Hypolipidemic Activity of Peony Seed Oil Rich in α‐Linolenic,is Mediated Through Inhibition of Lipogenesis and Upregulation of Fatty Acid β‐Oxidation

Peony seed oil (PSO) is a new resource food rich in α‐Linolenic Acid(ALA) (38.66%). The objective of this study was to assess the modulatory effect of PSO on lipid metabolism. Lard oil, safflower oil (SFO), and PSO were fed to wistar rats with 1% cholesterol in the diet for 60 d. Serum and liver lipids showed significant decrease in total cholesterol (TC), triglyceride (TG), and low density lipoprotein‐cholesterol (LDL‐C) levels in PSO fed rats compared to lard oil and SFO fed rats. ALA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), contents were significantly increased, whereas linoleic acid (LA), arachidonic acid (AA) levels decreased in serum and liver of PSO fed rats. Feeding PSO increased ALA level and decreased n‐6 to n‐3 polyunsaturated fatty acid (PUFA) ratio. The hypolipidemic result of PSO indicated that PSO participated in the regulation of plasma lipid concentration and cholesterol metabolism in liver. The decreased expression of sterol regulatory element‐binding proteins 1C (SREBP‐1c), acetyl‐CoA carboxylase (ACC), and fatty acid synthase (FAS)‐reduced lipid synthesis; Activation of peroxisome proliferator–activator receptor (PPARα) accompanied by increase of uncoupling protein2 (UP2) and acyl‐CoA oxidase (AOX) stimulated lipid metabolism and exerted an antiobesity effect via increasing energy expenditure for prevention of obesity.     

摄食不同来源磷脂对大鼠脂质代谢及脑内磷脂脂肪酸组成的影响

研究了摄食不同来源磷脂对大鼠脂质代谢及其脑内磷脂脂肪酸组成的影响。雄性SD大鼠按体重随机分为大豆油对照组(添加9%)、牛乳磷脂组(添加5%)、大豆磷脂组(添加5%)、蛋黄磷脂组(添加5%),喂食3周。检测了血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、游离脂肪酸(FFA)及肝脏TC、TG、磷脂(PL)的含量,并用气相色谱法测定了脑内磷脂脂肪酸的组成变化。结果显示:与大豆油对照组相比,3种磷脂均不同程度提高了大鼠体重、脏器指数,蛋黄磷脂效果显著;3种磷脂不同程度降低了血清TC、TG和FFA含量,牛乳磷脂降低血清FFA显著,大豆磷脂降低血清TC、TG显著,蛋黄磷脂降低FFA显著,大豆磷脂显著提升了血清HDL-C含量;3种磷脂不同程度降低了肝脏TC、TG、PL含量,牛乳磷脂与大豆磷脂降低肝脏TG、TC显著,而蛋黄磷脂降低肝脏TG显著;3种磷脂对脑内磷脂脂肪酸组成的影响各不相同,牛乳磷脂显著提高了脑内磷脂饱和脂肪酸含量,而大豆磷脂和蛋黄磷脂提高了DHA等多不饱和脂肪酸含量。研究表明,3种磷脂均有降血脂、肝脂作用,以大豆磷脂作用尤为明显,大豆磷脂和蛋黄磷脂的益智作用可能优于牛乳磷脂。     

Effect of lycopene on biomarkers of oxidative stress in rats supplemented with ω−3 polyunsaturated fatty acids

