Effects Of Dietary Fish Oil Research Articles

Histology and transcriptomic analysis reveal effects of dietary fish oil and soybean oil on lipid absorption and immune inflammation in the foregut of adult female spotted scat (Scatophagus argus)

The foregut is the main site of lipid absorption in fish, but the effect of different lipid sources on the foregut lipid absorption and metabolism in adult female spotted scat is still unclear. In this experiment, adult female spotted scat (length = 19.48 ± 1.13 cm, weight = 242.83 ± 50.90 g) were fed two iso-nitrogenous (45 % crude protein) and iso-lipidic (12.5 % crude lipid) diets configured with either 8 % fish oil (FO) or 8 % soybean oil (SO) for 60 days. Histological observations, serum measurements and transcriptome sequencing were used to investigate the effects of the oil sources on the foregut. Histological observation showed that the foregut folds of the SO group were shorter and narrower than those of the FO group, and nuclear vacuolation and villous atrophy were observed in the intestinal cells of fish in the SO group, indicating an inflammatory reaction. Both serum triglyceride and total cholesterol levels were significantly higher in the FO group than in the SO group. Transcriptome analysis revealed 1355 differentially expressed genes between the FO and SO groups. Genes related to lipid metabolism (adipor2 and creb3l3) and cholesterol absorption and efflux (npc1l1 and sphk2) were up-regulated, whereas genes related to fatty acid synthesis and transport (fad1 and mfsd2ab) were down-regulated in the FO group. Circadian rhythm related genes ciart and nfil3, which are also involved in lipid metabolism, were up- and down-regulated, respectively in the FO group. The immune-related genes steap4, ddit4 and cldn6 which can inhibit inflammation, were up-regulated in the FO group, whereas pro-inflammation gene rnf225 was up-regulated in the SO group. In conclusion, compared with SO, FO may enhance the lipid absorption and reduce the inflammatory response in the foregut of the spotted scat. The results of this study provide a reference for the selection of dietary oil sources for adult female spotted scat.

The effect of peroxisome proliferator-activated receptor gamma (PPARγ) as a mediator of dietary fatty acids and thiazolidinedione in pulmonary arterial hypertension induced by cold stress of broilers

The objective of this experiment was to evaluate the effects of dietary fish oil and pioglitazone as peroxisome proliferators-activated receptor gamma (PPARγ) activating ligands on the reduction of cold-induced ascites in broiler chickens. A total of 480 one-day-old (Ross 308) male chicks were randomly allocated to four treatment groups with eight replicates of 15 birds each. The following treatments were used: 1) ambient temperature (negative control), with basal diet; 2) cold-induced ascites (positive control), with basal diet; 3) cold-induced ascites, with basal diet +10 mg/kg/day pioglitazone and 4) cold-induced ascites, with basal diet +1% of fish oil. When compared with the positive control, body weight gain was higher (P ≤ 0.05) for broilers fed diets containing fish oil and pioglitazone at 28, 42, and 0–42 d. Broilers under cold-induced ascites had the highest blood pressure at 21 and 42 d, while fish oil and pioglitazone treatment reduced the blood pressure (P ≤ 0.05). Red blood cells, white blood cells, hematocrit, erythrocyte osmotic fragility, bursa of Fabricius and spleen weights were improved (P ≤ 0.05) for chickens fed fish oil diets and pioglitazone compared to the cold-induced ascites (positive control). Exposure to cold temperature resulted in an increase in plasma T3 and T3/T4 ratio and decline in plasma T4 (P ≤ 0.05). In conclusion, PPARγ agonist pioglitazone and fish oil as source of omega-3 polyunsaturated fatty acid could be used as a strategy to reduce the negative effects of pulmonary arterial hypertension and ascites in broiler chickens.

