Fatty Acid Synthetase Activity Research Articles

Dietary Astaxanthin Can Promote the Growth and Motivate Lipid Metabolism by Improving Antioxidant Properties for Swimming Crab, Portunus trituberculatus.

This study aimed to assess the influence of varying dietary levels of astaxanthin (AST) on the growth, antioxidant capacity and lipid metabolism of juvenile swimming crabs. Six diets were formulated to contain different AST levels, and the analyzed concentration of AST in experimental diets were 0, 24.2, 45.8, 72.4, 94.2 and 195.0 mg kg-1, respectively. Juvenile swimming crabs (initial weight 8.20 ± 0.01 g) were fed these experimental diets for 56 days. The findings indicated that the color of the live crab shells and the cooked crab shells gradually became red with the increase of dietary AST levels. Dietary 24.2 mg kg-1 astaxanthin significantly improved the growth performance of swimming crab. the lowest activities of glutathione (GSH), total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and peroxidase (POD) were found in crabs fed without AST supplementation diet. Crabs fed diet without AST supplementation showed lower lipid content and the activity of fatty acid synthetase (FAS) in hepatopancreas than those fed diets with AST supplementation, however, lipid content in muscle and the activity of carnitine palmitoyl transferase (CPT) in hepatopancreas were not significantly affected by dietary AST levels. And it can be found in oil red O staining that dietary 24.2 and 45.8 mg kg-1 astaxanthin significantly promoted the lipid accumulation of hepatopancreas. Crabs fed diet with 195.0 mg kg-1 AST exhibited lower expression of ampk, foxo, pi3k, akt and nadph in hepatopancreas than those fed the other diets, however, the expression of genes related to antioxidant such as cMn-sod, gsh-px, cat, trx and gst in hepatopancreas significantly down-regulated with the increase of dietary AST levels. In conclusion, dietary 24.2 and 45.8 mg kg-1 astaxanthin significantly promoted the lipid accumulation of hepatopancreas and im-proved the antioxidant and immune capacity of hemolymph.

Effect of Tea Polyphenols, α-Lipoic Acid and Their Joint Use on the Antioxidant and Lipid Metabolism Performance of Hybrid Grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) Fed with High-Lipid Diets.

This study investigated tea polyphenols (TP), α-lipoic acid (ALA) and their joint use on the antioxidant and lipid metabolic performance of hybrid grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) took food with high-fat diets. Six high-lipid diets with isonitrogen (50% of dry matter) and isolipid (17% of dry value) were designed, in which a total content of 1,000 mg/kg additives were added to each group except for the control group (FL). The additives addition ratios in each group were ALA (AL), TP (PL), ALA : TP = 1 : 1 (EL), ALA : TP = 1 : 2 (OL), ALA : TP = 2 : 1 (TL). Each diet was divided into three repeat groups with 30 tails (6.84 ± 0.01 g) in each group and fed for 8 weeks. The consequences were as follows: (1) the highest weight gain rate, specific growth rate, as well as the lowest feed conversion ratio and ingestion rate were discovered in the OL team, which were opposite to the TL group. (2) The body fat content and muscle fat content in the fish oil group were the lowest (P < 0.05), while those of the TL group were the highest. (3) Serum catalase, glutathione peroxidase, total antioxidant capacity, and superoxide dismutase activities were the highest, and the content of reactive oxygen species was the lowest in the OL group. (4) The OL group has the highest hepatic lipase activity and the lowest very low-density lipoprotein content of the liver. In contrast, the TL group had the highest fatty acid synthetase (FAS) activity (P < 0.05). (5) The oil-red aspects of liver tissue displayed lipid particles in other groups were reduced to different degrees compared with FL group, and the OL group showed the best lipid-lowering effect. (6) Compared with the FL group, the relative expressions of FAS, acetyl-CoA carboxylase (acc), and apolipoprotein b-100 (apoB100) genes in the liver were decreased. The relative expressions of lipoprotein lipase (lpl) and peroxisome proliferators-activated receptors-α (pparα) genes related to lipid catabolism were increased, among which the OL group had the most significant change (P < 0.05). (7) According to the 7-day challenge test of Vibrio alginolyticus, the OL group had the highest survival rate. To sum up, both ALA and TP have positive effects on relieving the lipid metabolism disorder of hybrid grouper. If they are jointly used, adding ALA : TP in a ratio of 1 : 2 (OL) may have the best effect, and an addition ratio of 2 : 1 (TL) may inhibit the hybrid grouper growth and increase the feeding cost.

