Fatty Acid Composition Of Blood Research Articles

Changes in the Spectrum of Free Fatty Acids in Blood Serum of Dairy Cows during a Prolonged Summer Heat Wave.

Simple SummaryHeat stress leads to poor welfare, decreased productivity, and poor product quality. It is known that the content of fatty acids in the blood can reflect the physiological state of the body under normal and pathological conditions. They can be biomarkers for the state of biomembranes associated with inflammation and indicate the state of energy imbalance during chronic heat stress. They perform various functions in the body; therefore, the determination of the spectrum of free fatty acids can be used as biomarkers of these processes. The changes in the spectrum of free fatty acids in the blood serum of dairy cows revealed in our study will make it possible to better understand the physiological state of the organism and possibly indicate ways to maintain the health and milk productivity of animals under conditions of prolonged hyperthermia.This experiment was conducted to study the effect of a prolonged hot period on the fatty acid (FA) composition in blood serum of dairy cows. Eighteen multiparous Holstein cows were randomly assigned to the hyperthermia group (HYP, n = 8) in August (summer season) and the control group (CON, n = 10) in October (autumn season). Blood from animals of the HYP group was collected in one heat wave, which was preceded by a long period of heat stress (HS, temperature-humidity index (THI ≥ 72)). Blood from cows of the CON group was collected under thermal comfort conditions (THI < 68). The spectrum of free fatty acids (FFA) in the blood serum was analyzed by gas chromatography. The concentration of FFA increased, including saturated FAs and monounsaturated FAs, in the blood serum of cows under conditions of prolonged HS. This was associated with the mobilization of FA into the bloodstream from adipose tissue, as a consequence of negative energy balance. An increase in the ratio of n-6/n-3 polyunsaturated FAs may indicate biomembrane dysfunction and adversely affect dairy cows. This study showed that prolonged periods of heat can affect the FA composition of blood. How much this leads to changes in the FA composition of milk and the quality of food products remains to be seen in further research.

Growth, efficiency and the fatty acid composition of blood and muscle from previously grazed late-maturing bulls fed rumen protected fish oil in a high concentrate finishing ration

In bulls, with a genetic predisposition for leanness and reared in a grass-based production system dietary fish oil may further enhance the nutritional value of beef by increasing the concentration of the omega 3 polyunsaturated fatty acids (PUFA) eicosapentanoic acid (EPA) and docosahexanoic acid (DHA). The impact of including rumen protected fish oil in the finishing diet of late maturing breed bulls on their growth, feed efficiency, carcass fat classification, aspects of ultimate meat quality and the fatty acid composition of the M. Longissimus thoracis muscle (LT) was examined. Twelve month old bulls were supplemented with a barley-based concentrate (500g/kg dietary dry matter) from turn-out to pasture in spring until housing 94 days later. Bulls were housed indoors and offered ad libitum, either the same concentrate or a concentrate containing rumen protected fish oil (PFO) at a ration fat concentration of 50g/kg dry matter, along with grass silage to appetite, for 88 days pre-slaughter. Inclusion of PFO increased (P<0.05) concentrate consumption, but this was not reflected in carcass growth, classification or fat colour or in LT colour or tenderness. Concentrations of 18:2, EPA, DHA, total PUFA and the PUFA: saturated fatty acid ratio (0.19 v 0.14) were higher (P<0.05) in LT from PFO compared to control bulls. The increase in EPA + DHA, associated with PFO inclusion, from 7 to 12 mg/100g muscle is below the concentration required by European Commission regulations (40 mg/100g) to allow this beef to be labelled a “source of” EPA + DHA. Nevertheless, consuming beef from PFO bulls would make a greater contribution to the daily consumer requirement for omega-3 PUFA than beef from the control bulls. This has potential to add value to beef from the PFO production system.

Correction to: Testing the dogma that total phospholipid fatty acid composition of blood plays a role in kidney stone pathogenesis, using a high-low risk human model: results from a pilot study.

The authors would like to add the following paragraph in the acknowledgement section of the original version of the paper.

Testing the dogma that total phospholipid fatty acid composition of blood plays a role in kidney stone pathogenesis, using a high-low risk human model: results from a pilot study.

