Rapeseed Oil Diet Research Articles

Effects of high α-linolenic acid transgenic rapeseed oil diet on growth performance, fat deposition, flesh quality, antioxidant capacity, and immunity of juvenile largemouth bass (Micropterus salmoides).

Omega-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) increases in aquatic products contributes to improving meat quality, thereby positively impacting human health. Different from marine fish which primarily obtain n-3 LC-PUFAs directly from zooplankton and algae, freshwater fish mainly utilize dietary linolenic acid (ALA) as a substrate to synthesize n-3 LC-PUFAs. Our team has successfully created a transgenic rapeseed oil (TRO) with high ALA content. Therefore, we here assessed the impacts of four different diets (LR, low-fat rapeseed oil (RO) diet; HR, high-fat RO diet; LTR, low-fat TRO diet; HTR, high-fat TRO diet) on growth performance, lipid accumulation, fatty acid composition, antioxidant capacity, immunity and serum biochemical indexes of juvenile largemouth bass (Micropterus salmoides), an economically valuable freshwater fish. The results showed no significant difference in survival rate among the four dietary groups. No significant differences in body weight gain and final weight were found between the LR and LTR groups, as well as between HR and HTR groups. No matter if it was a high-fat or low-fat diet, compared with the RO diet, TRO diets significantly increased the content of n-3 LC-PUFA, improved meat quality, effectively alleviated lipid accumulation in livers and muscles of juvenile largemouth bass. In addition, using high-fat diets, TRO diet improved the antioxidant capacity and immune ability of juvenile largemouth bass, thereby promoting the overall health of fish. This study provides novel insights for fish feed formulation optimization from the perspective of genetically modified feed ingredients, and high-quality aquatic products for human consumption.

Effects of different vegetable oil sources on growth performance, body composition and tissue fatty acid composition of spotted knifejaw, Oplegnathus punctatus

During 8-weeks feeding trial, four experimental diets were designed to assess the effects of different lipid sources, including fish oil (FO), soybean oil (SO), rapeseed oil (RO) and linseed oil (LO) on growth performance, body composition and tissue fatty acid composition of Oplegnathus punctatus. Each diet was fed to triplicate groups (initial body weight 12.06 ± 0.09 g per fish). The weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER) of fish fed LO diets were not significantly different from those fed FO diets, but significantly higher than those fed SO and RO diets. Besides, although the contents of EPA or DHA in different vegetable oil diets were same, the EPA content in muscle and liver and DHA content in liver of the LO group were significantly higher than that of the SO and RO groups. In addition, the highest gene expression of fads2 presented in fish fed LO diets, whereas the gene expression of elovl5 was not significantly different in three vegetable oil groups. Fish fed the SO diet had the highest liver lipid content, hepatosomatic index (HSI), viscerosomatic index (VSI), aspartate transaminase (AST) and alanine transaminase (ALT) values. In conclusion, under experimental conditions, the complete substitution of LO for FO had not negative effect on the feed utilization and growth performance of O.punctatus.

Effects of different lipid sources on growth performance, fatty acids composition in tissue and expression of genes related to lipid metabolism in largemouth bass (Micropterus salmoides)

An eight-week feeding trial was conducted to investigate the effects of dietary lipid sources on growth performance, fatty acids composition in tissue and expression of genes related to lipid metabolism in juvenile largemouth bass (Micropterus salmoides). Four experimental diets were formulated to contain 6% coconut oil (CO), rapeseed oil (RO), linseed oil (LO) and fish oil (FO), respectively. Each diet was fed to triplicate groups of juvenile for 8 weeks. The results indicated that final body weight (FBW), percent weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), survival, hepatopancreas index (HSI), viscerosomatic index (VSI) and intraperitoneal fat ratio (IPF) were not significantly influenced by dietary different lipid sources (P＞0.05). Moreover, proximate composition in whole body, dorsal muscle and liver were also not significantly affected by dietary different lipid sources (P ＞0.05). Fish fed with FO diet was significantly higher MDA concentration in hepatic and serum than those fed with CO, RO and LO diets (P < 0.05). However, T-AOC, SOD and GSH activities in hepatic and serum were not affected by different lipid sources (P＞0.05). Fish fed with RO diet had significantly higher relative expression of fas and acc in liver than those fed the other diets, the highest expression of lpl was occurred at fish fed with CO diet (p < 0.05). Meanwhile, fish fed with CO and FO diets had significantly lower expression of elovl5 and Δ6fad in liver than those fed with RO diet (p < 0.05). In conclusion, the results of present study indicated that vegetable oils such as CO, RO and LO can potentially be used as dietary FO substitutes for juvenile largemouth bass.