Implications on growth performance, glucose metabolism, PI3K/AKT pathway, intestinal flora induced by dietary taurine in a high-carbohydrate diet for grass carp (Ctenopharyngodon idella).

An 8-week experiment was performed to investigate the influence on growth performance, plasma biochemistry, glucose metabolism and the insulin pathway of supplementation of dietary taurine to a high-carbohydrate diet for grass carp. In this study, fish were fed diets at one of two carbohydrate levels, 31·49 % (positive control) or 38·61 % (T00). The high-carbohydrate basal diet (T00), without taurine, was supplemented with 0·05 % (T05), 0·10 % (T10), 0·15 % (T15) or 0·20 % (T20) taurine, resulting in six isonitrogenous (30·37 %) and isolipidic (2·37 %) experimental diets. The experimental results showed that optimal taurine level improved significantly weight gain, specific growth rate (SGR), feed utilisation, reduced plasma total cholesterol levels, TAG and promoted insulin-like growth factor level. Glucokinase, pyruvate kinase and phosphoenolpyruvate carboxykinase activities showed a quadratic function model with increasing dietary taurine level, while hexokinase, fatty acid synthetase activities exhibited a positive linear trend. Optimal taurine supplementation in high-carbohydrate diet upregulated insulin receptor (Ir), insulin receptor substrate (Irs1), phosphatidylinositol 3-kinase (pi3k), protein kinase B (akt1), glycogen synthase kinase 3 β (gs3kβ) mRNA level and downregulated insulin-like growth factor (igf-1), insulin-like growth factor 1 receptor (igf-1R) and Fork head transcription factor 1 (foxo1) mRNA level. The above results suggested that optimal taurine level could improve growth performance, hepatic capacity for glycolipid metabolism and insulin sensitivity, thus enhancing the utilisation of carbohydrates in grass carp. Based on SGR, dietary optimal tributyrin taurine supplementation in grass carp was estimated to be 0·08 %.

Effect of Dietary Manganese on the Growth Performance, Lipid Metabolism, and Antioxidant Capacity in the Post-Larval Coho Salmon (Oncorhynchus kisutch).

In this study, post-larval coho salmon Oncorhynchus kisutch (initial weight 0.37 ± 0.03 g) were fed with 6 experimental diets with increasing manganese (Mn) content (2.4, 8.5, 14.8, 19.8, 24.6, and 33.7 mg kg-1) for 12 weeks. Our results indicated that the feed conversion rate (FCR), specific growth rate (SGR), condition factor (CF), crude protein, moisture, crude lipid, ash, whole-body Mn, and vertebral Mn were affected by the elevation of Mn content in the diet. The activities of hepatic GSH-PX, Mn-SOD, and CAT were enhanced with increasing Mn content in the diet and reached the highest value at 19.8 mg kg-1 Mn. However, the level of hydrogen peroxide (H2O2), superoxide anion (O2·-), and malondialdehyde (MDA) was reduced with increasing Mn content in the diet. In addition, the activity of hepatic lipase (HL) and lipoprotein lipase (LPL) was increased with the elevation of dietary Mn content and reached a peak value at 14.8 mg kg-1 Mn. The activity of fatty acid synthetase (FAS) and the content of nonesterified fatty acid (NEFA) were increased following the elevation of Mn content from 2.4 to 19.8 mg kg-1 in the diet. The results indicated that the appropriate dietary Mn supplementation improved the feeding efficiency, lipid metabolism, and antioxidant capacity of coho salmon. The dietary Mn requirement for post-larval coho salmon was 17.35 mg kg-1 and 19.75 mg kg-1 based on the SGR and FCR, respectively. An optimal dietary level of Mn enhances hepatic lipid metabolism, and the signaling pathway of PI3K/AKT/mTOR may be involved in regulating the activity of enzymes related to lipid metabolism.

