High Levels Of Linoleic Acid Research Articles

Proximate Composition of the Apple Seed and Characterization of Its Oil

Apple seeds, a common byproduct of apple processing, have been examined for their overall proximate composition, fatty acid and amino acid composition of the lipid and protein components, respectively, as well as their key mineral constituents. Proximate analysis indicated that apple seeds are rich in oil content and protein ranging from 27.5 to 28% and 33.8 to 34.5% respectively, comparing favorably with oilseeds. GC analysis indicated high levels of linoleic acid (~49%) with the other dominant fatty acids being oleic, palmitic and stearic acids, ranging from ~39, 7 and 2% respectively. Amino acid analysis indicates that there are substantial amounts of sulfur containing amino acids in the apple seed. The apple seeds also contain significant amounts of phosphorus, potassium, magnesium, calcium and iron, in the order of 720, 650, 510, 210 and 110 mg/100g, respectively. Based on the proximate composition of the apple seeds, if adequate amounts are available as a process byproduct, apple seeds could have value-added potential as a source of edible oil, with the oil cake potentially serving as an animal feed supplement.

Trans fatty acids in partially hydrogenated soybean oil inhibit prostacyclin release by endothelial cells in presence of high level of linoleic acid

Partially hydrogenated soybean oil (PHSBO) and natural soybean oil (SBO) were obtained from a commercial source and their fatty acids were fractionated into saturates, monoenes and diene fractions. The present study compared the effect of the total, monoene and diene fatty acid fractions of PHSBO with those of the SBO on the fatty acid composition of the cell phospholipids (PL) and the prostacyclin (PGI 2) release by endothelial cells (EC) in culture. Results showed that arachidonic acid (AA) level decreased significantly and linoleic acid (LA) significantly increased in the cells incubated with the diene fraction or the monoene fraction of PHSBO plus 18:2 at 3:1 ratio compared to the cell incubated with those fractions of SBO. These changes were attributed to the inhibition of LA conversion to AA by trans 18:1 and 18:2 isomers present in the monoene or diene fractions of PHSBO leading to a significant decrease of PGI 2 released by the cells incubated with monoene or diene fractions of PHSBO. The cells incubated with the monoene of PHSBO or SBO plus 18:2 at a 1:1 ratio showed no inhibition of LA conversion to AA and the level of AA was almost equal in their PL, but the PGI 2 released by the cells incubated with the monoene of PHSBO was significantly less than the cells incubated with the monoene of SBO. This decrease was not related to the inhibition of PGI 2 synthesizing enzymes or phospholipase (PLA 2) activities. Our data show that trans acids in PHSBO inhibited the PGI 2 release by the cells through controlling the level of AA as substrate, either by (a) inhibiting the conversion of LA to AA or (b) by shunting the free AA released by the PLA 2 action to metabolism by another pathway leaving less AA available for PGI 2 synthesis.

Cholesterolaemic influence of palmitic acid in thesn-1, 3v.thesn-2 position with high or low dietary linoleic acid in healthy young men

Healthy young men were fed four diets for 2 weeks each providing natural fats containing palmitic acid (16 : 0) predominantly in the sn-1, 3 position of dietary TAG or containing 16 : 0 predominantly in the sn-2 position with low or high levels of linoleic acid (18 : 2n-6). Two treatments supplied 16 : 0 in the sn-1, 3 positions from palmstearin with low (3 % energy) or high (>7 % energy) 18 : 2n-6 and two treatments supplied 16 : 0 in the sn-2 position from lard with high or low levels of 18 : 2n-6. Diets contained 30-35 % energy as fat, 7-11 % energy as 16 : 0 and moderate levels of cholesterol. Fasting serum cholesterol and lipoprotein concentrations were measured. Cholesterol fractional synthesis rate (FSR) was determined by 2H incorporation. Diets providing 16 : 0 in the sn-2 position resulted in lower fasting serum total cholesterol (TC) and a lower TC:HDL ratio than diets providing 16 : 0 in the sn-1, 3 positions. Diets with high levels of 18 : 2n-6 significantly decreased the TC:HDL ratio, reaffirming the well-known cholesterol-reducing effect of 18 : 2n-6. A lower non-esterified cholesterol FSR was observed with low dietary levels of 18 : 2n-6. No differences between dietary treatments were found for serum HDL-cholesterol, LDL-cholesterol or TAG. It is concluded that dietary fats containing 16 : 0 in the sn-2 position may result in slightly lower fasting TC than diets providing 16 : 0 in the sn-1, 3 positions, while the level of n-6 polyunsaturated fat influences endogenous cholesterol synthesis.