Eicosapentaenoic (C20:5 n−3, EPA) and docosahexaenoic (C22:6 n−3, DHA) fatty acids are highly susceptible to lipid oxidation and may contribute to oxidative stress. The purpose of this study was to evaluate if a diet rich in EPA and DHA could promote higher oxidation in both plasma and brain tissue of rats and if lycopene supplementation could revert the oxidation biomarkers to their baseline levels. Wistar rats were divided into four groups (7 rats/group): SOY group received AIN93M diet containing 8% soybean oil for 21 days; OMEGA group received 8% fish oil containing 2% EPA and 1% DHA instead of soybean oil for 21 days; OMEGA-L0.5 and OMEGA-L50 groups were fed a diet containing 8% fish oil for 11 days followed by lycopene supplementation (5 and 500 mg/kg diet, respectively) for 10 more days. The brain homogenate oxidation measured by TBARS suggested that supplementation with EPA and DHA reduced the oxidation rate and this effect was suppressed by lycopene at both concentrations. Antioxidant capacity measured by DPPH method in plasma of groups supplemented with EPA and DHA was nil while in SOY group it was 21.4%. Lycopene was not detected in the plasma of the animals. It is likely that antioxidants present in plasma have been depleted to keep malondialdehyde concentration measured by TBARS unchanged. Both plasma malondialdehyde concentration and antioxidant activity of groups with and without lycopene supplementation did not differ. Hence, diets rich in EPA and DHA did not promote higher oxidation in rat brain homogenate but reduced plasma antioxidant capacity. Lycopene did not show antioxidant plasma protection at both doses. Taking into account that plasma α-tocopherol concentration did not change among the groups and that rats synthesize ascorbic acid, additional research should be carried out to identify the oxidative results observed in this study.     

Mechanisms of Docosahexaenoic and Eicosapentaenoic Acid Loss from Pacific Saury and Comparison of Their Retention Rates after Various Cooking Methods

The docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) contents of Pacific saury (Cololabis saira), a fatty fish and staple of the Japanese diet, have been reported to decrease after cooking. This study compared the DHA and EPA contents remaining in saury after grilling, pan‐frying or deep‐frying to center temperatures of 75, 85, or 95 °C, and examined physical loss, lipid oxidation, and thermal degradation as mechanisms of DHA and EPA loss. Temperature changes inside the saury were monitored using thermocouples, while DHA and EPA contents, oxygen radical absorbance capacity, and measurements of lipid oxidation (that is, carbonyl value and thiobarbituric acid value) were determined chemically. Visualization of temperature distribution inside fish samples during cooking revealed large differences in heat transfer among cooking methods. True retention rates in grilled (DHA: 84 ± 15%; EPA: 87 ± 14%) and pan‐fried samples (DHA: 85 ± 16%; EPA: 77 ± 17%) were significantly higher than deep‐fried samples (DHA: 58 ± 17%; EPA: 51 ± 18%), but were not affected by final center temperatures despite differences in cooking times. Physical loss via cooking losses (grilling and pan‐frying) or migration into frying oil (deep‐frying) accounted for large quantities of DHA and EPA loss, while lipid oxidation and thermal degradation did not appear to be major mechanisms of loss. The antioxidant capacity of saury was not significantly affected by cooking treatments. The results of this study suggest that minimization of physical losses during cooking may increase DHA and EPA contents retained in cooked Pacific saury.     

Restoration of EPA and DHA in rainbow trout (Oncorhynchus mykiss) using a finishing fish oil diet at two different water temperatures

Feeding fish a fish oil finishing diet (FOFD) after grow-out on vegetable oil diet is one strategy to restore eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels. We investigated restoration of EPA and DHA in rainbow trout fed a FOFD preceded by a grow-out period on 50% or 75% palm fatty acid distillate (PFAD) diets at optimal (15 °C) or elevated (20 °C) water temperatures. Using the FOFD restored EPA and DHA in fillet and whole carcass of fish previously fed either 50% PFAD diet from 85% to 98% or 75% PFAD from 66% to 93% of values obtained for fish fed FO diet throughout. Water temperature did not influence EPA and DHA restoration. Growing rainbow trout with diets where FO was replaced by either 50% or 75% PFAD followed by a FOFD reduced FO usage by around 30% and 44% at 15 °C, respectively, and 32% and 48% at 20 °C, respectively.     