Dietary iron affects lipid deposition, nutritional element, and muscle quality in coho salmon (Oncorhynchus kisutch)

We investigated effect of dietary iron (Fe) on the lipid deposition, nutritional element, and muscle quality in coho salmon. Four level Fe diets at 23.7, 46.4, 77.3, and 127.7mg/kg were fed to the post-larval coho salmon for 12weeks. Our results showed that dietary Fe decreased the content of triglyceride and the activity of fatty acid synthetase, ATP-citrate lyase, and acetyl-CoA carboxylase. The content of Fe in muscle was increased with increasing dietary Fe levels, and dietary Fe affected the content of nutritional elements. In addition, dietary Fe levels affected the composition of fatty acids and the content of free amino acids, and increased muscle fiber size. The lower dietary Fe levels also affected the hardness, chewiness, resilience, springiness, cohesiveness, and gumminess of salmon muscle. In all, dietary Fe inhibited the lipid deposition and affected the content of nutritional element and muscle quality in coho salmon.

Tea polyphenols improve lipid metabolism in hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu) fed high-lipid diets

Long-term ingestion of high-lipid diets causes lipid metabolism disorder and excess lipid deposition. This investigation aimed to determine whether dietary tea polyphenols (TP) would alleviate the adverse effect of high-lipid diets in hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu). Six isonitrogenous (51 %) and isolipidic (16.7 %) diets were formulated: 0 %, 0.01 %, 0.02 %, 0.04 %, 0.08 % and 0.16 % dietary TP, and named TP1 (control), TP2, TP3, TP4, TP5, and TP6. After an 8-week feeding high-lipid diets trial, the results showed that weight gain rate significantly increased in TP-treated groups which had no difference in themselves. Protein efficiency ratio of TP4 group was significantly higher than that of the control group, while the other TP-treated groups had no significant difference from the control group. Hepatosomatic index dramatically decreased in TP-treated groups. TP markedly reduced lipid content and increased protein content of muscle and whole body. TP supplement significantly reduced contents of total cholesterol, low-density lipoprotein cholesterol and very low-density lipoprotein cholesterol, but increased content of high-density lipoprotein cholesterol in the serum. Hepatic lipase, lipoprotein lipase, and fatty acid synthetase activities in the liver significantly increased in TP-treated groups. The histology of hepatic tissue indicated that lipid droplet reduced with the increase of dietary TP, and there was no obvious difference in lipid-lowering effect observed in TP4 and TP5. Hepatic expression of peroxisome proliferator-activated receptors (α, β and γ), hormone-sensitive lipase, adipose triglyceride lipase, carnitine palmitoyl transferase1, sterol regulatory element-binding protein-1, acetyl-CoA carboxylase and fatty acid synthetase were distinctly up-regulated by dietary TP (P < 0.05). These results imply that dietary TP primarily mediated the activation of lipolysis to improve lipid metabolism in grouper fed high-lipid diets. Based on the broken-line regressions analysis of the serous LDL and hepatic VLDL contents, 0.045–0.067 % was recommended in juvenile grouper high-lipid diets for improving lipid metabolism.

Effects of Oat Complex High-Fiber Formula Powder on the Composition of Intestinal Microbiota and Enzyme Activities in Mice Induced by a High-Fat Diet.

Using oat-corn-konjac extruded mixed powder, oat bran micro powder, skim milk powder, Pueraria whole powder, and pumpkin powder as raw materials, a formula powder with high dietary fiber was prepared, and its effect on obesity in mice with a high-fat diet was investigated. After 7 days of adaptive feeding, the mice were divided into blank group, high-fat diet group, formula powder + high-fat diet group, and weight-loss drug + high-fat diet group. After 8 weeks of treatment, the body weight of mice were observed and measured to determine the composition of tract flora, liver leptin content, insulin content, and activities of AMP-activated protein kinase (AMPK), lipoprotein lipase (LPL), fatty acid synthetase (FAS), sterol-regulatory element-binding proteins (SREBPs), and acetyl CoA carboxylase 1 (ACC1). The results indicated that treatment with the formula powder could reduce the body weight of mice and increase the abundance of Bifidobacterium, Akkermansia, and Romboutsia compared to the group given a high-fat diet. Moreover, the leptin and insulin contents of the experimental group decreased from 5.67 μg/L to 0.12 μg/L and from 12.71 μg/L to 7.13 μg/L, respectively, compared to the control group, which was not significantly different from the blank group (P > 0.05). Also, the activities of AMPK and LPL increased, and the activities of FAS, SREBPs, and ACC1 were significantly decreased (P < 0.05). Some pathogenic bacteria were significantly positively correlated with leptin and FAS and significantly negatively correlated with LPL. Some beneficial bacteria were positively correlated with LPL. Therefore, the formula powder used in this study could reduce the body weight of mice, increase the abundance of some beneficial bacteria in the colonic intestinal microbiota, and improve the activities of enzymes related to lipid metabolism in the liver. This study provides a theoretical reference for the pathway by which high-fiber diet improves liver and intestinal metabolic abnormalities.

