Oxidative stress and antioxidant status in mouse kidney: effects of dietary lipid and vitamin E plus iron

The purpose of this study was to determine the effects of dietary fat, vitamin E, and iron on oxidative damage and antioxidant status in kidneys of mice. Sixty 1-month-old male Swiss-Webster mice were fed a basal vitamin E-deficient diet that contained either 8% fish oil + 2% corn oil or 10% lard with or without 1 g all-rac-alpha-tocopherol acetate or 0.74 g ferric citrate per kilogram of diet for 4 weeks. Significantly (P < 0.05) higher levels of lipid peroxidation products, thiobarbituric acid reactants (TBAR), and conjugated dienes were found in the kidneys of mice fed with fish oil compared with mice fed lard irrespective of vitamin E status. Mice maintained on a vitamin E-deficient diet had significantly higher renal levels of TBAR, but not conjugated dienes, than the supplemented group. Fish oil fed mice receiving vitamin E supplementation had lower levels of alpha-tocopherol than did mice in the lard fed group. Significantly higher levels of ascorbic acid were also found in the kidneys of mice fed with fish oil than were found in mice fed lard. The levels of protein carbonyls and glutathione (GSH), and activities of catalase, superoxide dismutase, selenium (Se)-GSH peroxidase, and non-Se-GSH peroxidase were not significantly altered by dietary fat or vitamin E. Dietary iron had no significant effect on any of the oxidative stress and antioxidant indices measured. The results obtained provide experimental evidence for the pro-oxidant effect of high fish oil intake in mouse kidney and suggest that dietary lipids play a key role in determining cellular susceptibility to oxidative stress.     

The influence of dietary vitamin E, fat, and methionine on blood cholesterol profile, homocysteine levels, and oxidizability of low density lipoprotein in the gerbil

A 90-day feeding study with gerbils was conducted to evaluate the influence of dietary vitamin E levels (25 mg/kg diet, 75 mg/kg, 300 mg/kg, and 900 mg/kg), two levels of dietary methionione (casein or casein+L-methionine (1% w/w)) and two sources of lipid (soybean oil [20%] or soybean oil [4%]+coconut oil [16%, 1:4 w/w]) upon serum lipids (total cholesterol, HDL-cholesterol, LDL-cholesterol). In addition, this study examined the effects of diet-induced hyperhomocysteinemia and supplemental dietary vitamin E on the oxidation of low density lipoproteins. Tissue vitamin E (heart, liver, and plasma) demonstrated a dose response (P≤0.001) following the supplementation with increasing dietary vitamin E (25, 75, 300, and 900 mg/kg). In addition, tissue vitamin E levels were found to be higher (P≤0.001) in those animals receiving a combination of coconut oil+soybean oil as compared to the group receiving soybean oil solely. Blood cholesterol profiles indicated an increase (P≤0.001) in total cholesterol and LDL cholesterol by the influence of saturated fat and supplemental methionine. Low-density lipoprotein cholesterol profile demonstrated a reduction (P≤0.001) at the higher dietary vitamin E levels (300 and 900 mg/kg) as compared to the 25 mg/kg and 75 mg/kg dietary vitamin E. Plasma protein carbonyls were not influenced by dietary vitamin E nor by supplemental methionine intake. In vitro oxidation of LDL showed that vitamin E delayed the lag time of the oxidation phase (P≤0.001) and reduced total diene production (P≤0.001). On the contrary, supplemental methionine decreased (P≤0.001) the delay time of the lag phase, whereas total diene production was increased (P≤0.001). Plasma lipid hydroperoxides were significantly reduced (P≤0.05) with supplemental dietary vitamin E, whereas supplemental L-methionine (1%) resulted in a significant (P≤0.05) increase in lipid plasma hydroperoxide formation. Plasma homocysteine was elevated (P≤0.001) with supplemental dietary L-methionine (1%) as well as the inclusion of dietary saturated fat. The present data showed that 1) a combination of dietary lipids (saturated and unsaturated fatty acids) as well as vitamin E and methionine supplementation altered blood cholesterol lipoprotein profiles; 2) in vitro oxidation parameters including LDL (lag time and diene production) and plasma hydroperoxide formations were affected by vitamin E and methionine supplementation; and 3) plasma homocysteine concentrations were influenced by supplemental methionine and the inclusion of dietary saturated fat.     