Dietary rapeseed (canola) oil suppresses testosterone production and increases plasma aldosterone level in stroke-prone spontaneously hypertensive rats (SHRSP)

Dietary rapeseed (canola) oil suppresses testosterone production and increases plasma aldosterone level in stroke-prone spontaneously hypertensive rats (SHRSP)

The effects of different lipid sources on the growth, intestinal health, and lipid metabolism of the pacific white shrimp (Litopenaeus vannamei)

It is an urgent problem to find suitable replacement of fish oil (FO) in aquatic feeds due to the stagnant production and rising prices of FO. To evaluate the substitution of vegetable oils for FO in the diet of Litopenaeus vannamei (L. vannamei), four diets containing FO, linseed oil (LO), soybean oil (SO) or rapeseed oil (RO) have been fed to L. vannamei for 30 days in this study, and the effects of different lipid sources on the growth, body composition, intestinal health, disease resistance and lipid metabolism of the shrimps were investigated. The results showed that the profiles of fatty acids in four diets and the muscles of the shrimps were discrepant. Further analysis demonstrated that the growth performance of the shrimps in LO and SO groups was similar as that in FO group. Moreover, it seemed that the intestinal health in the shrimps fed with LO or SO diet was improved. In contrast, RO diet reduced the weight gain rate and weakened the intestinal health of the shrimps. Consistently, the shrimps fed with RO diet displayed the highest mortality after Vibrio parahaemolyticus (V. parahaemolyticus) infection among all groups. Additionally, the contents of total cholesterol (T-CHO) and the gene expression of fatty acid synthase (FAS) in the hepatopancreas of the shrimps in RO group was significantly higher than that in FO group. In conclusion, LO or SO could be utilized as the substitution for FO in the diet of L. vannamei, while the replacement of FO with RO in the diet might induce the impaired intestinal health and the imbalance of lipid metabolism, leading to the reduced growth and disease resistance of the shrimp. The present study has provided the research basis for the further development of vegetable oils as a substitute for fish oil in shrimp diets.

Effect of a Low-Methane Diet on Performance and Microbiome in Lactating Dairy Cows Accounting for Individual Pre-Trial Methane Emissions.

