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FA Composition (fa + composition)
Selected AbstractsHow well can the fatty acid content of lake seston be predicted from its taxonomic composition?FRESHWATER BIOLOGY, Issue 9 2010A. BEC Abstract 1. Results from the few field studies that have tried to relate seston taxonomic and fatty acid (FA) composition suggest that phytoplankton composition only partially explains seston FA composition. However, in these studies, the heterotrophic components of seston (i.e. bacteria and heterotrophic protists) have not been accounted for. 2. The general premise of this article was that including the contribution of heterotrophs to seston biomass can improve understanding of the variability in seston FA composition. This was tested for an oligotrophic clearwater lake, in which the taxonomic and FA compositions of seston, fractionated into three size classes, were monitored every 2 weeks over a growth season. The relationship between seston taxonomic and FA composition was studied using canonical correlation analyses. 3. Because of their relative richness in branched FA and lack of highly unsaturated FAs (HUFA) compared to autotrophs and other protists, the contribution of bacteria to seston biomass was shown to explain an important part of the differences in FA composition between the different seston size classes. Phytoplankton seasonal succession also affected the FA composition of seston but only for size classes that were dominated by autotrophs. 4. The results also indicated that heterotrophic protists such as ciliates and heterotrophic nanoflagellates might substantially influence the seston FA, and especially, HUFA, composition. 5. The per cent of variability in seston FA composition that was explained by its taxonomic composition was still relatively low, even when taking account of heterotrophs. Hence, other possible influences, such as phytoplankton species composition, physiological state and the contribution of terrestrial detritus, need investigation. [source] Composition and Oxidative Stability of a Structured Lipid from Amaranth Oil in a Milk-Based Infant FormulaJOURNAL OF FOOD SCIENCE, Issue 2 2010Ashanty M. Pina-Rodriguez ABSTRACT:, Amaranth oil can be enzymatically modified to match breast milk fat analog requirements. We have developed a structured lipid (SL) from amaranth oil that, in combination with milk fat, delivers recommended amounts of docosahexaenoic acid (DHA) with palmitic acid specifically esterified at the,sn- 2 position of the triacylglycerol (TAG) backbone. The aim of this study was to study the final fatty acid (FA) contribution and oxidation stability of an infant formula prepared using the structured lipid DCAO (DHA-containing customized amaranth oil). DCAO was included as complementary fat in a "prototype" infant formula, and prepared in parallel with a "control" infant formula under the same processing conditions. The same ingredients but different complementary fat sources were used. A blend of the most commonly used vegetable oils (palm olein, soybean, coconut, and high-oleic sunflower oils) for infant formula was used instead of DCAO in the "control" formula. Additionally, "prototype" and "control" infant formulas were compared to a "commercial" product in terms of FA composition. The oxidative stability index (OSI) of the extracted fats from "prototype,""control," and "commercial" infant formulas were evaluated and compared to the OSI of the substrate fat replacers used. DCAO was the least stable compared to other fat analogs. The use of commercial antioxidants in DCAO containing products should prevent oxidation and therefore increase their stability. [source] Quantitative Lipid Metabolomic Changes in Alcoholic Micropigs With Fatty Liver DiseaseALCOHOLISM, Issue 4 2009Angela M. Zivkovic Background:, Chronic ethanol consumption coupled with folate deficiency leads to rapid liver fat accumulation and progression to alcoholic steatohepatitis (ASH). However, the specific effects of alcohol on key liver lipid metabolic pathways involved in fat accumulation are unknown. It is unclear whether lipid synthesis, lipid export, or a combination of both is contributing to hepatic steatosis in ASH. Methods:, In this study we estimated the flux of fatty acids (FA) through the stearoyl-CoA desaturase (SCD), phosphatidylethanolamine- N -methyltransferase (PEMT), and FA elongation pathways in relation to liver triacylglycerol (TG) content in Yucatan