Dietary Fish Oil Does Not Alter Glucose Tolerance in Conscious Rats

We examined the effect of dietary fish oil (MaxEPA) and sunflower seed oil on glucose tolerance in male Wistar rats. Semipurified diets containing 100 g oil/kg diet were administered for 30 d. The fish oil diet contained 26 g (n-3) fatty acids, 16 g eicosapentaenoic acid and 10.4 g docosahexaenoic acid/kg diet. Phospholipids from liver, pancreas, and pancreatic islets were enriched in eicosapentaenoic and docosahexaenoic acids by the fish oil diet. In unfed pentobarbital-anesthetized rats, both basal plasma insulin concentration and insulin responses to intravenous glucose were significantly lower for fish oil-fed rats although glucose responses were similar; however, incremental excursions in plasma insulin over the basal concentrations did not differ. Intravenous glucose tolerance was also examined in conscious unfed rats under minimal restraint. Responses of plasma glucose and insulin were similar for fish oil- and sunflower oil-fed groups. Furthermore, in another experiment, intravenous glucose tolerance tests were similar for conscious rats provided with either 100 g fish oil or corn oil/kg nonpurified diet. Thus, glucose-induced insulin secretion is lower in rats fed fish oil than in rats fed sunflower oil, when tests are conducted in pentobarbital-anesthetized animals but not when tests are performed in conscious rats; there was no effect on plasma glucose in either anesthetized or nonanesthetized rats. Therefore, substitution of (n-3) for (n-6) polyunsaturated fatty acids in tissue phospholipids does not alter plasma glucose or insulin in conscious male Wistar rats.

Dietary (n-3) Polyunsaturated Fatty Acids Improve Adipocyte Insulin Action and Glucose Metabolism in Insulin-Resistant Rats: Relation to Membrane Fatty Acids

To study the effects of dietary fish oil on insulin-stimulated glucose metabolism in adipocytes of insulin-resistant rats (rats fed 50% sucrose and 30% fat), eighteen 5-wk-old Sprague-Dawley rats were fed, for 6 wk, a diet containing 30% fat as either fish oil (FO) or a mixture of vegetable and animal oils [control oils (CO)]. A third reference group was fed a standard diet (62% corn starch and 13% fat). At the end of the 6-wk period, the two experimental groups had comparable plasma glucose concentrations that were higher than that found in the reference group. FO feeding corrected the hyperinsulinemia of the experimental rats (P < 0.05) to reach values in the reference group. Plasma triacylglycerol (P < 0.01) and cholesterol (P < 0.001) concentrations were also lower in rats fed FO than in those fed CO. The body weights of FO-fed rats were similar to that of CO-fed rats, but epididymal adipose tissue weight was lower (P < 0.01). Adipocytes of FO-fed rats, compared with those of CO-fed rats, had high insulin-stimulated glucose transport (P < 0.05), oxidation (P < 0.001) and incorporation into total lipids (P < 0.05). The incorporation of (n-3) polyunsaturated fatty acids in adipocyte membrane phospholipids was higher in FO-fed rats than in those fed CO (P < 0.0001). Insulin action was positively correlated with the fatty acid unsaturation index in membrane phospholipids. Thus dietary fish oil has beneficial effects on insulinemia, plasma lipids and insulin-stimulated glucose metabolism in insulin-resistant slightly diabetic rats.

Fish oil replacement by beef tallow in juvenile turbot diets: Effects on growth performance, body composition and volatile flavor compounds in the muscle