Whole blood production of thromboxane, prostacyclin and leukotriene B4 after dietary fish oil supplementation in man: effect of vitamin E

12 subjects were given 30 ml/day of a fish oil already stabilized with vitamin E (1.5 IU/g) and other natural antioxidants (fish oil, FO), and the same fish oil supplemented with extra vitamin E (to total 4.5 IU/g) (FO+E), in a randomized double-blind cross-over study. The whole blood production of thromboxane B₂, measured in serum, was reduced after 4 weeks of ingestion of both FO+E (by 47%, P < 0.01) and of FO (by 40%, P < 0.05) whereas 6-keto-PGF_1α increased slightly in both cases, by 4% and 5% respectively, both NS. Leukotriene B₄ production decreased on both FO+E (by 20%, NS) and FO (by 17%, P < 0.05). This study thus showed that a stabilized fish oil had marked effects on eicosanoid production, which may be important for its cardiovascular effect. Further supplementation with vitamin E had no additional effect, indicating that the vitamin E content (1.5 IU/g) in this stabilized fish oil might have been optimal.     

Dietary fish oil reduces systemic inflammation and ameliorates sepsis-induced liver injury by up-regulating the peroxisome proliferator-activated receptor gamma-mediated pathway in septic mice

This study investigated the effect of dietary fish oil on systemic inflammation and hepatic injury in mice with polymicrobial sepsis. Male ICR mice were assigned to a control group (C, n=30) and a fish oil group (FO, n=30). Mice in the C group were fed a semi-purified diet with 10% soybean oil, and those in the FO group were fed a fish oil diet (2.5% fish oil+7.5% soybean oil; w/w). Three weeks later, sepsis was induced by cecal ligation and puncture (CLP), and mice were sacrificed at 0, 6 and 24 h after CLP, respectively. Results showed that compared with C group, the FO group had lower plasma levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and nitrite at 6 and 24 h after CLP. Also, peritoneal lavage fluid concentrations of TNF-α and prostaglandin (PG) E2 were significantly lower at 24 h in the FO than in the C group. The FO group had lower myeloperoxidase activities at 6 h after CLP in various organs. Plasma aminotransferase and alanine aminotransferase activities revealed significantly decreased in the FO group. The DNA-binding activity of peroxisome proliferators-activated receptor gamma (PPARγ) and mRNA expression of I kappaB alpha (IκBα) were up-regulated while nuclear factor (NF)-κB p65 DNA-binding activity, inducible nitric oxide synthase protein expression and the concentration of nitrotyrosine were significantly decreased in the FO group in liver after CLP. These results indicate that dietary fish oil administration may attenuate systemic inflammation and up-regulate hepatic PPARγ DNA-binding activity, which may consequently have ameliorated liver injury in these septic mice.     

The effect of dietary menhaden,olive, and coconut oil fed with three levels of vitamin E on plasma and liver lipids and plasma fatty acid composition in rats