micropigs fed a 40% ethanol folate-deficient diet with or without supplementation with S -adenosyl methionine (SAM) compared with controls. Flux through the SCD and PEMT pathways was used to assess the contribution of lipid synthesis and lipid export respectively on the accumulation of fat in the liver. Liver FA composition within TG, cholesterol ester (CE), phosphatidylethanolamine, and phosphatidylcholine classes was quantified by gas chromatography. Results:, Alcoholic pigs had increased liver TG content relative to controls, accompanied by increased flux through the SCD pathway as indicated by increases in the ratios of 16:1n7 to 16:0 and 18:1n9 to 18:0. Conversely, flux through the elongation and PEMT pathways was suppressed by alcohol, as indicated by multiple metabolite ratios. SAM supplementation attenuated the TG accumulation associated with alcohol. Conclusions:, These data provide an in vivo examination of liver lipid metabolic pathways confirming that both increased de novo lipogenesis (e.g., lipid synthesis) and altered phospholipid metabolism (e.g., lipid export) contribute to the excessive accumulation of lipids in liver affected by ASH. [source] Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the AzoresJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2008Oldemiro A Rego Abstract BACKGROUND: Season of the year associated with dietary changes has been recognized as a factor implicated in milk fat fatty acid (FA) profile in dairy cows. However, a lack of information exists concerning cows grazing all year round as is practiced in the Azores, where cows are supplemented in winter with maize silage plus concentrates, while in spring the higher grass allowance only requires supplementation with concentrate. The main objective of this study was to detect any seasonal variation of FA profile of milk fat from milk sampled in bulk tanks of 12 Azorean dairy herds. RESULTS Compared to winter milk, milk fat from spring presented a higher proportion of CLA cis -9,trans -11 (14.3 versus 9.6 g kg,1 FA), C18:1 trans -11 (32 versus 22 g kg,1 FA), C18:2 trans -11,cis -15 (3.7 versus 2.2 g kg,1 FA), CLA trans -11,cis -13 (0.34 versus 0.23 g kg,1 FA) and C18:3 n-3 (5.7 versus 5.4 g kg,1 FA). The C18:2 n-6/C18:3 n-3 ratio was lower (P < 0.05) in spring. Branched-chain FA, except the anteiso -C15:0, were higher in spring, while odd-chain FA (C15:0) were higher in winter. CONCLUSION: Dairy herd management in the Azores presents a seasonal variation of milk fat FA composition, where the spring milk may present increased potential benefits for human consumers. Copyright © 2008 Society of Chemical Industry [source] Plasma lipids and inflammation in active inflammatory bowel diseasesALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2009G. ROMANATO Summary Background, Ulcerative colitis (UC) and Crohn's disease (CD) can cause metabolic and inflammatory alterations. Aim, To evaluate the relationships between inflammatory parameters, plasma lipids and phospholipid fatty acid (FA) composition in patients with active UC and CD. Methods, Diet, the Harvey,Bradshaw Activity Index (HBAI), inflammatory parameters, lipoproteins and FA composition were assessed in 60 CD and 34 UC. Results, No differences in clinical parameters were observed in the two groups. Total cholesterol correlated inversely with the number of bowel movements in both groups and directly with BMI in UC. Arachidonic acid correlated inversely with HBAI in UC and total and HDL cholesterol were inversely related to C-reactive protein (CRP) in CD while HDL correlated with CRP in UC. Docosapentaenoic acid was the only polyunsaturated n -3 FA that was correlated to CRP in both groups. Total cholesterol was independently associated in the multiple regression analysis with the number of bowel movements and systemic inflammation. Conclusions, Total and LDL cholesterol were lower in the active UC and CD than in the healthy subjects and were correlated with the systemic inflammatory status. Phospholipid FA composition was correlated to the systemic inflammatory status, but was unrelated to dietary intake and intestinal disease activity. [source] Rapid analysis of Jatropha curcas gene functions by virus-induced gene silencingPLANT BIOTECHNOLOGY JOURNAL, Issue 9 2009Jian Ye Summary Jatropha curcas L. is a small, woody tree of the Euphorbiaceae family. This plant can grow on marginal land in the tropical and subtropical regions and produces seeds containing up to 30% oil. Several