Conjugated linoleic acid conversion by dairy bacteria cultured in MRS broth and buffalo milk

To evaluate strains of Lactobacilli, Bifidobacteria and Streptococci for their ability to produce conjugated linoleic acid (CLA) from free linoleic acid (LA). Eight dairy bacteria tolerant to LA were grown in MRS broth containing LA (200 microg ml(-1)) and CLA was assessed. Seven bacteria were able to form CLA after 24 h of incubation, varying percentage conversion between 17% and 36%. Lactobacillus casei, Lactobacillus rhamnosus, Bifidobacterium bifidum and Streptococcus thermophilus showed the highest LA conversion and were inoculated into buffalo milk supplemented with different concentration of LA. The production of CLA at 200 microg ml(-1) of LA was two- or threefold in milk than MRS broth. All evaluated strains were able to produce CLA from high LA levels (1000 microg ml(-1)). The most tolerant strain to LA was Lact. casei. Lacttobacillus rhamnosus produced the maximum level of CLA at high LA concentrations (800 microg ml(-1)). The selected bacteria may be considered as adjunct cultures to be included on dairy fermented products manufacture. Low concentration of LA must be added to the medium to enhance CLA formation. The production of CLA by strains using milks from regional farms as medium offer a possible mechanism to enhance this beneficial compound in dairy products and those the possibility to develop functional foods.

Lipid and fatty acid profiles of Castanea sativa Mill. Chestnuts of 17 native Portuguese cultivars

In recent years, chestnuts have increasingly become important in human nutrition because of their nutrient contents and potential beneficial health effects. In Portugal, Trás-os-Montes e Alto Douro is the most important region for chestnut production, generating 85% of the total national output. In 1994, three chestnut protected designation of origin (PDO) areas were created: Terra Fria, Soutos da Lapa, and Padrela within the jurisdiction area of the Regional Agricultural Services of Trás-os-Montes Region. Seventeen cultivars were selected from these PDO to evaluate crude fat content and fatty acid (FA) composition over a period of 2 years. Total fat extraction was performed according to AOAC methodology, using a Soxhlet apparatus for 16 h. Petroleum ether was used for extraction and FAs were identified and quantified by gas chromatography. The cultivars studied confirm that chestnuts have low crude fat content, low saturated fatty acids (SFA) (17%) and high unsaturated fatty acids (USFA) (83%). The major FAs are linoleic, oleic and palmitic; these accounted for more than 85% of the total FA content. From the results two potentially health-beneficial cultivars were identified: cv. Lada, with high linoleic acid content, and cv. Aveleira, with higher USFA content. With respect to FA profiles of chestnuts from the three PDO regions, Padrela chestnuts consistently contained the highest level of linoleic acid. The variation detected among cultivars and PDO areas may reflect differences in genotype and are influenced by environmental and growing conditions. The Longal chestnuts, the only traditional cv. growing on two different PDO areas, had better nutritional qualities in PDO Terra Fria, which confirm that the ecological conditions where chestnut orchards are established influences nut quality.

Analytical characterization of hemp (Cannabis sativa) seed oil from different agro‐ecological zones of Pakistan