The effect of dietary fats with varying degrees of unsaturation in the presence of different concentrations of vitamin E on tissue lipid levels was studied in rats. Rats were fed either menhaden oil, olive oil or coconut oil at 15% levels with either 0.1, 0.3 or 0.6 mg/g of vitamin E as alpha-tocopherol for four weeks. Rat serum and liver were analyzed for total cholesterol, HDL-cholesterol, triacylglycerol and phospholipids. In addition, fatty acid composition of serum lipids was also analyzed. Serum total cholesterol and triacylglycerol were significantly lower in rats fed menhaden oil than in those fed olive or coconut oil, while the HDL-cholesterol was significantly higher in serum of rats fed menhaden and olive oil than in those fed coconut oil. Levels of vitamin E in the diet had only a significant effect on serum cholesterol and liver phospholipids. The Pearson correlation coefficient showed a significant positive relationship between serum triacylglycerol and total cholesterol, and a negative correlation between triacylglycerol and HDL-cholesterol, and between total and HDL-cholesterol.In the liver, total cholesterol was significantly higher in rats fed coconut oil than in rats fed menhaden oil. Total liver phospholipids were lower in rats fed either coconut oil or olive oil compared to those fed menhaden oil, especially with higher levels of vitamin E intake. Higher levels of vitamin E in the diet appear to increase triacylglycerol and phospholipids in livers of rats fed menhaden oil. In the liver a significant negative correlation was observed between phospholipids and cholesterol. The type and degree of unsaturation (polyunsaturated fatty acids in menhaden oil, monounsaturated fatty acids in olive oil and saturated fatty acids in coconut oil) significantly affected plasma and tissue lipids.     

Effect of dietary fish oil on tumor-induced hyperlipidemia and tumor growth in rats implanted with a methylcholanthrene-induced sarcoma

Male Fischer 344 rats implanted with a methylcholanthrene-induced sarcoma (MCS), along with normal (or control) animals, were fed diets containing either 10% com oil (CO) or 2% CO + 8% fish oil (FO), designated as diets CO and FO, respectively, in a study designed to determine the effect of dietary FO on serum lipids (in the presence or absence of a tumor) and the growth and fatty acid composition of the MCS. For both diets, MCS-bearing rats had significantly (p < 0.05) higher serum levels of triglycerides, cholesterol, phospholipids, and total lipids than controls. For both controls and tumor-bearers, serum levels of all these lipids were, with the exception of cholesterol for the tumorbearers, significantly lower in rats receiving the FO diet than for the corresponding groups receiving the CO diet. Relative to rats fed the CO diet, those fed the FO diet had significantly higher serum levels of some fatty acids (e.g., 20:5n-3) but significantly lower levels of others (e.g., 18:2n-6), regardless of tumor status. For the tumor-bearers, differences in the levels of fatty acids in MCS tissue reflected differences in the fatty acid composition of total serum lipids. Sarcoma growth was unaffected by diet. Thus, feeding dietary FO resulted in changes in the lipid status of both control and tumor-bearing rats. Since sarcoma growth was unaffected by diet, the reduction in the severity of MCS-induced hyperlipidemia by FO appears to be due to an effect of the oil per se.     

Vitamin E supplementation alters HDL-cholesterol concentration and paraoxonase activity in rabbits fed high-cholesterol diet: comparison with probucol

Vitamin E and probucol are well-known antioxidants that prevent cells from the oxidative stress, which is a risk factor of atherosclerosis. Male rabbits were fed either 0.03% vitamin E or 0.05% probucol in a 0.5% high-cholesterol (HC) diet for 8 weeks. Vitamin E and probucol significantly suppressed an increase in plasma total-cholesterol (total-C) and low-density lipoprotein cholesterol compared to HC-control group. However, plasma high-density lipoprotein-cholesterol (HDL-C) and HDL-C/total-C ratio levels and plasma paraoxonase activity were only significantly higher in vitamin E group after 8 weeks. Hepatic ACAT activity was significantly lower in both vitamin E and probucol groups than in HC-control group, while HMG-CoA reductase activity was the highest only in the probucol group. Total fecal sterol content was significantly higher in probucol and vitamin E groups than in the two control groups. Some atherogenic signs were discovered in the aortic fatty streak of HC-control group, yet not in other groups. Hepatic mRNA expressions of apo B-100 and apo C-III were significantly lower in probucol group than in other groups. Vitamin E supplementation was found to alter the plasma HDL-C-related factors; meanwhile, probucol supplementation was very effective in enhancing cholesterol metabolism, except for a negative effect that reduced plasma HDL-C concentration.     

High dietary intake of alpha-tocopherol acetate enhances the non-specific immune response of gilthead seabream (Sparus aurata L.)

