Basis Of Fatty Acid Composition Research Articles

Расчет характеристик биодизельного топлива на основе жирнокислотного состава липидов некоторых биотехнологически значимых микроорганизмов

Расчет характеристик биодизельного топлива на основе жирнокислотного состава липидов некоторых биотехнологически значимых микроорганизмов

Genome-wide association studies for fatty acid metabolic traits in five divergent pig populations

Fatty acid composition profiles are important indicators of meat quality and tasting flavor. Metabolic indices of fatty acids are more authentic to reflect meat nutrition and public acceptance. To investigate the genetic mechanism of fatty acid metabolic indices in pork, we conducted genome-wide association studies (GWAS) for 33 fatty acid metabolic traits in five pig populations. We identified a total of 865 single nucleotide polymorphisms (SNPs), corresponding to 11 genome-wide significant loci on nine chromosomes and 12 suggestive loci on nine chromosomes. Our findings not only confirmed seven previously reported QTL with stronger association strength, but also revealed four novel population-specific loci, showing that investigations on intermediate phenotypes like the metabolic traits of fatty acids can increase the statistical power of GWAS for end-point phenotypes. We proposed a list of candidate genes at the identified loci, including three novel genes (FADS2, SREBF1 and PLA2G7). Further, we constructed the functional networks involving these candidate genes and deduced the potential fatty acid metabolic pathway. These findings advance our understanding of the genetic basis of fatty acid composition in pigs. The results from European hybrid commercial pigs can be immediately transited into breeding practice for beneficial fatty acid composition.

Genome-Wide Association Analyses for Fatty Acid Composition in Porcine Muscle and Abdominal Fat Tissues

Fatty acid composition is an important phenotypic trait in pigs as it affects nutritional, technical and sensory quality of pork. Here, we reported a genome-wide association study (GWAS) for fatty acid composition in the longissimus muscle and abdominal fat tissues of 591 White Duroc×Erhualian F2 animals and in muscle samples of 282 Chinese Sutai pigs. A total of 46 loci surpassing the suggestive significance level were identified on 15 pig chromosomes (SSC) for 12 fatty acids, revealing the complex genetic architecture of fatty acid composition in pigs. Of the 46 loci, 15 on SSC5, 7, 14 and 16 reached the genome-wide significance level. The two most significant SNPs were ss131535508 (P = 2.48×10−25) at 41.39 Mb on SSC16 for C20∶0 in abdominal fat and ss478935891 (P = 3.29×10−13) at 121.31 Mb on SSC14 for muscle C18∶0. A meta-analysis of GWAS identified 4 novel loci and enhanced the association strength at 6 loci compared to those evidenced in a single population, suggesting the presence of common underlying variants. The longissimus muscle and abdominal fat showed consistent association profiles at most of the identified loci and distinct association signals at several loci. All loci have specific effects on fatty acid composition, except for two loci on SSC4 and SSC7 affecting multiple fatness traits. Several promising candidate genes were found in the neighboring regions of the lead SNPs at the genome-wide significant loci, such as SCD for C18∶0 and C16∶1 on SSC14 and ELOVL7 for C20∶0 on SSC16. The findings provide insights into the molecular basis of fatty acid composition in pigs, and would benefit the final identification of the underlying mutations.

Vibrio caribbeanicus sp. nov., isolated from the marine sponge Scleritoderma cyanea

A Gram-negative, oxidase-positive, catalase-negative, facultatively anaerobic, motile, curved rod-shaped bacterium, strain N384(T), was isolated from a marine sponge (Scleritoderma cyanea; phylum Porifera) collected from a depth of 795 feet (242 m) off the west coast of Curaçao. On the basis of 16S rRNA gene sequencing, strain N384(T) was shown to belong to the genus Vibrio, most closely related to Vibrio brasiliensis LMG 20546(T) (98.8% similarity), Vibrio nigripulchritudo ATCC 27043(T) (98.5%), Vibrio tubiashii ATCC 19109(T) (98.6%) and V. sinaloensis DSM 21326(T) (98.2%). The DNA G+C content of strain N384(T) was 41.6 mol%. An analysis of concatenated sequences of five genes (gyrB, rpoA, pyrH, mreB and ftsZ; 4068 bp) demonstrated a clear separation between strain N384(T) and its closest neighbours and clustered strain N384(T) into the 'Orientalis' clade of vibrios. Phenotypically, the novel species belonged to the arginine dihydrolase-positive, lysine decarboxylase- and ornithine decarboxylase-negative (A+/L-/O-) cluster. The novel species was also differentiated on the basis of fatty acid composition, specifically that the proportions of iso-C(13:0), iso-C(15:0), C(15:0), iso-C(16:0), C(16:0), iso-C(17:0), C(17:1)ω8c and C(17:0) were significantly different from those found in V. brasiliensis and V. sinaloensis. The results of DNA-DNA hybridization, average nucleotide identity and physiological and biochemical tests further allowed differentiation of this strain from other described species of the genus Vibrio. Collectively, these findings confirm that strain N384(T) represents a novel Vibrio species, for which the name Vibrio caribbeanicus sp. nov. is proposed, with the type strain N384(T) ( = ATCC BAA-2122(T) = DSM 23640(T)).