A 12-week feeding trial was conducted to evaluate the effects of dietary fish oil (FO) replacement by beef tallow (BT) on the growth performance and body composition of juvenile turbot (average initial weight, 19.6 g). The control diet contained 6% added FO (of dry matter, Diet FO-C). Beef tallow was supplemented into Diet FO-C, replacing added FO at different levels, i.e., 25%, 50%, 75%, and 100%, formulating the other 4 experimental diets, designated as 25BT, 50BT, 75BT, and 100BT, respectively. The feeding trial was conducted in a flow-through seawater system. Each diet was randomly fed to triplicate tanks (30 fish in each tank). The results showed that a cubic regression relationship was observed between weight gain and dietary FO replacement level. Although total FO replacement by BT significantly reduced the growth of juvenile turbot, no significant difference was observed between FO-C and 75BT. Diet BT decreased the whole-body crude lipid content but increased the whole-body moisture and ash contents. Dietary BT regulated the proximate composition of fish tissues in a dose dependent manner. High dietary BT levels did not reduce the n-3 long-chain polyunsaturated fatty acid content (% total fatty acid) in the muscle. Partial FO replacement (25 and 50%) by BT even significantly increased the muscle DHA content. The fatty acid composition of the liver, subcutaneous adipose tissue around the fin, and intestine generally reflected those of the diets. No significant difference was observed in muscle and liver mitochondrial DNA copy number among groups, indicating the similar general energy supply status. Dietary BT significantly reduced the concentration of triacylglycerol, cholesterol and malondialdehyde in the serum. The volatile flavor compound in muscle was analyzed with gas chromatography-ion migration spectrometry (GC-IMS). Dietary BT resulted in lower number and abundance of flavor aldehydes and alcohols in the muscle. In conclusion, beef tallow can replace 75% added fish oil (appr. 45% of total fish oil including the residual fish oil in fishmeal) in the diets of turbot, without reducing fish growth. Dietary beef tallow significantly affected the body composition and volatile flavor compound composition in the muscle.

Ovary transcriptomic analysis reveals regulation effects of dietary fish oil on hormone, lipid, and glucose metabolism in female adult spotted scat (Scatophagus argus)

In the aquaculture industry, fish oil is widely used as a nutritional supplement to promote the gonadal maturation of broodstocks, while the mechanism of fish oil on ovary development remain unclear. Herein, female adult spotted scat (Scatophagus argus) with most ovaries at phase II were fed with diets containing 8% soybean oil (SO) or 8% fish oil (FO) for 60 days. The final average fish body weight was similar between FO and SO groups. The average gonadosomatic index (GSI) of FO group was higher (non-significant) than that of SO group. Finally, the phase IV ovary of the FO and SO groups were 7 and 5 out of 10, respectively. The serum estradiol (E2) level of the FO group was significantly higher than that of the SO group. The proportions of n-3 long-chain polyunsaturated fatty acids (LC-PUFA, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)) in the ovaries were much higher in the FO group than in the SO group. These results suggest that the maturity level of the FO group is relatively higher than that of the SO group. Transcriptome sequencing was used to detect the ovary gene expression. Comparatively, the ovary transcriptome analysis showed 68 up-regulated and 193 down-regulated genes in the FO group. The expression levels of Jund and Jun necessary for the ovary maturation were up-regulated in the FO group, while Pparγ and Cxcl12, which could inhibit the ovary development, were down-regulated in the FO group. Cyp3a27 coding the enzyme for degrading the estrogen was significantly down-regulated in the FO group and coincided with the increase of its serum E2. Kif5b which could regulate the glucose metabolism was up-regulated in the FO group. Serum insulin level was also increased in the FO group. Additionally, Aldh3a2 and Plin2 related to lipid metabolism were significantly down-regulated in the FO group. Briefly, dietary fish oil can influence the expression of genes related to steroid hormone, glucose and lipid metabolism. This study will clarify the mechanism of dietary fish oil in promoting ovary development in teleost fish.

Long-term effects of adolescent exposure to olanzapine in C57BL/6J mice and the impact of dietary fish oil supplementation.

Second-generation antipsychotic (SGA) medications can produce abnormal weight gain and metabolic dysfunction in children, but little is known about the post-treatment consequences of adolescent SGA exposure. The objective of this study was to determine the long-term, post-treatment effects of adolescent olanzapine exposure on weight and metabolic function and whether dietary fish oil (FO) modulated any observed effects of olanzapine. Male and female mice were fed a high-fat, high-sugar (HF-HS) diet or an HF-HS diet supplemented with fish oil (HF-HS-FO) and were treated with olanzapine or vehicle for 29days beginning on postnatal day 37. In male mice, adolescent olanzapine treatment suppressed weight gain during and after treatment and improved metabolic function in adulthood; dietary fish oil reduced weight gain, increased expression of fatty acid oxidation genes, and decreased expression of genes associated with fatty acid synthesis and inflammation. In contrast, few effects were observed in female mice. The current results suggest that adolescent olanzapine exposure can produce long-term alterations in weight and metabolic function in male mice and that dietary fish oil can reduce adverse effects of lifelong consumption of an HF-HS diet. Because expected adverse effects of adolescent olanzapine treatment were not observed, the potential beneficial effects of dietary fish oil for SGA-induced weight gain and metabolic dysfunction could not be evaluated.