Efficacy of silkworm (Bombyx mori L.) chrysalis oil as a lipid source in adult Wistar rats

The effects of silkworm chrysalis oil, rich in n-3 α-linolenic acid (ALA), on lipid metabolism in Wistar rats were investigated. The rats were fed diets containing 7% soybean oil (control), silkworm chrysalis oil (SWO), or fish oil (FO) for 8 weeks. Plasma triglyceride and glucose levels were significantly lower in the SWO group after 8 weeks compared to the control and FO groups. The total cholesterol and blood urea nitrogen levels were higher in the control group than in the SWO and FO groups at 8 weeks post-consumption. However, aspartate amino transferase and alanine amino transferase levels were not significantly different among all groups. A higher arachidonic acid (AA) content was detected in the control group, while lower AA levels were observed with the increase in EPA and DHA in the SWO and FO groups. These results suggest that n-3 α-linolenic acid-rich silkworm chrysalis oil can improve hyperlipidaemia and hyperglycaemia.     

Screening for yeasts incorporating the exogenous eicosapentaenoic and docosahexaenoic acids from crude fish oil

The screening for yeasts incorporating exogenous eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) into their cellular lipids was conducted. Two percent of oil from fish scraps was added to a yeast isolation medium as a sole carbon source. From 143 soil samples, we isolated 23 yeast strains, nine of them were found to be capable of quickly assimilating the scrap fish oil. These nine strains, in addition to four previously isolated triglyceride-assimilating and lipase-producing strains, Yarrowia lipolytica and three Geotrichum species (FO274A, FO347-2 and FO401B), were cultured in a growth medium at 30 degrees C. Strains FO726A, FO765A and FO347-2 were selected on the basis of dry cell weight production and ability to store EPA and DHA in their cells, and their performance was further compared by varying cultivation temperature and time. From 1 g of the scrap fish oil, FO726A yielded 620 mg of dry cells, containing 47.1% lipid, 38.1% triglyceride, 3.3% EPA, and 4.9% DHA, when cultured at 25 degrees C for 36 h. Strain FO726A apparently has the highest ability to incorporate EPA and DHA into its cellular lipids. Results from further experiments showed that the incorporated EPA and DHA mainly existed in the form of triglyceride in the FO726A cell. These results suggest that FO726A is suitable for the production of cell mass rich in EPA and DHA for feed.     

Effects of Trans and Conjugated LC N‐3 Polyunsaturated Fatty Acids on Lipid Composition and Abdominal Fat Weight in Rats

ABSTRACT: Trans and conjugated fatty acids may exhibit either beneficial or detrimental bioactive effects depending on their metabolic properties. This study was conducted to elucidate if isomerization and conjugation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) demonstrate more favorable bioactivity on lipid metabolism compared to unmodified EPA and DHA. The effects of dietary intake of trans and conjugated forms of EPA and DHA on lipid metabolism were evaluated in animal trials and compared to a control group fed soybean oil. None of the experimental diets showed significant differences from the control in terms of body weight; however, the white adipose tissue weight of rodents fed trans DHA, conjugated EPA (CEPA), and conjugated DHA (CDHA) was significantly lower than the control. Triacylglycerol levels in plasma were significantly decreased in groups fed trans DHA (17.2 mg/dL) and CDHA (31.9 mg/dL) relative to the control (51.3 mg/dL). The total cholesterol concentrations were significantly lower than the control (68.0 mg/dL) in all experimental groups (47.3 to 53.7 mg/dL) except CEPA (58.3 mg/dL). Fatty acid compositions of lipids extracted from rodent livers were influenced by the dietary fatty acid profiles, with all groups showing higher concentrations of stearic acid and lower levels of linoleic acid compared to the control. Rodents fed trans DHA did not have detectable levels of these fatty acid isomers in their livers, suggesting either quick metabolism or a difficulty with bio‐absorption.     

Porcine hemoglobin promotes lipid excretion to feces more strongly than globin protein in rats

In an effort to clarify whether the lipid-lowering effect of hemoglobin is due to globin protein or heme, this study investigated the effects of dietary porcine hemoglobin (PH) and porcine globin (PG) on lipids contents of serum, liver, and feces in rats. Five-week-old male Wistar rats were divided into 3 dietary groups of 7 rats each, with one group receiving a control diet and the other groups receiving diets containing 1.25% (w/w) PH or 1.18% (w/w) PG for 4 weeks. The PH diet decreased triacylglycerol content in serum and cholesterol in serum and liver, whereas the PG diet reduced triacylglycerol content in serum and cholesterol in liver. Fecal lipid excretion in the PH group was significantly higher than in the PG group. Therefore, PH affected lipid excretion to feces due to globin protein as well as heme.     

