Variation In Fatty Acid Composition Research Articles

The effects of spatial and temporal ecological variation on fatty acid compositions of wild great tits Parus major

In birds, fatty acids (FA) have three main functions; they are structural components of cell membranes, metabolic fuel, and inflammatory molecules. Environmental factors, such as diet and ambient temperature, affect FA composition, thereby function and ultimately fitness. Thus, variation in FA compositions can be the underlying mechanism for varying performance of birds in different habitats. Here we examine variation in plasma FA composition in nestling and adult great tits Parus major, between 1) deciduous and coniferous, and 2) sun‐exposed and shaded habitats.The main results revealed that nestlings had a higher proportion of α‐linolenic acid (α‐LNA) in deciduous habitats and arachidonic acid in coniferous habitats. This reflects a difference in caterpillar availability between habitats with the deciduous habitat being caterpillar‐rich, whereas the coniferous habitats are rich in spiders. In addition, α‐LNA increased with nestling body condition in the coniferous habitat, supporting the importance of caterpillars for fledging success in this species. In line with dietary intake, the proportion of the essential α‐LNA and linoleic acid (LA) increased over the course of the day for all birds. In the deciduous habitat, adult females showed a positive association between LA and body condition. Furthermore, habitat sun‐exposure showed significant interactions with body condition for polyunsaturated FAs in nestlings, and with saturated FA in adult males, which is in accordance with the homeoviscous hypothesis stating that the proportion of saturated FA should decrease with decreasing ambient temperature.Taken together, small‐scale heterogeneity in habitat structure significantly influences FA compositions of great tits. Many of the results can be linked to dietary, and possibly, ambient temperature differences between habitats. These habitat effects on FA compositions can lead to different capacities of individual birds to deal with infections and low temperatures, two stressors that cause major mortality among wild birds.

Seasonal and sexual variations of fatty acid composition in fillet of Capoeta erhani

The lowest lipid levels of Capoeta erhani observed in winter and vice versa in summer. The fatty acid composition of the fillets was significantly different among seasons ( P 0.05). The ratios of the unsaturated fatty acids (UFAs) were higher than half of the total fatty acids among all seasons. The level of PUFA was highest in autumn (25.91%), and lowest in summer (22.11%). Among seasons and sexes, the levels of total n3 PUFAs in total fatty acids changed from 15.43% to 21.89% and n6 PUFAs from 3.8% to 7.97%, respectively. The level of n3 PUFAs was present in excess that of the n6 PUFAs. The ratios of the n3 PUFAs to n6 PUFAs in the fillets of C. erhani were highest in autumn for both sexes and remarkably influenced by seasons.

Effects of phylogeny and climate on seed oil fatty acid composition across 747 plant species in China

Seed oil has long been recognized as an important source of food, industry and biodiesel. In biological aspect, seed oil fatty acid composition (FAC) affects lipid fluidity and cellular metabolism, depending on temperature. Hence, the variation of FAC in seeds may reflect adaptive strategies for seed survival and seedling establishment under contrasting climate conditions. In this study, we investigated the relative effects of phylogeny and climate on seed oil FAC, testing the hypothesis that the degree of fatty acid unsaturation increases in colder climates. A large seed oil FAC dataset representing 747 species from 207 sites across China was compiled and a general linear model was used to partition total variance in FAC into taxonomic ranks (family, genus and species) and environmental components. Multiple regression analysis was conducted to examine the relative effects of mean annual temperature (MAT) and mean annual precipitation (MAP). Phylogenetically independent contrast (PIC) analysis was used to test the evolutionary association of FAC with climate at the family level. The results showed that seed oil FAC varied considerably across plant species, with phylogeny explaining a greater proportion of variance than environment; however, FAC showed obvious large-scale spatial patterns. Total unsaturated fatty acid (UFA) content increased with increasing latitude. The degree of fatty acid unsaturation, as indicated by the ratio of UFA to saturated fatty acids and iodine value, was negatively correlated with MAT and to a lesser extent with MAP. The PIC results indicated that at the family level, nearly all significant phenotypic correlations of FAC with spatial and climatic variables were evolutionarily convergent. These results indicate that despite strong phylogenetic constraints on FAC, fatty acid unsaturation in seed oil appears to evolve as an adaptive strategy in colder climates. The affiliation of phylogenetic and climate in seed oil FAC may assist in the search of potential oil plants with particular FAC for food and fuel needs.

