant distinctions between the mutant lines in the biochemical composition of the oil. A strong negative correlation between the content of linoleic and linolenic acids was demonstrated, as well as a positive relationship of average strength between the content of stearic and oleic acids for the both varieties. The mutant accessions obtained can be used as donor material for conducting breeding work on flax in various directions.

Variation of fatty acids composition in the hydrocarbon producer Botryococcus braunii BOT 22

Botryococcus braunii Bot-22, a hydrocarbon rich microalga known as a potential source of jet fuel, was photoautotrophically grown in a beveled shape flat-panel photobioreactor in continuous cultures. Two photon flux densities (PFD) 50 and 500 μmol photons m−2 s−1, two dilution rates, 0.178 and 0.357 d−1 and two different inlet oxygen concentrations were applied to find suitable conditions for biodiesel production by B. braunii. The main fatty acids detected by GC-FID, were oleic acid, palmitic acid, α-linolenic acid, erucic acid and stearic acid. By doubling the dilution rate from 0.178 to 0.357 d−1 at 500 μmol photons m−2 s−1 light intensity, the PUFAs decreased from 17.65% to 9.98%. In lower dilution rate, the sum of suitable fatty acids percentage for biodiesel known as oleic, palmitic, stearic, and linoleic acids was higher than all other conditions. In cell density lower than 6 g L−1, C16 and C18 fatty acids constituted main composition of microalgae oil content. The maximum productivity of suitable fatty acids for biodiesel mentioned above, all together, was achieved at higher dilution rate, 21% of inlet oxygen concentration and higher light intensity while the highest hydrocarbon productivity achieved at higher dilution rate, higher light intensity and 4% of inlet oxygen concentration.

Variations in fatty acid composition of Laoshan goat milk from partum to 135days postpartum.

The objective of this study was to characterize the variations in fatty acid (FA) profile during 7days of colostrum production and 5months of mature milk production in Laoshan goats. The individual FA profiles of each sample were investigated by gas chromatography-mass spectrometry. Significant differences in FAs were found between colostrum and mature milk. The contents of saturated fatty acids (SFA), unsaturated fatty acids (UFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA), and sum of C6, C8, and C10 (SC6+C8+C10 ) were all significantly affected by lactation period. Furthermore, there was no significant difference in the ratio of UFA/SFA or C18:2 (cis9, cis12-octadecadienoic acid)/C18:3 (all cis-9,12,15-octadecatrienoic acid) during the lactation period. The highest concentrations of SC6+C8+C10 , UFA, MUFA, and PUFA appeared in colostrum, but the highest SFA content was in mature milk. The highest proportions of SC6+C8+C10 and SFA were 11.32% and 79.55% on 5th day and 135th day respectively. By contrast, the lowest proportion of UFA was 20.45% on the 135th day. C14:0 (10.93%-12.87%), C16:0 (27.54%-36.65%), C18:0 (10.47%-14.59%), and C18:1 (18.80%-30.61%) were the most predominant FAs in goat milk with significant differences during the 135days lactation period except C18:0. In conclusion, the results of this study suggest that the lactation time has a pronounced effect on the FA compositions of goat milk.

Engineering the fatty acid synthesis pathway in Synechococcus elongatus PCC 7942 improves omega-3 fatty acid production

BackgroundThe microbial production of fatty acids has received great attention in the last few years as feedstock for the production of renewable energy. The main advantage of using cyanobacteria over other organisms is their ability to capture energy from sunlight and to transform CO2 into products of interest by photosynthesis, such as fatty acids. Fatty acid synthesis is a ubiquitous and well-characterized pathway in most bacteria. However, the activity of the enzymes involved in this pathway in cyanobacteria remains poorly explored.ResultsTo characterize the function of some enzymes involved in the saturated fatty acid synthesis in cyanobacteria, we genetically engineered Synechococcus elongatus PCC 7942 by overexpressing or deleting genes encoding enzymes of the fatty acid synthase system and tested the lipid profile of the mutants. These modifications were in turn used to improve alpha-linolenic acid production in this cyanobacterium. The mutant resulting from fabF overexpression and fadD deletion, combined with the overexpression of desA and desB desaturase genes from Synechococcus sp. PCC 7002, produced the highest levels of this omega-3 fatty acid.ConclusionsThe fatty acid composition of S. elongatus PCC 7942 can be significantly modified by genetically engineering the expression of genes coding for the enzymes involved in the first reactions of fatty acid synthesis pathway. Variations in fatty acid composition of S. elongatus PCC 7942 mutants did not follow the pattern observed in Escherichia coli derivatives. Some of these modifications can be used to improve omega-3 fatty acid production. This work provides new insights into the saturated fatty acid synthesis pathway and new strategies that might be used to manipulate the fatty acid content of cyanobacteria.