Effect of dietary n-3 fatty acid and rooibos (Aspalathus linearis) supplementation on semen quality, sperm fatty acids and reproductive performance of aged male broiler breeders.

The purpose of this study was to assess the effects of dietary fish oil (FO) and rooibos supplementation on semen quality, fatty acids composition and reproductive performance of aged male broiler breeders. Seventy-two 47-week-old Ross broiler breeder roosters were randomly assigned to a 2 × 3 factorial arrangements to include two FO concentrations (0% and 2%) and 3 rooibos concentrations (0%, 1.5% and 3%) for 13 weeks consecutive. The different diets affected semen parameters significantly (p < 0.05), except for the semen concentration and abnormality of the sperm. The sperm of the FO and 3% rooibos-treated group showed better motility and viability when compared to the other groups (p < 0.05). The susceptibility of semen to lipid peroxidation was increased in roosters fed the rooibos-free diets (p < 0.05), but it was reduced (p < 0.05) when the diet was supplemented with 1.5% and 3% rooibos. In addition, at 64 weeks, the highest concentration of testosterone was observed in the roosters fed a diet that included 2% FO and 3% rooibos (p < 0.05); however, the difference in testosterone levels between Week 52 and Week 64 was not significant (p > 0.05). The fertility rate of collected eggs from the FO and 3% rooibos group was higher (p < 0.05) than that of the other groups at the end of the experiment. In conclusion, dietary inclusion of FO along with rooibos improved seminal quality and reproduction performance in aged roosters.

Corrigendum: Liver Transcriptomic Analysis of the Effects of Dietary Fish Oil Revealed a Regulated Expression Pattern of Genes in Adult Female Spotted Scat (Scatophagus argus)

Dear Prof. Erchao Li,I hope this email finds you well and in good health. Thank you for publishing our article “Liver transcriptomic analysis of the effects of dietary fish oil revealed a regulated expression pattern of genes in adult female spotted scat (Scatophagus argus)” https://doi.org/10.3389/fmars.2021.784845. Unfortunately, there is an error in the affiliations caused during the proofreading, and we could not notice it.We will be glad if you can help us with the necessary correction. Find attached the correct affiliation. I am hoping to hear from you soon.Yours sincerely,Tuo Wang

Liver Transcriptomic Analysis of the Effects of Dietary Fish Oil Revealed a Regulated Expression Pattern of Genes in Adult Female Spotted Scat (Scatophagus argus)

Despite the significance of n-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) in fish oil in promoting the maturation of female broodstocks, the detailed mechanism of the effect on the expression of hepatic reproduction-related genes is still unclear. In this study, transcriptome sequencing was used to analyze the effect of the higher dietary n-3 LC-PUFA level on gene expression in the liver of adult females spotted scat. Two-year-old female spotted scat (average weight, 242.83 ± 50.90 g) were fed with diets containing 8% fish oil (FO) or 8% soybean oil (SO) for 40 days. The fatty acid profile in the serum, liver, and ovary was analyzed, and high proportions of n-3 LC-PUFA were observed in the FO group. The final average fish body weight and gonadosomatic index were similar between the FO and SO groups. The serum vitellogenin (Vtg) and hepatosomatic index (HSI) of the FO group were significantly higher and lower than that of the SO group, respectively. Comparatively, the liver transcriptome analysis showed 497 upregulated and 267 downregulated genes in the FO group. Among them, the expression levels of three estrogen-regulated genes (i.e., Vtga, Vtgb, and Zp4) were significantly higher in the FO than in the SO group. This expression pattern could be related to the upregulation of Hsd17b7 (the key gene for the synthesis of liver steroid hormone) and the downregulation of the Hsp90 (the estrogen receptor chaperone). The expression levels of Foxo1a and Lep, which are involved in the lipid metabolism, decreased significantly in the FO group, which may be related to the lower level of HSI in the FO group. The genes related to liver LC-PUFA absorption and transport, Fabp2 and Mfsd2ab, were significantly upregulated in the FO group, indicating that fish actively adapt to high-fish-oil diets. In brief, high-fish-oil diets can influence the expression of genes related to liver n-3 LC-PUFA metabolism and reproduction, inhibit the accumulation of liver fat, and promote the liver health and gonad development. This study will contribute to clarifying the mechanism of dietary n-3 LC-PUFA on promoting reproductive development in teleost fish.