Simple SummaryLow methane-emitting dietary ingredients have been identified in extensive research conducted during the past decade. This study investigated the effects of replacing grass silage with maize silage, with or without rapeseed oil supplementation, on the methane emissions and performance of dairy cows. Pre-trial measurements of methane-emissions were used in the evaluation. Partial replacement of grass silage with maize silage did not affect methane emissions but reduced dairy cow performance. Adding rapeseed oil to the diet substantially reduced methane emissions due to modified rumen microbiota, resulting in impaired nutrient intake, digestibility, and yield of energy-corrected milk. Correcting for individual cow characteristics of methane emissions did not affect the magnitude of suppression of methane emissions by dietary treatments.This study examined the effects of partly replacing grass silage (GS) with maize silage (MS), with or without rapeseed oil (RSO) supplementation, on methane (CH4) emissions, production performance, and rumen microbiome in the diets of lactating dairy cows. The effect of individual pre-trial CH4-emitting characteristics on dietary emissions mitigation was also examined. Twenty Nordic Red cows at 71 ± 37.2 (mean ± SD) days in milk were assigned to a replicated 4 × 4 Latin square design with four dietary treatments (GS, GS supplemented with RSO, GS plus MS, GS plus MS supplemented with RSO) applied in a 2 × 2 factorial arrangement. Partial replacement of GS with MS decreased the intake of dry matter (DM) and nutrients, milk production, yield of milk components, and general nutrient digestibility. Supplementation with RSO decreased the intake of DM and nutrients, energy-corrected milk yield, composition and yield of milk fat and protein, and general digestibility of nutrients, except for crude protein. Individual cow pre-trial measurements of CH4-emitting characteristics had a significant influence on gas emissions but did not alter the magnitude of CH4 emissions. Dietary RSO decreased daily CH4, yield, and intensity. It also increased the relative abundance of rumen Methanosphaera and Succinivibrionaceae and decreased that of Bifidobacteriaceae. There were no effects of dietary MS on CH4 emissions in this study, but supplementation with 41 g RSO/kg of DM reduced daily CH4 emissions from lactating dairy cows by 22.5%.

Comparison of EPA and DHA utilization in Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) fed two diets with different content of fish oil and rapeseed oil

ABSTRACT Atlantic salmon and rainbow trout with initial weights of 460–468 g were fed two diets either high in fish oil (FO) or rapeseed oil (RO) content. The abilities of the fish to metabolize and deposit lipid and n-3 fatty acids were compared. Growth rates, FCR, and fat digestibility were similar in both species. Rainbow trout showed higher condition factors and lower dress-out percentage and hepatosomatic index than salmon. Whole-body content of EPA and DHA were higher in both species fed the FO diet than in the RO diet, but indicated higher capacities to produce DHA in rainbow trout than in salmon. The total fat content in the RO group was lower and DHA higher in rainbow trout liver than in salmon, indicating a greater ability of rainbow trout to increase metabolism to DHA.

High broodstock fads2 expression combined with nutritional programing through broodstock diet improves the use of low fishmeal and low fish oil diets in gilthead seabream (Sparus aurata) progeny

One of the factors that limits the replacement of fish meal (FM) and fish oil (FO) by plant ingredients in diets for marine fish, is their lack of long chain-polyunsaturated fatty acids (LC-PUFA). LC-PUFA are essential fatty acids for these fish species, which lack sufficient fatty acyl desaturase 2 (Fads2) activity to synthesize them. Nutritional programing or the use of broodstock with a higher Fads2 activity could improve marine fish ability to synthesize LC-PUFA and their ability to use low FM and FO diets. The aim of this study was to determine the effect of gilthead seabream broodstock with inherently high or inherently low fads2 gene expression and nutritional programing with broodstock diets rich in FO or rapeseed oil (RO) on the progeny growth performance, liver morphology, biochemical composition and expression of selected genes. Sea bream juveniles (2.31± 0.01 g initial body weight, mean ± SD) obtained from broodstock with either high (H) or low (L) fads2 expression and fed a broodstock diet based on FO or RO were randomly distributed into 12 × 250 L tanks and nutritionally challenged for 45 days with a diet containing only 7.5% FM and no FO. The highest growth was found in juveniles from broodstock with a high fads2 expression and fed the RO diet, whereas the lowest growth was obtained in those from broodstock with a low fads2 expression and fed the RO diet. Juveniles from broodstock with high fads2 expression showed significantly higher fads2 expression in liver and increased PUFA contents in liver and muscle. Replacement of FO by RO in broodstock diets led to a significantly increased hepatic 18:3n-6/18:2n-6 ratio and reduction in the viscerosomatic index of the progeny juveniles, the hepatocyte size and the ghr-1/ghr-2 expression in muscle. Overall, the results showed significant trans-generational effects of both the broodstock fads2 expression and the type of lipid in the broodstock diet on the metabolism and performance of the juvenile progeny challenged with a diet low in FM and FO.