Short-term hypobaric treatment alleviates chilling injury by regulating membrane fatty acids metabolism in peach fruit.

Short-term hypobaric treatment (SHT) on postharvest quality and membrane fatty acids metabolism were studied in peach fruit (Prunus persica [L.] Batsch., cv. Feicheng) during shelf life after cold storage. SHT was effective in alleviating chilling injury (CI) and maintaining postharvest quality. SHT reduced the production of malondialdehyde (MDA) and electrolyte leakage (EL), and increased membrane fluidity. In addition, SHT plays an imperative role in reducing saturated fatty acid (SFA), increasing unsaturated fatty acid (USFA), and keeping a higher unsaturation level in peach fruit. Meanwhile, SHT enhanced the activity of fatty acid synthetase (FAS), upregulated the expression levels of FAD2, FAD3-1, FAD3-2, and FAD7 genes at the early stage of storage, as well as inhibited the activity of lipoxygenase (LOX) and gene expression of LOX1. These results suggested that SHT could increase fatty acids unsaturation by regulating FAS activity, FAD and LOX1 gene expression, thus maintain high membrane stability and alleviate CI. PRACTICAL APPLICATIONS: CI is an important factor affecting the postharvest quality of peaches in cold storage, and metabolism of membrane fatty acids is one of the main CI response mechanisms. Our previous study has shown that SHT could alleviate CI in peach fruit. Therefore, it is of great significance to investigate the regulation of membrane fatty acids metabolism under SHT. Results from this study suggest that the enhancement of chilling tolerance by SHT in peaches could be explained, at least in part, as being due to enhanced FAS activity, upregulated the expression of FAD gene, and inhibited LOX1 to maintain higher unsaturation level. All in all, we explored the response mechanism of membrane fatty acids metabolism under SHT in peach fruit, and supplied theoretical guidance for application of the technology.

Flaxseed Oil and Heated Flaxseed Supplements Have Different Effects on Lipid Deposition and Ileal Microbiota in Albas Cashmere Goats.

Simple SummaryWith the grassland desertification intensified, pasture carrying capacity decreased, and grass seasonal changed, stall-feeding fattening has become an effective means to protect the natural environment. The stall-feeding fattening increased the cashmere goats’ weight but reduced the meat quality and increased the saturated fatty acids content in muscle and fat tissue of cashmere goats. Supplementing flaxseed and flaxseed oil rich-in linolenic acid (ALA) to diet to improve meat quality is an effective nutritional regulation means. Previous research results of our team showed that compared to diet supplemented with flaxseed oil, added flaxseed increased linoleic acid biohydrogenation by reducing the Ruminobacter relative abundance and increasing the relative abundance of Prevotellaceae_UCG-001 and Fretibacterium in rumen, protected ALA away from biohydrogenation, and more n-3 polyunsaturated fatty acids entered the post-intestinal tract. Based on the previous research, this study explored whether the ALA flowing into the posterior intestine can reduce fat deposition and blood lipid by affecting intestinal microbiota. The results showed that adding flaxseed grain to diet decreased the growth performance, lipid deposition, and blood lipid content of goats by regulating the blood lipid-related enzyme activity, which positively associated with [Eubacterium]_coprostanoligenes_group, but negatively associated with unclassified_f_Peptostreptococcaceae, Intestinibacter, and Ruminococcus_2.The present study investigated the effect of flaxseed grain or flaxseed oil on ileal microbiota and lipid deposition of cashmere goats. Sixty kid goats (average body weight 18.6 ± 0.1 kg) were allocated to three treatments, fed for 90 days, with control treatment: basal diet (CON, total-mixed ration), experimental treatment: basal diet with added flaxseed oil (LNO), experimental treatment: basal diet with added heated flaxseed grain (HLS). The final body weight, body weight gain, the weight of kidney fat, omental fat, tail fat, and fat tissue, the activity of fatty acid synthetase, acetyl-coa carboxylase, and malic dehydrogenase, and the relative abundance (RA) of unclassified_f_Peptostreptococcaceae and Intestinibacter were remarkably higher in the LNO treatment than in the HLS treatment, but the [Eubacterium]_coprostanoligenes_group RA showed the opposite result. The content of triglyceride, cholesterol, and low-density lipoprotein cholesterol were significantly higher in the CON and LNO treatments than in the HLS treatment, while the hormone-sensitive lipase activity and the non-esterified fatty acid content showed the opposite result. In conclusion, the flaxseed grain is more efficient than flaxseed oil in ameliorating the blood lipid profiles and it is a potential product for decreasing the lipid deposition of cashmere goats.