Quantitative genetic basis of fatty acid composition in the GIFT strain of Nile tilapia ( Oreochromis niloticus) selected for high growth

The quantitative genetic basis of fatty acid composition was examined in the Genetically Improved Farmed Tilapia (GIFT) strain of Nile tilapia selected for high breeding value for body weight and in the contemporaneous control selected for average breeding value. Gas chromatography analysis of 514 frozen fillet samples, obtained from the offspring of 104 sires and 154 dams from two generations in 2006 and 2007, showed that the fish possess all important fatty acids (FA), with the amount of omega-3 polyunsaturated fatty acids being 3.6%. The ratio of unsaturated to saturated fatty acids was greater than one (1.4) in the GIFT fillets, which is in line with the current dietary recommendation. Genetic analysis of FA was combined with 5532 performance and fillet records, and 2000 fillet samples analyzed for flesh composition and flesh quality attributes. A restricted maximum likelihood method applied to bivariate or trivariate mixed model was carried out in a full pedigree comprising a total of 18,970 animals to estimate genetic parameters and correlated responses in FA composition to the selection program. The estimates of heritability for individual FA varied from zero to medium, suggesting that FA composition of the GIFT fillet can respond to selection. Genetic correlations among FA within the same group (saturated, monounsaturated or polyunsaturated FA) were generally synergetic, but were antagonistic between groups. There were also both favourable and unfavourable genetic associations between important high chain polyunsaturated fatty acids and performance, fillet and flesh quality traits. Correlated changes in FA composition were measured by comparing least square means of the selection and control lines. Overall, selection for high growth resulted in very little change in FA composition. One notable change was that the content of heptadecanoic acid (C17:0) decreased in the selection relative to control line, which is beneficial for human health. In summary, the set of genetic parameters estimated and the response realized in the GIFT strain indicate that FA composition of tilapia or fish in general can be altered by genetic means.

Diversity of Frankia strains nodulating HippÖphae salicifolia D. Don using FAME profiling as Chemotaxonomic markers

Twelve Frankia strains isolated from Hippophae salicifolia D. Don or Alnus glutinosa or Comptonia peregrine, showed the significant variation in fatty acid composition viz. palmitic acid (16:0), oleic acid (18:1), linoleic acid (18:2), linolenic acid (18:3), arachidic acid (20:0) and erucic acid (22:1) suggesting the strain specific variability among the Frankia strains. Presence of Erucic acid (22:1), a major component of the oil obtained from the seeds of Brassica sp., albeit in lesser amount in the few studied frankial strains, is the first report. Cluster analysis on the basis of fatty acid composition suggests the presence of two distinct clusters with similitude coefficient ranging from 0.75 to 1.00. Cluster I with HsIi2 showed great divergence from other 11 frankial strains (Cluster II). The two sub groups were distinguished in cluster II: IIa contained five strains isolated from H. salicifolia and these strains are distantly related to the strains of cluster IIb isolated from different host. There is high degree of similarity among the frankial strains of Cluster IIb which suggests that the frankial strains might be evolved from the same ancestor. FAME profiling might be useful tool in the study of polyphasic approach based taxonomy and phylogenetic relationship.