Dietary Rapeseed Oil Supplementation Reduces Hepatic Steatosis in Obese Men-A Randomized Controlled Trial.

Effective treatment for obesity associated non-alcoholic fatty liver disease (NAFLD) is limited. Dietary supplementation of n-3 polyunsaturated fatty acids, specifically alpha linolenic acid (ALA), can resolve intrahepatic lipid content (IHL). This study investigates the effect of daily supplementation of either refined rapeseed (RA), containing high amounts of ALA, or refined olive (OL) oil on IHL and glucose metabolism in NAFLD patients. 27 obese men consumed an isocaloric diet including either 50 g of RA or OL daily for 8 weeks. Hepatic proton magnetic resonance spectroscopy, hyperinsulinemic-euglycemic clamp studies and blood tests are performed before and at the end of the study. At 8 weeks a significant reduction in IHL is observed for RA (13.1 ± 1.6 before versus 11.1 ± 1.6% after intervention) versus OL (13.3 ± 2.5 before versus 15.7 ± 2.7% after intervention). For RA, a 21% reduction (P < 0.02) in serum free fatty acids (FFA) and a 1.68-fold increase (P = 0.03) of serum interleukin-6 (IL-6) is observed after 8 weeks. RA has a beneficial effect on hepatic lipid metabolism as shown by reduced IHL and serum FFA. RA induced IL-6 production seems to be liver protective confirming previous results.

Effects of replacement of dietary fish oil by rapeseed oil on growth performance, anti-oxidative capacity and inflammatory response in large yellow croaker Larimichthys crocea

A 12-week feeding trial was conducted to evaluate the effects of replacement of dietary fish oil by rapeseed oil on the growth, anti-oxidative capacity and inflammatory responses of large yellow croaker Larimichthys crocea (initial body weight: 36.02 ± 0.58 g). The control diet was designed to contain 6.5% of fish oil, and named as FO. Based on it, the fish oil was 50% and 100% replaced by rapeseed oil to make the other two diets (FR and RO, respectively). Results showed that the specific growth rate was significantly reduced, and the crude lipid contents in muscle and liver were significantly increased in the RO group. The total anti-oxidative capacity and expressions of superoxide dismutase 1 and 2, glutathion peroxidase and nuclear factor erythroid 2-related factor 2 in liver of fish fed RO were significantly lower. Dietary rapeseed oil significantly decreased expressions of arginase I and interleukin 10, and increased expressions of TNFα, interleukin 1β, toll-like receptor 22 and myeloid differentiation factor 88 in liver. In conclusion, high dietary rapeseed oil could suppress growth performance and liver anti-oxidative capacity, and induce inflammation of large yellow croaker.

Influence of dietary plant fats and antioxidant supplementations on performance, apparent metabolizable energy and protein digestibility, lipid oxidation and fatty acid composition of meat in broiler chicken

This study aimed to evaluate the effects of dietary different antioxidants and plant oils on performance, apparent metabolizable energy and protein digestibility, meat quality and meat fatty acid composition of broiler chickens. In all, 480 male broiler chicks of 1‐day old were assigned in a completely randomized design with factorial arrangement 2 × 5 (plant oil sources [soybean and rapeseed oils] and antioxidant sources [vitamin E, Thyme, Rosemary and Satureja essential oils] furthermore control treatment without antioxidant). The results indicated that at 1–42 d of age, growth performance and carcass yield of birds were not influenced by dietary plant oils and antioxidant supplementations. Dietary Thyme essential oil (300 mg/kg) resulted in an increase in crude protein digestibility and birds fed on diets without antioxidant showed increase in the apparent metabolizable energy (p < .01). Birds receiving the combination of soybean oil with Rosemary essential oil had lowest malondialdehyde concentration in comparison to birds receiving other treatments (p < .05) in the drumstick meat. Also, birds receiving the combination of soybean oil with vitamin E had lowest malondialdehyde concentration in comparison to birds receiving other treatments (p < .05) in the breast meat. The results indicated that treatments did not influence water holding capacity of meat. Also, dietary rapeseed oil and Thyme essential oil supplementations, separately, decreased saturated fatty acid (p < .01) and increased unsaturated fatty acid and unsaturated to saturated fatty acids ratio (p < .01) of drumstick meat tissue in broiler chicken (p < .01). In conclusion, dietary rapeseed oil and Thyme essential oil increased in n‐3 polyunsaturated fatty acids in the drumstick meat (p < .01) and a combination of dietary soybean oil, Rosemary essential oil and vitamin E decreased the lipid oxidation in the meat of broiler chickens (p < .05).