Altered hepatic glycolysis, lipogenesis, and blood biochemistry of tiger puffer (Takifugu rubripes) under two different culture systems

Tiger puffer (Takifugu rubripes) is one of the most commercially important fish species cultivated and consumed in East Asian countries, including Japan, South Korea and China. In this study, the hepatic glycolysis, and lipogenesis, and serum biochemistry of tiger puffers subjected to short-term culture in offshore sea cage aquaculture system (OSCS) and recirculating aquaculture system (RAS) were evaluated. Results showed that the activity of hepatic phosphofructokinase, and lipoprotein lipase, ATP level, and serum cortisol content of the male tiger puffers reared in OSCS were significantly higher than those of female tiger puffers reared in OSCS and those of fish reared in RAS. The lowest hepatic fatty acid synthetase activity, lipid droplet number, serum aspartate aminotransferase activity, Na+ and Cl− concentrations were observed in male tiger puffers reared in OSCS. However, serum glucose, triglyceride, total cholesterol, K+ concentrations and alanine aminotransferase activity of tiger puffers reared in RAS and OSCS showed no significant differences. Hepatic glycolysis and lipogenesis were profoundly affected by rearing system and gender. The interaction effect of gender and rearing system on hepatic lipoprotein lipase activity, lipid droplet number and serum Na+ level was observed. These results indicate male tiger puffers exhibited different metabolic status in hepatic glycolysis, lipogenesis, and serum biochemical parameters when reared under two different culture systems. These findings will provide important information for improving tiger puffer (Takifugu rubripes) farming and profitable production using the RAS and OSCS aquaculture systems in the north coast of China.

Addition of l-carnitine to formulated feed improved growth performance, antioxidant status and lipid metabolism of juvenile largemouth bass, Micropterus salmoides

l-carnitine is essential for fatty acids transportation from cytosol into the mitochondrial matrix, and promotes the β-oxidation of long-chain fatty acids to provide energy for fish. The aim of this study was to research the effect of dietary l-carnitine on the growth performance, antioxidant capacity and lipid metabolism in juvenile largemouth bass, Micropterus salmoides. Four formulated diets (Diet 1, Diet 2, Diet 3 and Diet 4) were supplemented with graded levels (0, 0.1, 0.2 and 0.3 g/kg) of l-carnitine. The results showed dietary supplementation of 0.1 g/kg l-carnitine significantly increased weight gain, while 0.3 g/kg l-carnitine supplementation decreased viscerasomatic index and intraperitoneal ratio of largemouth bass. The Plasma high density lipoprotein cholesterol (HDL-C) content of the fish which fed Diet 2 and Diet 4 were significantly higher than the fish fed Diet 1. Fish fed Diet 1 had significantly lower hepatic glutathione peroxidase (GSH-Px) activity and mRNA expression than fish fed Diet 2, Diet 3 and Diet 4. Contrary, fish fed Diet 1 had significantly higher hepatic fatty acid synthetase (FAS) activity and the mRNA expression than fish fed Diet 2, Diet 3 and Diet 4. Fish fed Diet 2, Diet 3 and Diet 4 had significantly increased the activity of hepatic carnitine palmitoyltransferase (CPT1), but no significant effect on the expression of hepatic CPT1 gene than fish fed Diet 1. In conclusion, these results confirmed that dietary supplemented of l-carnitine was beneficial for promoting growth in largemouth bass and could improve the antioxidant capacity. Furthermore, l-carnitine could play an important role in fatty acids metabolism.

Wnt10b Participates in Regulating Fatty Acid Synthesis in the Muscle of Zebrafish.