Previous studies have suggested that ω-3 and ω-6 polyunsaturated fatty acid (PUFA) composition in plasma and red blood cell (RBC) total phospholipids plays a role in urolithiasis. Our aim was to test the robustness of this dogma by retrospectively comparing baseline profiles of these parameters in subjects from high- and low-stone-risk groups. The documented difference in stone occurrence in white (relatively common) (W) and black (rare) (B) subjects prompted us to select these groups as the high-low risk model for the study. Blood and urine samples were obtained from ten subjects in each group and were analysed for PUFAs and stone risk factors, respectively. Concentrations of linoleic acid (LA), eicosadienoic acid (EDA) and arachidonic acid (AA) in plasma and or/RBC total phospholipids were significantly higher in B. Differences in other PUFA profiles were also observed. There was no inter-group difference in AA/LA ratios. Urinary oxalate was significantly higher while urinary phosphate was significantly lower in B. We speculate that elevated AA in B might arise because of a possibly enhanced elongation of LA to EDA, as well as an enhanced ∆-8-desaturation of EDA to dihomo-gamma-linolenic acid (DGLA), which is the immediate precursor of AA. Alternatively, we speculate that the ∆-5-desaturation step of DGLA to AA might be more highly activated in this group. Irrespective of the mechanism, our observed inter-group differences in phospholipid PUFA composition are in conflict with previously published dogma which relates PUFA characteristics to high- and low-stone risk.

Energy-Protein Supplementation and Lactation Affect Fatty Acid Profile of Liver and Adipose Tissue of Dairy Cows.

This article addresses the hypothesis that lactation stage, parity and energy-protein feed additive affect fatty acid composition of blood, liver and adipose tissue of cows. The experiment was conducted on 24 Polish Holstein-Friesian cows divided into two feeding groups. One group of cows was fed solely a total mixed ration, while the other group was fed a ration with the addition of 2 kg of energy-protein supplement per cow/day. During the experiment, the samples of liver, adipose tissue and blood were taken and their fatty acid compositions were determined. Analysis of variance was applied to fatty acid relative weight percentage to determine the effect of the stage of lactation, parity, and energy-protein supplement on the fatty acid composition of the tissues. Stage of lactation had a significant impact on the content of many fatty acids in all examined tissues. We found that parity had no effect on fatty acid composition of blood, whereas it significantly affected C16:1 c9 in liver, and C16:1 c9 and C18:0 in adipose tissue. Energy-protein supplement significantly affected the content of most fatty acids in blood (e.g., C18:1 t11 and C18:3 n-3) and liver (C18:3 n-3, both isomers of conjugated linolenic acid and n-3 fatty acids derived from fish oil), but it did not affect the profile of the adipose tissue of cows. According to our best knowledge, this is the first study showing the relationship between parity, stage of lactation and the composition of fatty acids in blood, liver and adipose tissue of cows.

Intra-annual variation in the foraging ecology of the endangered endemic Barau’s Petrel (Pterodroma baraui) from Réunion Island, south-western Indian Ocean: insights from a multifaceted approach

Population modelling for one of Reunion Island’s endemic seabirds, the Barau’s Petrel (Pterodroma baraui), has highlighted its vulnerability to extinction. Conservation action demands information on its biology during different stages of its life cycle. Whilst most aspects of the species’ terrestrial ecology have been studied, at-sea information is scarce and frequently contradictory. In this context, we combine three complementary techniques to provide new information on the trophic ecology of the Barau’s Petrel and to augment recent telemetry data. Colonies were visited periodically through a single breeding season and samples gathered from adults, downy chicks, and fledglings, permitting intra-annual comparisons within and among ontogenetic stages. Stomach contents consisted mostly of accumulated cephalopod beaks, whereas structures from other molluscs, fishes, and arthropods were rare. Variations in carbon stable isotopes matched the patterns of adult foraging behaviour, as described using telemetry, and wide variation in nitrogen isotope values indicated dietary opportunism. Finally, the total fatty acid composition of blood differed greatly among adults, further suggesting opportunistic feeding; however, consistently low incidences of long-chain monounsaturated and n-3 fatty acids indicated little importance of fish. These results offer additional insight into the Barau’s Petrels’ trophic ecology are in concordance with recent telemetry data and will assist in preliminary assessment of the threats to the species whilst foraging. We also illustrate the value of an integrated approach to diet determination for endangered species, where hyper-ethical approaches need to be considered, and when isotope and fatty acid baseline data are not available and are not logistically attainable.