Insights into Geographic and Temporal Variation in Fatty Acid Composition of Croton Nuts Using ATR-FTIR

Croton megalocarpus seedcake oils from 30 different locations in south central Kenya were analyzed for their fatty acid composition using ATR-FTIR to determine the efficacy of a simple procedure for measuring initial geographic and subsequent temporal variation during five months of seed storage. To our knowledge, this is the first report showing variation in how oils in untreated nuts from different locations change during storage, and how these differences are correlated with local environments. These variations are important to forensic authentication efforts and they provide insights into ways to optimize Croton oil composition.

Production of fucoxanthin, chrysolaminarin, and eicosapentaenoic acid by Odontella aurita under different nitrogen supply regimes

Microalgae are recognized as promising producers of many bioactive products, but their utility is limited due to high production costs. We subjected the marine diatom Odontella aurita to three nitrogen supply regimes [initial low nitrogen (ILN), initial high nitrogen (IHN), and initial high nitrogen plus supplementary nitrogen (SN)] to investigate the accumulation of three high-value bioactive components: fucoxanthin, chrysolaminarin and eicosapentaenoic acid (EPA). We found that SN conditions maximized fucoxanthin accumulation: a maximum productivity of 6.01mgL-1d-1 was obtained, a 4.32-fold and 1.42-fold increase over production in the ILN and IHN groups, respectively. After nitrogen was depleted in the growth medium, chrysolaminarin became the dominant energy storage compound. Chrysolaminarin content rose to 60.33% of dry weight (DW) in the ILN group, and 46.27% of DW in the IHN group. Variations in fatty acid composition across the different nitrogen supply regimes indicated that EPA primarily accumulated in the glycolipids, especially when nitrogen supply was sufficient. The maximum productivity of chrysolaminarin (161.55mgL-1d-1) and EPA (9.37mgL-1d-1) was observed in the IHN group. However, IHN conditions did not maximize overall content of either compound. Our results demonstrated that O.aurita is potentially useful as a producer of a variety of bioactive products; the compounds produced by this species can be controlled by altering the nitrogen supply.

Effect of genetic background on the stability ofsunflower fatty acid composition in different high oleic mutations.

The effect of genetic background on the stability of fatty acid composition in sunflower near isogenic lines (NILs) carrying high-oleic Pervenets (P) or high-oleic NM1 mutations was studied. The materials were field-tested in different locations and at different sowing dates to evaluate a wide range of environmental conditions. Relationships were established between the fatty acids and the minimum night temperature (MNT) and the response was characterized. A genetic background effect for the fatty acid composition was found in both groups of NILs. The NM1-NILs showed an oleic level higher than 910 g kg-1 and they were more stable across environments with a zero or low dependence on the genetic background; on the other hand, high oleic materials bearing the P mutation showed lower levels of oleic acid, with a higher variation in fatty acid composition and a highly significant dependence on the genetic background. The NM1 mutation is the best option to develop ultra-high oleic sunflower oil that is stable across environments and genetic backgrounds, making its agronomical production more efficient and predictable. © 2018 Society of Chemical Industry.