Asian countries have selected Jatropha for large scale planting as a biodiesel feedstock. Nevertheless, Jatropha also possesses several undesirable traits that may limit its wide adoption. An improved understanding of plant development and the regulation of fatty acid (FA) and triacylglyceride biosynthesis in Jatropha is particularly facilitative for the development of elite crops. Here, we show that a tobacco rattle virus (TRV) vector can trigger virus-induced gene silencing (VIGS) in Jatropha. Our optimized method produced robust and reliable gene silencing in plants agroinoculated with recombinant TRV harbouring Jatropha gene sequences. We used VIGS to investigate possible functions of 13 Jatropha genes of several functional categories, including FA biosynthesis, developmental regulation and toxin biosynthesis, etc. Based on the effects of VIGS on the FA composition of newly emerged leaves, we determined the function of several genes implicated in FA biosynthesis. Moreover, VIGS was able to discriminate independent functions of related gene family members. Our results show that VIGS can be used for high-throughput screening of Jatropha genes whose functions can be assayed in leaves. [source] A 10-kDa acyl-CoA-binding protein (ACBP) from Brassica napus enhances acyl exchange between acyl-CoA and phosphatidylcholinePLANT BIOTECHNOLOGY JOURNAL, Issue 7 2009Olga P. Yurchenko Summary The gene encoding a 10-kDa acyl-CoA-binding protein (ACBP) from Brassica napus was over-expressed in developing seeds of Arabidopsis thaliana. Biochemical analysis of T2 and T3 A. thaliana seeds revealed a significant increase in polyunsaturated fatty acids (FAs) (18:2cis,9,12 and 18:3cis,9,12,15) at the expense of very long monounsaturated FA (20:1cis,11) and saturated FAs. In vitro assays demonstrated that recombinant B. napus ACBP (rBnACBP) strongly increases the formation of phosphatidylcholine (PC) in the absence of added lysophosphatidylcholine in microsomes from ,YOR175c yeast expressing A. thaliana lysophosphatidylcholine acyltransferase (AthLPCAT) cDNA or in microsomes from microspore-derived cell suspension cultures of B. napus L. cv. Jet Neuf. rBnACBP or bovine serum albumin (BSA) were also shown to be crucial for AthLPCAT to catalyse the transfer of acyl group from PC into acyl-CoA in vitro. These data suggest that the cytosolic 10-kDa ACBP has an effect on the equilibrium between metabolically active acyl pools (acyl-CoA and phospholipid pools) involved in FA modifications and triacylglycerol bioassembly in plants. Over-expression of ACBP during seed development may represent a useful biotechnological approach for altering the FA composition of seed oil. [source] Expression of a cDNA encoding palmitoyl-acyl carrier protein desaturase from cat's claw (Doxantha unguis-cati L.) in Arabidopsis thaliana and Brassica napus leads to accumulation of unusual unsaturated fatty acids and increased stearic acid content in the seed oilPLANT BREEDING, Issue 2 2007M. Bondaruk Abstract A cDNA encoding palmitoyl-acyl carrier protein (ACP)-desaturase from cat's claw (Doxantha unguis-cati L.) was expressed in Arabidopsis thaliana and Brassica napus L. with the goal of decreasing the saturated fatty acid (FA) content of the seed oil. In general, transformation of Arabidopsis resulted in a greater change in the FA composition of the seed oil than for B. napus. An increase in palmitoleic acid (16:1cis,9) was obtained in transgenic lines, suggesting that the 16:0-ACP-desaturase cDNA was expressed in the manner originally intended. Other effects on lipid metabolism, however, were observed in the seed of transgenic plants. In Arabidopsis, there was a large increase in the proportions of cis -vaccenic acid (18:1cis,11) and cis -13-eicosenoic acid (20:1cis,13), possibly generated through elongation of 16:1cis,9. Elongation of 18:1cis,11 to 20:1cis,13, however, was not observed in B. napus indicating that certain aspects of lipid metabolism in the model plant, Arabidopsis, may not apply to B. napus. As well, the appearance of 18:1cis,11 was accompanied by a decrease in the proportion of oleic acid (18:1cis,9). Although the introduced ACP-desaturase resulted in synthesis of some unsaturated FAs, the overall saturated FA content was maintained at similar levels to the control or was enhanced. Increased levels of saturation were mainly associated with an increase in stearic acid, which unlike 16:0, is considered non-atherogenic. The results suggest that