To determine the effects of three high levels of dietary intake of alpha-tocopherol acetate (vitamin E) on the non-specific immune response of gilthead seabream (Sparus aurata L.), specimens were fed a commercial diet (100 mg alpha-tocopherol kg-1) as control, or vitamin E supplemented diets (600, 1200 or 1800 mg alpha-tocopherol acetate kg-1) for 15, 30 or 45 days. Growth, serum alpha-tocopherol levels, natural haemolytic complement activity and head-kidney leucocyte migratory, respiratory burst and phagocytic activities were studied at each of the assay times. A positive correlation between alpha-tocopherol acetate intake and serum alpha-tocopherol levels was observed, the increase being linked to both the dosage and length of treatment. Specimens fed the diet supplemented with 600 mg vitamin E kg-1 showed no enhancement in any of their immune parameters, while those fed the diet supplemented with 1200 mg vitamin E kg-1 presented a slightly higher (but not statistically significant) specific growth rate than fish fed the other diets. In addition, serum haemolytic activity and the phagocytosis of head-kidney leucocytes were enhanced by the dietary intake of 1200 mg vitamin E kg-1 after 30 and 45 days of treatment, although leucocyte migration and respiratory burst activity remained unaffected. The highest vitamin E dietary dose used, 1800 mg kg-1, unexpectedly provoked no immunostimulation. These results indicate that a moderate level of vitamin E in the diet (1200 mg kg-1) stimulates the seabream's non-specific immune system after 30 days of administration. Lower or higher vitamin E concentrations may not be so effective, because of an imbalance in the vitamin E ratio with other antioxidants. The proposed dietary levels of vitamin together with the indicated administration time could be useful for reducing the susceptibility of farmed fish to infectious diseases.     

Effects of dietary fat energy restriction and fish oil feeding on hepatic metabolic abnormalities and insulin resistance in KK mice with high-fat diet-induced obesity

We investigated the effects of dietary fat energy restriction and fish oil intake on glucose and lipid metabolism in female KK mice with high-fat (HF) diet-induced obesity. Mice were fed a lard/safflower oil (LSO50) diet consisting of 50 energy% (en%) lard/safflower oil as the fat source for 12 weeks. Then, the mice were fed various fat energy restriction (25 en% fat) diets — LSO, FO2.5, FO12.5 or FO25 — containing 0, 2.5, 12.5, or 25 en% fish oil, respectively, for 9 weeks. Conversion from a HF diet to each fat energy restriction diet significantly decreased final body weights and visceral and subcutaneous fat mass in all fat energy restriction groups, regardless of fish oil contents. Hepatic triglyceride and cholesterol levels markedly decreased in the FO12.5 and FO25 groups, but not in the LSO group. Although plasma insulin levels did not differ among groups, the blood glucose areas under the curve in the oral glucose tolerance test were significantly lower in the FO12.5 and FO25 groups. Real-time polymerase chain reaction analysis showed fatty acid synthase mRNA levels significantly decreased in the FO25 group, and stearoyl-CoA desaturase 1 mRNA levels markedly decreased in the FO12.5 and FO25 groups. These results demonstrate that body weight gains were suppressed by dietary fat energy restriction even in KK mice with HF diet-induced obesity. We also suggested that the combination of fat energy restriction and fish oil feeding decreased fat droplets and ameliorated hepatic hypertrophy and insulin resistance with suppression of de novo lipogenesis in these mice.     

Blood pressure and serum lipids from SHR after diets supplemented with evening primrose, sunflowerseed or fish oil

Spontaneously hypertensive rats (SHR) at 4 weeks of age were fed a diet supplemented with sunflowerseed oil (SO), evening primrose oil (EPO), fish oil (FO) or EPO + FO for 22 weeks. A diet with commercially available pellets served as control. Systolic blood pressure was significantly lower during and after FO, EPO and EPO + FO, whereas the lower level after SO was not significant when compared with the controls. Serum triglycerides and total cholesterol were lowest after EPO followed FO. The combination of both EPO and FO resulted in unexpected high values of triglycerides and cholesterol. HDL-cholesterol was likewise highest after EPO + FO. The results indicate a quantitatively different depression of blood pressure and serum lipids from SHR by individual polyunsaturated fatty acids (PUFA).     