AbstractCold‐pressed oil content of Cannabis sativa (hemp) seeds from three different agro‐ecological zones of Pakistan ranged from 26.90 to 31.50%. Protein, fiber, ash, and moisture content were found to be 23.00–26.50, 17.00–20.52, 5.00–7.60, and 5.60–8.50%, respectively. Results of some other physical and chemical parameters of the oil were as follows: iodine value, 154.00–165.00; refractive index (40°C), 1.4698–1.4750; density (24°C), 0.9180–0.9270 mg ml−1; saponification value, 184.00–190.00; unsaponifiable matter, 0.70–1.25%; and color (1‐in cell), 0.50–0.80 R+27.00–32.00 Y. The induction period (Rancimat, 20 L h−1, 120°C) of the nondegummed and degummed oils ranged from 1.35 to 1.72 h and from 1.20 to 1.49 h, respectively. Specific extinctions at 232 and 270 nm were 3.50–4.18 and 0.95–1.43, respectively. The hemp oils investigated were found to contain high levels of linoleic acid, 56.50–60.50%, followed by α‐linolenic, oleic, palmitic, stearic, and γ‐linolenic acids: 16.85–20.00, 10.17–14.03, 5.75–8.27, 2.19–2.79, and 0.63–1.65%, respectively. Tocopherols (α, γ, and δ) in the nondegummed oils were found to be 54.02–60.40, 600.00–745.00, 35.00–45.60, respectively, and were reduced to 29.90–50.00, 590.00–640.00, and 30.40–39.50 mg kg−1, respectively, after degumming. The results of the present analytical study, compared with those found in the typical literature on hempseed oils, showed C. sativa indigenous to Pakistan to be a potentially valuable nonconventional oilseed crop of comparable quality.

Quality evaluation of Artemia urmiana Günther (Urmia Lake, Iran) with special emphasis on its particular cyst characteristics (International Study on Artemia LXIX)

Artemia urmiana cysts were collected from seven sites in Urmia Lake, Iran. Biometrical analysis revealed that the mean values for the untreated cysts ranged from 262.7 to 286.6 μm, decapsulated cysts from 258.6 to 273.9 μm, and the chorion thickness ranged from 1.2 to 9.3 μm. The cyst samples were tested for their buoyancy at salinities of 35, 50, 100, 150 and 200 g/l. Two cyst batches from Great Salt Lake ( Artemia franciscana) were also tested as reference material. It was found that the majority of Urmia cysts (over 60%) sank after 72 h even at the salinity of 200 g/l, while, GSL cysts reached a much lower figure (less than 10%) after the same time period. Transmission electron microscopy studies of the Urmia cyst chorion revealed a thinner alveolar layer and a thicker fibrous layer in comparison with the respective layers of A. franciscana cysts. A. urmiana instar-I nauplii biometry was also performed (total naupliar length: 466.3–505 μm). Six reproductive and four life span characteristics were investigated at salinities of 35, 50, 100, 140 and 180 g/l in order to evaluate A. urmiana performance at different salinities. A. urmiana individuals showed a preference for high salinity, since high mortality was recorded at 35 and 50 g/l. No significant differences were found between the three highest salinities (100, 140 and 180 g/l) tested ( P > 0.05), with the exception of offspring per brood, reproductive period, and total life span. The analysis of highly unsaturated fatty acid (HUFA) profile of instar-I nauplii hatched from collected cyst batches resulted in low levels of eicosapentaenoic acid (20:5n-3) and high levels of linolenic acid (18:3n-3) ranging from 1.8 to 7.2 and from 32.7 to 54.7 mg/g DW, respectively. Only traces of docosahexaenoic acid (22:6n-3) were found.

Fatty acids in must prepared from 11 grapes grown in Japan: Comparison with wine and effect on fatty acid ethyl ester formation

FA components of 11 musts made from grape cultivars grown for making red wine in various regions of Japan and of wines made from the musts were compared to elucidate variety-dependent characteristics and to clarify their effect on FA ethyl ester (FAEE) formation in wine. Sixteen FA with carbon chain lengths from 12 to 26 were detected in all musts, with palmitic, linoleic, and linolenic acids generally predominating. Higher levels of linoleic acid were found in musts from a cold region (Hokkaido), and higher levels of oleic acid occurred in musts from a warm region (Honshu). Moreover, the unsaturation indexes (1.31-1.56) of five grape musts from the cold region showed significant differences among varieties, corresponding to the grapevines' degree of cryotolerance. The FA levels (610-6,610 nmol/100 mL) of all wines were extremely low (1.2-12.8%) compared with those of must, but the FA compositions were similar to those of must. Additionally, significant amounts of FAEE, possibly derived from yeast activity, were found in wines by using a solid-phase extraction method. The amounts of FAEE in wine significantly differed among samples (245-904 nmol/100 mL) and were inversely correlated with the percentage of linoleic acid in musts (R = -0.883). Thus, higher linoleic acid levels in must may be related to lower FAEE formation by yeast.