The effects of feeding fish oil on uterine secretion of PGF2alpha, milk composition, and metabolic status of periparturient Holstein cows

The objectives were to determine the effect of dietary fish oil (FO) on uterine secretion of PGF2alpha, milk production, milk composition, and metabolic status during the periparturient period. Holstein cows were assigned randomly to diets containing FO (n = 13) or olive oil (OO, n = 13). Cows were fed prepartum and postpartum diets that provided approximately 200 g/d from 21 d before the expected parturition until 21 d after parturition. The FO used contained 36% eicosapentaenoic acid (EPA, C20:5, n-3) and 28% docosahexaenoic acid (DHA, C22:6, n-3). Blood samples were obtained from 14 d before the due date until d 21 postpartum. A total of 6 FO and 8 OO cows without periparturient disorders were used in the statistical analyses of PGF2alpha-metabolite (PGFM) and metabolite concentrations. Length of prepartum feeding with OO or FO did not differ. Proportions of individual and total n-3 fatty acids were increased in caruncular tissue and milk of cows fed FO. The combined concentrations of EPA and DHA in caruncular tissue were correlated positively with the number of days supplemented with FO. Cows fed FO had reduced concentrations of plasma PGFM during the 60 h immediately after parturition compared with cows fed OO. Concentrations of prostaglandin H synthase-2 mRNA and protein in caruncular tissue were unaffected by diet. Production of milk and FCM were similar between cows fed the two oil diets. However, cows fed FO produced less milk fat. Feeding FO reduced plasma concentrations of glucose. Dietary fatty acids given during the periparturient period can reduce the uterine secretion of PGF2alpha in lactating dairy cows and alter the fatty acid profile of milk fat.     

Effects of dietary fish oil replacement with flaxseed oil on tissue fatty acid composition and expression of desaturase and elongase genes

BACKGROUND: This study was conducted to evaluate the effects of total or partial substitution of dietary fish oil (FO) by flaxseed oil (FlaxO) in Jade Tiger hybrid abalone on fatty acid composition of muscle, gonad and digestive gland, and the expression of desaturase and elongase genes. Abalone were fed five different experimental diets in which FO (control diet) was serially replaced by 25%, 50%, 75% and 100% FlaxO respectively. RESULTS: Muscle, gonad and digestive gland of abalone fed the control diet and the diets containing 25%, 50% and 75% FlaxO showed significantly higher (P < 0.05) levels of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) compared to those fed the 100% FlaxO. The results also showed that Δ‐6 desaturase and elongase gene expression in muscle was increased in a graded manner by increasing dietary FlaxO. The expression of both genes was higher in abalone fed the FlaxO‐substituted diets compared to the abalone fed FO. CONCLUSION: The replacement of FO with FlaxO in commercial abalone diets at levels of 25–75% can improve the composition of health‐benefiting n‐3 polyunsturated fatty acids in tissues of cultured hybrid abalone, and achieve similar outcomes to FO supplementation. Copyright © 2011 Society of Chemical Industry     

NMR结合GC-MS技术分析鱿鱼肝脏油脂及其脂肪酸组成

利用NMR结合GC/MS技术对鱿鱼肝脏油脂及其脂肪酸组成进行分析。₁NMR结果表明,鱿鱼肝脏总脂脂肪酸中,多不饱和脂肪酸与饱和脂肪酸的含量比约为7:5,n-3型多不饱和脂肪酸占脂肪酸总量的35%;₁₃C NMR结果表明,鱿鱼肝脏总脂以甘油三酯(71.87%)为主,其次是游离脂肪酸(20.98%)和磷脂(5.29%),胆固醇(1.13%)和胆固醇酯(0.73%)含量较低,鱿鱼肝油中的DHA和EPA主要以游离形式存在,分别占DHA总量和EPA总量的61.24%和63.11%;GC/MS结果显示,鱿鱼肝脏总脂脂肪酸主要为C16:0、C18:1、C20:1、EPA和DHA,多不饱和脂肪酸的含量高达38.80%,且EPA和DHA占脂肪酸总量的31.50%,表明鱿鱼肝脏具有较高的营养价值及开发前景。     

