Effect of flaxseed oil in diet on fatty acid composition in the liver of Nile tilapia (Oreochromis niloticus)

This study analyzed the effects of different concentrations of flaxseed oil (FO) on the proximate composition and the contents of alpha-linolenic acid (LNA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), and docosahexaenoic (DHA, 22:6n-3) fatty acids in the liver of cultured Nile tilapia (Oreochromis niloticus). During the five-month culture period, tilapias were given diets with incremental concentrations of FO (0.00%; 1.25%; 2.50%; 3.75%, and 5.00%) as a replacement of sunflower oil (control). There was no significant difference in moisture and ash content in the liver between treatments. Protein values ranged from 12.1% (treatment II) to 13.9% (treatment V) and total lipids ranged from 5.6% (treatment V) to 7.2% (treatment II). There was no significant difference between most treatments. Fatty acid methyl esters (FAMEs) were quantitatively analyzed by capillary gas chromatography against a C(23:0), internal standard. Variations in concentrations (in mg g(-1) of total lipids) of fatty acids between treatment I and treatment V ranged from 4.2 to 51.2 (LNA), from 0.2 to 2.3 (EPA), and from 10.6 to 56.2 (DHA), respectively. This experiment demonstrated that increasing amounts of LNA in feed may markedly increase the amounts of LNA, EPA, and DHA in the liver of Nile tilapia.     

Incorporation of Omega-3 Fatty Acids in Nile Tilapia (Oreochromis niloticus) Fed Chia (Salvia hispanica L.) Bran

This study evaluated the effect of the inclusion of chia bran in the diet of Nile tilapia on the composition of n‐3 fatty acids (FA). Omega‐3 fatty acids provide health benefits such as reducing the risks of coronary heart disease, hypertension and inflammation, and the precursor alpha‐linolenic acid is considered strictly essential because it cannot be synthesized by humans, therefore must be ingested. Tilapias grown in tanks for a period of 45 days were treated with diets supplemented with either soybean oil (TI) or chia bran (TII). Proximal composition analysis of the feeds showed no significant difference. Feed FA quantification showed that the chia diet (TII) had a higher alpha‐linolenic acid (LNA) content. A significant increase was observed in the concentrations of LNA (8.38–81.31 mg 100 g^?1 fillets), eicosapentaenoic acid (1.12–1.56 mg 100 g^?1 fillets) and docosahexaenoic acid (19.55–26.55 mg 100 g^?1 fillets) in tilapia fillets between 0 and 45 days for TII. Total lipids at 45 days under TII were fractionated into neutral lipids (67.66 %) and polar lipids (18.90 %). Thus, dietary supplementation with chia bran contributed to raising the nutritional quality of Nile tilapia fillets.     

Dnmt3aa but Not Dnmt3ab Is Required for Maintenance of Gametogenesis in Nile Tilapia (Oreochromis niloticus)

Dnmt3a, a de novo methyltransferase, is essential for mammalian germ line DNA methylation. Only one Dnmt3a is identified in mammals, and homozygous mutants of Dnmt3a are lethal, while two Dnmt3a paralogs, dnmt3aa and dnmt3ab, are identified in teleosts due to the third round of genome duplication, and homozygous mutants of dnmt3aa and dnmt3ab are viable in zebrafish. The expression patterns and roles of dnmt3aa and dnmt3ab in gonadal development remain poorly understood in teleosts. In this study, we elucidated the precise expression patterns of dnmt3aa and dnmt3ab in tilapia gonads. Dnmt3aa was highly expressed in oogonia, phase I and II oocytes and granulosa cells in ovaries and spermatogonia and spermatocytes in testes, while dnmt3ab was mainly expressed in ovarian granulosa cells and testicular spermatocytes. The mutation of dnmt3aa and dnmt3ab was achieved by CRISPR/Cas9 in tilapia. Lower gonadosomatic index (GSI), increased apoptosis of oocytes and spermatocytes and significantly reduced sperm quality were observed in dnmt3aa^−/− mutants, while normal gonadal development was observed in dnmt3ab^−/− mutants. Consistently, the expression of apoptotic genes was significantly increased in dnmt3aa^−/− mutants. In addition, the 5-methylcytosine (5-mC) level in dnmt3aa^−/− gonads was decreased significantly, compared with that of dnmt3ab^−/− and wild type (WT) gonads. Taken together, our results suggest that dnmt3aa, not dnmt3ab, plays important roles in maintaining gametogenesis in teleosts.     