a mechanism exists further downstream in oil biosynthesis to counteract the decrease in saturation brought about by the 16:0-ACP-desaturase action. [source] The identification of QTL that affect the fatty acid composition of milk on sheep chromosome 11ANIMAL GENETICS, Issue 3 2010M. García-Fernández Summary In this work, we analysed 11 genetic markers localized on OAR11 in a commercial population of Spanish Churra sheep to detect QTL that underlie milk fatty acid (FA) composition traits. Following a daughter design, we analysed 799 ewes distributed in 15 half-sib families. Eight microsatellite markers and three novel SNPs identified in two genes related to fatty acid metabolism, acetyl-CoA carboxylase , (ACACA) and fatty acid synthase (FASN), were genotyped in the whole population under study. The phenotypic traits considered in the study included 22 measurements related to the FA composition of the milk and three other milk production traits (milk protein percentage, milk fat percentage and milk yield). Across-family regression analysis revealed four significant QTL at the 5% chromosome-wise level influencing contents of capric acid (C10:0), lauric acid (C12:0), linoleic conjugated acid (CLA) and polyunsaturated fatty acids (PUFA) respectively. The peaks of the QTL affecting C10:0 and PUFA contents in milk map close to the FASN gene, which has been evaluated as a putative positional candidate for these QTL. The QTL influencing C12:0 content reaches its maximum significance at 58 cM, close to the gene coding for the glucose-dependent insulinotropic polypeptide. We were not able to find any candidate genes related to fat metabolism at the QTL influencing CLA content, which is located at the proximal end of the chromosome. Further research efforts will be needed to confirm and refine the QTL locations reported here. [source] Polymorphism of the pig acetyl-coenzyme A carboxylase , gene is associated with fatty acid composition in a Duroc commercial lineANIMAL GENETICS, Issue 4 2009D. Gallardo Summary Acetyl-coenzyme A carboxylase , (ACACA) catalyses the first committed step in the biosynthesis of long-chain fatty acids (FA) by converting acetyl-CoA into malonyl-CoA. In pigs, the ACACA gene maps to a chromosome 12 QTL with important effects on FA composition. In the present study, we have sequenced the coding region of the pig ACACA gene in 15 pigs, identifying 21 polymorphic sites that were either synonymous or non-coding. Ten of these SNPs segregated in a Duroc commercial population (n = 350) for which lipid metabolism and meat and carcass quality trait records were available. Significant associations were found between two linked single nucleotide polymorphisms (c.4899G>A and c.5196T>C) and percentages of carcass lean, intramuscular fat, monounsaturated, saturated (myristic, palmitic and stearic) and polyunsaturated (linoleic) FAs in the longissimus thoracis et lumborum muscle, along with serum HDL-cholesterol concentration. The most important allele substitution effects were observed for the polyunsaturated/saturated FA ratio (13,21% of the phenotypic mean) as well as for the percentages of ,-6 and polyunsaturated FAs, especially linoleic acid (7,16% of the phenotypic mean). These results suggest the existence of a causal mutation, mapping to the chromosomal region containing the pig ACACA gene, with marked effects on FA composition of meat. [source] Changes in lipid content, fatty acid composition and lipid class composition of eggs and developing larvae (0,40 days old) of cultured common dentex (Dentex dentex Linnaeus 1758)AQUACULTURE NUTRITION, Issue 4 2008G. GIMÉNEZ Abstract Total lipid content, fatty acid (FA) composition and lipid class composition of common dentex eggs spawned at different times and larvae reared under different culture conditions until 40 days posthatch (dph) were analysed to get a general pattern of lipid composition during larval development. Two groups of larvae were kept under starvation to compare their FA composition with that obtained from normally fed larvae. To compare FA use or accumulation during larval development, results were grouped according to the developmental stage of the larvae instead of age in days posthatch. Saturated and monounsaturated FAs decreased along larval development, while polyunsaturated fatty acid (PUFA) content increased. The ratio of docosahexaenoic acid (DHA)/eicosapentaenoic acid shifted from 4 to 5 in early developmental stages to lower than 1 after