Deleterious effects of lard-enriched diet on tissues fatty acids composition and hypothalamic insulin actions

Altered tissue fatty acid (FA) composition may affect mechanisms involved in the control of energy homeostasis, including central insulin actions. In rats fed either standard chow or a lard-enriched chow (high in saturated/low in polyunsaturated FA, HS-LP) for eight weeks, we examined the FA composition of blood, hypothalamus, liver, and retroperitoneal, epididymal and mesenteric adipose tissues. Insulin-induced hypophagia and hypothalamic signaling were evaluated after intracerebroventricular insulin injection.HS-LP feeding increased saturated FA content in adipose tissues and serum while it decreased polyunsaturated FA content of adipose tissues, serum, and liver. Hypothalamic C20:5n-3 and C20:3n-6 contents increased while monounsaturated FA content decreased. HS-LP rats showed hyperglycemia, impaired insulin-induced hypophagia and hypothalamic insulin signaling.The results showed that, upon HS-LP feeding, peripheral tissues underwent potentially deleterious alterations in their FA composition, whist the hypothalamus was relatively preserved. However, hypothalamic insulin signaling and hypophagia were drastically impaired. These findings suggest that impairment of hypothalamic insulin actions by HS-LP feeding was not related to tissue FA composition.

Effects of trans MUFA from dairy and industrial sources on muscle mitochondrial function and insulin sensitivity

Epidemiological studies suggest that chronic consumption of trans MUFA may alter muscle insulin sensitivity. The major sources of dietary trans MUFA (dairy fat vs. industrially hydrogenated oils) have different isomeric profiles and thus probably different metabolic consequences. These effects may involve alterations in muscle mitochondrial oxidative capacity, which may in turn promote insulin resistance if fatty acid oxidation is reduced. We report that in Wistar rats, an 8 week diet enriched (4% of energy intake) in either dairy, industrial, or control MUFA did not alter insulin and glucose responses to an intraperitoneal glucose tolerance test (1g/kg). In C2C12 myotubes, vaccenic and elaidic acids did not modify insulin sensitivity compared with oleic acid. Furthermore, the ex vivo total, mitochondrial and peroxisomal oxidation rates of [1-(14)C]oleic, vaccenic, and elaidic acids were similar in soleus and tibialis anterior rat muscle. Finally, an 8 week diet enriched in either dairy or industrial trans MUFA did not alter mitochondrial oxidative capacity in these two muscles compared with control MUFA but did induce a specific reduction in soleus mitochondrial ATP and superoxide anion production (P<0.01 vs. control). In conclusion, dietary trans MUFA of dairy or industrial origin have similar effects and do not impair muscle mitochondrial capacity and insulin sensitivity.

Fermented soybeans by Monascus starter change fatty acid composition of blood and liver in diet‐induced obese rats

Soybeans that are consumed a lot in Asia contain essential fatty acid, linoleic acid, and have a preventive effect of cardiovascular disease. Isoflavones, main bioactive materials of soybean, are found in glycosidic form but fermented isoflavones are converted to aglycone form and increased bioavailability. The Monascus fermented products forms the red mycelium and bioactive monacolin K. This study, therefore, was performed to investigate the effects of Monascus starter on fatty acid composition of blood and liver. Sprague‐Dawley weanling male rats were provided either control low fat (10% fat, LF) or high fat (45% fat, HF) for inducing obesity for 9 weeks and, then were provided three different diets containing casein, steamed soybeans, and Monascus starter treated soybeans for 5 weeks. Monascus starter significantly decreased body weight gain and increased fecal fat excretion. Monascus showed a significant increase of plasma unsaturated fatty acids in HF, and not in LF. There was no difference in fatty acid composition of liver in LF groups. However, Monascus increased unsaturated fatty acids and showed relatively higher ratio of polyunsaturated fatty acids to saturated fatty acids among HF groups, The above results confirm that Monascus fermented soybean products prevent obesity and cardiovascular disease by improving lipid metabolism. &lt;This study was supported by 2006 Seoul R&amp; D Program&gt;