Component Fatty Acids of Acidic Glycerophospholipids in Rice Grains: Universal Order of Unsaturation Index in Each Lipid among Varieties

In five acidic glycerophospholipids (phosphatidylglycerol, phosphatidylinositol, cardiolipin and two N-acyl phospholipids containing ethanolamine) from grains of japonica and indica rices, phosphatidylglycerol had commonly the lowest unsaturation index and cardiolipin had the highest. The order of unasaturation index in each lipid did not depend on the variety of rice. It was assumed that unsaturation index of the lipids changed with temperature during grain ripening except for cardiolipin. Cardiolipin usually had a high level of linoleic acid and a low level of palmitic acid compared with other lipids.

Abnormal Fatty Acid Profile of Blood Cell Phospholipids and Dietary Fatty Acid Intake in Patients with Ulcerative Colitis

To elucidate the efficacy of dietary therapy for ulcerative colitis (UC), we analyzed the dietary fatty acid intakes, fatty acid compositions of phospholipids in the plasma and blood cells, and serum cytokines of 12 patients with UC. Correlations among fatty acid compositions in the diet, blood cell phospholipids and serum cytokines were also investigated in UC patients. Although the fat energy ratio was lower in the UC patients than in the controls, no significant difference was observed in their fatty acid intakes. Significantly higher linoleic acid levels were observed in the erythrocyte, mononuclear cell and neutrophil phospholipids of the UC patients compared with the controls. Concerning neutrophil phospholipids, two times higher levels of linoleic acid and arachidonic acid and lower levels of eicosapentaenoic acid (EPA) were observed in the UC patients compared with those in the controls. The serum TNF-α concentration was correlated positively with molar percentage of linoleic acid (r = 0.675, p < 0.02) and negatively with the n-3 polyunsaturated fatty acid (PUFA) (r = -0.584, p < 0.05) in the plasma phospholipids of UC patients. Dietary EPA intake was correlated negatively with the n-6 PUFA molar percentage in the phospholipids of the plasma, mononuclear cells and neutrophils. From these findings, we suggest that a diet high in n-3 PUFA and low in linoleic acid should be recommended for UC patients.

Linoleic acid increases monocyte deformation and adhesion to endothelium

Fatty acids have been implicated in having both anti- or pro-inflammatory actions, which may contribute to the progression and severity of atherosclerosis. Linoleic acid has been shown by others to decrease CD18 expression and leukocyte adhesion under static conditions. We investigated the effect of steric acid (18:0), oleic acid (18:1), and linoleic acid (18:2) on the cortical tension (a measure of cell membrane deformability) and adhesion characteristics of the monocytic cell line Mono Mac 6 (MM6) cells to TNF-α activated HUVEC under fluid flow. Linoleic acid concentrations up to 23 μM decreased cortical tension and increased adhesion frequencies. Increased adhesion was not due to altered cell morphology or adhesion kinetics and occurred despite decreases in receptor expression (CD18 and CD11a). At higher levels of linoleic acid (≥46 μM), cell dissociation constants significantly increased. Results show that decreasing cortical tension increased the probability that contact between MM6 cells and endothelium would produce an adhesive interaction, possibly due to increased deformation of the microvilli and the cell membrane cortex. However, more deformable cells rolled more erratically at low shear rates. The different behavior during initial contact and rolling suggest that adhesion is influenced by two force-dependent mechanisms, deformation of microvilli and a steric barrier. Incubation of MM6 with 23 μM steric or oleic acid did not significantly affect cortical tension. However, cells incubated with steric acid greatly increased their adherence to HUVEC and cells incubated with oleic acid showed no significant effect, indicating factors other than deformability may dominate.

Omega-3 fatty acids in colorectal cancer prevention.

Omega-3 fatty acids in colorectal cancer prevention.