An integrated analytical approach for the compositional evaluation of different stages of fully ripened Jatropha curcas seed oil

The present study aims to determine the compositional changes including physicochemical characterization of Jatropha seed oil at three different stages of ripening (green: JO‐I; yellow: JO‐II; and brown: JO‐III). The moisture and oil content of Jatropha seeds was 60.83–10.12% and 34–32 (wt%) for JO‐I to JO‐III stages, respectively. The moisture content and acid value (mg KOH/g) of the oil was 8.88–4.05% and 0.62–2.86. Fatty acid composition (wt%) of the oil (JO‐I‐III stage) showed that palmitic (C16:0) acid decreases from 16.98 to 14.40 while as stearic (C18:0) acid increases from 7.19 to 7.57. The content of the monounsaturated acid (wt%) oleic (9‐cis C18:1) acid was 53.13, 41.96, and 60.93, while a diunsaturated acid, linoleic (9‐cis 12‐cis C18:2) acid, was 12.39, 32.52, and 14.93 in the JO‐I to JO‐III stages respectively, which was also confirmed by 1H NMR. The percentage of diunsaturated (9‐cis 12‐cis C18:2) acid follows a reverse trend to the monounsaturated (9‐cis C18:1) acid. The stage JO‐II (yellow) seems to be a turning point in the seed development. The studies also revealed the presence of sterol glucosides in early stage (JO‐I) of seed development; which declined at later stages. The results showed that variation in fatty acid composition together with the physicochemical properties can be helpful in understanding the biosynthesis of seed development.Study describes the compositional changes including physicochemical characterization of Jatropha seed oil at three different stages of ripening (green: JO‐I; yellow: JO‐II; and brown: JO‐III) using integrated analytical techniques (i.e. 1H, 13C NMR, GC).

A high-throughput fatty acid profiling screen reveals novel variations in fatty acid biosynthesis in Chlamydomonas reinhardtii and related algae.

Analysis of fatty acid methyl esters (FAMEs) by gas chromatography (GC) is a common technique for the quantitative and qualitative analysis of acyl lipids. Methods for FAME preparation are typically time-consuming and labor-intensive and require multiple transfers of reagents and products between reaction tubes and autosampler vials. In order to increase throughput and lower the time and materials costs required for FAME preparation prior to GC analysis, we have developed a method in which 10-to-20-mg samples of microbial biomass are transferred to standard GC autosampler vials, transesterified using an emulsion of methanolic trimethylsulfonium hydroxide and hexane, and analyzed directly by GC without further sample handling. This method gives results that are essentially identical to those obtained by the more labor- and material-intensive FAME preparation methods, such as transmethylation with methanolic HCl. We applied this method to the screening of laboratory and environmental isolates of the green alga Chlamydomonas for variations in fatty acid composition. This screening method facilitated two novel discoveries. First, we identified a common laboratory strain of C. reinhardtii, CC-620, completely lacking all ω-3 fatty acids normally found in this organism and showed that this strain contains an inactivating mutation in the CrFAD7 gene, encoding the sole ω-3 desaturase activity in this organism. Second, we showed that some species of Chlamydomonas make Δ6-unsaturated polyunsaturated fatty acids (PUFA) rather than the Δ5 species normally made by the previously characterized laboratory strains of Chlamydomonas, suggesting that there is species-specific variation in the regiospecificity and substrate selectivity of front-end desaturases in this algal genus.

