Serum bile acid and unsaturated fatty acid profiles of non-alcoholic fatty liver disease in type 2 diabetic patients

BACKGROUND The understanding of bile acid(BA)and unsaturated fatty acid(UFA)profiles,as well as their dysregulation,remains elusive in individuals with type 2 diabetes mellitus(T2DM)coexisting with non-alcoholic fatty liver disease(NAFLD).Investigating these metabolites could offer valuable insights into the pathophy-siology of NAFLD in T2DM.AIM To identify potential metabolite biomarkers capable of distinguishing between NAFLD and T2DM.METHODS A training model was developed involving 399 participants,comprising 113 healthy controls(HCs),134 individuals with T2DM without NAFLD,and 152 individuals with T2DM and NAFLD.External validation encompassed 172 participants.NAFLD patients were divided based on liver fibrosis scores.The analytical approach employed univariate testing,orthogonal partial least squares-discriminant analysis,logistic regression,receiver operating characteristic curve analysis,and decision curve analysis to pinpoint and assess the diagnostic value of serum biomarkers.RESULTS Compared to HCs,both T2DM and NAFLD groups exhibited diminished levels of specific BAs.In UFAs,particular acids exhibited a positive correlation with NAFLD risk in T2DM,while theω-6:ω-3 UFA ratio demonstrated a negative correlation.Levels ofα-linolenic acid andγ-linolenic acid were linked to significant liver fibrosis in NAFLD.The validation cohort substantiated the predictive efficacy of these biomarkers for assessing NAFLD risk in T2DM patients.CONCLUSION This study underscores the connection between altered BA and UFA profiles and the presence of NAFLD in individuals with T2DM,proposing their potential as biomarkers in the pathogenesis of NAFLD.

Distinctive roles of unsaturated and saturated fatty acids in hyperlipidemic pancreatitis

AIM: To investigate how the saturated and unsaturated fatty acid composition influences the susceptibility of developing acute pancreatitis. METHODS: Primary pancreatic acinar cells were treated with low and high concentrations of different saturated and unsaturated fatty acids, and changes in the cytosolic Ca2+ signal and the expression of protein kinase C(PKC) were measured after treatment. RESULTS: Unsaturated fatty acids at high concentrations, including oleic acid, linoleic acid, palmitoleic acid, docosahexaenoic acid, and arachidonic acid, induced a persistent rise in cytosolic Ca2+ concentrations in acinar cells. Unsaturated fatty acids at low concentrations and saturated fatty acids, including palmitic acid, stearic acid, and triglycerides, at low and high concentrations were unable to induce a rise in Ca2+ concentrations in acinar cells. Unsaturated fatty acids at high concentrations but not saturated fatty acids induced intra-acinar cell trypsin activation and cell damage and increased PKC expression.CONCLUSION: At sufficiently high concentrations, unsaturated fatty acids were able to induce acinar cells injury and promote the development of pancreatitis. Unsaturated fatty acids may play a distinctive role in the pathogenesis of pancreatitis through the activation of PKC family members.

Expression profile of polyunsaturated fatty acids in colorectal cancer

AIM:To investigate the relationship between the metabolism of polyunsaturated fatty acids(PUFAs)andtumor-associated factors for predicting the outcome of colorectal carcinoma(CRC)in Chinese patients.METHODS:Fresh-frozen malignant and normal tissues from 82 Chinese patients with CRC were analyzed for PUFA composition using gas-liquid chromatography.The levels of vascular endothelial growth factor(VEGF),cyclooxygenase-2(COX-2),prostaglandin E2 and platelet-derived growth factor(PDGF)were measured by enzyme-linked immunosorbent assay,and the levels of VEGF,p53 and Ki-67 were measured by immunohistochemistry.RESULTS:In malignant tissue,compared with normal tissue,the levels of totalω-6 PUFAs(24.64%±3.41%vs 26.77%±3.37%,P=0.00)and linoleic acid(LA)(15.46%±3.51%vs 18.30%±2.83%,P<0.01)were lower,whereas the levels of totalω-3 PUFAs(1.58%±0.74%vs 1.35%±0.60%,P<0.01)and dihomo-gamma-linolenic acid(DGLA)(1.32%±0.69%vs 0.85%±0.29%,P<0.01)were significantly higher.The ratios of arachidonic acid(AA)/LA(0.53±0.22 vs0.42±0.19,P<0.01)and AA/totalω-6 PUFAs(0.31±0.09 vs 0.27±0.10,P<0.01)were also significantly higher in malignant tissue.The levels of PDGF(353.10±148.85 pg/m L vs 286.09±104.91 pg/m L,P<0.01),COX-2(125.21±70.29 ng/m L vs 67.06±42.22 ng/m L,P<0.01)and VEGF(357.11±128.76 pg/m L vs211.38±99.47 pg/m L,P<0.01)were also higher in malignant tissue compared to normal tissue.COX-2was inversely correlated with LA(R=-0.3244,P<0.05)and positively correlated with AA/totalω-6 PUFAs(R=0.3083,P<0.05)and AA/LA(R=0.3001,P<0.05).The tissue level of LA was highest in poorly differentiated tumors(19.9%±6.3%,P<0.05),while the ratio of AA/ω-3 PUFAs was lowest in these tumors(10.8±2.6,P<0.05).In VEGF-positive tumors,the level of LA was higher(16.2%±3.7%vs 13.9%±2.7%,P<0.01),while the AA/ω-3PUFA,AA/ω-6 PUFA,and AA/LA ratios were lower than in VEGF-negativetumors(5.0±1.8 vs 6.7±3.3,0.30±0.09 vs 0.34±0.09,0.50±0.21 vs 0.61±0.21,P<0.01).CONCLUSION:The metabolism of PUFAs may playan important role in the evolution of inflammationdriven tumorigenesis in CRC and may be considered apotential marker for prognosis.