Regulation of Dietary Lipid Sources on Tissue Lipid Classes and Mitochondrial Energy Metabolism of Juvenile Swimming Crab, Portunus trituberculatus.

An 8-weeks feeding trial with swimming crab, Portunus trituberculatus, was conducted to investigate the effects of different dietary lipid sources on the lipid classes, lipid metabolism, and mitochondrial energy metabolism relevant genes expression. Six isonitrogenous and isolipidic experimental diets were formulated to contain fish oil (FO), krill oil (KO), palm oil (PO), rapeseed oil (RO), soybean oil (SO), and linseed oil (LO), respectively. A total of 270 swimming crab juveniles (initial weight 5.43 ± 0.03 g) were randomly divided into six diets with three replications, each consisted of 45 juvenile crabs. The results revealed that crabs fed KO had highest lipid content in hepatopancreas and free fatty acids in serum among all diets. The anabolic pathway relevant genes: fas and acc were up-regulated in KO diet. The catabolic pathway relevant genes, hsl, was up-regulated in LO diet, while cpt1 was up-regulated in KO diet. Whereas, the genes involved in the transport and uptake of fatty acids such as fabp1 and fatp4 were down-regulated in crab fed PO and RO diets. Furthermore, the gene expression levels of transcription factors: srebp-1 and hnf4α in KO and SO diets were the highest among all diets. FO and KO diets had significantly higher unsaturation index of mitochondrial membrane than others. The genes related to mitochondrial energy metabolism, such as Atpase6, sirt1, and sirt3 were significantly up-regulated in KO and SO diets. In summary, dietary KO and SO supplementation could improve the lipid metabolism, promote energy production for juvenile swimming crab and improve physiological process and function including molting. These findings could contribute to deepen the understanding of the physiological metabolism of dietary fatty acids for swimming crab.

Effects of supplementation with different rapeseed oil sources and levels on production performance, egg quality, and serum parameters in laying hens

ABSTRACTThis study was to determine the effects of rapeseed oil on production performance, egg quality, and serum parameters in laying hens. A total of 1,080 hens (33-wk-old) were randomly divided into a 1 plus 4 × 2 factorial design including four different rapeseed oil sources [high erucic acid of Mianyang city (MH); high erucic acid of Deyang city (DH); low erucic acid of Mianyang (ML); low erucic acid of Deyang (DL)] at two levels (2% and 4%) for 12 wk. The egg production and egg weight were decreased (P < 0.05) during 9 to 12 wk and 1 to 12 wk, while the average daily feed intake (ADFI) and feed conversion ratio were decreased (P < 0.01) in all phases compared to the control group. Adding ML as oil source had higher (P < 0.05) egg weight compared to DH in all periods in spite of levels. Meanwhile, layers fed 4% rapeseed oil decreased (P < 0.01) egg production compared with 2% in all phases except 1 to 4 wk. Regardless of rapeseed oil sources, hens fed 4% oil decreased (P < 0.05) egg weight in contrast to 2% during the whole experiment except 5 to 8 wk. The ADFI was lower (P < 0.01) in 4% oil inclusion groups compared with 2% during overall phase. Rapeseed oil decreased the yolk color (P < 0.01) and yolk ratio (P = 0.02) and increased (P < 0.01) the albumen height and Haugh unit at 12 wk. Dietary rapeseed oil supplementation resulted in a decreased total triglyceride (TG; P < 0.01) and increased high-density lipoprotein cholesterol (P = 0.02). Regardless of rapeseed oil levels, layers fed MH had higher TG (P < 0.01), TC (P < 0.05), low-density lipoprotein cholesterol (P < 0.05), alanine transaminase (P < 0.01) than those fed other sources. Taken together, the addition of rapeseed oil decreased laying performance, reduced TC and TG in the serum, and increased Haugh unit, with low erucic acid or 2% group showed more pronounced results among all treatments.