Potential dietary influence on the stable isotopes and fatty acid composition of migratory anchovy (Coilia mystus) around the Changjiang Estuary

The stable carbon and nitrogen isotopes and fatty acid composition of tapertail anchovy (Coilia mystus) at four migration stages collected around the Changjiang Estuary were analysed to investigate the variations in the trophic biomarkers during the fish migration. δ13 C and δ15N values of C. mystus ranged from −21.5 to −15.4‰ and from 6.9–15.8‰, respectively. Both δ13C and δ15N were enriched during migration. Polyunsaturated fatty acids were the dominant fatty acids and the major fatty acids found in C. mystus were C20:5n-3, C22:6n-3, C20:4n-6, C16:0, C18:0, C16:1n-7, C18:1(n-9, n-7) and C20:1 + C22:1. Significant changes among C. mystus at different migration stages were found both in the fatty acid composition and specific fatty acid concentration. Though the enrichment of stable isotopes may due to multiple factors (e.g. diet shift, environment and ontogeny), the dietary influence can be determined by the variation in fatty acid composition. Changes in the concentrations of benthic markers (C18:1n-7 and C20:4n-6) and pelagic markers (C18:1n-9 and C20:1 + C22:1) in C. mystus during the migration may suggest that benthic and pelagic food sources alternately dominated the anchovies' diet during different migration stages. It seems that application of multiple biomarkers in the trophic study of migratory fish will elevate the reliability of the analysis.

Fatty acid composition and desaturase gene expression in flax (Linum usitatissimum L.).

Little is known about the relationship between expression levels of fatty acid desaturase genes during seed development and fatty acid (FA) composition in flax. In the present study, we looked at promoter structural variations of six FA desaturase genes and their relative expression throughout seed development. Computational analysis of the nucleotide sequences of the sad1, sad2, fad2a, fad2b, fad3a and fad3b promoters showed several basic transcriptional elements including CAAT and TATA boxes, and several putative target-binding sites for transcription factors, which have been reported to be involved in the regulation of lipid metabolism. Using semi-quantitative reverse transcriptase PCR, the expression patterns throughout seed development of the six FA desaturase genes were measured in six flax genotypes that differed for FA composition but that carried the same desaturase isoforms. FA composition data were determined by phenotyping the field grown genotypes over four years in two environments. All six genes displayed a bell-shaped pattern of expression peaking at 20 or 24 days after anthesis. Sad2 was the most highly expressed. The expression of all six desaturase genes did not differ significantly between genotypes (P = 0.1400), hence there were no correlations between FA desaturase gene expression and variations in FA composition in relatively low, intermediate and high linolenic acid genotypes expressing identical isoforms for all six desaturases. These results provide further clues towards understanding the genetic factors responsible for FA composition in flax.Electronic supplementary materialThe online version of this article (doi:10.1007/s13353-014-0222-0) contains supplementary material, which is available to authorized users.

Seasonal variation in the composition and melting behavior of milk fat

Dairy bulk tank milk was sampled during 1yr from 2 conventional (C1 and C2) and 1 organic dairy (O1) for studying the seasonal variation as well as the variation between dairies in the composition and properties of milk fat. The composition of fatty acids (FA) as well as triglycerides (TAG) in milk fat was analyzed, and the melting properties of milk fat were analyzed by use of differential scanning calorimetry. The main differences in fat content and composition of FA in milk fat between dairies included a higher fat content, greater proportion of C18:0, and smaller proportion of C16:0 in milk from dairy C2, which could be associated with a higher frequency of Jersey herds supplying milk to this dairy. The organic milk was characterized by a higher proportion of C18:3n-3, C18:2 cis-9,trans-11, C6 to C14, a lower proportion of C18:1 cis-9, and a higher melting point of the low-melting fraction. The TAG composition showed a greater proportion of C24 to C38 TAG in milk fat from dairy O1 and a greater proportion of C52 to C54 TAG in milk fat from dairy C2, which was in accordance with the differences in FA composition. Melting point of the low-melting fraction was higher for milk fat from dairy O1 compared with dairies C1 and C2, whereas no differences between dairies were observed with respect to melting points of the medium- and high-melting fractions. The seasonal variation in FA composition was most pronounced for dairy O1 although similar patterns were observed for all dairies. During the summer, the content of C18:0 and C18:1 cis-9 in milk fat was greater, whereas the content of C14:0 and C16:0 was lower. In addition, the content of C18:2 cis-9,trans-11 and C18:1 trans-11 increased in late summer for dairy O1. The differential scanning calorimetry thermograms of individual milk fat samples could be divided into 3 groups by principal component analysis. For dairy O1, summer samples belonged to group 1, spring and autumn samples to group 2, and winter samples to group 3. For dairy C1 winter samples (group 2), were separated from other samples (group 1), and for dairy C2 all samples were in group 1. Individual melting points were related to FA composition, and the melting point of the low-melting fraction was positively correlated to the content of C14:0 and C16:0 in milk fat and negatively correlated to the content of C18:1 cis-9 and C18:0.