metamorphosis. Arachidonic acid levels remained constant along larval development. Larvae kept 6 days under starvation consumed most of their n-3 PUFA while conserving the DHA to values at day 0. The results presented here are useful for the design of nutritional experiments, because there were differences detected in terms of lipid and FA composition between developmental stages with higher differences mainly found in first-feeding larvae and early developmental stages. [source] Dietary n-3/n-6 ratio affects the biochemical composition of Eurasian perch (Perca fluviatilis) semen but not indicators of sperm qualityAQUACULTURE RESEARCH, Issue 9 2010Emilie Henrotte Abstract In general, the effects of dietary fatty acids (FA) on sperm quality have received less attention than egg quality, and were never studied in perch. This study investigated the effects of dietary FAs on the quality and chemical composition of sperm in Eurasian perch (Perca fluviatilis). Two experimental diets containing 16% lipids and 45% proteins were compared. The n-3/n-6 ratios tested were 0.2 for diet 1 (D1) and 7.0 for diet 2 (D2). No significant effects of the n-3/n-6 ratio were observed on the sperm characteristics, either in terms of the sperm volume (around 1.2 mL) and density, spermatozoa motility (94%) and velocity, or the sperm osmolality. All these parameters corresponded to semen of good quality in Eurasian perch. Interestingly, both the FA composition and the lipid class profile of the semen were correlated to the tested diet. However, basal levels of certain highly unsaturated FAs such as eicosapentaenoic acid, 20:5 n-3 and docosahexaenoic acid, 22:6 n-3, were maintained in the sperm irrespective of the diet tested. Perch semen was characterized by high levels of cholesterol, phosphatidylethanolamine and phosphatidylcholine. In conclusion, the dietary n-3/n-6 ratio affects the lipid composition of perch semen but not the indicators of sperm quality. [source] Egg and larval quality, and egg fatty acid composition of Eurasian perch breeders (Perca fluviatilis) fed different dietary DHA/EPA/AA ratiosAQUACULTURE RESEARCH, Issue 9 2010Emilie Henrotte Abstract In Eurasian perch (Perca fluviatilis), the variability in spawning quality is a major limiting factor for successful production, especially when breeders are fed with an artificial diet. The influence of the dietary DHA/EPA/AA ratio on the egg and larval quality and on the fatty acid and lipid class composition of eggs has been investigated in perch broodstock. Two experimental diets (16% lipids) with two different DHA/EPA/AA ratios, D1 (3/2/2) and D2 (23/9/1), were compared with a natural diet consisting of cultured carp juveniles, CC (10/10/1) and with a commercial diet for salmonids, CDS (14/16/1). Percentages of fertilization and hatching were comparable between fish fed D1, D2 and CC, with the highest hatching rate observed for D1 (63.5 ± 3.8%). These diets supported better values than the CDS. Larval survival and TL50 observed after osmotic stress were higher for the D1 group, followed by larvae produced by fish fed D2 and CC. Larvae from fish fed D1, D2 and CC were significantly more robust than larvae from the CDS group. Differences were observed regarding the fatty acid (FA) profile in the eggs, which was related to the dietary FA composition. The results indicate that a ratio of 3/2/2 seemed to be effective for obtaining eggs and larvae of good quality. [source] n-3 Fatty acid supplementation in burned paediatric patientsACTA PAEDIATRICA, Issue 12 2009MC Marín Abstract Aim:, To determine the effect of dietary supplementation with n-3 fatty acids (FA) in paediatric burned patients who had less than 20% of total body surface affected. Methods:, Burned patients were randomly assigned into two groups, one of them received a supplement of n-3 FA during 5 weeks; the other group was considered as not n-3 supplemented burned group. A third group of no burned patients was selected as control. Blood samples were collected at admission and in burned groups at the final of the study. Plasma and erythrocyte phospholipid FA composition and some biochemical parameters related to the clinical evolution: total plasma proteins and C3 and C4 complement proteins were determined. Results:, In the early post-burn patients, there is an increase in saturated and monounsaturated FAs in plasma phospholipids, and a decrease in polyunsaturated FAs compared with control. These alterations are in favour of