Evaluation of Fatty Acid Profile of Wagyu Beef by ATR-FTIR Spectroscopy

Japanese black Wagyu beef has its characteristics of fatty well-marbled texture, flavor, and tenderness which are affected by fatty acid composition. The aim of this study was to develop an analytical method for evaluating the fatty acid profile of Wagyu beef by Fourier transform infrared (FTIR) spectroscopy. In the current study, attenuated total reflection–FTIR (ATR-FTIR) spectroscopy and gas chromatography (GC) were applied to the fat tissues, and the solvent-extracted fats which were sampled from subcutaneous, inter- and intramuscular fat tissues. Results of GC analysis showed that monounsaturated fatty acids (MUFA) content became larger in the order of intramuscular, intermuscular, and subcutaneous fats, and saturated fatty acids (SFA) became smaller in the same order. Subcutaneous fat could be discriminated from inter- and intramuscular fats on the basis of fatty acid composition by principal component analysis. The ATR-FTIR analysis revealed that the shift of the peak positions of alkene C–H stretching vibration at around 3,006 cm−1 occurred depending on the unsaturation degree of fatty acids in beef fat. Partial least squares (PLS) regression analysis with leave-one-out cross-validation was applied to the combined regions of 2,800–3,050 and 1,000–1,500 cm−1 for the fat tissues and the extracted fats. The correlation coefficients of the PLS validation models predicting the content of the MUFA and SFA for solvent-extracted fats were higher than those for fat tissues, and the coefficients (R 2) of determination more than 0.873 were obtained for solvent-extracted fats and 0.522 for fat tissues.

Oxidative stability of bovine milk determined by individual variability in herd irrespective of selenium status

The effect of supplementing dairy cows with organic selenium (25 mg day −1) on oxidative stability of milk when exposed to Cu(II) ions or to fluorescent light was evaluated using solid-phase micro-extraction gas chromatography with flame ionisation detection. Neither formation of volatile lipid (hexanal) and protein (dimethyl disulfide) oxidation products nor radical scavenging activity was affected by selenium supplementation. We found that other factors must be determinant for the oxidative stability of milk, and that these factors vary considerably between individual cows. Milk from two cows that were either sensitive or resistant to oxidation was compared in an attempt to identify the molecular basis for these differences. It was found that oxidation of milk could not solely be explained on the basis of fatty acid composition, or content of low molecular weight antioxidants, such as uric acid, ascorbic acid, and tocopherol.

Fatty Acid Composition of Tobacco Seed Oil and Synthesis of Alkyd Resin

AbstractThe fatty acid composition of tobacco seed oil revealed that the oil is rich in unsaturated fatty acids, having linoleic acid (71.63%), oleic acid (13.46%) and palmitic acid (8.72%) as the most abundant unsaturated and saturated fatty acids respectively. So the tobacco oil was characterized as semi‐drying type on the basis of fatty acid composition. The synthesis of alkyd resin was carried out by alcoholysis or monoglyceride process using an alkali refined tobacco seed oil, pentaerythritol, cis‐1,2,3,6‐tetrahydrophthalic anhydride along with lithium hydroxide as catalyst. The alkyd resin so prepared was found to be bright and of low color with high gloss. The drying and hardness properties and adhesion of the tobacco seed oil derived alkyd resin were also found a bit superior to those of other alkyd resins of the same oil length. In addition, the water and acid resistance of the said alkyd was also found comparable to the other alkyds.

Tocopherols and tocotrienols as free radical-scavengers in refined vegetable oils and their stability during deep-fat frying

The aim of this study was to assess the effect of total tocopherols and tocotrienols of refined vegetable oils on oil radical-scavenging activity and to investigate the stability of the various homologues during the deep-fat frying of French fries. Eight different refined vegetable oils were investigated, having variable levels of natural tocopherols and tocotrienols. A direct correlation between the radical-scavenging capacity of the oils, measured by the DPPH test, and the total content of natural tocopherols and tocotrienols was found. Frying experiments showed that the stability of the different tocopherols and tocotrienols present in the refined vegetable oils basically depend on two factors: the fatty acid composition of the oil, in particular polyunsaturated fatty acid content, and the kind of tocopherol and tocotrienol homologues present. The more oxidizable the oil, on the basis of fatty acid composition, the more stable were the tocopherolic antioxidants. Among the different homologues, γ-tocotrienol in palm super olein proved to be the least stable during the deep-fat frying, thus preserving the other homologues.