N-3 fatty acids and pregnancy outcomes

To discuss new data from the literature on the relationship between the supply of n-3 polyunsaturated fatty acids during pregnancy and pregnancy outcomes, evaluated as the fatty acid composition of blood and breast milk, fetal and infantile development and maternal health. Supplementation of alpha-linolenic acid in high doses or docosahexaenoic acid in low doses did not result in a significant enhancement of the blood docosahexaenoic acid status of the offspring. In contrast, supplementation of docosahexaenoic acid in relatively high doses led to significant increases in infantile docosahexaenoic acid values and to a significant enhancement of breast milk docosahexaenoic acid content. Electroretinogram data obtained during the first week of life and pattern-reversal visual evoked potentials investigated at 50 and 66 weeks postconception were significantly associated with the docosahexaenoic acid status of the infant at birth. Children whose mothers received docosahexaenoic acid supplementation during pregnancy and lactation scored better in mental processing tests carried out at 4 years than children whose mothers received placebo. Beneficial health outcomes are more likely to result from supplementation with docosahexaenoic acid itself, rather than its precursor alpha-linolenic acid. Trials have shown that a higher maternal docosahexaenoic acid intake during pregnancy may be favourable for the visual and cognitive development of the offspring. The significant positive association between maternal docosahexaenoic acid intake during pregnancy and the children's mental processing scores at 4 years suggest that optimization of the docosahexaenoic acid status of expectant women may offer long-term developmental benefits to their children.

Effects of Exercise on the Fatty-Acid Composition of Blood and Tissue Lipids

This article reviews the effects of acute and chronic exercise on the fatty-acid composition of animal and human tissues (plasma, skeletal muscle, heart, adipose tissue, liver, artery and erythrocytes), as reported in 68 studies spanning four decades. The most consistently observed effect has been an increase in the relative amount of unsaturated, especially monounsaturated, non-esterified fatty acids in plasma of both animals and humans after acute exercise. Chronic exercise seems to increase the proportion of polyunsaturated fatty acids and omega6 fatty acids, while decreasing the proportion of monounsaturated fatty acids in animal and human adipose tissue. Additionally, chronic exercise seems to decrease the relative amount of unsaturated fatty acids in liver lipids of animals and humans. There is no consensus regarding the effect of exercise on the fatty-acid composition of lipids in any other tissue. In general, the effects of exercise are independent of nutrition and, regarding skeletal muscle, muscle fibre type. The available literature shows that, in addition to modifying the concentrations of animal and human tissue lipids, exercise also changes their fatty-acid profile. Unfortunately, the available studies are so much divided among exercise models, species and biological samples that a cohesive picture of the plasticity of the fatty-acid pattern of most tissues toward exercise has not emerged. Future studies should focus on determining the fatty-acid profile of separate lipid classes (rather than total lipids) in separate subcellular fractions (rather than whole tissues), examining tissues and organs on which no data are available and exploring the mechanisms of the exercise-induced changes in fatty-acid composition.

Digestion, Milk Production, Milk Composition, and Blood Composition of Dairy Cows Fed Formaldehyde Treated Flaxseed or Sunflower Seed

Forty midlactation Holstein cows averaging 635kg of body weight (SE = 8) were allotted at wk 25 of lactation to ten groups of four cows blocked for similar calving dates to determine the effects of formaldehyde treatment of flaxseed and sunflower seed on fatty acid composition of blood and milk, milk yield, feed intake, and apparent digestibility. Cows were fed a total mixed diet based on grass silage and supplements for ad libitum intake over a 10-wk period. Cows within each block were assigned to one of the four isonitrogenous supplements based on either untreated whole flaxseed, formaldehyde-treated whole flaxseed, untreated whole sunflower seed, or formaldehyde-treated whole sunflower seed. Cows fed whole flaxseed compared with sunflower seed maintained greater dry matter (DM) intake (20.3 vs. 18.9 kg/d). Intake of DM, expressed as a percentage of body weight, was increased by adding formaldehyde to oilseeds (3.24 vs. 2.98%). Milk production was similar for cows fed flaxseed and those fed sunflower. Formaldehyde treatment of flaxseed and sunflower seed increased milk production by an average of 2.65 kg/d. Efficiency of fat-corrected milk yield per kilogram of DM intake was increased by formaldehyde treatment (1.31 vs. 1.21), and it was greater with sunflower seed than with flaxseed (1.33 vs.1.21). Protein concentration in milk was greater for cows fed flaxseed (3.38%) compared with those fed sunflower seed (3.21%) and formaldehyde had no effect. Apparent digestibility of DM was not affected by type of seed but it was greater for cows fed formaldehyde-treated seeds. Cows fed formaldehyde-treated flaxseed had the greatest apparent digestibilities of acid detergent and neutral detergent fiber compared with those fed the other diets. Apparent digestibilities of fatty acids were greater for sunflower seed than for flaxseed-based diets. In general, formaldehyde treatment had limited effect on milk fatty acid composition, suggesting that formaldehyde was not very effective in protecting polyunsaturated fatty acids against ruminal biohydrogenation. Feeding flaxseed resulted in the lowest omega 6 to omega 3 fatty acid ratio. The data suggest that both flaxseed and sunflower seed are acceptable fat sources for midlactating cows and that flaxseed increases milk protein percentage compared to sunflower seed.