Individual variations in fatty acid composition and concentration as indicators of the nutritional condition of wild pointhead flounder larvae

We investigated the fatty acid compositions and concentrations of wild marine fish larvae with a highly accurate method because our knowledge of them has been seriously limited compared with cultured larvae. This study presents estimates of the fatty-acid-based nutritional condition of individual larvae in the field. Because the pointhead flounder Cleisthenes pinetorum displays relatively high stock size fluctuations, we investigated the developmental change in the fatty acid compositions of the body trunk, head, and eye and the annual fluctuations in the fatty acid concentrations in the trunk. We show that the process of fatty acid accumulation is not uniform across body parts and that the trunk is a better indicator of larval nutritional status than other parts because there is less time lag. Starved larvae with simultaneously high docosahexaenomic acid ratios and low total fatty acid concentrations, as observed in laboratory experiments, are rare in the wild. Thus, starved larvae must be removed rapidly by predators before they can experience a relatively long period of starvation in the wild. Fatty acid accumulation was greater in the larvae of the 2005 year class than in those of the 2006 year class in their first feeding stage, according to the optimal model derived with generalized linear model. A previous study indicated that the 2005 year class showed stronger recruitment than the 2006 year class. We conclude that the fatty acid analysis of wild larvae is a useful index of their nutritional status and mortality, especially in the first feeding stage.

Phenotypic and genotypic background underlying variations in fatty acid composition and sensory parameters in European bovine breeds.

BackgroundConsuming moderate amounts of lean red meat as part of a balanced diet valuably contributes to intakes of essential nutrients. In this study, we merged phenotypic and genotypic information to characterize the variation in lipid profile and sensory parameters and to represent the diversity among 15 cattle populations. Correlations between fat content, organoleptic characteristics and lipid profiles were also investigated.MethodsA sample of 436 largely unrelated purebred bulls belonging to 15 breeds and reared under comparable management conditions was analyzed. Phenotypic data -including fatness score, fat percentage, individual fatty acids (FA) profiles and sensory panel tests- and genotypic information from 11 polymorphisms was used.ResultsThe correlation coefficients between muscle total lipid measurements and absolute vs. relative amounts of polyunsaturated FA (PUFA) were in opposite directions. Increasing carcass fat leads to an increasing amount of FAs in triglycerides, but at the same time the relative amount of PUFAs is decreasing, which is in concordance with the negative correlation obtained here between the percentage of PUFA and fat measurements, as well as the weaker correlation between total phospholipids and total lipid muscle content compared with neutral lipids. Concerning organoleptic characteristics, a negative correlation between flavour scores and the percentage of total PUFA, particularly to n-6 fraction, was found. The correlation between juiciness and texture is higher than with flavour scores. The distribution of SNPs plotted by principal components analysis (PCA) mainly reflects their known trait associations, although influenced by their specific breed allele frequencies.ConclusionsThe results presented here help to understand the phenotypic and genotypic background underlying variations in FA composition and sensory parameters between breeds. The wide range of traits and breeds studied, along with the genotypic information on polymorphisms previously associated with different lipid traits, provide a broad characterization of beef meat, which allows giving a better response to the variety of consumers’ preferences. Also, the development and implementation of low-density SNP panels with predictive value for economically important traits, such as those summarized here, may be used to improve production efficiency and meat quality in the beef industry.

Variation in fatty acid composition of three turkish slit flower opium poppy (Papaver somniferum L.) lines

Variation in fatty acid composition of three turkish slit flower opium poppy (Papaver somniferum L.) lines

Seasonal variation in fatty acid composition in various parts of broccoli cultivars