Effects of different dietary amounts of LCPUFA n3 and vitamin B6 on lipid composition and antioxidant defences in rat kidney

Our previous report demonstrated that, when vitamin deficiency is associated with high contents of long chain polyunsaturated fatty acids (LCPUFA) n3, lipid peroxidation susceptibility in rat heart and liver increases. In this paper, we evaluated the effect of the same dietary administration on lipid composition and antioxidant defenses of rat kidney. Results showed that vitamin B(6) deficiency, when associated with a fish oil diet, as compared to vegetable oil condition, increased relative kidney weight and decreased pyridoxal-5P contents. The different LCPUFA n3 dietary contents produced, on kidney phospholipids, effects interlaced with those of vitamin B(6) deficiency; in particular fish oil and vitamin B(6) deficient diet caused a significant decrease of arachidonic acid showing that the processes of elongation and desaturation of linoleic acid were slowed. Also, peroxidation susceptibility was higher, as demonstrated both by increased TBARS formation and glutathione peroxidase activity, and by decreased vitamin E contents and reduced glutathione/oxidized glutathione ratio.     

Combined effect of DHA and alpha-tocopherol enrichment on sperm quality and fertility in the turkey

The aim of the present study was to characterize the dietary effects of n-3 LC-PUFA and alpha-tocopheryl acetate (vE) on the quality, phospholipid fatty acid composition, alpha-tocopherol content (alpha-T) and in vitro susceptibility to lipid peroxidation in turkey semen. Fertility of fresh semen was also evaluated. Male turkeys were randomly divided and fed either a control diet or a fish oil and vE rich diet (FO diet) from 40 to 60 weeks of age. The FO diet increased the proportion of n-3 fatty acids in spermatozoa and as a consequence the (n-3)/(n-6) ratio also increased. These changes did not affect the proportion of n-9 PUFAs, particularly of C22:3n-9, in semen. The sperm content of alpha-T was dependent by the dietary supplementation of the vitamin and the sperm content was more than doubled supplying 120 mg kg(-1) of feed to the males compared to the 60 mg kg(-1) of feed in the control diet. In agreement with the major content of alpha-T in spermatozoa collected from the FO group were significantly less susceptible to in vitro induced oxidation. The reproductive capacity of the male breeders was not affected by the diet; however the result is considered of some relevance for field conditions where even very small changes have economic interest being applied to large bird population.     

Dietary fatty acid composition rather than vitamin E supplementation influence ex vivo cytokine and eicosanoid response of porcine alveolar macrophages

This study examined the influence of different dietary fat sources (animal fat, sunflower oil, and fish oil) and supplementation of vitamin E (85, 150 and 300 mg all-rac-alpha-tocopheryl acetate/kg diet) on the ex vivo synthesis of eicosanoids and cytokines by porcine alveolar macrophages. Supplementation of vitamin E provoked an increase in the concentration of alpha-tocopherol of the macrophages irrespective of fat sources. Fish oil increased the macrophage n-3 content with 100% and 40%, and reduced the n-6 with 60% and 53% in comparison with sunflower oil and animal fat, respectively. Fish oil decreased the production of TNF-alpha, IL-8, LTB4, and PGE2 (but not IL-6) relative to the other dietary fat sources, and no difference was observed between sunflower oil and animal fat. Positive correlations were found between the n-6 fatty acid content and the production of PGE2, and the PGE2 production was positively correlated with TNF-alpha and IL-8. Negative correlations were found between the n-3 PUFA content and the concentration of PGE2, TNF-alpha and IL-8. In conclusion, dietary fish oil supplemented at a level of 5%, but not supplemental vitamin E, influenced the inflammatory responses of alveolar macrophages isolated from weaned pigs relatively to animal fat and sunflower oil.     