Effects of dietary fish oil and corn oil on gonadosomatic and hepatosomatic index, gonadal histology, 17β‐oestradiol level and fatty acids profile of mahseer ( Tor tambroides ) broodstock in captivity

The present research was conducted to investigate the effects of fish oil (FO) substitutions with corn oil (CO) on the gonad development of female Tor tambroides broodstocks, a high value freshwater fish. Three isonitrogenous (450 g kg−1 crude protein) and isolipidic (105 g kg−1 crude lipid) were formulated to contain FO and CO at a ratio of 1:0, 1:1 and 0:1, respectively, and fed to female fish (n = 10 fish × 3 replicate × 3 treatment; average weight = 910.0 ± 130.0 g) for five months. At the end of the feeding trial, there were no significant differences (p > .05) on the gonadosomatic index (GSI), hepatosomatic index, 17β-oestradiol (E2) concentration and muscle fatty acids (FA) composition. However, fish fed with diet containing FO to CO at a ratio of 1:1 demonstrated higher percentage of GSI, E2 concentration (ng ml−1) and the presence of vitellogenic oocytes in the histological data compared to the other two feeding diets. The FA composition also highlighted that T. tambroides broodstocks can elongate polyunsaturated FA to highly unsaturated FA. Based on these preliminary results, it shows that T. tambroides prefer diets with supplementation of both n3 and n6 oil source. However, more studies need to be done to strengthen this conclusion.

Interactive effect of dietary fish oil and pyrimidine nucleotide supplementation on the fatty acid composition of juvenile rainbow trout Oncorhynchus mykiss : Enhancement of ARA and DHA contents in the fillet of fish fed‐supplemented diet

The present study investigated interactive effect of different levels of dietary fish oil and pyrimidine nucleotide supplementation on growth and fatty acid composition of juvenile rainbow trout. Six experimental diets were formulated with two different levels of fish oil. High fish oil (HFO) diet contains 120 g/kg fish oil, while low fish oil (LFO) diet contains 40, 60 and 20 g/kg fish, linseed and rapeseed oils respectively. Uridine 5’-monophosphate (UMP) or cytidine 5’-monophosphate (CMP) disodium salt was supplemented onto each diet at 1.5 g/kg respectively. For control diet, UMP and CMP were not supplemented to HFO and LFO diets respectively (HFO-Cont. and LFO-Cont.). Rainbow trout with initial average body weight of 13.5 g were randomly placed into 12 tanks and offered one of the six diets for 12 weeks. Growth, feed utilization and hepatosomatic index (HSI) of fish were not influenced by either fish oil or pyrimidine nucleotide supplementation. This trend was also similar on the crude lipid content in the liver and proximate composition in the muscle and whole fish body. In addition, fatty acid composition in the liver was influenced by fish oil level, but not by pyrimidine nucleotide supplementation. Interestingly, pyrimidine nucleotide supplementation affected 20:4n-6 and 22:6n-3 contents in the muscle of fish. In summary, although dietary UMP and CMP have no positive effect on growth, it affected on the fatty acid composition of fish by increasing muscular 20:4n-6 and 22:6n-3 contents particularly when it is supplemented in low fish oil-based diet.

Effects of High Levels of Dietary Linseed Oil on the Growth Performance, Antioxidant Capacity, Hepatic Lipid Metabolism, and Expression of Inflammatory Genes in Large Yellow Croaker (Larimichthys crocea).