Fatty acid composition of eggs produced by hens fed diets containing groundnut, soya bean or linseed

The influence of the diet's fatty acid composition on the fatty acid composition, weight, fat and cholesterol contents of chicken eggs was studied in an experiment in which laying hens were fed diets of similar proximate composition but containing either groundnut, soya bean or linseed. The fatty acid composition of the egg fat corresponded with that of the diets: groundnut feeding produced a high oleic acid content of the eggs, soya bean feeding resulted in a high level of linoleic acid and linseed feeding raised the level of α-linolenic acid. Incorporation of groundnut versus linseed into the diet raised the arachidonic acid content of the eggs. Feeding the linseed diet produced higher contents of eicosapentaenoic and docosahexaenoic acid. The three experimental diets did not differently influence the cholesterol and fat contents of the eggs, but linseed versus soya bean significantly reduced egg weight by on average 3.4%. It is indicated that eggs, depending on their composition, can contribute significantly to man's daily requirement of docosahexaenoic acid; high intakes of this fatty acid might reduce coronary heart disease.

Allelic variation in linolenic acid content of high erucic acid Ethiopian mustard and incorporation of the low linolenic acid trait into zero erucic acid germplasm

AbstractZero erucic acid germplasm of Ethiopian mustard is characterized by high levels of linolenic acid (about 21%). Two genetic sources of low linolenic acid (N2‐4961 and HF‐186, about 5%), have been developed in a high erucic acid background. The objectives of this research were to study the genetic relationship between the two low linolenic acid lines and to transfer the trait to zero erucic acid germplasm. F1 seed generations from crosses between both lines had higher average linolenic acid concentration than both parents. F2 seeds segregated for linolenic acid content following a continuous variation from 1.8 to 7.4%, exceeding the limits of the parental distribution ranges. Transgressive recombinants with very low linolenic acid concentration (0.7‐2.7%) were confirmed in the F3 seed generation. The results suggested that N2‐4961 and HF‐186 possess alleles for low linolenic acid at different loci. Transgressive low linolenic acid F3 plants were crossed with plants of a zero erucic acid line and a selection for zero erucic, low linolenic acid was conducted. As a result, a zero erucic acid F3:4 line containing 1.5 ± 0.7% linolenic acid was developed.

Effects of fish oil on lymphocyte proliferation, cytokine production and intracellular signalling in weanling pigs

It has been widely documented that fish oil attenuates inflammatory responses partially via down-regulation of T-lymphocyte function. To determine the anti-inflammatory role of fish oil in weanling pigs, we investigated the effects of fish oil and its functional constituents on peripheral blood lymphocyte proliferation, cytokine production and subsequent intracellular signalling in inflammatory-challenged weanling pigs and in in vitro cultured lymphocytes. Fish oil (7%) or corn oil (7%) was supplemented to 72 crossbred pigs (7.6 ± 0.3 kg BW and 28 ± 3 days of age) in a 2 × 2 factorial experiment that included an Escherichia coli lipopolysaccharide (LPS) challenge (challenged or not challenged). On day 14 and 28 of the experiment, 200 μg/kg BW of LPS or an equivalent amount of sterile saline was administered to the pigs by intraperitoneal injection. Blood samples were collected on days 15 and 29 to determine peripheral blood lymphocyte proliferation, interleukin-1β (IL-1β) and interleukin-2 (IL-2) production. The results showed that inflammatory challenge decreased average daily gain (P < 0.05) and average daily feed intake (P < 0.05) during days 15 - 28. Fish oil supplementation had no effect on growth performance. Inflammatory challenge increased lymphocyte proliferative response to concanavalin A (Con A) (P < 0.05) following each challenge. Fish oil tended to suppress (P < 0.1) the proliferation following the first challenge. Similarly, fish oil tended to reduce IL-1β production (P < 0.1) following the second challenge and IL-2 (P < 0.1) production following the first challenge in both challenged and unchallenged pigs compared with corn oil. In parallel in vitro experiments, peripheral blood lymphocytes of weanling pigs were incubated with various concentrations of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or linoleic acid (LA) (0, 20, 40, 60, 80, 100 μg/ml). EPA, DHA and high levels of LA predominantly suppressed IL-1β (P < 0.05), IL-2 (P < 0.05) production and subsequent lymphocyte proliferation (P < 0.05). Low levels of LA increased (P < 0.05) IL-2 production. Compared with LA, EPA resulted in a stronger inhibition of lymphocyte proliferation (P < 0.05) and IL-2 (P < 0.01), and DHA resulted in a stronger inhibition of IL-1β (P < 0.05) and IL-2 (P < 0.01). To elucidate the mechanism(s) by which fish oil and its functional constituents suppressed lymphocyte function, the kinetics of intracellular [Ca2 +]i and protein kinase C activity were determined in in vitro experiments. EPA, DHA and LA exerted very similar dose-dependent stimulatory effects on intracellular Ca2 +. EPA and DHA inhibited protein kinase C activity (P < 0.05), while LA had no significant effect (P > 0.05). These results suggest that fish oil and its functional constituents (EPA and DHA) exerted an anti-inflammatory effect by down-regulation of lymphocyte activation in weanling pigs, possibly by manipulation of intracellular signalling.