Seasonal study of the lipid composition in different tissues of the common octopus (Octopus vulgaris)

Seasonal variation of octopus (Octopus vulgaris) lipid composition was investigated in four tissues: arm, mantle, ovary and digestive gland. A non‐homogeneous fat distribution was observed, with the digestive gland exhibiting a higher (p <0.05) lipid content than the other tissues. The ovary showed a higher (p <0.05) fat content than both muscle tissues, reaching its highest (p <0.05) value in winter. Neutral lipids – free fatty acids (FFA), triacylglycerols, and sterols (ST) – exhibited their highest (p <0.05) concentrations in the digestive gland and their lowest (p <0.05) values in muscle tissues. The phospholipid (PL) content of the ovary was the highest (p <0.05) of all tissues analysed, with the PL content also being significantly (p <0.05) higher in the digestive gland than in arm and mantle. The concentrations of most lipid classes (FFA, PL and ST) exhibited a seasonal variation. The fatty acid composition showed a remarkable difference between the digestive gland and all other tissues analysed. Thus, the digestive gland exhibited higher (p <0.05) contents in monounsaturated fatty acids and also lower (p <0.05) contents in both saturated (SFA) and polyunsaturated (PUFA) fatty acids. The highest mean values in SFA and PUFA were observed in ovary and muscle tissues, respectively. A seasonal effect was observed for SFA and PUFA.     

Fatty acid composition of French infant formulas with emphasis on the content and detailed profile oftrans fatty acids

The aim of the present study was to identify and quantitatetrans isomers of C18 fatty acids in some French infant formulas. Twenty powdered infant formulas were purchased in pharmacies and supermarkets in order to assess theirtrans mono- and poly-unsaturated fatty acids content. The fatty acid profiles were examined using methyl and isopropyl ester derivatives. The combination of gas-liquid chromatography, high-performance liquid chromatography, and silver nitrate thin-layer chromatography was needed to describe the detailed fatty acid compositions of the samples, includingtrans isomers of unsaturated C18 fatty acids. All the samples containedtrans isomers of C18∶1 acid (mean level 1.97±0.28% of total fatty acids), with vaccenic acid being generally the major isomer (15 out of 20 samples), thus indicating the origin from bovine milk. All the formulas also contained various isomers of linoleic and α-linolenic acids, but at lower levels.Trans PUFA isomers are the same as those present in deodorized oils. In conclusion, all the infant formulas analyzed in this study contained sometrans fatty acids, including isomers of essential fatty acids. This should be taken into account in the dietary intake of the newborn.     

Effect of chlorine dioxide treatment on lipid oxidation and fatty acid composition in salmon and red grouper fillets

Chlorine dioxide (CIO₂) has been explored as a potential substitute for aqueous chlorine to clean seafood products. In an attempt to understand the interaction of CIO₂ with organic compounds, duplicate fillets of Atlantic salmon (Salmo salar) and red grouper (Epinephelus morio) were treated for 5 min with freshly prepared aqueous CIO₂ at 20, 40, 100, and 200 ppm total available CIO₂ in 3.5% brine. Thiobarbituric acid (TBA) values and fatty acid composition were determined. CIO₂-treated salmon and red grouper showed a dose-related increase in TBA; the 100 and 200 ppm groups had significantly (P<0.05) greater TBA values than controls and the 20 ppm group. Treated red grouper and salmon did not differ in percentage monounsaturated and polyunsaturated fatty acids compared to controls, although differences occurred with some individual fatty acids. Thus, CIO₂ treatment did not greatly affect fatty acid composition of treated fillets.     