There are 19 Wnt genes in mammals that belong to 12 subfamilies. Wnt signaling pathways participate in regulating numerous homeostatic and developmental processes in animals. However, the function of Wnt10b in fatty acid synthesis remains unclear in fish species. In the present study, we uncovered the role of the Wnt10b signaling pathway in the regulation of fatty acid synthesis in the muscle of zebrafish. The gene of Wnt10b was overexpressed in the muscle of zebrafish using pEGFP-N1-Wnt10b vector injection, which significantly decreased the expression of glycogen synthase kinase 3β (GSK-3β), but increased the expression of β-catenin, peroxisome proliferators-activated receptor γ (PPARγ), and CCAAT/enhancer binding protein α (C/EBPα). Moreover, the activity and mRNA expression of key lipogenic enzymes ATP-citrate lyase (ACL), acetyl-CoA carboxylase (ACC) and fatty acid synthetase (FAS), and the content of non-esterified fatty acids (NEFA), total cholesterol (TC), and triglyceride (TG) were also significantly decreased. Furthermore, interference of the Wnt10b gene significantly inhibited the expression of β-catenin, PPARγ, and C/EBPα, but significantly induced the expression of GSK-3β, FAS, ACC, and ACL. The content of NEFA, TC, and TG as well as the activity of FAS, ACC, and ACL significantly increased. Thus, our results showed that Wnt10b participates in regulating fatty acid synthesis via β-catenin, C/EBPα and PPARγ in the muscle of zebrafish.

Evaluation of hypolipidemic peptide (Val-Phe-Val-Arg-Asn) virtual screened from chickpea peptides by pharmacophore model in high-fat diet-induced obese rat

Chickpea peptides (ChPs) were found to significantly decrease serum total cholesterol (TC), total triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) content, and increase serum high-density lipoprotein cholesterol (HDL-C) content (P < 0.05) in high fat diet-induced obese rats. The activities of fatty acid synthetase (FAS) and 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) could be significantly inhibited by ChPs. Additionally, peroxisome proliferator-activated receptors (PPAR)α and LDL receptor (LDLR) expressions were up-regulated, and sterol regulatory element-binding protein (SREBP)-2 expression was down-regulated by ChPs significantly (P < 0.05). Fecal TC and bile acid (TBA) were also found to be increased significantly (P < 0.05) in ChPs with high-fat diet treatment groups. Moreover, the micellar solubility of cholesterol decreased after the treatment with ChPs in vitro. A reductase (HMGR) inhibitor (VFVRN) was found using pharmacophore model. VFVRN was found to have high hypolipidemic effects by using Hypo1, which was a novel scaffold of HMGR. VFVRN was confirmed in HepG2 cell that it could inhibit the TC synthesis by decreasing the expressions of SREBP-1c, SREBP-2, liver X receptor (LXR)α and HMGR.

The hypolipidemic effects of peptides prepared from Cicer arietinum in ovariectomized rats and HepG2 cells.

The lack of estrogen in postmenopausal women is a key risk factor for disorders of lipid metabolism and for obesity. Except in cases where estrogen replacement therapy (ERT) is being used, chickpea peptides (ChPs) may be a potential candidate for treating hyperlipidemia. In ovariectomized rats model, ChPs were found to decrease body weight, adipose tissue size, total cholesterol (TC), total triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and the atherogenic index (AI) in serum and liver TC and TG. Serum high-density lipoprotein cholesterol (HDL-C), bile acids in liver and feces, fecal TC and TG were observed to increase significantly (P < 0.05). ChPs play a role in inhibiting the activities of fatty acid synthetase (FAS) and HMG-CoA reductase (HMGR). The expression of peroxisome proliferator-activated receptors (PPAR)γ and sterol regulatory element-binding protein (SREBP)-1c were downregulated and the expression of liver X receptor (LXR) α, estrogen receptor(ER)α and ERβ were upregulated by ChPs. In HepG2 cell experiments, the cellular TC levels decreased and the uptake of NBD-cholesterol increased significantly after treatment with Mw < 1 kDa and Mw < 5 kDa ChPs fractions. Val-Phe-Val-Arg-Asn (VFVRN) could inhibit TC biosynthesis by decreasing the expression of HMGR. We demonstrated that ChPs could effectively regulate lipid metabolism disorders and restrain obesity caused by estrogen deficiency. Val-Phe-Val-Arg-Asn identified from ChPs could reduce the expression of HMGR to inhibit cholesterol biosynthesis. © 2018 Society of Chemical Industry.