Epoxidation of Unsaturated Fatty Acid Methyl Esters in the Presence of SO_3H-functional Brφnsted Acidic Ionic Liquid as Catalyst

The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst.

Effects of unsaturated fatty acids on calcium-activated potassium current in gastric myocytes of guinea pigs

AIM: To investigate the effects of exogenous unsaturated fatty acids on calcium-activated potassium current [IK(Ca)] in gastric antral circular myocytes of guinea pigs. METHODS: Gastric myocytes were isolated by collagenase from the antral circular layer of guinea pig stomach. The whole-cell patch clamp technique was used to record /K(Ca) in the isolated single smooth muscle cells with or without different concentrations of arachidonic acid (AA), linoleic acid (LA), and oleic acid (OA). RESULTS: AA at concentrations of 2,5 and 10 μmol/L markedly increased IK(Ca) in a dose-dependent manner. LA at concentrations of 5, 10 and 20 μmol/L also enhanced /K(Ca) in a dose-dependent manner. The increasing potency of AA, LA, and oleic acid (OA) on /K(Ca)at the same concentration (10μmol/L) was in the order of AA>LA>OA. AA (10 μmol/L)-induced increase of Ik(ca) was not blocked by H-7 (10 μmol/L), an inhibitor of protein kinase C (PKC), or indomethacin (10 μmol/L), an inhibitor of the cyclooxygenase pathway, and 17-octadecynoic acid (10 μmol/L), an inhibitor of the cytochrome P450 pathway, but weakened by nordihydroguaiaretic acid (10μmol/L), an inhibitor of the lipoxygenase pathway. CONCLUSION: Unsaturated fatty acids markedly increase Ik(Ca), and the enhancing potencies are related to the number of double bonds in the fatty acid chain. The lipoxygenase pathway of unsaturated fatty acid metabolism is involved in the unsaturated fatty acid-induced increase of IK(Ca) in gastric antral circular myocytes of guinea pigs.

Biosynthesis of Unsaturated Fatty Acids via Mortierella Isabellina Cultivated in a Medium Containing Butanol

Mortierella isabellina was found to accumulate large amounts of unsaturated fatty acids when it was grown in a medium containing butanol(5 g/L) and yeast extract(10 g/L) and cultivated at 25 ℃ for 5 d during which additional feeding butanol of 2 g/L was fed after being cultivated for 48 h . The resultant mycelial lipids accounted for 40 1% of the dry mycelia, while about 34% of butanol in the medium was converted. The mycelial lipids contained four kinds of unsaturated fatty acids, i.e ., palmitoleic(4 9%), oleic(54 1%), linoleic(10 4%) and linolenic(5 4%) acids. Those accounted for 74 8% of the total fatty acids. The effects of the culture conditions, such as cultivation temperature, initial pH of the medium and additional feeding butanol in the course of cultivation, on the production of mycelial lipids by M. isabellina were studied.

Efficacy of poly-unsaturated fatty acid therapy on patients with nonalcoholic steatohepatitis