To evaluate seasonal variation in fatty acid composition in broccoli, 12 commercial cultivars of broccoli were grown in spring and fall season at the field of NIHHS, and their floret, leaf and stem parts were used for the fatty acid composition analyses. Among 14 fatty acids detected in broccoli, linolenic, palmitic and linoleic acids were major fatty acids comprising more than 80% of total fatty acids in both the seasons and all the parts. Likewise, stearic and oleic acids were also present in considerable amount while remaining fatty acids; caproic, lauric, myristic, pentadecanoic, palmitoleic, heptadecanoic, arachidic, behenic and lignoceric acids showed their minor compositional ratio. Among the three parts, stem exhibited highest SFAs (49.681% in spring and 50.717% in fall season) compared to MUFA and PUFA, while highest compositional ratio of PUFAs were observed in leaves (62.588% in spring and 68.931% in fall season), which indicates leaves as a good source of health beneficial fatty acids. In contrast, floret part exhibited highest SFA (48.786%) and PUFA (57.518%) in spring and fall seasons, respectively. Major fatty acids; palmitic, linoleic and linolenic acid showed lowest cultivar dependent variation (below 10%) and leaf showed least variation in both the seasons compared to floret and stem. Our results suggest that all the fatty acids are significantly influenced by genotype of cultivars (C), plant parts (P) and growing seasons (S). Among the 14 fatty acids, myristic and palmitic acid showed highest positive or negative correlationship with oleic (r=<TEX>$0.912^{**}$</TEX>) and linolenic acid (r=-<TEX>$0.933^{**}$</TEX>), respectively. The most abundant fatty acid, linolenic acid, showed either negative or no correlation ship with other fatty acids while palmitic acid, a second major fatty acid, exhibited either positive or negative correlation ship.

Effects of additional Mg2+ on the growth, lipid production, and fatty acid composition of Monoraphidium sp. FXY-10 under different culture conditions

The effects of supplementing the culture medium with Mg2+ on the growth, lipid production, and fatty acid composition of Monoraphidium sp. FXY-10 were studied under photoautotrophic, heterotrophic, and mixotrophic conditions. Under the photoautotrophic condition, microalgae supplemented with 100 μM Mg2+ grew significantly better than the control group and exhibited a secondary growth state. The final cell density was 1.25-fold higher than that of the control group (2.98 g L−1), and the peak lipid content reached 59.8 % (control group 52.3 %). Culture under the heterotrophic condition did not significantly increase the growth rate, but the experimental group (100 μM Mg2+ supplementation) achieved a 37.03 % lipid content compared to 28.47 % by the control group. The lipid productivity of the experimental group (100 μM Mg2+ supplementation) was higher, reaching 65.93 mg L−1 day−1 compared with 56.10 mg L−1 day−1 for the group without additional Mg2+. Under the mixotrophic condition, the experimental group achieved a final density of 3.10 g L−1, which was higher than that of the control group (2.98 g L−1). There was also no variation in fatty acid composition between the experimental group and the control group. Under the heterotrophic and mixotrophic conditions, the experimental group produced more than 50% saturated fatty and mono-unsaturated fatty acids, and the degree of unsaturation was <137. This result was relatively lower than that of the control.

Genome-wide association and prediction of direct genomic breeding values for composition of fatty acids in Angus beef cattle.

BackgroundAs consumers continue to request food products that have health advantages, it will be important for the livestock industry to supply a product that meet these demands. One such nutrient is fatty acids, which have been implicated as playing a role in cardiovascular disease. Therefore, the objective of this study was to determine the extent to which molecular markers could account for variation in fatty acid composition of skeletal muscle and identify genomic regions that harbor genetic variation.ResultsSubsets of markers on the Illumina 54K bovine SNPchip were able to account for up to 57% of the variance observed in fatty acid composition. In addition, these markers could be used to calculate a direct genomic breeding values (DGV) for a given fatty acids with an accuracy (measured as simple correlations between DGV and phenotype) ranging from -0.06 to 0.57. Furthermore, 57 1-Mb regions were identified that were associated with at least one fatty acid with a posterior probability of inclusion greater than 0.90. 1-Mb regions on BTA19, BTA26 and BTA29, which harbored fatty acid synthase, Sterol-CoA desaturase and thyroid hormone responsive candidate genes, respectively, explained a high percentage of genetic variance in more than one fatty acid. It was also observed that the correlation between DGV for different fatty acids at a given 1-Mb window ranged from almost 1 to -1.ConclusionsFurther investigations are needed to identify the causal variants harbored within the identified 1-Mb windows. For the first time, Angus breeders have a tool whereby they could select for altered fatty acid composition. Furthermore, these reported results could improve our understanding of the biology of fatty acid metabolism and deposition.