The impact of fatty acid profile on the physicochemical properties of commercial margarines in Brazil

This study aimed to evaluate how lipid profiles affect the physicochemical properties, fatty acid profiles, and nutritional qualities of Brazilian margarines. We analyzed the texture profiles of 13 margarine samples and characterized their fatty acid composition, solid fat content, crystallization kinetics by NMR and thermal behavior by differential scanning calorimetry. The samples had total fat content ranging from 20% to 82% and low trans fatty acid (TFA) levels, except for two samples (5–7% elaidic acid). The fatty acid compositions of all samples showed a predominance of linoleic (23%–46%), oleic (20%–46%), and palmitic acids (7%–14%), indicating that they were formulated with soybean and palm oils. Saturated fat content ranged from 23% to 31%. Compared to the other evaluated samples, those with higher content of lipid and saturated fatty acids (SFAs) exhibited increased hardness and stickiness but reduced spreadability and adhesiveness. The presence of TFAs resulted in increased plasticity of the samples. Reformulation resulted in products with greater SFA levels, which had a negative impact as it increased the atherogenic index (AI: 0.22–0.48). The HF55 sample contained canola oil-based fat and presented the best nutritional and physical properties. This study is the first to report a complete evaluation of representative margarines, with essential information in reformulating to achieve lower SFA.     

Dietary fatty acids influence the growth and fatty acid composition of the yellow mealworm <Emphasis Type="Italic">Tenebrio molitor</Emphasis> (Coleoptera: Tenebrionidae)

Fat is the second most abundant component of the nutrient composition of the mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) that represents also an interesting source of PUFA, especially n-6 and n-3 fatty acids, involved in prevention of cardiovascular diseases. This study investigated the possibility of modifying the fat content and the FA composition of yellow mealworms through feeding and how this would be influenced by developmental stages, pupal sex, and generation with the future aim of applying this coleopteran as a diet supplement for human health. Growth rate and cumulative mortality percentage on the different feeding substrates were also evaluated to select the optimal conditions for a mass-raising of this insect species. Despite the different fat content in the six different breeding substrates used, T. molitor larvae and pupae contained a constant fat percentage (>34% in larvae and >30% in pupae). A similar total fat content was found comparing larvae and male and female pupae of the second generation to those of the first generation. On the contrary, FA composition differed both in larvae and pupae reared on the different feeding substrates. However, the exemplars reared on the diets based on 100% bread and 100% oat flour showed SFA, PUFA percentages, and an n-6/n-3 ratio more suitable for human consumption; the diet based on beer yeast, wheat flour, and oat flour resulted in a contemporary diet that most satisfied the balance between a fat composition of high quality and favorable growth conditions.     

Effect of grass vs. concentrate feeding on the fatty acid profile of different fat depots in lambs

The aim of this study was to produce high‐quality meat from lambs under different feeding conditions, as measured by the accumulation of n‐3 fatty acids and conjugated linoleic acids (CLA) in muscle and subcutaneous fat. In total, 13 male crossbred lambs (Black Head×Gotland), each at 24 kg live weight, were divided into two feeding groups. Lambs were kept either on pasture (pasture grazing, n = 6) or in the stable (concentrate feeding, n = 7). The linolenic acid (C18:3n‐3) contained in the grass was absorbed and deposited into the different lipid classes of muscle and subcutaneous fat. The proportion of total n‐3 fatty acids in the different lipids of grazing lambs was significantly (p = 0.05) higher compared to that in concentrate‐fed lambs. The n‐6/n‐3 ratio (mean ± SEM) in muscle of grazing lambs was 1.2 ± 0.09 in contrast to 2.3 ± 0.09 (p = 0.05) of the animals kept in the stable. In subcutaneous fat, this ratio was 0.9 ± 0.2 in lambs kept on pasture versus 3.5 ± 0.2 (p = 0.05) after indoor keeping. The relative concentration of C18:1trans‐11 in total muscle lipids, phospholipids, triacylglycerols and subcutaneous fat was significantly increased by grass feeding compared to concentrate feeding. Significant influences of feeding were shown for saturated fatty acids. In concentrate‐fed lambs, a lower content of saturated fatty acids was detected. The proportion of CLAcis‐9,trans‐11 (1.9 ± 0.2% vs. 1.1 ± 0.1% in muscle, 2.5 ± 0.2% vs. 1.4 ± 0.2% in subcutaneous fat, 0.7 ± 0.04% vs. 0.4 ± 0.04% in phospholipids) in lambs was significantly (p = 0.05) higher after grazing than after concentrate feeding, respectively.     