A growth experiment was conducted to evaluate the effects of dietary fish oil (FO) replaced by linseed oil (LO) on the growth performance, antioxidant capacity, hepatic lipid metabolism, and expression of inflammatory genes in large yellow croaker (Larimichthys crocea). Fish (initial weight: 15.88 ± 0.14 g) were fed four experimental diets with 0% (the control), 33.3%, 66.7%, and 100% of FO replaced by LO. Each diet was randomly attributed to triplicate seawater floating cages (1.0 × 1.0 × 2.0 m) with 60 fish in each cage. Results showed that the growth performance of fish fed the diet with 100% LO was markedly decreased compared with the control group (P < 0.05), while no remarkable difference was observed in the growth performance of fish fed diets within 66.7% LO (P > 0.05). The percentage of 18:3n-3 was the highest in the liver and muscle of fish fed the diet with 100% LO among the four treatments. When dietary FO was entirely replaced by LO, fish had a markedly higher total cholesterol, total triglyceride, low-density lipoprotein cholesterol content, and alanine transaminase activity in the serum than the control group (P < 0.05). The concentration of malondialdehyde was markedly higher, while the activity of catalase was markedly lower in fish fed the diet with 100% LO than the control group (P < 0.05). When dietary FO was entirely replaced by LO, hepatic lipid content, transcriptional levels of fatp1 and cd36, and CD36 protein expression were significantly higher, while transcriptional level of cpt-1 and CPT-1 protein expression were significantly lower than the control group (P < 0.05). As for the gene expression of cytokines, fish fed the diet with 100% LO had markedly higher transcriptional levels of il-1β, tnfα, and il-6 than the control group (P < 0.05). In conclusion, the substitution of 66.7% FO with LO had no significant effects on the growth performance of fish, while 100% LO decreased the growth performance and increased the inflammation and hepatic lipid content of fish. The increase of hepatic lipid content was probably due to the increased fatty acid uptake and decreased fatty acid oxidation in fish.

Effect of Dietary Fish Oil on Semen Quality and Reproductive Performance of Iranian Zandi Rams.

The current study was conducted to evaluate the effect of dietary fish oil on the semen quality and fertility potential of Zandi rams. For this purpose, a total of 15 Iranian Zandi rams were randomly assigned into three equal groups. The first group was a negative control and were fed without oil supplement. The second group was a positive control, and their diet contained palm oil, and the last group had a diet containing fish oil. All the diets were isocaloric and isonitrogenous. The rams were fed for 70 days, and the semen smaples were collected every 10 days. In experiment I, the evaluated parameters included semen volume, sperm concentration, motility, membrane integrity, and viability. In experiment II, 210 Iranian Zandi rams received CIDR for 12 days and 400 IU of equine chorionic gonadotropin at the time of CIDR removal. Then, they were assigned into three equal groups and artificially inseminated with semen samples. According to the obtained results, the supplementation of ram diet with fish oil as a source of omega-3 fatty acids improved the semen volume, sperm concentration, total motility, progressive motility, viability, membrane integrity, pregnancy rate, parturition rate, and lambing rate of the rams (P≤0.05). In conclusion, fish oil as a dietary supplement for rams could be an effective strategy to improve the semen quality of rams for artificial insemination and other goals.

Effects of dietary fish oil and alpha-tocopherol supplementation on selected blood parameters and fatty acid profiles in mares and their foals.