Mapping the low palmitate fap1 mutation and validation of its effects in soybean oil and agronomic traits in three soybean populations

fap 1 mutation is caused by a G174A change in GmKASIIIA that disrupts a donor splice site recognition and creates a GATCTG motif that enhanced its expression. Soybean oil with reduced palmitic acid content is desirable to reduce the health risks associated with consumption of this fatty acid. The objectives of this study were: to identify the genomic location of the reduced palmitate fap1 mutation, determine its molecular basis, estimate the amount of phenotypic variation in fatty acid composition explained by this locus, determine if there are epistatic interactions between the fap1 and fap nc loci and, determine if the fap1 mutation has pleiotropic effects on seed yield, oil and protein content in three soybean populations. This study detected two major QTL for 16:0 content located in chromosome 5 (GmFATB1a, fap nc) and chromosome 9 near BARCSOYSSR_09_1707 that explained, with their interaction, 66-94% of the variation in 16:0 content in the three populations. Sequencing results of a putative candidate gene, GmKASIIIA, revealed a single unique polymorphism in the germplasm line C1726, which was predicted to disrupt the donor splice site recognition between exon one and intron one and produce a truncated KASIIIA protein. This G to A change also created the GATCTG motif that enhanced gene expression of the mutated GmKASIIIA gene. Lines homozygous for the GmKASIIIA mutation (fap1) had a significant reduction in 16:0, 18:0, and oil content; and an increase in unsaturated fatty acids content. There were significant epistatic interactions between GmKASIIIA (fap1) and fap nc for 16:0 and oil contents, and seed yield in two populations. In conclusion, the fap1 phenotype is caused by a single unique SNP in the GmKASIIIA gene.

Seasonal Variations in Maternal Provisioning of Crepidula fornicata (Gastropoda): Fatty Acid Composition of Females, Embryos and Larvae

Recruitment success of marine invertebrate populations not only depends on the number of recruits but also on their quality which affects their survival. In species characterized by a mixed development (encapsulated embryonic development and release of planktotrophic larvae), the offspring quality depends on both maternal provisioning and larval feeding. Here, we investigated potential changes of maternal provisioning over the whole reproductive period in a gastropod with a mixed development: Crepidula fornicata . In its introduction area, C . fornicata reproduces from February to October, which implies that both adults and larvae are exposed to different food availabilities. Maternal provisioning was assessed by measuring the fatty acid (FA) composition of females, encapsulated embryos and larvae, in February, May, July and September 2009. FA are essential resources for the development of embryos and larvae, and are key biomarkers of offspring quality. Our results showed differences in FA composition between muscles, visceral masses, and encapsulated embryos. In particular, FA composition of embryos was similar to that of the visceral mass. Seasonal variations in FA composition were observed: in the middle of the reproductive season (May and July), female tissues and embryos showed a higher proportion of polyunsaturated fatty acids and especially ω3, as compared to the beginning and end of the reproductive season (February and September). This showed that through maternal provisioning the quality of C . fornicata offspring was higher in the middle of the reproductive season. Whether this would result in an increase of recruitment success and juvenile performance would require further investigations.

Variation in oil content and fatty acid composition in preselected argan trees with morphological characters and geographical localization

The aim of this study is to examine the variability of yield and fatty acid composition of argan seed oil (Argania spinosa L.) in four provenances, and to find the relationship between fatty acid composition and environmental conditions. Twenty genotypes were preselected and evaluated for fatty acids composition during 3 years (2008–2010). The oil was extracted by a Soxhlet and the fatty acids composition was determined using gas chromatography. The results revealed a variation in seed oil content (51.83–57.50 %). Total saturated fatty acids content (C14:0; C16:0; C18:0; C20:0) ranged from 19.53 to 20.29 %, with lower content in Had Dra and Biougra than other provenances. However, the concentration of total unsaturated fatty acids ranged from 79.56 to 80.29 %, with a higher percentage of monounsaturated fatty acid (C16:1; C18:1; C20:1) (47.60 %) in Aoulouz and a higher percentage of polyunsaturated fatty acid (C18:2; C18:3) (35.53 %) in Biougra provenance. No correlation between oil content and fatty acid compositions with the morphological data (mother tree, fruit and seed forms) was found. The geographical localization and fatty acid content were not correlated with oil content. The study proved a significant contribution of environmental conditions to the variation in fatty acid composition. We conclude that there is a highly significant variation both in oil content and fatty acid composition in the argan provenances that can be used for its improvement.