Expression analysis of candidate genes for fatty acid composition in adipose tissue and identification of regulatory regions

The aim of this work was to study the genetic basis of the backfat expression of lipid-related genes associated with meat quality traits in pigs. We performed a genome-wide association study with the backfat gene expression measured in 44 genes by qPCR and the PorcineSNP60 BeadChip genotypes in 115 Iberian x Landrace backcross animals. A total of 193 expression-associated SNPs located in 19 chromosomal regions were associated with expression levels of ACSM5, ELOVL6, FABP4, FADS2, and SLC27A4 genes. Three expression quantitative trail loci (eQTLs) corresponding to ACSM5, FABP4, and FADS2 were classified as cis-acting eQTLs, whereas the remaining 16 eQTLs have trans-regulatory effects. Remarkably, a SNP in the ACSM5 promoter region and a SNP in the 3′UTR region of FABP4 were the most associated polymorphisms with the ACSM5 and FABP4 expression levels, respectively. Moreover, relevant lipid-related genes mapped in the trans-eQTLs regions associated with the ACSM5, FABP4, FADS2, and SLC27A4 genes. Interestingly, a trans-eQTL hotspot on SSC13 regulating the gene expression of ELOVL6, ELOLV5, and SCD, three important genes implicated in the elongation and desaturation of fatty acids, was identified. These findings provide new data to further understand the functional regulatory mechanisms implicated in the variation of fatty acid composition in pigs.

Comparative Study on Quality Characteristics and Variations in Fatty Acid Composition of Different Varieties of Rapeseed and Mustard (Brassica spp.)

With a view to studying the qualitative features and the variations in fatty acid composition of 6 rapeseed (B. campestris and B. napus) and mustard (B. juncea) varieties, an experiment was conducted. Among these varieties, BARI Sarisha-14 presented the value of 168.4 which was recorded the highest. Both BARI Sarisha-11 and BARI Sarisha-14 was found with the highest iodine value of 39.44; and the highest amount of acid value was recorded from BARI Sarisha-11 (1.867). Gas-liquid chromatographic (GLC) method has been used to determine the composition of essential fatty acid in the seeds of Brassica spp. (L.). From the GLC analysis, it was found that erucic acid, oleic acid, linoleic acid and lenolenic acid were the prime fatty acids in all the varieties. Erucic acid was in the range of 41.11 – 51.28%, oleic acid was the highest both in BARI Sarisha-11 and BARI Sarisha- 13 contained (18.69%), while BARI Sarisha-9 contained the highest amount of the unsaturated linoleic (17.75%) and linolenic (15.83%) acids. Moreover, palmitic acid, stearic acid and archidic acid were also present in small amount.

Nutritional quality in terms of lipid content and fatty acid composition of neutral and polar lipids in the adductor muscle of the oyster Crassostrea gigas (Thunberg, 1794) farmed in the Bizert lagoon (Tunisia) in relation with sexual cycle and environmental settings

Monthly variations of fatty acid composition of the two fractions polar lipids (PL) and neutral lipids (NL) in the adductor muscle of cupped oyster Crassostrea gigas, were studied from May 2005 until June 2006 in the Bizert lagoon, related to environmental parameters and reproductive events. C. gigas showed a clear cycle of energy storage and utilization in the site of study. Total PL and NL content varied significantly during the year and showed a negative and significant correlation with the gametogenic condition index which can be explained by transfer of fatty acids from the adductor muscle to gonads to support the gametogenic cycle. Nevertheless, PL and NL have no significant correlations either with temperature or chlorophyll a registered in the site of study. The adductor muscle proved to be less influenced by chlorophyll a richness of the farming environment. The dominance of total polyunsaturated fatty acids (PUFAs) over the saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) in both PL and NL fractions was established throughout the period of study. Oysters analyzed were characterized by high levels of PUFAs n−3 and high n−3/n−6 PUFAs ratio in both PL and NL fractions. PUFAs n−3 and SFAs of PL and PUFAs and SFAs of NL, showed a negative and significant correlation between them. In fact, low temperature values produce generally an increase in the PUFAs percentages in order to maintain the fluidity of cell membranes. We deduce that annual variations of fatty acids content in PL and NL fractions of the adductor muscle of C. gigas seem to be in relation with the reproductive events. According to our results, the adductor muscle tissues were relatively poor in fatty acids (maximum values (% of dry weight) of PL and NL respectively were 2.04±0.33 and 1.75±0.9). Lipids fluctuations were not pronounced all over the period of study in the site of sampling due to low effects of the environment richness and phases of the sexual cycle which aspires the adductor muscle contents of fatty acids to support other organs in the gametogenic process. But this organ arrives despite its difficulties to maintain a high level of n−3/n−6 PUFA and having a good nutritional quality.