Effect of dietary rapeseed and soybean oil on growth performance, carcass traits, and fatty acid composition of pigs

ABSTRACT The objectives of this investigation were to examine the impact of the dietary inclusion of rapeseed and soybean oil and the length of their feeding before slaughter on growth performance, quantitative and qualitative carcass traits, and fatty acid composition in longissimus lumborum muscle (LLM) of pigs. The experiment was conducted with 72 pigs (36 barrows and 36 gilts), divided into six oil-containing diet groups and one control group. Diets of the experimental groups were supplemented with 4% rapeseed (ROD) [...]

Effect of Duration of Dietary Rapeseed and Soybean Oil Feeding on Physical Characteristics, Fatty Acid Profile, and Oxidative Stability of Pig Backfat.

Simple SummaryThe fatty acid profile of pig backfat directly reflects the fatty acid profile of the pig diet. The increased intake of n-3 fatty acids, whose higher content is in vegetable oils, can decrease the risk of heart disease incidence and vascular disorders. The aim of this study was to evaluate the effect of rapeseed and soybean oils and the duration of supplementing the pig diet until slaughter on physical characteristics, fatty acid profile and lipid oxidation of backfat. With the supplementation of oil in the diet for 6 weeks until slaughter, the value of lightness and perforation part of backfat significantly decreased. A dose of 40 g/kg of rapeseed oil in the last 4 weeks before slaughter is sufficient for improving the fatty acid profile without adversely affecting the consistency of the backfat. From the point of view of human health, rapeseed oil is a more suitable source of unsaturated fatty acid than soybean oil in composing the diet for pigs.This study compared the effect of two vegetable oils and their feeding duration on pig backfat quality. The experiment was conducted with 60 DanBred pigs that were fed a diet supplemented (40 g/kg) with rapeseed or soybean oil for 2, 4 or 6 weeks before slaughter at 152 d of age. The supplementation of both vegetable oils in the diets for 6 weeks negatively changed backfat consistency. The pigs fed soybean oil for 4 (17.64%) and 6 weeks (18.52%) before slaughter showed an increase in backfat linoleic acid content (p = 0.002), whereas, in contrast to the other groups, rapeseed oil in the diet for 6 weeks (2.38%) increased α-linolenic acid content (p = 0.039). The content of PUFAs (p = 0.024) and n-6 PUFAs (p = 0.003) was increased by adding soybean oil to the diet for 4 and 6 weeks. The ratio of n-6/n-3 PUFAs was decreased (p = 0.040) by supplementing rapeseed oil for 4 and 6 weeks. The oil feeding duration decreased (p < 0.001) the atherogenic and thrombogenic indices. The lipid oxidative stability of backfat stored for 3 and 5 days increased (p < 0.001) in pigs fed dietary vegetable oils for 6 weeks prior to slaughter. In conclusion, the feeding of rapeseed oil for 4 weeks before slaughter is sufficient for improving the FA profile without negative effect on the consistency of the backfat.

Fucosterol Causes Small Changes in Lipid Storage and Brassicasterol Affects some Markers of Lipid Metabolism in Atlantic Salmon Hepatocytes.