Effects of vitamin C and vitamin E on lipid peroxidation, blood serum metabolites, and mineral concentrations of laying hens reared at high ambient temperature

This study was conducted to determine the effects of vitamin C (L-ascorbic acid) and vitamin E (alpha-tocopherol acetate) on serum concentrations of lipid peroxidation (MDA) and triiodothyronine (T3), thyroxine (T4), adrenocorticotropic hormone (ACTH), and some metabolite and mineral in laying hens reared at high ambient temperatures ranging from 25 degrees C to 35 degrees C. One hundred twenty laying hens (18 wk old; Hy-Line) were divided into 4 groups, 30 hens per group. The laying hens were fed either a basal diet (control) or the basal diet supplemented with either 250 mg of L-ascorbic acid/kg of diet (vitamin C), 250 mg of alpha-tocopherol acetate/kg of diet (vitamin E), or 250 mg of L-ascorbic acid plus 250 mg alpha-tocopherol acetate/kg of diet (combination). Separately or as a combination vitamins C and E increased serum vitamin C and vitamin E concentrations (p < 0.001) but decreased serum MDA concentration (p < 0.05). Serum concentrations of vitamin E and vitamin C were found highest but serum MDA concentration was lowest in the combination group. Supplemental vitamins C and E either separately or in a combination increased serum T3 and T4 concentrations (p < 0.05), whereas decreased serum ACTH concentration (p < 0.01). Serum glucose and cholesterol concentrations decreased, whereas serum protein concentration increased (p < 0.05) when vitamins C and E singly or together were added to the diet. Vitamin C and vitamin E supplementation resulted in an increase in serum concentrations of Ca, P, and K (p < 0.01) but a decrease in serum concentration of Na (p < 0.05). The results of the present study suggest that supplemental vitamin C and vitamin E alter serum lipid peroxidation, vitamin C, vitamin E and metabolite status, and diets supplemented with a combination of these two vitamins offer a good management practice in laying hens reared at high temperatures. In addition, the results suggest that dietary vitamin C and vitamin E act synergistically.     

Dietary fish oil supplemented with vitamin E improves quality indicators of rooster cold-stored semen through reducing lipid peroxidation

Cockerel semen is sensitive to cooling, which limits chilled storage of semen for more than 24 h. Results of artificial insemination with cold-stored semen are not desirable. This study was conducted to evaluate the effects of dietary fish oil and vitamin E (vitE) for cold-storage of rooster semen and its effects on parameters of semen during 48 h cooling preservation. Roosters were assigned into four dietary treatments; 1) control group received a basal diet, 2) vitE group received a basal diet supplemented with 200 mg/kg vitE, 3) fish oil group (FO) received a basal diet supplemented with 2% fish oil and 4) fish oil and vitE group received a basal diet supplemented with 2% fish oil and 200 mg/kg vitE (FO + vitE). Semen samples were collected after 40 days of feeding and then diluted and cooled to 5 °C for preservation up to 2 days. Several quality indicators of sperm such as motion characteristics, membrane integrity, and viability, and abnormal morphology, activity of mitochondria, lipid peroxidation and acrosome integrity of the sperm were assessed at different times of storage (0, 24 and 48 h). None of sperm were significantly affected by the diets at the start of storage (0 h, p > 0.05). FO and FO + vitE improved the percentage of total motility, viability, and mitochondria activity at 24 h (P ≤ 0.05). After 48 h, only FO + vitE group produced the higher percentage of total motility, viability and membrane integrity (P ≤ 0.05). Lipid peroxidation was significantly reduced in sperm obtained from roosters fed diets of FO + vitE and vitE compared to FO and control (P ≤ 0.05) at times of 24 and 48 h. There was no significant difference between control and vitE groups in none of parameters (P > 0.05). Integrity of acrosome and abnormal morphology were not significantly affected by the diets (P > 0.05). Supplementation of roosters' diet with 2% fish oil and 200 mg/kg vitamin E improved the quality of cold-stored semen by supporting several indicators of sperm quality through reducing lipid peroxidation.     

n-6 and n-3 fatty acids ratio and vitamin E in porcine maternal diet influence the antioxidant status and immune cell eicosanoid response in the progeny