Digestion, Milk Production, Milk Composition, and Blood Composition of Dairy Cows Fed Whole Flaxseed

A total of 90 lactating Holstein cows averaging 628kg (SE = 8) of body weight (BW) were allotted at calving to 30 groups of three cows blocked for similar calving dates to determine the effects of feeding whole untreated flaxseed on milk production and composition, fatty acid composition of blood and milk, and digestibility, and to determine whether flaxseed could substitute for other sources of fat such as Megalac and micronized soybeans. Cows were fed a total mixed diet based on grass and corn silage and fat supplements for ad libitum intake. The experiment was carried out from calving up to wk 16 of lactation. Cows within each block were assigned to one of the three isonitrogenous, isoenergetic, and isolipidic supplements based on either whole flaxseed (FLA), Megalac (MEG), or micronized soybeans (SOY). Intake of dry matter and change in BW were similar among diets. Cows fed FLA had greater milk yield than those fed MEG (35.7 vs. 33.5 kg/d) and there was no difference between cows fed FLA and those fed SOY (34.4 kg/d). Fat percentage was higher in the milk of cows fed MEG (4.14%) than in the milk of those fed FLA (3.81%) or SOY (3.70%), but milk protein percentage was higher for cows fed FLA (2.98%) than for those fed MEG (2.86%) and SOY (2.87%). Digestibilities of acid detergent fiber, neutral detergent fiber, and ether extract were lower for cows fed FLA than for those fed SOY and MEG. Retention of N was similar among diets. Feeding FLA resulted in the lowest omega-6-to-omega-3-fatty-acids ratio, which would improve the nutritive value of milk from a human health point of view. The data suggest that micronized soybeans and Megalac can be completely substituted by whole untreated flaxseed as the fat source in the diet of early lactating cows without any adverse effect on production and that flaxseed increased milk protein percentage and its omega-6-to-omega-3-fatty-acids ratio.

Essential fatty acids in Atlantic salmon: effects of increasing dietary doses of n-6 and n-3 fatty acids on growth, survival and fatty acid composition of liver, blood and carcass

Atlantic salmon fry (4 g) were fed for 4 months on semi-synthetic diets containing fatty acid methyl esters of either 18:2 n-6, 18:3 n-3 or a mixture of equal amounts of 20:5 n-3 and 22:6 n-3. The different amounts of polyunsaturated fatty acids added were 0, 0.1, 0.2, 0.5, 1 and 2% (by dry weight). Increasing levels of dietary n-3 fatty acids up to 1% gave faster growth rates in salmon fry, and fish fed the mixture of 20:5 n-3 and 22:6 n-3 seemed to grow faster than fish fed only 18:3 n-3. No significant effect on growth rate was seen when the dietary level of 18:2 n-6 was increased. Dietary inclusions of n-3 fatty acids reduced the mortality of salmon, while dietary 18:2 n-6 had no such beneficial effects. The dietary treatments caused substantial changes in the fatty acid composition of blood and liver phospholipids (PL), whereas the total lipid fraction of the carcass was less affected. Increasing doses of 18:2 n-6 in the diet resulted in an increased percentage of 20:4 n-6 in liver and blood PLs, while the percentage of 20:3 n-9 decreased. The percentage of 18:2 n-6 also increased in liver, blood and carcass. Dietary 18:3 n-3 resulted in increased percentages of 18:3 n-3 and 20:5 n-3 in liver PLs, while the percentage of 20:3 n-9 decreased. There was, however, no significant increase in the percentage of 22:6 n-3. Dietary 18:3 n-3 produced no significant changes in the composition of blood fatty acids, but increased the percentage of 18:3 n-3 in the carcass. The dietary combination of the n-3 fatty acids 20:5 and 22:6 resulted in an increased percentage of 22:6 n-3 in blood and liver lipids and a decreased percentage of 20:3 n-9, but there were no changes in the percentage of 20:5 n-3.