Salmon Protamine Decreases Serum and Liver Lipid Contents by Inhibiting Lipid Absorption in an In Vitro Gastrointestinal Digestion Model and in Rats

Protamine has been used as an antiheparin drug and a natural preservative in various food products. However, limited studies have evaluated the physicochemical and functional properties of protamine. Hence, we assessed the mechanisms underlying the inhibition of lipid absorption following salmon protamine intake in in vitro and in vivo studies. In initial experiments, a salmon protamine hydrolyzate (PH) was prepared using in vitro simulated gastrointestinal digestion suppressed pancreatic lipase activity and micellar cholesterol solubility. This PH had higher bile acid‐binding capacity and emulsion breakdown activity than casein hydrolyzate and l ‐arginine. However, the hypolipidemic functions of protamine were dramatically reduced by pancreatin digestion. In further experiments, groups of male Wistar rats were fed an AIN‐93G diet containing 5% (wt/wt) salmon protamine or a protamine amino acid mixture. After 4 wk of feeding with experimental diets, reductions in serum and liver triacylglycerol (TAG) and cholesterol contents were observed in the presence of protamine, reflecting inhibition of TAG, cholesterol, and bile acid absorption. These data suggest that the formation of insoluble PH–bile acid complexes is critical before the bile acid‐binding capacity is reduced. Therefore, dietary salmon protamine may ameliorate lifestyle‐related diseases such as hyperlipidemia and obesity.     

Vegetable oil blends with α-linolenic acid rich Garden cress oil modulate lipid metabolism in experimental rats

Vegetable oil blends with modified fatty acid profile are being developed to improve n-6/n-3 polyunsaturated fatty acid (PUFAs) ratio in edible oils. The objective of this study is to develop vegetable oil blends with α-linolenic acid (ALA) rich Garden cress oil (GCO) and assess their modulatory effect on lipid metabolism. Sunflower oil (SFO), Rice bran oil (RBO), Sesame oil (SESO) were blended with GCO at different ratios to obtain n-6/n-3 PUFA ratio of 2.3–2.6. Native and GCO blended oils were fed to Wistar rats at 10% level in the diet for 60 days. Serum and liver lipids showed significant decrease in Total cholesterol (TC), Triglyceride (TG), LDL-C levels in GCO and GCO blended oil fed rats compared to native oil fed rats. ALA, EPA, DHA contents were significantly increased while linoleic acid (LA), arachidonic acid (AA) levels decreased in different tissues of GCO and GCO blended oils fed rats. In conclusion, blending of vegetable oils with GCO increases ALA, decreases n-6 to n-3 PUFA ratio and beneficially modulates lipid profile.     

SHELF LIFE OF SPRAY-DRIED MILK FORMULATIONS SUPPLEMENTED WITH N-3 FATTY ACIDS

Studies were carried out to assess the shelf life of spray‐dried milk formulation containing linseed oil (LSO) or fish oil (FO) as a source of n‐3 polyunsaturated fatty acids (PUFA) in comparison with a milk formulation containing groundnut oil (GNO) stored at 4, 27 and 37C in tin cans for a period of up to 6 months. Total protein, fat, carbohydrate, moisture and solubility index of formulations stored for 6 months were comparable with fresh samples. The fresh samples containing LSO contained 20% ∝ linolenic acid (LNA). At the end of 6 months, the ∝ LNA levels were found to be 18.4, 18.0 and 16.2% in samples stored at 4, 27 and 37C, respectively. The fresh samples containing FO had 2.4% eicosapentaenoic acid (EPA). At the end of 6 months, the EPA levels were found to be 2.2, 2.0 and 1.6% in samples stored at 4, 27 and 37C, respectively. The docosahexaenoic acid (DHA) level in the freshly prepared sample containing FO was 2.1%. At the end of 6 months, the DHA levels were found to be 1.7, 1.6 and 1.3% in samples stored at 4, 27 and 37C, respectively. The whiteness of the formulation containing GNO, LSO or FO remained unaltered for a period of 5 months, but dropped marginally when n‐3 PUFA‐containing formulations were stored at 37C for 6 months. Acceptability scores of formulations were similar for 5 months storage but declined significantly in the FO formulation at the end of 6 months of storage. All n‐3 PUFA‐enriched milk formulations were stable and accepted well for up to 5 months when stored at different temperatures.     