Chemical composition of Acacia colei and Acacia tumida seeds—potential food sources in the semi-arid tropics

The seeds of Acacia colei (Maslin and Thomson) and A. tumida (F. Muell ex Benth.) are traditional foods of Australian Aboriginal people. Chemical analysis was carried out on seeds of A. colei trees growing in Maradi district, Niger Republic and A. tumida from a natural stand near Kunanurra in north western Australia. Crude protein (N × 6.25) ranged from 23.4% for whole A. colei seed to 30.6% for a water-processed A. colei sample and 20.4% for A. tumida. True proteins were 19.9, 25 and 18.5% and ether extracts 10.9, 18.9 and 8.1% for these samples, respectively. Amino acid analysis indicated that tryptophan was the first limiting amino acid in all the acacia samples. Dietary fibre, calculated on defatted and ethanol extracted samples, was highest in whole A. colei with the seed coat (47.9%) and lowest in the processed A. colei (31.9%). Total soluble sugar was highest in A. tumida (14.6%). Both A. colei and A. tumida seeds contained high levels of linoleic acid. Fat soluble vitamins (carotenoids, ergocalciferol and α-tocopherol) were generally inadequate while the water-soluble vitamins (B group) were in sufficient to large quantities. Processing A. colei with water reduced thiamine, niacin, riboflavin and pantothenic acid contents by 12, 31, 42 and 74%, respectively. Potassium was the predominant mineral in all the acacia samples. Iron, magnesium, calcium and zinc were in high concentrations; the availability of iron was low but that of other elements was adequate.

Detection of Adulteration of Minced Beef Meat with Lard and Pork Meat Using some Molecular and Immunological Techniques

Detection of pork meat or lard in food as adulterants is of considerable importance nd interest in many parts of the world. This study was carried out to evaluate some traditional as well as recent methods being used in food analysis in order to detect pork meat or lard in beef meat. The traditional techniques include Amino and Fatty acids analyses, but the recent techniques were Polyacrylamide Gel Electrophoresis and Enzyme Linked Immunosorbent Assay (ELISA]. Raw and cooked beef meat admixtures contained 1, 5 and 10% of pork meat were subjected to analyses using the above mentioned techniques. Gas liquid chromatograph IGLC] analysis of fatty acids showed that beef meat fat contained high level of both palmitic acid [C16:0] and stearic acid [C 18:0]. Whereas pork [lard] had high levels of linoleic acid [C 18:2] as well as Eicosinic acid [C20:0]. Amino acids analyses were not clear method for the detection of adulteration due to the absence of clear difference in amino acids composition. Polyacrylamide-Gel-

Analytical Characterization of Salicornia bigelovii Seed Oil Cultivated in Pakistan

Seeds of Salicornia bigelovii (hybrid variety sos-10) were collected from five coastal areas of Pakistan on the Arabian Sea. Hexane-extracted oil content was 27.2-32.0%. Results of other physical and chemical parameters of the extracted oil were as follows: iodine value, 128.0-130.5; refractive index (40 degrees C), 1.4680-1.4695; unsaponifiable matter, 1.63-2.00%; saponification value, 178.6-189.0; density (30 degrees C), 0.9036-0.9074. Tocopherols (alpha, gamma, and delta) in the oil ranged up to 200 mg/kg. The S. bigelovii seed oil was found to contain high levels of linoleic acid (74.66-79.49%) and less oleic acid (12.33-16.83%). Saturated fatty acids, palmitic and stearic acids, ranged from 7 to 8.50% and from 1.24 to 1.69%, respectively. Linolenic acid (C(18:3) omega-3) was found within the range of 1.50-2.31%. The induction period (Rancimat, 20 L/h, 120 degrees C) of the crude oil was 1.40-1.70 h. Specific extinctions at 232 and 270 nm were 1.90-2.40 and 0.40-0.62, respectively. Many parameters of S. bigelovii seed oil were quite compatible with those of safflower oil.