A Temperature-sensitive Mechanism That Regulates Post-translational Stability of a Plastidial ω-3 Fatty Acid Desaturase (FAD8) in Arabidopsis Leaf Tissues

Trienoic fatty acids (TAs) are the major constituents in plant membrane lipids. In Arabidopsis, two plastidial isozymes of omega-3 fatty acid desaturase, FAD7 and FAD8, are the major contributors for TA production in leaf tissues. Despite a high degree of structural relatedness, activities of these two isozymes are regulated differentially in response to temperature. Elevated temperatures lead to decreases in leaf TA level due to temperature sensitivity of FAD8 activity. A series of FAD7-FAD8 chimeric genes, each encoding a functional plastidial omega-3 desaturase, were introduced into the Arabidopsis fad7fad8 double mutant. Constructs with or without a c-Myc epitope tag were tested. Functionality of each chimeric gene in response to temperature was assayed by Northern and Western analyses and by examining the fatty acid composition. All transformants harboring a chimeric gene containing the FAD8-derived C-terminal coding region (44 amino acids) showed a marked decrease in TA level when exposed to high temperature, similarly as transgenic lines complemented with the native form of FAD8. The reduction of TA level was accompanied by a decrease in the amount of omega-3 desaturase protein but not necessarily by a decrease in its transcript level. Analysis of the decay of c-Myc-tagged products after inhibiting protein synthesis revealed that the FAD8-derived C-terminal region acts in an autoregulatory fashion to destabilize the protein at high temperature. This suggests that the regulation of post-translational stability of FAD8 provides an important regulatory mechanism for modifying its activity in response to temperature, mediating a decrease in TA level at elevated temperatures.

Differences in the intracellular lipids of sake yeast in main mash seeded respectively with two kinds of seed mash: Kimoto and sokujo-moto

In sake brewing, yeast cells grown in the traditional seed mash ( kimoto) are enriched in palmitic acid, and those in the popular seed mash ( sokujo-moto) are enriched in linoleic acid. Lipid composition of yeast in the main mash seeded with respective seed mash was determined. The amount of intracellular phospholipids (PLs) of yeast showed little change throughout the fermentation period, while intracellular triglyceride (TG) content decreased dramatically during the growth phase in the main mash. In the main mash seeded with sokujo-moto, the linoleic acid content of intracellular phosphatidyl ethanolamine (PE) was reduced from 30.6% of the original seed mash yeast to 6–9%, whereas the content of intracellular phosphatidyl choline (PC) was merely reduced from the original 48.4% to 26–30% during fermentation. Moreover, even after 4–5 generations of growth in the main mash, the percent of linoleic acid in PC did not notably decrease. The intracellular TG of seed mash yeast is therefore supposed to be a major source of linoleic acid in the early stage of growth in main mash. On the other hand, linoleic acid content in PLs of yeast were detectable only in low quantities (5–10%) during the fermentation of main mash seeded with kimoto as well as that seeded with kimoto (5.5%). Since there was no increase in linoleic acid content, the main mash during rapid growth phase seemed to be deficient in linoleic acid and, therefore, the digestion of raw materials, which contains large amounts of linoleic acid, failed to actively proceed. The ratio of PC PE of the cells was 0.67 in kimoto, and 1.62 in sokujo-moto. The same sort of difference in the PC PE ratio was also seen between the corresponding main mash. The presence of linoleic acid increased the PC PE ratio at the stationary phase of growth, and was decreased in the presense of 16% ethanol. Thus, kimoto could be differentiated from sokujo-moto on the basis of fatty acid composition in PC and by the PC PE ratio of the yeast in the main mash.