The effects of fish oil (40ml/day) supplementation, with or without synthetic all-rac-alpha-tocopherol-acetate (2,500IU/day), during the last 65days before expected parturition were investigated in 15 adult mares (553±24kg BW) and their foals. Mares were assigned to one of three diets: control (n=5), control plus fish oil and alpha-tocopherol (n=4; FO+AT) or control with just fish oil (n=6; FO). Blood samples were obtained from the mares before a 15-day dietary adaptation period (T1) and from mares and foals the first (T2) and fifth (T3) days post-partum. Colostrum was collected at T2 and milk at T3. Routine haematological, biochemical and alpha-tocopherol analyses were undertaken on all blood samples. Fatty acid concentrations were determined in the foal serum and alpha-tocopherol concentrations measured in the milk and colostrum. Diet had no effect on haematology or biochemistry in the mares. Alpha-tocopherol concentrations were significantly higher at T2 & T3 in the FO+AT mares. Foal WBCs were higher in FO (11.33±2.59×109 /l), comparing to FO+AT and control groups (9.18±1.24×109 /l and 7.26±1.03×109 /l, respectively), at T3 (p<.05). There was no significant effect of the fish oil supplementation on the foal's serum fatty acid profile. In the FO+AT group, both colostrum and milk alpha-tocopherol concentrations (2.56±0.36 and 1.36±0.22µg/ml, respectively) were higher compared than those of the FO group (1.33±0.39 and 0.72±0.31µg/ml, respectively; p<.05). Additional 2,500IU/day of synthetic alpha-tocopherol in the last 65days of pregnancy increased alpha-tocopherol concentrations in colostrum and milk and the foal's serum. 40ml/day fish oil, however, did not significantly increase serum eicosapentaenoic acid and docosahexaenoic acid concentrations in the foals.

Effects of Dietary Fish Oil and/or Sake Lees on the Concentration of Serum Lipids and Anxiety Behavior in Rats

Effects of Dietary Fish Oil and/or Sake Lees on the Concentration of Serum Lipids and Anxiety Behavior in Rats

Ezetimibe Markedly Reduces Hepatic Triglycerides and Cholesterol in Rats Fed on Fish Oil by Increasing the Expression of Cholesterol Efflux Transporters.

Besides diet therapy, hypolipidemic pharmacological therapy may be a crucial component of nonalcoholic fatty liver disease (NAFLD) treatment. Ezetimibe may be a promising drug for treatment of NAFLD. n-3 polyunsaturated fatty acids, which are abundant in fish oil, reduce serum and hepatic cholesterol and triglycerides in rodents. The aim of this study was to examine the combined effects of dietary fish oil and ezetimibe on lipid metabolism in rats. Seven-week-old male Sprague-Dawley rats were allocated to four different diets containing 1) 10% soybean oil (C), 2) 10% fish oil (F), 3) 10% soybean oil + 0.005% ezetimibe, and 4) 10% fish oil + 0.005% ezetimibe (F+E) for 4 weeks, when the liver, jejunum, blood, and fecal samples were collected. Compared with the C group, the F+E diet decreased hepatic triglycerides and cholesterol 84% and 86%, but it did not increase fecal cholesterol. In liver, the expression of lipogenic enzymes was decreased in the F+E diet, whereas β-oxidation-related genes were not increased. Abcg5/g8 mRNA expression was increased 1380%/442% when ezetimibe was added to the F diet. These gene expression changes are related to the decrease in hepatic lipids. In jejunum, Abcg5/g8 mRNA was increased 244%/841% when ezetimibe was added to the F diet. Hepatic induction of Abcg5/8 rather than intestinal induction correlates with the marked decrease in liver cholesterol when ezetimibe was added to the F diet. These data suggest that fish oil diet and ezetimibe in combination may be a beneficial therapy for NAFLD by increasing hepatic Abcg5/g8 and decreasing lipogenic genes. SIGNIFICANCE STATEMENT: There is currently no single treatment for NAFLD. Thus, lifestyle modifications including dietary regulation and physical activity are also important options. In this study, ezetimibe, a cholesterol absorption inhibitor, was evaluated for the treatment of liver steatosis in rats fed on the different diets. We found that ezetimibe and fish oil in combination markedly improved fatty liver by increasing cholesterol efflux transporters. The combination therapy of fish oil agents and ezetimibe may be effective for NAFLD.

Modulation of the Liver Protein Carbonylome by the Combined Effect of Marine Omega-3 PUFAs and Grape Polyphenols Supplementation in Rats Fed an Obesogenic High Fat and High Sucrose Diet.