Dietary effects on growth,liver peroxides,and serum and lipoprotein lipids in rats fed a thermoxidised and polymerised sunflower oil

The effect on food intake, weight gain, liver lipid peroxides, lipemia and lipoprotein composition was determined in rats fed a diet with 15% sunflower oil used repeatedly for frying and containing ∽19% polar material (group 2). These dietary effects were compared over a 4 week study period with those found in rats fed a control diet that contained 15% unused sunflower oil with ∽5% polar material (group 1). Both groups had similar food and nutrient intakes (except for linoleic acid, significantly lower (P<0·01) in group 2), yet the final weight gain and food efficiency and protein efficiency ratios were significantly lower in group 2. As a consequence of thermoxidised oil ingestion, liver homogenates from group 2 presented higher (P<0·02) levels of thiobarbituric acid reactive substances (TBARS) Liver TBARS levels were significantly correlated (P<0·01) with the amount of thermoxidised substances ingested. No treatment effect was found on VLDL lipid composition. However, the LDL fraction of group 2 animals appears enriched (P<0·05) in total and free cholesterol. In group 2 rats, phospholipids, and total and esterified cholesterol were significantly increased (P<0·05) in HDL. As a consequence of the changes in the lipoprotein composition, the amount of all forms of serum cholesterol, and serum phospholipids was significantly higher (at least P<0·05) while the amount of serum triacylglycerols remained unchanged in rats fed the used oil. HDL-phospholipids were significantly correlated (P<0·02) with the amount of thermoxidised compounds ingested. The increase in serum cholesterol and phospholipids, and in HDL-cholesterol and HDL-phospholipid concentration seens in group 2 rats may be a protective mechanism against the peroxidative stress produced by the ingestion of used sunflower oil. © 1998 SCI.     

Influence of dietary therapy containing sunflower oil fortified with phospholipids on the lipid metabolism in patients with hypertension and obesity

It was investigated the influence of dietary therapy containing sunflower oil with phospholipids (PL) on the lipid profile of plasma and composition of fatty acids of red blood cells in patients with hypertension and obesity. The results show that after the period of three weeks for each diet the unrefined sunflower oil supplemented with PL (30 gr oil containing 10, 8 gr PL) in diet had more influence on lowering of blood pressure (specially on diastolic BP). This diet reduced serum total cholesterol, low density lipoprotein (LDL), apolipoprotein A 1, apoB and fibrinogen more than the refined sunflower oil diet. This oil presents useful source of polyunsaturated fatty acids and essential PL for diets aimed at prevention of heart disease.     

Atlantic salmon (Salmo salar) muscle structure integrity and lysosomal cathepsins B and L influenced by dietary n-6 and n-3 fatty acids