Assessment of the effects of sex and harvesting season on lipid and fatty acid composition of Sparidae species

In the present study, the lipid amount and fatty acid profile of different Sparidae species, including gilthead seabream, juvenile gilthead seabream, annular seabream, white seabream, common two-banded seabream were evaluated. Fish were seasonally collected from Köyceğiz Lagoon (Muğla, South Western Turkey) from June 2018 to June 2019 and after collection, the sex of each specimen was recorded. According to the results of the study, the highest lipid amount was found in female annular seabream individuals as 8.09 ± 0.78% in November and the lowest lipid amount was found in male juvenile gilthead seabream as 0.98 ± 0.12% in March. Palmitic acid and oleic acid were determined as the most abundant SFA and MUFA for all species, respectively. The highest value of DHA, which was the predominant PUFA was assessed as 15.33 ± 0.26% in female white seabream in November whereas the lowest value (3.83 ± 0.36%) was found in gilthead seabream in December. The n-6/n-3 ratio was determined between 0.27 ± 0.00 (for male common two-banded seabream in July)-1.20 ± 0.03 (for male gilthead seabream in December) and it followed within the range of healthy values for all species. As a conclusion, it was found that values of lipid and fatty acid profiles among the examined Sparidae species vary among the season of collection. The results of the study gave the seasonal nutritional values of four economically-important Sparidae species that being rich in healthy polyunsaturated fatty acids such as DHA, have beneficial in human nutrition.     

Knockout of KASIII regulation changes fatty acid composition in canola (Brassica napus)

In contrast to the dominating unsaturated C₁₈ fatty acid, medium‐chain fatty acids (MCFA) are nearly absent in the oil of common canola. Modification of canola oil towards higher contents of C₈ to C₁₄ fatty acids would create new possibilities for oleo‐chemical usages, in both the nutritional and the non‐food sectors. For this purpose, spring oilseed rape (cv. ‘Drakkar’) was genetically modified by introduction of MCFA‐encoding genes from Cuphea species containing approximately 90% MCFA in their seed oil. Two different single constructs involving the 3‐ketoacyl‐acyl carrier protein synthase (KAS)III from C. lanceolata were used, one harbouring the wild‐type gene, ClKASIIIbwt, and the other containing the point‐mutated gene, ClKASIIIbmut, along with two double constructs containing ClKASIIIbmut in combination with a medium‐chain thioesterase gene from C. lanceolata (ClFatB3) or C. hookeriana (ChFatB2). For both single‐gene constructs, a phenotype with an increased content of MCFA was not detected; however, the ClKASIIIbwt transformants produced up to 6.7% palmitic acid (C₁₆). In T2 seeds bearing the ClKASIIIbmut/ClFatB3 double‐gene construct, contents of up to 2.9% capric (C₁₀) and 11.4% palmitic acid were achieved. The best transformant with the gene construct ClKASIIIbmut/ChFatB2 contained 1.4% caprylic acid (C₈) and 7.9% C₁₀, and these results were confirmed in T3 seeds.     