proinflammatory response to burn injury. In n-3 FA supplemented group, these changes were further reverted, and a favourable response in the amount of total plasma proteins and in C3 and C4 proteins of the complement system was demonstrated. Conclusion:, Dietary n-3 FA supplementation might be beneficial for patients suffering thermal injury. [source] Fatty acid composition in breast milk and serum phospholipids of healthy term Chinese infants during first 6 weeks of lifeACTA PAEDIATRICA, Issue 11 2007YM Peng Abstract Aim: To compare the fatty acid (FA) pattern in early and mature breast milk with that in plasma phospholipids of cord blood and breast-fed infants. Methods: Forty-five mother,infant pairs from western Shanghai were studied. All infants, born at term with normal weight and length, were examined at birth and days 5 and 42. FA was analyzed by capillary gas,liquid chromatography. Results: Cord blood showed higher concentration of long-chain polyunsaturated FA (LCPUFA) but lower saturated (SFA) and monounsaturated (MUFA) FA than postnatal infants' plasma. SFA decreased with age in the infants, but MUFA and linoleic acid (LA, 18:2,6) increased. LCPUFA were lower in the plasma of 5-day-old infants than in cord blood, but LA was 80%, ,-linolenic acid (ALA, 18:3,3) 33% and the ratio ,-6/,-3 42% higher. At day 42, LA increased further, LCPUFA remained similar, and was in breast milk lower than at day 5, while ALA and ,-linolenic acid (18:3,6) were higher. The activity index of desaturases indicated high ,9 activity in breast milk and high activity of ,5 desaturase in the infants. Conclusion: Breast milk FA composition changed markedly from day 5 to 42 with increasing correlation to infants' plasma. Calculation of desaturase activities suggested high capacity of LCPUFA synthesis. [source] Dietary intervention increases n-3 long-chain polyunsaturated fatty acids in skeletal muscle membrane phospholipids of obese subjects.CLINICAL ENDOCRINOLOGY, Issue 2 2006Implications for insulin sensitivity Summary Objective, Cross-sectional studies suggest that the fatty acid (FA) composition of phospholipids in skeletal muscle cell membrane may modulate insulin sensitivity in humans. We examined the impact of a hypocaloric low-fat dietary intervention on membrane FA composition and insulin sensitivity. Design, Muscle membrane FA profiles were determined in muscle (vastus lateralis) biopsies from 21 obese subjects before and after 6 months of dietary restriction. Diet instructions emphasized low intake of FA of marine origin by recommending lean fish and prohibiting fatty fish and fish oil supplements. Insulin resistance was estimated by the homeostasis model assessment (HOMA-IR). Results, The mean weight loss was 5·1 kg (range ,15·3 to +1·3 kg). BMI decreased from 36·5 to 34·9 kg/m2 (P = 0·003). Saturated FA (SFA) decreased 11% (P = 0·0001). Polyunsaturated FA (PUFA)n-6 increased 4% (P = 0·003). Long-chain PUFAn-3 increased 51% (P = 0·0001), mainly due to a 75% increase (P < 0·0001) in docosahexaenoic acid. Changes in HOMA-IR correlated significantly with changes in long-chain PUFAn-3 (R = ,0·57, P < 0·01), SFA (R = 0·58, P < 0·01) and waist circumference (R = 0·46, P < 0·05). A multivariate linear regression analysis that included changes in weight, fat mass, waist circumference, plasma lipids, PUFA, SFA and long-chain PUFAn-3 indicated that SFA and long-chain PUFAn-3 were independent predictors of HOMA-IR (R2 = 0·33, P < 0·01). Conclusions, A hypocaloric low-fat dietary intervention programme increased incorporation of long-chain PUFAn-3 and reduced SFA in skeletal muscle membrane phospholipids of obese subjects, a setting that may impact on insulin action. [source] Factors influencing the fatty acid determination in fats and oils using Fourier transform near-infrared spectroscopyEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 9 2007Hormoz Azizian Abstract Fourier transform near-infrared (FT-NIR) technology is matrix dependent and thus highly dependent on factors that influence the absorption spectra. Ignoring these factors during the development of FT-NIR models will affect the accuracy and reliability of the classification of fats and oils and the determination of their fatty acid (FA) composition. Four factors were studied: the temperature at which samples are scanned, differences in FA chain length and number of double bonds, and the presence of non-triacylglycerol components. The results showed that an increase in