Influence of Source and Percentage of Fat Added to Diet on Performance and Fatty Acid Composition of Egg Yolks of Two Strains of Laying Hens

We conducted a trial to study the influence of strain of hen (white vs. brown) and source and percentage of added fat to diet on productive performance and fatty acid (FA) profile of the egg yolk. There were nine dietary treatments: a control diet without added fat and eight diets arranged as a 2 × 4 factorial (5 vs. 10% added tallow, olive, soy, or linseed oil). Each treatment was replicated five times, and the trial lasted 12 wk. White hens produced yolks with more saturated FA (P < 0.001) and less monounsaturated FA (P < 0.001) and polyunsaturated FA (P < 0.05) than brown hens. Fat supplementation improved egg mass output (P < 0.05) and feed efficiency of hens (P < 0.001). Linseed and soy oil diets produced greater egg mass than diets based on tallow or olive oil (59.6, 59.4, 57.9, and 57.1%, respectively; P < 0.001). The proportion of saturated FA in the yolk decreased as the percentage of added fat increased (36.5, 32.3, and 31.0% for diets containing 0, 5, and 10% added fat, respectively; P < 0.001). When the alpha-linolenic acid content of the diets increased from 0 to 0.8%, the arachidonic, docosapentanoic, and docosahexanoic acids in the egg yolk increased. Increases in the alpha-linolenic acid content of the diet over 2.3% did not further augment the concentration of docosapentanoic or docosahexanoic acid of the yolk and, in fact, decreased that of arachidonic acid. Only diets supplemented with linseed oil produced eggs with measurable amounts of eicosapentanoic acid. Diets supplemented with soy oil, with moderate levels of α-linolenic acid and high levels of linoleic acid, increased arachidonic and docosahexanoic acids in the egg yolk but not eicosapentanoic acid.

Interactions and Antigen Dependence of Dietary n-3 and n-6 Polyunsaturated Fatty Acids on Antibody Responsiveness in Growing Layer Hens

Effects of four levels of dietary linoleic acid (LA), an n-6 fatty acid, and four levels of alpha-linolenic acid (LNA), an n-3 fatty acid, and their interactions on immune responses in growing layer hens were studied. Immune responses were induced by injection with keyhole limpet hemocyanin (KLH) or Mycobacterium butyricum particles at 35 d of age. Antibody (Ab) responses were measured until 21 d after immunization. In addition, delayed-type hypersensitivity, lymphocyte proliferation, weekly feed intake, and BW gain were studied. At Day 7 after immunization, anti-M. butyricum titers in the M. butyricum-immunized hens were decreased by the increase of dietary LA (P < 0.05). In the period from 10 to 14 d after immunization, anti-KLH Ab titers in KLH-immunized animals were affected by the interaction of dietary LA with LNA (P < 0.01). High dietary levels of LA or LNA increased the anti-KLH Ab response. However, at high levels of dietary LA and LNA, anti-KLH Ab titers were not increased. In the same period, anti-M. butyricum Ab titers of M. butyricum-immunized hens were affected by the interaction of dietary LA with LNA (P < 0.05). At low levels of LA and LNA, increased LA levels decreased the Ab response, whereas increased LNA levels at low LA levels hardly affected the anti-M. butyricum response. At a high level of LA, increased dietary LNA increased the anti-M. butyricum response. In vitro proliferation of peripheral blood leukocytes after stimulation with concanavalin A (ConA) was higher in chickens with a high level of dietary LNA. Feed intake decreased when the dietary levels of LA or LNA increased. However, BW gain was not affected by dietary treatments. Feed conversion was more efficient in birds fed high levels of LA and LNA. The present study indicates that various factors affect the Ab responses. First, the interaction of n-6 and n-3 polyunsaturated fatty acids (PUFA) is more important than the separate effects of n-3 or n-6. Second, the actions of dietary PUFA were different between antigens of a different nature. Third was the nature of the antigen affects when dietary PUFA exert their actions and the persistence of these effects. The presence of these multiple factors affecting immune responses should be considered when comparing effects of dietary PUFA on immune responses.