Effect of fatty acid positional distribution and triacylglycerol composition on lipid by-products formation during heat treatment: II. Trans isomers

This study examined the effect of the fatty acid positional distribution and of the triacylglycerol (TG) composition on heat-induced trans isomerization of linoleic and linolenic acids. For this, we synthesized diacid TG molecules that were acylated only with linoleic acid (L) or with linolenic acid (Ln) along with palmitic acid (P). The fatty acid of interest was positioned either in the central position (PLP and PLnP, respectively) or in one of the two outer positions (PPL and PPLn, respectively). Monoacid TG, i.e., trilinolein and trilinolenin, were also synthesized and mixed with tripalmitin in a 1:2 ratio. This model TG was also compared to another TG model, which consisted of a canola oil and its randomized counterpart whose fatty acid positional distribution and TG composition were determined by means of high-performance liquid chromatography. After heating, the content of trans isomers was determined by gas-liquid chromatography with a polar capillary column. In model TG, polyunsaturated fatty acids in monoacid TG (LLL and LnLnLn) exhibited the highest degree of isomerization, compared to diacid TG, and this effect was greatest at 220°C. At this temperature, an effect of the TG structure was observed only with linolenic acid. In that situation, 18:3n-3 acylated in the central position of the TG molecule (PLnP) displayed the highest sensitivity to trans geometrical isomerization. Although to a lesser extent, the same trends as for the pure TG model were observed with the canola oil model with regard to the influence of the fatty acid positional distribution and TG molecular species.     

Effect of fatty acid positional distribution and triacylglycerol composition on lipid by-products formation during heat treatment: II. Trans isomers

This study examined the effect of the fatty acid positional distribution and of the triacylglycerol (TG) composition on heat-induced trans isomerization of linoleic and linolenic acids. For this, we synthesized diacid TG molecules that were acylated only with linoleic acid (L) or with linolenic acid (Ln) along with palmitic acid (P). The fatty acid of interest was positioned either in the central position (PLP and PLnP, respectively) or in one of the two outer positions (PPL and PPLn, respectively). Monoacid TG, i.e., trilinolein and trilinolenin, were also synthesized and mixed with tripalmitin in a 1:2 ratio. This model TG was also compared to another TG model, which consisted of a canola oil and its randomized counterpart whose fatty acid positional distribution and TG composition were determined by means of high-performance liquid chromatography. After heating, the content of trans isomers was determined by gas-liquid chromatography with a polar capillary column. In model TG, polyunsaturated fatty acids in monoacid TG (LLL and LnLnLn) exhibited the highest degree of isomerization, compared to diacid TG, and this effect was greatest at 220°C. At this temperature, an effect of the TG structure was observed only with linolenic acid. In that situation, 18:3n-3 acylated in the central position of the TG molecule (PLnP) displayed the highest sensitivity to trans geometrical isomerization. Although to a lesser extent, the same trends as for the pure TG model were observed with the canola oil model with regard to the influence of the fatty acid positional distribution and TG molecular species.     

Identification of nine acetylenic fatty acids, 9-hydroxystearic acid and 9,10-epoxystearic acid in the seed oil ofJodina rhombifolia hook et arn. (Santalaceae)

In addition to some usual fatty acids, the seed oil ofJodina rhombifolia (Santalaceae) contains nine acetylenic fatty acids [9-octadecynoic acid (stearolic acid) (1.1%),trans-10-heptadecen-8-ynoic acid (pyrulic acid) (20.1%), 7-hydroxy-trans-10-heptadecen-8-ynoic acid (2.3%),trans-10,16-heptadecadien-8-ynoic acid (0.7%), 7-hydroxy-trans-10,16-heptadecadien-8-ynoic acid (0.1%),trans-11-octadecen-9-ynoic acid (ximenynic acid) (20.3%), 8-hydroxy-trans-11-octadecen-9-ynoic acid (12.2%),trans-11,17-octadecadien-9-ynoic acid (1.5%), 8-hydroxy-trans-11,17-octadecadien-9-ynoic acid (1.3%), 9-hydroxystearic acid (<0.1%) and 9,10-epoxystearic acid (0.7%)]. The fatty acids have been analyzed by gas chromatography/mass spectrometry of their methyl ester and 4,4-dimethyloxazoline derivatives. The hydroxy fatty acid methyl esters have been examined also as trimethyl-silyl ethers. Furthermore, the fatty acid methyl esters (FAME) have been fractionated according to their polarity (FAME-A: nonhydroxy; FAME-B: hydroxy fatty acids) and to their degree of unsaturation (FAME-A1/A2; FAME-B1/B2) by preparative thin-layer chromatography and argentation chromatography, respectively. All of these fractions have been analyzed by ultraviolet and infrared spectroscopy, and the fractions FAME-A and FAME-B have been analyzed further by nuclear magnetic resonance (¹H,¹³C, 2D H/C, attached proton test) spectroscopy and gas chromatography/mass spectrometry. This work is dedicated to the 65th birthday of Prof. Dr. K. Pfeilsticker, Institut of Food Science, University Bonn (Germany).     