Essential fatty acids in Atlantic salmon: time course of changes in fatty acid composition of liver, blood and carcass induced by a diet deficient in n-3 and n-6 fatty acids

Atlantic salmon fry (4 g) were fed a semi-synthetic diet devoid of n-3 and n-6 polyunsaturated fatty acids (PUFA) for 4 months. External signs of nutritional imbalance during the period were slow growth rate and increased mortality. Some symptoms of essential fatty acid deficiency appeared in the fatty acid composition of the blood and liver during the fourth month. At that time, the percentages of n-3 and n-6 PUFA of triacylglycerols (TAG) were nearly exhausted, and the percentages of 22:6 n-3 and of 20:5 n-3 in phospholipids (PL) showed a marked decrease. This decrease in the PUFA level of the PL was paralleled by the appearance of 20:3 n-9, whereas in the TAG an increase in the percentage of 18:1 n-9 was observed. After 4 months the monounsaturated fatty acid 18:1 n-9 constituted nearly 50% of the fatty acids in the TAG fraction of the liver. The time course of the changes in fatty acid composition of liver and blood lipids was quite similar, whereas the carcass lipid composition appeared to respond slowly to a diet devoid of essential fatty acids.

Iron Intake Influences Essential Fatty Acid and Lipid Composition of Rat Plasma and Erythrocytes

In view of the clinical importance of iron deficiency as well as the known role of iron in stearic acid desaturation, the effects of higher or lower iron intake on fatty acid composition of blood and liver in the rat were studied. Male Sprague-Dawley rats were fed purified diets that contained iron at 12, 27 or 237 mg/kg. After 12 wk the lipid and fatty acid composition of plasma, erythrocytes and liver was analyzed. Linoleic acid in plasma phospholipids and triacylglycerols was higher, but arachidonic acid was lower in the group fed 12 mg/kg iron than in the groups fed 27 or 237 mg/kg iron. Liver fatty acid and lipid composition was not different between groups. In the group fed 237 mg/kg iron, plasma cholesterol and triacylglycerols were 150%, erythrocyte cholesterol was 137% and erythrocyte phospholipids were 148% of levels in the rats fed 27 mg/kg iron. The fatty acid data suggest a mild impairment in essential fatty acid metabolism in moderately iron-deficient rats. The lipid data suggest a significant alteration in the total lipid content of plasma and erythrocytes of iron-supplemented rats.

Influence of pregnancy and an oxidized lipid diet on the fatty acid composition of blood and tissue.

RECENTLY it has been shown that a diet which is low in vitamin E and which contains 5 per cent of oxidized lipid is capable of producing the generalized Shwartzman reaction in pregnant rats1,2. This reaction is characterized by an episode of disseminated intravascular coagulation and, in the past, has only been produced experimentally by intravenous injection of bacterial endotoxin. The fact that the only variant in the diet which was responsible for its lethal effect was the oxidized lipid plus the fact that an increase in stainable lipid could be demonstrated in the kidney, liver, and placentas of some animals led to an investigation of the distribution of fatty acids in the blood and tissues of these animals. It seemed appropriate to compare the fatty acid compositions of tissue lipids of pregnant and non-pregnant female rats fed the oxidized lipid diet (20 per cent casein, 61 per cent corn starch, 10 per cent brewers' yeast, 4 per cent salt mixture, and 5 per cent of the ethyl esters of a molecularly distilled fraction of oxidized cod liver oil) with those of similar rats fed a pellet stock diet containing approximately 5 per cent fat.

Essential fatty acids in the chick. II. Polyunsaturated fatty acid composition of blood, heart and liver

The polyunsaturated fatty acids in plasma, liver, and heart of chicks were determined at intervals during essential fatty acid deficiency. The marked decreases in dienoic and tetraenoic acids, and increase in trienoic, were partially corrected by feeding methyl linoleate. The evidence indicates that dienoic acid is converted to tetraenoic and pentaenoic acids, and possibly also to hexaenoic acid.