Five groups of lactating sows were fed diets containing 8% of either added rapeseed oil, fish oil or sunflower oil and 60 mg vitamin E/kg feed, or the diets with sunflower oil and fish oil, respectively, supplemented with 500 mg vitamin E/kg. Supplementation of vitamin E to the sows increased the concentration of alpha-tocopherol of the muscle, and addition of sunflower oil decreased the activity of glutathione peroxidase in liver cytosol compared to fish oil and rapeseed oil. The composition of fatty acids of alveolar macrophages (AM) of piglets was influenced by the dietary fat sources provided the sows, i.e., the ratio of n-6:n-3 fatty acids was highest in AM of piglets suckling sows of the sunflower oil treatments, and lowest in AM of piglets suckling sows fed fish oil with the rapeseed oil treatment in between. The ex vivo synthesis of prostaglandin E(2) and thromboxane B(2) in AM of piglets suckling sows fed sunflower oil was elevated compared to piglets suckling sows fed fish oil. Vitamin E supplementation to sows enhanced the synthesis of these eicosanoids, and also the concentration of alpha-tocopherol in the AM of the piglets.     

Reduction of oxidative stress and apoptosis in hyperlipidemic rabbits by ellagic acid

Oxidative stress is one of the major risk factors for coronary artery disease. Ellagic acid is a phenolic compound present in fruits and nuts, and has been found to have antioxidative property. Twenty-four New Zealand white (NZW) rabbits were assigned randomly into four dietary groups. The normal group was fed regular rabbit chow, and the cholesterol group was fed a high fat and cholesterol diet. The ellagic acid (E) group and probucol group were fed the same diet as the cholesterol group plus the addition of 1% (w/w diet) ellagic acid and probucol, respectively. Oxidative stress [as measured by plasma lipids, oxygen free radicals and thiobarbituric acid reactive substances (TBARS)] increased in the cholesterol group compared with the normal group; however, it decreased in the probucol and E groups compared with the cholesterol group. Forty-five percent of the intimal surface of the thoracic aorta was covered with atherosclerotic lesions in the cholesterol group, but only 2-3% was covered in the E and probucol groups. The aortic level of 8-(OH)dG and the expression of caspase-8, caspase-9 and Fas ligand were also suppressed after ellagic acid supplement. These results indicated that ellagic acid could prevent atherosclerosis via suppression of oxidative stress and apoptosis in hyperlipidemic rabbits.     

Partial replacement of dietary fish oil with blends of vegetable oils (rapeseed, linseed and palm oils) in diets for European sea bass (Dicentrarchus labrax L.) over a long term growth study: effects on muscle and liver fatty acid composition and effectiveness of a fish oil finishing diet

Triplicate groups of European sea bass (Dicentrarchus labrax L.), of initial mass 5 g, were fed one of three practical type diets for 64 weeks. The three diets differed only in the added oil and were 100% fish oil (FO; diet A), 40% FO/60% vegetable oil blend (VO; diet B) where the VO blend was rapeseed oil, linseed oil and palm oil in the ratio 10/35/15 by weight and 40% FO/60% VO blend (diet C) where the ratio was 24/24/12 by weight. After final sample collection the remaining fish were switched to a 100% FO finishing diet for a further 20 weeks. After 64 weeks fish fed 60% VO diet B had significantly lower live mass and liver mass than fish fed diets A and C although SGR, FCR and length were not different between groups. There were no differences in any of the above parameters after either 14 or 20 weeks on the FO finishing diet. Fatty acid compositions of flesh were correlated to dietary fatty acids although there was selective retention of docosahexaenoic acid (22:6n-3; DHA) regardless of dietary input. Inclusion of dietary VO resulted in significantly reduced flesh levels of DHA and eicosapentaenoic acid (20:5n-3; EPA) while 18:1n-9, 18:2n-6 and 18:3n-3 were all significantly increased in fish fed the 60% VO diets. Fatty acid compositions of liver showed broadly similar changes, as a result of dietary fatty acid composition, as was seen in flesh. However, the response of flesh and liver to feeding a FO finishing diet was different. In flesh, DHA and EPA values were not restored after 14 or 20 weeks of feeding a FO finishing diet with the values in fish fed the two 60% VO diets being around 70% of the values seen in fish fed FO throughout. Conversely, and despite liver DHA and EPA levels being reduced to only 40% of the value seen in fish fed 100% FO after 64 weeks, the levels of liver DHA and EPA were not significantly different between treatments after feeding the FO finishing diet for 14 weeks. However, a 200 g portion of sea bass flesh, after feeding the experimental diets for 64 weeks followed by a FO diet for 14 weeks, contained 1.22 and 0.95 g of EPA + DHA for fish fed FO or 60% VO, respectively. Therefore, sea bass grown for most of the production cycle using diets containing 60% VO can still contribute a significant quantity of healthy n-3 HUFA to the human consumer.     