The influence of temperature on the growth and fatty-acid composition of Skeletonema costatum in a batch photobioreactor

The influence of temperature on the growth and fatty-acid composition of the microalga Skeletonema costatum (CCAP 1077/b) has been studied. The maximum specific rates of growth (μ_m) and productivity (P_B) were reached between 293 and 298 K. The experimental values of μ_m–T were adjusted to the function: μ = μ′_o · T · exp(-E_a/RT) ? μ_d · exp(-E_d/RT). The total content of the saturated acids reached a minimum at 293 K, wheras the maximum amounts of polyunsaturated acids and Σn ? 3 HUFA (highly unsaturated n ? 3 fatty acids) occurred at 293 and 295·5 K, respectively.     

Effect of dietary lipids on fatty acid composition of body lipid in rainbow trout (Salmo gairdneri)

Three isocaloric diets were prepared. Diet 1 (Control) contained 22% herring oil. In diets 2 and 3, a third and a half of the herring oil was replaced, respectively, by an animal fat (lard) which contained a high percentage of saturated fatty acids. Each diet was fed to duplicate groups of rainbow trout for 14 wk. The results of the feeding trial indicated that the concentration of the saturated fatty acids in trout body lipid did not increase despite the high concentration of these fatty acids in Diets 2 and 3. Fish growth, feed efficiency, mortality and the level of fatty acid deposited in fish body lipid and phospholipids are discussed. Technical Paper No. 4440, Oregon Agricultural Experiment Station, Oregon State University, Corvallis, OR 97331.     

Effects of different nitrogen doses on thymoquinone and fatty acid composition in seed oil of black cumin (Nigella sativa L.)

Black cumin, Nigella sativa L. belonging to Ranunculaceae, is a valuable medicinal plant because of the curative effects of seed and oil. Despite studies on black cumin, there are few studies on the effects of nitrogen on fatty acid composition, no records on thymoquinone yield, and the thymoquinone content of the seed oil. In this study, the effects of different nitrogen doses on the seed oil yield, thymoquinone ratio/yield, and fatty acid compositions were investigated. Field studies with nitrogen doses (0, 40, 60, 80, and 100 kg/ha) were studied using the randomized plot design. As a result of the research, nitrogen doses significantly affected the oil and thymoquinone yields while insignificant on the thymoquinone ratio. The highest oil yield with 501.6 kg/ha was obtained from 80 kg/ha of the nitrogen doses, while the highest thymoquinone yield with 10.24 kg/ha was obtained from the control plots. Thymoquinone yields were in the same statistical group with other nitrogen doses, except for means of 100 kg/ha nitrogen doses. Linoleic, oleic, and palmitic acids were major fatty acids of black cumin, and their variations were insignificant in nitrogen applications. The values of butyric, capric, and linolenic acids varied significantly in different nitrogen doses. As a result of the study, it was determined that the highest oil yield was obtained from 80 kg/ha nitrogen application. It has been determined that nitrogen doses above 60–80 kg/ha should be avoided for the seed oil and thymoquinone yields in black cumin.