AIM: To examine whether poly-unsaturated fatty acid(PUFA) therapy is beneficial for improving nonalcoholic steatohepatitis(NASH).METHODS: In total, 78 patients pathologically diagnosed with NASH were enrolled and were randomly assigned into the control group and the PUFA therapy group(added 50 mL PUFA with 1:1 ratio of EHA and DHA into daily diet). At the initial analysis and after 6mo of PUFA therapy, parameters of interest including liver enzymes, lipid profiles, markers of inflammation and oxidation, and histological changes were evaluated and compared between these two groups.RESULTS: At the initial analysis, in patients with NASH, serum levels of alanine aminotransferase(ALT)and aspartase aminotransferase(AST) were slightly elevated. Triglyceride(TG), total cholesterol(TC) and low-density lipoprotein cholesterol levels, markers of systemic inflammation [C-reactive protein(CRP)] and oxidation [malondialdehyde(MDA)], as well as fibrosis parameters of type Ⅳ collagen and pro-collagen typeⅢ pro-peptide were also increased beyond the normal range. Six months later, ALT and AST levels were significantly reduced in the PUFA group compared with the control group. In addition, serum levels of TG and TC, CRP and MDA, and type Ⅳ collagen and procollagen type Ⅲ pro-peptide were also simultaneously and significantly reduced. Of note, histological evaluation showed that steatosis grade, necroinflammatory grade, fibrosis stage, and ballooning score were all profoundly improved in comparison to the control group, strongly suggesting that increased PUFA consumption was a potential way to offset NASH progression.CONCLUSION: Increased PUFA consumption is a potential promising approach for NASH prevention and reversal.

A Study on the Inhibition Effect and Mechanism of Unsaturated Fatty Acid on Zinc Electrode in 40% KOH Solutions

The adsorption and inhibition behaviors of unsaturated fatty acid on Zinc/solution interface in 40%KOH solutions were investigated by means of electrochemical techniques. The results show that the corrosion of Zinc in 40%KOH solution is inhibited with linoleic acid and oleic acid, the adsorption action of unsaturated fatty acids on Zinc suface follows Flory Huggins isotherm and belongs to the kind of chemical adsorption, and linoleic acid and oleic acid are all mixed suppressed inhibitors and their inhibitive behaviors depend on negative catalytic effect.

Impacts of the unsaturation degree of long-chain fatty acids on the volatile fatty acid profiles of rumen microbial fermentation in goats in vitro

This study investigated the impacts of the degree of unsaturation （unsaturity） of long-chain fatty acids on volatile fatty acid （VFA） profiles of rumen fermentation in vitro. Six types of long-chain fatty acids, including stearic acid （C18：0, control group）, oleic acid （C18：1, n-9）, linoleic acid （C18：2, n-6）, a-linolenic acid （C18：3, n-3）, arachidonic acid （C20：4, n-6） and eicosapentaenoic acid （C20：5, n-3）, were tested. Rumen fluid from three goats fitted with ruminal fistulae was used as inoculum and the inclusion rate of long-chain fatty acid was at 3% （w/w） of substrate. Samples were taken for VFA analysis at 0, 3, 6, 9, 12, 18 and 24 h of incubation, respectively. The analysis showed that there were significant differences in the total VFA among treatments, sampling time points, and treatment×time point interactions （P〈0.01）. a-Linolenic acid had the highest total VFA （P〈0.01） among different long-chain fatty acids tested. The molar proportion of acetate in total VFA significantly differed among treatments （P〈0.01） and sampling time points （P〈0.01）, but not treatment×time point interactions （P〉0.05）. In contrast, the molar proportion of propionate did not differ among treatments during the whole incubation （P〉0.05）. However, for butyrate molar proportions, significant differences were found not only among sampling time points but also among treatments and treatment×time point interactions （P〈0.01）, with eicosapentaenoic acid having the highest value （P〈0.01）. Additionally, no statistically significant differences were found in the acetate to propionate ratios among treatments groups （P〉0.05）, even the treatments stearic acid and a-linolenic acid were numerically higher than the others. The inclusion of 3% long-chain unsaturated fatty acids differing in the degree of unsaturation brought out a significant quadratic regression relation between the total VFA concentration and the double bond number of fatty acid. In conclusion, the a-linolenic acid with 3 double bonds appeared better for improving rumen microbial fermentation and the total VFA concentration.

Rumen metagenome reveals the mechanism of mitigation methane emissions by unsaturated fatty acid while maintaining the performance of dairy cows

Dietary fat content can reduce the methane production of dairy cows;however,the relevance fatty acid(FA)composition has towards this inhibitory effect is debatable.Furthermore,in-depth studies elucidating the effects of unsaturated fatty acids(UFA)on rumen function and the mechanism of reducing methane(CH4)production are lacking.This study exposed 10 Holstein cows with the same parity,similar milk yield to two total mixed rations:low unsaturated FA(LUFA)and high unsaturated FA(HUFA)with similar fat content.The LUFA group mainly added fat powder(C16:0>90%),and the HUFA group mainly replaced fat powder with extruded flaxseed.The experiment lasted 26 d,the last 5 d of which,gas exchange in respiratory chambers was conducted to measure gas emissions.We found that an increase in the UFA in diet did not affect milk production(P>0.05)and could align the profile of milk FAs more closely with modern human nutritional requirements.Furthermore,we found that increasing the UFA content in the diet lead to a decrease in the abundance of Methanobrevibacter in the rumen(|linear discriminant analysis[LDA]score|>2 and P 2 and P<0.05),which ultimately decreased CH4 production(P<0.05).Our results illustrated the mechanism involving decreased CH4 production when fed a UFA diet in dairy cows.We believe that our study provides new evidence to explore CH4 emission reduction measures for dairy cows.