Thifluzamide affects lipid metabolism in zebrafish (Danio reio)

Thifluzamide, a succinate dehydrogenase inhibitor (SDHI) fungicide, has been widely used in rice fields throughout the world and causes hepatotoxicity in zebrafish (Danio reio). This study was conducted to investigate the effect of thifluzamide on lipid metabolism in zebrafish after exposure to a control or, 0.019, 0.19, or 1.90mg/L thifluzamide for 28days. Following exposure, pathological changes in the liver were evaluated. Total cholesterol (TCHO) level, and triglyceride (TG) levels as well as hepatic lipase (HL), lipoprotein lipase (LPL), fatty acid synthetase (FAS) and carnitine palmitoyltransferase (CPT-I) activities were measured. In addition, the expression levels of genes related to lipid metabolism were quantified. No obvious accumulation of lipid droplets was detected in the liver following any of the thifluzamide treatments. TCHO and TG levels were significantly decreased. FAS activity was markedly decreased, and CPT-I activity was significantly increased in the 0.19 and 1.90mg/L groups. However, no apparent changes in HL and LPL activities were observed in any of the treatment groups. Additionally, the expression of genes related to lipid metabolism showed corresponding changes. The results suggest that altered gene expression and enzyme activities might be responsible for the changes in lipid metabolism, as evidenced by the decreased TCHO and TG levels. Overall, thifluzamide altered lipid metabolism and led to events that might contribute to developmental toxicity in exposed zebrafish.

Effects of fasting on the activities and mRNA expression levels of lipoprotein lipase (LPL), hormone-sensitive lipase (HSL) and fatty acid synthetase (FAS) in spotted seabass Lateolabrax maculatus.

To investigate the effects of fasting on lipid metabolism in spotted seabass muscle and liver tissues, we analyzed mRNA levels and enzyme activities of lipoprotein lipase (LPL), hormone-sensitive lipase (HSL) and fatty acid synthetase (FAS), and the relationship among fat content, mRNA level, and enzyme activity during fasting of 35days. The results showed that expressions of all the three genes were ubiquitous. During the fasting experiment, the hepatosomatic index (HSI) and fat content of muscle and liver tissues significantly decreased before 5days of fasting (P < 0.05). mRNA levels of LPL increased significantly after 5days of fasting in liver and 7days in muscle. Abundance of HSL transcripts increased significantly after 14days of fasting in both muscle and liver. The activities of LPL and HSL presented a trend that increased firstly, decreased subsequently, and then raised again with the prolonged fasting experiment (P < 0.05). However, activities and mRNA levels of FAS decreased significantly after 1day of fasting in both muscle and liver. Moreover, activities and mRNA levels of FAS showed a moderate correlation in muscle. These results suggested that FAS had a sooner response to fasting than LPL and HSL in both muscle and liver tissues. LPL and HSL played important roles in lipolysis mainly by increasing enzyme activities in the early stage of fasting and mRNA levels in the later stage of fasting in both muscle and liver. Our results also provided useful information on regulating muscle fat content by fasting.

Effect of Dietary Surfactin Supplementation on Parameters Related to Lipid Metabolism of Orange-Spotted Grouper

This trial was conducted to investigate the effects of dietary surfactin supplementation on parameters related to lipid metabolism of orange-spotted grouper (Epinephelus coioides) juveniles. Three hundred and sixty fish were randomly divided into 6 treatment groups, and fed dietary surfactin levels: S0 (control group), S25, S50, S100, S150, and S200 mg/kg, respectively. Four replicates with 15 fish per tank were randomly assigned to each group. The trial period was 56 days. The lipid levels in serum, liver, and whole fish, and some lipid metabolism enzymes in the liver were measured. When compared to fish fed no surfactin, fish fed diets supplemented with surfactin presented lower levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, and higher levels of high-density lipoprotein cholesterol in serum; lower lipid levels in whole fish and liver (only 100 and 150 mg/kg surfactin groups) were observed. Dietary 100 mg/kg surfactin supplementation had the most influence on lipids level in serum, whole fish, and liver of orange-spotted grouper juveniles. Lower levels of fatty acid synthetase and higher activity of hepatic lipase and lipoprotein (lipase in liver) were affected only by 100 mg/kg surfactin supplementation in diet. The levels of acetyl CoA carboxylase were similar in all groups. This suggests that appropriate supplementation levels of surfactin in the diet of orange-spotted grouper juveniles might have beneficial effects on lipid metabolism to improve fish health status