Five New Legionella Species Isolated from Water

Fourteen Legionella-like strains isolated from aquatic sources have been characterized serologically, biochemically, and in terms of DNA relatedness. The strains grew on buffered charcoal-yeast extract agar but not on blood agar and displayed phenotypic characteristics typical of the family Legionellaceae, including a requirement for cysteine, cellular fatty acid compositions in which branched-chain acids predominate, and the possession of isoprenoid quinones of the ubiquinone series with more than 10 isoprene units in their side chains. All were nonfermentative, lacked urease, were incapable of nitrate reduction, and reacted positively with a DNA probe specific for the Legionellaceae. DNA hybridization studies in which the hydroxyapatite method was used demonstrated that the strains represented five new species of the genus Legionella. Nine of the strains were more than 90% interrelated, and the name Legionella londiniensis sp. nov. is proposed for this group. Two strains formed a second hybridization group, for which the name Legionella nautarum sp. nov. is proposed, while the three remaining species, Legionella geestiana sp. nov., Legionella quateirensis sp. nov., and Legionella worsleiensis sp. nov., are each represented by a single strain. The levels of relatedness of the new species to each other are 23% or less, and the levels of relatedness to other members of the genus ranged from 0 to 36%. L. geestiana, L. nautarum, and L. londiniensis are serologically unrelated to all other known Legionella species. L. worsleiensis cannot be separated from Legionella pneumophila serogroup 4 by serological methods and is also serologically indistinguishable from L. quateirensis; distinctions may be made on the basis of fatty acid composition and biochemical reactions.

Differentiation of Gram-Negative, Nonfermentative Bacteria Isolated from Biofilters on the Basis of Fatty Acid Composition, Quinone System, and Physiological Reaction Profiles

Gram-negative, nonfermentative bacteria isolated from biofilters for off-gas treatment of animal-rendering-plant emissions were differentiated by whole-cell fatty acid analysis, quinone analysis, and numerical taxonomy based on their physiological reaction profiles. The last system consisted of 60 physiological tests and was arranged as a microtest system on microtitration plates. Based on fatty acid analyses, 31 isolates were separated into six clusters and five single-member clusters. The isolates of two clusters were identified as Alcaligenes faecalis and Pseudomonas diminuta. The remaining nine clusters were characterized by their fatty acid profiles, quinone systems, and physiological reaction profiles. Clusters resulting from fatty acid analyses were compared with those resulting from physiological reaction profiles. Six clusters could be confirmed this way. The efficiency of the physiological test system was increased by the prearrangement of the isolates according to their quinone type.

Differentiation of free-living Anabaena and Nostoc cyanobacteria on the basis of fatty acid composition.

The cellular fatty acids of free-living, nitrogen-fixing cyanobacteria belonging to the genera Anabaena and Nostoc were analyzed to differentiate the genera. The fatty acid compositions of 10 Anabaena strains and 10 Nostoc strains that were grown for 12 days on BG-11o medium were determined by gas-liquid chromatography-mass spectroscopy. Of the 53 fatty acids detected, 17 were major components; the average level for each of these 17 fatty acids was at least 0.9% of the total fatty acids (in at least one of the genera). These fatty acids included (with mean percentages in the Anabaena and Nostoc strains, respectively) the saturated fatty acids 16:0 (30.55 and 23.23%) and 18:0 (0.77 and 1.27%); several unsaturated fatty acids, including 14:1 cis-7 (2.50 and 0.11%), 14:1 cis-9 (3.10 and 3.41%), a polyunsaturated 16-carbon (sites undetermined) fatty acid with an equivalent chain length of 15.30 (1.20 and 1.03%), 16:4 cis-4 (0.95 and 0.87%), 16:3 cis-6 (2.16 and 1.51%), 16:1 cis-7 (1.44 and 0.36%), 16:1 cis-9 (6.53 and 18.76%), 16:1 trans-9 (4.02 and 1.35%), 16:1 cis-11 (1.62 and 0.42%), 18:2 cis-9 (10.16 and 12.44%), 18:3 cis-9 (18.19 and 17.25%), 18:1 cis-9 (4.01 and 5.10%), and 18:1 trans-9 (0.92 and 1.94%); and the branched-chain fatty acids iso-16:0 (2.50 and 1.14%) and iso-15:1 (0.34 and 2.05%).(ABSTRACT TRUNCATED AT 250 WORDS)

High incorporation of esential fatty acids by the Rotifer Brachionus plicatilis fed on the Prymnesiophyte Alga Pavlova lutheri

The lipid and fatty acid compositions of rotifers (Brachionus plicatilis) fed on yeast or on the unicellular prymnesiophyte Pavlova lutheri, an alga commonly used in Australian hatcheries, were compared by TLC-FID, GC and GC-MS. Significantly higher relative proportions of energy-rich triacylglycerol were present in the Pavlova-fed rotifers than in the yeast-fed animals, and total lipid content reached a maximum between 12 and 24 h. High incorporation of the essential fatty acids eicosapentaenoic acid (EPA; 20: 5ω3) and docosahexaenoic acid (DHA; 22:6ω3) occurred in the Pavlova-fed rotifers. EPA and DHA content was 11.6% of total fatty acids after 3 h of feeding and reached 20 and 23% after 24 and 48 h respectively. The proportion of essential fatty acids in rotifers fed Pavlova compares very favourably with data obtained by overseas workers using a variety of microalgae and dietary supplements. On the basis of fatty acid composition alone, these results confirm the suitability of P. lutheri as a feedstock for Australian mariculture operations.