Diet-induced obesity has been linked to metabolic disorders such as cardiovascular diseases and type 2 diabetes. A factor linking diet to metabolic disorders is oxidative stress, which can damage biomolecules, especially proteins. The present study was designed to investigate the effect of marine omega-3 polyunsaturated fatty acids (PUFAs) (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) and their combination with grape seed polyphenols (GSE) on carbonyl-modified proteins from plasma and liver in Wistar Kyoto rats fed an obesogenic diet, namely high-fat and high-sucrose (HFHS) diet. A proteomics approach consisting of fluorescein 5-thiosemicarbazide (FTSC) labelling of protein carbonyls, visualization of FTSC-labelled protein on 1-DE or 2-DE gels, and protein identification by MS/MS was used for the protein oxidation assessment. Results showed the efficiency of the combination of both bioactive compounds in decreasing the total protein carbonylation induced by HFHS diet in both plasma and liver. The analysis of carbonylated protein targets, also referred to as the ‘carbonylome’, revealed an individual response of liver proteins to supplements and a modulatory effect on specific metabolic pathways and processes due to, at least in part, the control exerted by the supplements on the liver protein carbonylome. This investigation highlights the additive effect of dietary fish oils and grape seed polyphenols in modulating in vivo oxidative damage of proteins induced by the consumption of HFHS diets.

Effect of dietary fish oil on enhanced inflammation and disturbed lipophagy in white adipose tissue caused by a high fat diet

Fish oil containing omega-3 polyunsaturated fatty acids (PUFA) attenuates chronic inflammation found in obesity, leading to a reduction in insulin resistance. The effect of fish oils containing omega-3 PUFA in the lipophagy pathway is unknown. In the present study, we examined whether omega-3 PUFA affects anti-inflammatory or lipophagy pathways in high fat diet-induced obesity. There was a significant increase in body weight gain in mice fed a high fat diet (HFD) or HFD with fish oil (HFD-FO), but not in mice fed a normal diet (ND). Although there was no significant difference between body weight gain and plasma insulin levels in the HFD and HFD-FO mice, the intake of HFD-FO prevented glucose intolerance and peripheral insulin resistance induced by HFD. In addition, macrophage infiltration and cytokine levels in white adipose tissue (WAT) in HFD-FO mice were decreased, compared with HFD mice. There were no significant differences between lipophagy related proteins and their mRNA levels in the HFD-FO and HFD groups. These results suggest that supplementation with fish oil might be beneficial in preventing insulin resistance caused by a high fat diet through an anti-inflammatory effect, but not lipophagy activation.

Effects of replacing fish oil with wheat germ oil on growth, fat deposition, serum biochemical indices and lipid metabolic enzyme of juvenile hybrid grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂)

Fish oil was one of most important feed ingredients for carnivorous marine fish species, but the production might not cover all the necessary quantity for aquaculture. Meanwhile wheat germ oil could be a potential alternative for fish oil in aquatic feed. Hence, a 70 day feeding trial was conducted to investigate the effects of dietary fish oil replaced by wheat germ oil (WGO) on the growth, lipid and fatty acids deposition, and lipid metabolic enzymes activities of juvenile hybrid grouper (initial weight 55.31 ± 0.68 g), E. fuscoguttatus♀ × E. lanceolatus♂. Six isonitrogenous and isoenergetic experimental diets were formulated with 0%, 20%, 40%, 60%, 80% and 100% replacement of fish oil by WGO. Survival rate, weight gain rate, specific growth rate, and feed conversion ratio were similar among fish fed with different diets. Viserosomatic index and mesenteric fat ratio were significantly increased by dietary WGO. No significant differences were observed in the compositions of whole body, muscle and liver. C18: 3n-3 and C18:2n-6 contents in tissues were significantly increased, but EPA and DHA were significantly decreased by dietary WGO. No significant differences were found on the activities of hepatopancreas lipoprotein lipase, hepatic lipase and fatty acid synthase, while the activity of intestinal lipase was decreased. Total cholesterol, high density lipoprotein cholesterol, and low density lipoprotein cholesterol in plasma were not affected, but triglyceride was increased by dietary WGO. It can be concluded from the results that about 71.8% dietary fish oil can be replaced by WGO in diets with 50% crude protein and 12% crude lipid for subadult hybrid grouper, and fatty acids deposition and biosynthesis of this species was quite different from that of other fish species.