Effect of Dietary Surfactin Supplementation on Parameters Related to Lipid Metabolism of Orange-Spotted Grouper

This trial was conducted to investigate the effects of dietary surfactin supplementation on parameters related to lipid metabolism of orange-spotted grouper (Epinephelus coioides) juveniles. Three hundred and sixty fish were randomly divided into 6 treatment groups, and fed dietary surfactin levels: S0 (control group), S25, S50, S100, S150, and S200 mg/kg, respectively. Four replicates with 15 fish per tank were randomly assigned to each group. The trial period was 56 days. The lipid levels in serum, liver, and whole fish, and some lipid metabolism enzymes in the liver were measured. When compared to fish fed no surfactin, fish fed diets supplemented with surfactin presented lower levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, and higher levels of high-density lipoprotein cholesterol in serum; lower lipid levels in whole fish and liver (only 100 and 150 mg/kg surfactin groups) were observed. Dietary 100 mg/kg surfactin supplementation had the most influence on lipids level in serum, whole fish, and liver of orange-spotted grouper juveniles. Lower levels of fatty acid synthetase and higher activity of hepatic lipase and lipoprotein (lipase in liver) were affected only by 100 mg/kg surfactin supplementation in diet. The levels of acetyl CoA carboxylase were similar in all groups. This suggests that appropriate supplementation levels of surfactin in the diet of orange-spotted grouper juveniles might have beneficial effects on lipid metabolism to improve fish health status

Changes in activities and mRNA expression of lipoprotein lipase and fatty acid synthetase in large yellow croaker,Larimichthys crocea(Richardson), during fasting

Over-winter fasting and man-made food deprivation to increase meat quality are common in the process of large yellow croaker (Larimichthys crocea) aquaculture. This study aimed to determine the changes in lipoprotein lipase (LPL) and fatty acid synthetase (FAS) activities and mRNA expressions, and the relationships between these changes and fat content in large yellow croaker liver and muscle tissues during fasting. A total of 2933 bp LPL cDNA, including an open reading frame of 1533 bp encoding 510 amino acids, and a 1233 bp fragment of FAS cDNA coding 411 amino acids were cloned. Expressions of both genes were ubiquitous. During a 35-day fasting period, the hepatosomatic index and fat content in muscle and liver were significantly decreased (P < 0.05). mRNA levels of LPL increased significantly during the fasting period except the first 3 days, and FAS mRNA levels decreased significantly in both muscle and liver (P < 0.05) although there were some fluctuations. Muscle and liver LPL activities were significantly higher following fasting for 7 days, decreased to the initial value following fasting for 14 days, and elevating significantly afterwards (P < 0.05). FAS activities in muscle and liver maintained a significantly decreasing trend during the short-term fasting (P < 0.05) and kept obviously rising thereafter (P < 0.05). Activities and mRNA levels of both LPL and FAS were not always consistent, which implied that both pre-translational and post-translational regulations existed during fasting. Our results suggest that the reasonable fasting time is 21 days before harvesting when fat content decreased significantly.

Tumour necrosis factor-α inhibits hepatic lipid deposition through GSK-3β/β-catenin signaling in juvenile turbot (Scophthalmus maximus L.)

In this study, the mechanism that TNFα inhibits lipid deposition through GSK-3β/β-catenin signaling was investigated in the liver of juvenile turbot (Scophthalmus maximus L.) by injection of TNFα or TNFα inhibitor pomalidomide (POM). It was found that TNFα inhibited the expression of GSK-3β and induced β-catenin expression. TNFα inhibited the expression of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα), as well as the activity of lipoprotein lipase (LPL) and fatty acid synthetase (FAS). In addition, the level of triglyceride (TG), total cholesterol (TC), nonesterified fatty acid (NEFA), and glycerol was decreased by TNFα treatment in the liver. In the plasma, the level of TG, TC, low density lipoprotein cholesterol (LDL-C), NEFA, and glycerol was decreased, but high density lipoprotein cholesterol (HDL-C) was increased by TNFα treatment. However, compared to TNFα, POM had the opposite effect on the biochemical indexes and genes related to lipid deposition in the liver. The results indicated that TNFα may regulate hepatic lipid metabolism and fat distribution through GSK-3β/β-catenin signaling as well as transcription factors PPARγ and C/EBPα in juvenile turbot.