This study had two main objectives: first, to evaluate the impact of different types and levels of dietary n-6 and n-3 fatty acids (FAs) on Atlantic salmon muscle structure integrity; second, to highlight a possible role of lysosomes and lysosomal degrading enzymes, cathepsins, in fish muscle structure integrity, in relation to dietary fatty acids. Four groups of Atlantic salmon (90 g starting weight) in fresh water tanks were fed one of four diets containing 23% crude lipids, with 100% of the added oils as either fish oil (FO), rapeseed oil (RO), eicosapentaenoic acid (EPA) enriched-oil or docosahexaenoic acid (DHA) enriched-oil. The RO diet was characterised by low levels of EPA + DHA (10% of total FAs), whereas the EPA and DHA diets were characterised by very high levels of EPA + DHA (>50% of total FAs). Fatty acid composition of the muscle crude lysosomal fraction (CLF) generally reflected the diets. Salmon fed the RO diet presented a muscle CLF FA composition close to the one of the FO group, showing moderate PUFA levels, and comparable cathepsin B and cathepsin L activities, relative gene expression of cathepsin B and cathepsin L in the muscle and rate of myofibre–myofibre detachments post-mortem. Salmon fed the EPA and DHA-enriched-oil diets presented a fairly similar muscle CLF FA composition, but different from the FO and RO groups. In the EPA and DHA groups, the percentage of PUFAs in the muscle CLF, the rate of myofibre–myofibre detachments and the relative gene expression of cathepsin B were higher than in the FO and RO groups. Cathepsin B and cathepsin L total activities in the muscle were however lower in the EPA and DHA groups 0 h post-mortem. Dietary lipids influenced the level of lysosomal degrading enzyme activity cathepsin B and cathepsin L as well as the relative gene expression of cathepsin B. Feeding Atlantic salmon with rapeseed oil and extreme levels of EPA + DHA highlighted the impact of fatty acid composition of the diet on salmon muscle integrity and the complexity of the process involving muscle lysosomes and cathepsins in relation to these dietary fatty acids.     

Effect of dietary lipid sources on odour‐active compounds in muscle of turbot (Psetta maxima)

Odour‐active compounds in muscle of turbot (Psetta maxima) fed experimental diets containing fish oil (FO), soybean oil (SO) or linseed oil (LO) were investigated by a gas chromatography/olfactometry technique. Thirty‐one areas associated with odours were detected in muscle extracts. Among the compounds responsible for these odours, 23 were formed by oxidation of unsaturated fatty acids. Independently of diet, (E)‐2‐penten‐1‐ol and (E)‐3‐hexen‐1‐ol contribute strongly to the odour of turbot. (E,Z)‐2,6‐Nonadienal, (E)‐2‐pentenal and (E,E)‐1,3‐(Z)‐5‐octatriene seem to contribute strongly to the odour of turbot fed diets containing high levels of n‐3 PUFA (FO and LO groups). Hexanal and decanal show a high detection frequency in turbot fed diets containing vegetable oils. Odorous compounds which are not formed by lipid oxidation (methional, 1‐acetyl pyrazine, 4‐ethyl benzaldehyde and 2‐acetyl‐2‐thiazoline) were not affected by dietary lipid sources. © 2001 Society of Chemical Industry     

Total lipid,fatty acid composition and lipid oxidation of Indian white shrimp (Fenneropenaeus indicus) fed diets containing different lipid sources

BACKGROUND: Seafood is an important constituent of the human diet. In Iran, Indian white shrimp (Fenneropenaeus indicus) is the major cultured shrimp species as a result of market demand, local availability and growth rate. It is mainly reared using commercial feed. The purpose of this study was to evaluate the effects of replacing 50% of the fish oil by vegetable oils in shrimp feed on total lipid, fatty acid composition and lipid oxidation of shrimp muscle. RESULTS: No significant differences in total lipid content (6.1–7.3 g kg^?1) were found between edible tissues of shrimp fed different diets. The major fatty acids in shrimp muscle were palmitic, oleic, lionoleic, stearic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Higher levels of EPA and DHA were observed in muscle of shrimp fed a diet containing fish oil. Oxidative rancidity, measured as thiobarbituric acid reactive substances, for all shrimps did not exceed 0.2 mg malonaldehyde kg^?1 muscle tissue, which was low and acceptable. CONCLUSION: This study had shown that the fatty acid composition of feed directly affects the fatty acid composition of Indian white shrimp muscle. Farmed Indian white shrimp can be considered as a species of low fat and shrimp muscle was quite stable to oxidation during storage. Copyright © 2009 Society of Chemical Industry