不同脂肪源对泥鳅稚鱼生长性能及脂肪酸组成的影响

为研究饲料不同脂肪源对泥鳅稚鱼生长性能及鱼体脂肪酸组成的影响, 实验选择初始体重为(10.002.00) mg的健康泥鳅稚鱼1500尾, 随机分为5组, 每组3个重复, 每个水箱100尾鱼, 分别投喂5种含有鱼油(FO)、大豆油(SO)、玉米油(CO)、花生油(PeO)和棕榈油(PaO)的配合饲料, 每种饲料3个重复, 饲养期为40d。结果显示, 摄食不同脂肪源饲料的泥鳅稚鱼在增重率、成活率、饲料系数等生长性能指标和体成分上没有显著差异(P0.05), 但是, 摄食FO组鱼体极性脂肪含量显著高于其他植物油组(P0.05)。鱼油组鱼体中性和极性脂肪中总n-3系脂肪酸含量和EPA+DHA含量显著高于其他植物油组(P0.05)。植物油组鱼体极性脂肪中20:4n-6含量显著高于鱼油组(P0.05), 表明泥鳅稚鱼具有将C18转换为C20的能力。研究表明, 在饲料中添加足量磷脂, 鱼油、大豆油、玉米油、花生油、棕榈油都可以用作泥鳅稚鱼期专用饲料脂肪源。     

美洲鳗鲡幼鱼饲料中鱼油的适宜添加水平研究

为研究饲料中鱼油添加水平对美洲鳗鲡(Anguilla rostrata)幼鱼生长性能、消化酶、体成分及肝脏脂肪代谢的影响, 以确定美洲鳗鲡幼鱼饲料中鱼油的适宜添加水平, 选用初始体重(8.34±0.12) g的美洲鳗鲡幼鱼800尾, 随机分成5组, 每组4个重复, 每个重复40尾; 分别投喂添加0(对照组)、3%(FO3组)、6%(FO6组)、9%(FO9组)和12%(FO12组)鱼油的试验饲料, 试验期56d。结果表明, 饲料中添加鱼油显著影响美洲鳗鲡幼鱼生长性能, FO6组美洲鳗鲡幼鱼的增重率、投饵率和饲料效率显著高于其他处理组(P<0.05)。与对照组相比, 鱼油添加组美洲鳗鲡幼鱼肠道脂肪酶活性显著提高(P<0.05), 蛋白酶和淀粉酶活性显著降低(P<0.05); FO6组、FO9组和FO12组全鱼粗脂肪含量显著提高(P<0.05), 全鱼粗蛋白质含量在FO12组显著降低(P<0.05), 全鱼水分和灰分含量无显著变化(P>0.05); FO9组和FO12组脂肪酸合成酶活性显著降低(P<0.05), FO12组脂蛋白酯酶和肝脂酶活性显著升高(P<0.05)。综上, 饲料中添加适宜鱼油水平可以提高美洲鳗鲡幼鱼的生长性能, 调节肠道脂肪酶活性、全鱼粗脂肪含量和肝脏脂肪代谢酶水平或活性; 美洲鳗鲡幼鱼获得最佳增重率和饲料效率时, 饲料中鱼油添加水平推荐为6.43%—6.78%。