Several feeding trials with Atlantic salmon fed naturally high phytosterol concentrations due to dietary rapeseed oil inclusion have shown changes in lipid metabolism and increased hepatic lipid storage in the fish. An in vitro trial with Atlantic salmon hepatocytes was, therefore, performed to study the possible direct effects of phytosterols on lipid storage and metabolism. The isolated hepatocytes were exposed to seven different sterol treatments and gene expression, as well as lipid accumulation by Oil Red O dyeing, was assessed. Fucosterol, a sterol found in many algae species, had an effect on the size of individual lipid droplets, leading to smaller lipid droplets than in the control without added sterols. A sterol extract from soybean/rapeseed led to an increase in the percentage of hepatocytes with visible lipid droplets at 20× magnification, while hepatocytes of both the sterol extract-treated groups and fucosterol-treated groups had a larger proportion of their area covered with lipids compared to control cells. Brassicasterol, a sterol characteristic of rapeseed oil, was the only sterol treatment leading to a change in gene expression, affecting the expression of the nuclear receptors, peroxisome proliferator-activated receptor gamma (pparg) and retinoid X receptor (rxr). The current study thus shows that phytosterols can have direct, although subtle, effects on both hepatic lipid storage and gene expression of Atlantic salmon in vitro.

Effect of dietary fatty acid composition on growth, fatty acids composition and hepatic lipid metabolism in juvenile turbot (Scophthalmus maximus L.) fed diets with required n3 LC-PUFAs

A 12-week feeding experiment was conducted to investigate the effects of dietary fatty acids composition on growth performance, lipid deposition and some genes expression of hepatic lipid metabolism in juvenile turbot (Scophthalmus maximus L.) (mean initial body weight, 9.49±0.03g) fed diets with required n3 LC-PUFA. Juvenile turbot were fed diets with palm oil (PO), rapeseed oil (RO), soybean oil (SO) or linseed oil (LO) replacing the same levels of fish oil (FO), respectively. Each diet was randomly fed to triplicate tanks, and each tank was stocked with 35 fish. The results showed that growth performance and feed utilization of turbot fed diets with required n3 LC-PUFA were independent of dietary fatty acids composition. As expected, C16:0, C18:1n, C18:2n-6, C18:3n-3 and n3 LC-PUFAs level in liver were up to the maximum in the PO, RO, SO, LO and FO group, respectively, and significantly higher than that in the other groups (P<0.05). Fish fed the diet with RO had the lowest plasma triglyceride and the highest HDL-c/LDL-c, although no significant difference of plasma triglyceride had been found between the RO group and the LO group. Hepatic lipid content in fish fed diets with SO, RO, and LO was significantly higher compared with PO and FO groups. The higher activities of hepatic G6PD and ME were found in fish fed diets with PO or FO compared to LO. The relative expression of LPL, LXR, and ApoB-100 gene in the RO group and the LO group, MTP gene in the LO group, PPARα and FAS genes in the PO group, and PPARγ gene in the SO group were significantly higher than those in the FO group. These results indicated that the increase in hepatic lipid deposition of turbot induced by the SO, RO, and LO diets are associated with up-regulation of some genes involved in lipids biosynthesis metabolism.

Dietary Intake of Structured Lipids with Different Contents of Medium-Chain Fatty Acids on Obesity Prevention in C57BL/6J Mice.

Three medium- and long-chain triacylglycerols (MLCT) with different contents of medium-chain fatty acids (MCFA) (10% to 30%, w/w) were prepared and evaluated for their anti-obesity potential in C57BL/6J mice. The group fed with a high fat diet of MLCT containing 30% (w/w) MCFA showed significantly decreased body weight and fat mass (P < 0.05) relative to the control mice fed an obesity-inducing high fat rapeseed oil diet. In addition, serum parameters including triacylglycerols, total cholesterol, glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein A1 and apolipoprotein B in the treatment group fed with 30% (w/w) MCFA were close to those of mice fed with a low fat rapeseed oil diet, but significantly different (P < 0.05) from those of the obesity control group. Moreover, the intake of MLCT with high content of MCFA reduced the size of adipocytes. In addition, the visceral fat and liver weights, as well as the liver triacylglycerol for 3 treatment groups were lower than those of the obesity control group. These results demonstrate the great potential of MLCT with high content of MCFA in weight loss.