the recording temperature decreased the absorption peak intensity, but not the position. FT-NIR spectral differences were linked to variations in molecular vibrations resulting from the number of carbon atoms or double bonds in the FA. The FT-NIR method could clearly differentiate between chain lengths from 10:0 to 18:0 and numbers of double bonds from zero (18:0) to three (18:3). Contaminants in triacylglycerols altered the FT-NIR spectra, resulting in increased errors in the FA content. An increased concentration of ,-sitosterol in triolein decreased or increased the observed contents of cis9-18:1 and cis11-18:1, respectively. An FT-NIR model adjusted for the phytosterol content corrected this discrepancy. The revised FT-NIR model was successfully used to provide the accurate FA compositions of commercial sunflower oils. [source] How well can the fatty acid content of lake seston be predicted from its taxonomic composition?FRESHWATER BIOLOGY, Issue 9 2010A. BEC Abstract 1. Results from the few field studies that have tried to relate seston taxonomic and fatty acid (FA) composition suggest that phytoplankton composition only partially explains seston FA composition. However, in these studies, the heterotrophic components of seston (i.e. bacteria and heterotrophic protists) have not been accounted for. 2. The general premise of this article was that including the contribution of heterotrophs to seston biomass can improve understanding of the variability in seston FA composition. This was tested for an oligotrophic clearwater lake, in which the taxonomic and FA compositions of seston, fractionated into three size classes, were monitored every 2 weeks over a growth season. The relationship between seston taxonomic and FA composition was studied using canonical correlation analyses. 3. Because of their relative richness in branched FA and lack of highly unsaturated FAs (HUFA) compared to autotrophs and other protists, the contribution of bacteria to seston biomass was shown to explain an important part of the differences in FA composition between the different seston size classes. Phytoplankton seasonal succession also affected the FA composition of seston but only for size classes that were dominated by autotrophs. 4. The results also indicated that heterotrophic protists such as ciliates and heterotrophic nanoflagellates might substantially influence the seston FA, and especially, HUFA, composition. 5. The per cent of variability in seston FA composition that was explained by its taxonomic composition was still relatively low, even when taking account of heterotrophs. Hence, other possible influences, such as phytoplankton species composition, physiological state and the contribution of terrestrial detritus, need investigation. [source] Effects of dietary protein, and fat level and rapeseed oil on growth and tissue fatty acid composition and metabolism in Atlantic salmon (Salmo salar L.) reared at low water temperaturesAQUACULTURE NUTRITION, Issue 4 2007V. KARALAZOS Abstract A 12-week feeding trial was conducted to elucidate the interactive effects of dietary fat, protein contents and oil source on growth, whole body proximate composition, protein productive value (PPV) and fatty acid (FA) composition of muscle and liver in Atlantic salmon (Salmo salar L.)` at low water temperatures (4.2 °C). Triplicate groups of Atlantic salmon (initial weight 1168 g) were fed six isoenergetic diets, formulated to provide either 390 g kg,1 protein and 320 g kg,1 fat (high-protein diets) or 340 g kg,1 protein and 360 g kg,1 fat (low-protein diets). Within each dietary protein/fat level, crude rapeseed oil (RO) comprised 0, 30 or 60% (R0, R30, R60, respectively) of the added oil. After 12 weeks, the overall growth and feed conversion ratio (FCR) were very good for all treatments [thermal growth coefficient (TGC): 4.76 (±0.23); FCR: 0.85 (±0.02)]. Significant effects were shown owing to the oil source on specific growth rate and TGC only. The liver and muscle FA compositions were highly affected by the graded inclusion of RO. The PPV was significantly affected by the dietary protein level. The results of this study suggest that more sustainable, lower protein diets with moderate RO inclusion can be used in Atlantic salmon culture at low water temperatures with no negative effects on growth and feed conversion, no major detrimental effects on lipid and FA metabolism and a positive effect on protein sparing. [source] | |||||||||||||||||||