The Long-Chain Fatty Acid Composition of Species Representing the Genus Rhodotorula Harrison

Summary The long-chain fatty acids of nine species of the genus Rhodotorula were extracted and analyzed as methyl esters by GLC. All species were characterized by the presence of palmitic acid (C 16:0), stearic acid (C 18:0), oleic acid (C 18:1), linoleic acid (C 18:2) and linolenic acid (C 18:3) as major fatty acids. On the basis of fatty acid composition the species were diveded into two major groups. Group I was characterized by a high mean percentage oleic acid (C 18:1) and low mean percentage linoleic acid (C 18:2), and group II by a high mean percentage linoleic acid (C 18:2) and lower mean percentage oleic acid (C 18:1). With this method, it was possible to identify the nine species of Rhodotorula within 5 days compared to the 10 days and longer with the more conventional methods.

Chemical composition of dietary species of marine unicellular algae and rotifers with emphasis on fatty acids

The lipid profiles of a few species of marine unicellular algae and yeast were studied with emphasis on fatty acids as part of a search for the nutritional value of plankton to the diet of marine fish larvae commonly used in marine hatcheries. The general proximate chemistry of rotifers was closely related to the proximate chemistry of the diet organism, exhibiting a higher content of protein and carbohydrate and a lower content of lipid. Major lipids in all algae, yeast and rotifers comprised mono-, di- and tri-glycerides and polar lipids. The algae Chaetoceros gracilis Schutt, Isochrysis galbana Parke and their respective algaefed rotifers exhibited higher amounts of neutral lipids, consisting mainly of cyclic and branched polyunsaturated components. Fatty acid composition of the algae was species-specific, with the highest ratio of polyethylenic to saturated and monoethylenic acid in I. galbana and Phaeodactylum tricornutum Bohlin, and the highest content (15%) of n-3 highly unsaturated fatty acids in Nannochloropsis salina and P. tricornutum. A closely mirrored distribution of the fatty acids, but with a lower amount of n-3 highly unsaturated fatty acids, was present in the respective algae-fed rotifers. Comparison of the fatty acid spectrum of Artemia sp. and Euterpina acutifrons grown in the laboratory on I. galbana with zooplankton samples of E. acutifrons and Oitona nana collected from the sea showed a higher concentration of docosahexaenoic acid (22:6 n-3) in the naturally collected sample. The results indicate that the efficacy of the food algae C. gracilis and I. galbana in increasing the survival of fish larvae in marine hatcheries is not obvious on the sole basis of fatty acid composition.

Fatty Acid Composition as a Guide to the Classification of Selected Genera of Yeasts Belonging to the Endomycetales

Summary: Gas chromatography was used to determine the long-chain fatty acid composition of 33 strains representing 17 genera of the Saccharomycetaceae, Endomycetaceae, Metschnikowiaceae and Saccharomycodaceae. The similarities between the strains were calculated on the basis of fatty acid composition, resulting in three groups. Group I strains contained oleic acid (C18 : 1) as the major fatty acid, while group II strains had substantial proportions of both oleic acid and linoleic acid (C18 : 2). Strains of group III were characterized by a high percentage of palmitoleic acid (C16 : 1). The one strain of Metschnikowia reukaufii studied fell within the range of variation of group II, but it contained a slightly higher proportion of palmitoleic acid than the other strains in this group.

High oleic sunflower: Physical and chemical characteristics

AbstractTreatment of normal varieties of sunflowerseed with chemical mutagens and development of their progenies have resulted in hydrids bearing oil with oleic acid contents in excess of 80% and linoleic acid contents less than 10%. Fatty acids compositions are unaffected by climatic conditions. Analyses of the seed, oil and meal produced from the first commercial U.S. production show values not to differ significantly from normal high linoleic sunflower, except where anticipated on the basis of fatty acid composition.