Dietary Lipid Sources Influence Fatty Acid Composition in Tissue of Large Yellow Croaker (Larmichthys crocea) by Regulating Triacylglycerol Synthesis and Catabolism at the Transcriptional Level.

An 8-week feeding trial was conducted to evaluate the effects of dietary lipid sources on growth performance, fatty acid composition, rate-limiting enzyme activities and gene expression related to lipid metabolism in large yellow croaker (Larmichthys crocea). Five iso-nitrogenous and iso-lipidic experimental diets were formulated to contain different lipid sources, such as fish oil (FO), soybean oil (SO), linseed oil (LO), rapeseed oil (RO) and peanut oil (PO), respectively. Triplicate groups of 50 fish (initial weight 13.77±0.07g) were stocked in 15 floating net cages (1.5m×1.5m×2.0m). Fish fed the diets containing RO and LO had lower weight gain and specific growth rates than those fed the FO, SO and PO diets. Survival, feed efficiency, protein efficiency ratio, hepatosomatic index, viscerasomatic index and condition factor were not significantly affected by different dietary lipid sources. Fish fed the diet containing FO had higher lipid content in whole body compared with the other groups, whereas fish fed the SO diet had the lowest muscle lipid content. Fatty acid profiles of muscle and liver reflected the fatty acid composition of the diets. Plasma glucose, triglyceride, and the enzymatic activity of aspartate aminotransferase and alanine aminotransferase were significantly influenced by different dietary lipid sources, while total protein, cholesterol, superoxide dismutase or malondialdehyde in plasma were not affected by the different dietary lipid sources. Fish fed the LO diet had lower adipose triglyceride lipase and fatty acid synthase activities in liver than those fed the diets containing FO and RO, while the LO diet resulted in the highest hepatic carnitine palmitoultransferase-1 activity. Hepatic gene relative expression of adipose triglyceride lipase and carnitine palmitoyltransferase-1 in fish fed PO diet was significantly higher than all other groups, whereas fish fed the SO and LO diets had lower relative expression levels of lipoprotein lipase than the other groups. The highest relative expression levels of fatty acid synthase and acyl-CoA diacylglycerol acyltransferase-2 were observed in the FO group, while the highest relative expression of glucose 6-phosphate dehydrogenase occurred in fish fed the FO and RO diets. In summary, based on the growth performance, FO and SO appear to be suitable lipid sources for large yellow croaker, with the findings of this study also providing a molecular insight into the role of lipid metabolic mechanism in response to different dietary lipid sources.

Finishing feeding strategy as an instrument for modification of fatty acid composition of brook char (Salvelinus fontinalis)

This study investigated the possibility of using a finishing feeding strategy and to apply a dilution model for the calculation of the content of fatty acids (FA) in farmed brook char (Salvelinus fontinalis). Four duplicate groups of fish with an initial weight 153.3 ± 4.9 g−1 were kept in a flow-through system for 135 days, during which they more than triplicated their weight. Control groups were fed the same unmodified commercial diet with 100 % fish oil (FO) or with 60 % fish oil and 40 % rapeseed oil (RO) mixture. Two groups were fed by RO diet followed by 45 (RO:45FO) and 90 (RO:90FO) days of FO diet, respectively, at the end of the growing period. The fillet FA composition at the end of the experiment corresponded with the FA composition of the lipid source in the diet for the tested groups. A significant (p < 0.05) impact on FA composition with a decreasing tendency in the representation of n-3 HUFA with a prolonged feeding period with the RO diet was observed. The application of a dilution model enabling the prediction of the content of a given fatty acid in a given time was successfully performed.