Hydroperoxide formation in different lean meats

Peroxide is one of the compounds that are indicated to be toxic in the human digestion system. Lean fresh meat samples were collected from beef, lamb, pork and chicken to investigate their hydroperoxide formation potential. Total peroxides of fresh comminuted raw meat were determined by analysing protein-bound peroxides and hydroperoxide compounds in water–methanol and chloroform extracted phases. The amount of total peroxides was ranked as: beef>pork>lamb>chicken. Hydroperoxide formation was examined at different pH values and at different incubation times, using beef and chicken samples. All peroxides were transient, with a maximum value after 2–4h of incubation at 37°C. When pH fell from 7 to 1.5, the different peroxides fell by 10–20%. Non-polar peroxide formation could largely (70%) be described by variation in fatty acid composition and hemin content of the meat, while protein-bound peroxide variation was less explained by these variables. Liposome addition increased (40%) the amount of protein-bound peroxides.

Comparison of the lipid properties of healthy and pansteatitis‐affected African sharptooth catfish, Clarias gariepinus (Burchell), and the role of diet in pansteatitis outbreaks in the Olifants River in the Kruger National Park, South Africa

Pansteatitis has been identified in wild populations of sharptooth catfish, Clarias gariepinus (Burchell), and Nile crocodiles, Crocodylus niloticus Laurenti, inhabiting the same waters in the Olifants River Gorge in the Kruger National Park, South Africa. Mesenteric and pectoral fat tissue was investigated microscopically and by fatty acid analysis in healthy and pansteatitis-affected catfish from both captive and wild populations. Variation in fatty acid composition between pectoral and mesenteric fat was noted. Composition of mesenteric fat differed between fish from various localities as a result of differences in diet. Pansteatitis in the captive population, resulting from ingestion of high amounts of dietary oxidized fat, reflected higher levels of unsaturated fatty acids within the mesenteric fat. Mesenteric fat of pansteatitis-affected wild catfish was characterized by an increase in moisture content, a decrease in fat content and a decrease in stearic and linoleic acids. The n-3 to n-6 fatty acid ratio of mesenteric fat was higher in pansteatitis-affected wild catfish than in healthy catfish from the same locality, reflecting higher polyunsaturated fat intake by pansteatitis-affected fish. The possible role of alien, invasive, phytoplankton-feeding silver carp, Hypophthalmichthys molitrix (Valenciennes), in the aetiology of pansteatitis in both catfish and crocodiles in the Olifants Gorge is discussed.

Genes involved in muscle lipid composition in 15 European Bos taurus breeds

Consumers demand healthy and palatable meat, both factors being affected by fat composition. However, red meat has relatively high concentration of saturated fatty acids and low concentration of the beneficial polyunsaturated fatty acids. To select animals prone to produce particular fat types, it is necessary to identify the genes influencing muscle lipid composition. This paper describes an association study in which a large panel of candidate genes involved in adipogenesis, lipid metabolism and energy homoeostasis was tested for effects on fat composition in 15 European cattle breeds. Sixteen genes were found to have significant effects on different lipid traits, and among these, CFL1 and MYOZ1 were found to have large effects on the ratio of 18:2/18:3, CRI1 on the amount of neutral adrenic acid (22:4 n-6), MMP1 on docosahexaenoic acid (22:6 n-3) and conjugated linoleic acid, PLTP on the ratio of n-6:n-3 and IGF2R on flavour. Several genes - ALDH2, CHRNE, CRHR2, DGAT1, IGFBP3, NEB, SOCS2, SUSP1, TCF12 and FOXO1 - also were found to be associated with both lipid and organoleptic traits although with smaller effect. The results presented here help in understanding the genetic and biochemical background underlying variations in fatty acid composition and flavour in beef.