Growth Response and Fatty Acid Composition of Juvenile Procambarus clarkii Fed Different Sources of Dietary Lipid

An experiment was conducted to evaluate the effects of feeding various sources of dietary lipid on weight gain, feed conversion, survival and fatty acid composition of juvenile red swamp crawfish, Procam-barus clarkii. Six semi-purified diets containing vitamin-free casein, defatted soybean meal, 0. 5% choline chloride, 0. 5% glycine and 0. 5% cholesterol were supplemented with 6. 0% of either anchovy oil, linseed oil, soybean oil, rapeseed oil, safflower oil or pork lard. Each diet was fed to crawfish (3. 07±0. 21 g average weight) in three replicate aquaria for 60 days. Survival rate, weight gain and feed conversion were best for crawfish fed the diet containing anchovy oil. Crawfish fed the linseed oil diet had the second highest weight gain, followed by crawfish on soybean oil, repaseed oil, safflower oil and pork lard diets, respectively. Feed conversion values were a reflection of weight gain. Results showed that both n-6 and n-3 fatty acids are dietary essential for juvenile Procambarus clarkii, although n-3 fatty acids promoted faster growth than n-6. However, highly unsaturated fatty acids (HUFA) (20 : 5n-3 and 22 :6n-3) had better growth-promoting effect than 18 : 3n-3, due probably to the limited ability of crawfish to bioconvert fatty acids to polyenoic forms of longer chain length. The fatty acid composition of the crawfish generally reflected that of the dietary lipids, especially for the diets containing unsaturated fatty acids.

Branched chain amino acids alter fatty acid profile in colostrum of sows fed a high fat diet

Background:Branched chain amino acids(BCAAs)are important substrates for milk protein synthesis in the mammary gland,and are tightly related to lipid metabolism.No study has been performed examining the role of BCAAs with high fat diets on milk fat synthesis.This study was designed to investigate the effect of dietary BCAAs on growth performance of piglets,progeny body weight,and milk fat composition in sows fed a high fat diet.Four diets(CON=control diet;HF=high fat diet with 8%soybean oil;HF-MB=HF plus 0.39%BCAAs;HF-HB=HF plus 0.78%BCAAs)were fed to sows from late gestation to weaning.Results:Compared to HF,BCAAs(HF-MB and HF-HB)increased the litter weight(P<0.05)and overall litter weight gain(P<0.05)at weaning and increased colostrum fat content by 27.3–35.8%(P<0.01).Fatty acid profiles between the two doses of BCAAs were similar.Compared with HF,HF-MB tended to decrease the percentage of C18:3n3(P=0.063)and increased the percentage of C18:1n9c(P=0.03).In addition,BCAAs in HF-MB increased the concentration of total fatty acid by 22.1%in colostrum(P=0.03)but decreased that in serum at parturition by 53.2%(P=0.027).The fatty acids in colostrum that increased with BCAAs were C15:0,C17:0,C20:3n6,C20:4n6,C20:5n3 and C22:6n3(P=0.00~0.04).Colostrum fatty acids of C20:0,C21:0,C22:0,C16:1,C20:1,C18:1n9c also tended to be increased(0.05<P<0.1)with BCAAs.The change in sow serum fatty acid profile due to BCAAs was different from that in colostrum.Conclusions:BCAAs in high fat diet of sows altered the fatty acid composition in colostrum and enhanced litter growth.Our study indicated that BCAAs supplementation can enhance mammary fatty acid uptake and mammary fat synthesis and that supplemental BCAAs and fat in late gestation and lactation diets for sows can improve reproductive performance.

Effect of dietary soybean oil and antioxidants on fatty acids and volatile compounds of tail subcutaneous and perirenal fat tissues in fattening lambs

Background： Fat is the primary source of the volatiles that determine the characteristic flavors of animal products.Because unsaturated fatty acids（UFAs） contribute to changes in flavor as a result of the oxidation process, a feeding trial was performed to investigate the effects of dietary soybean oil or antioxidants on the fatty acid and volatile profiles of the tail subcutaneous（SF） and perirenal fat tissues（PF） of fattening lambs. Thirty-six Huzhou lambs were assigned to four dietary treatments in a randomized block design. The lambs＇ diets were supplemented with soybean oil（0 or 3 % of DM） or antioxidants（0 or 0.025 % of DM）.Results： Neither soybean oil nor antioxidant supplementation had an effect on lamb growth（P 〉 0.05）. In regard to tail SF, soybean oil supplementation increased the 18：2n6t（P 〈 0.05） and the total amount of volatile acids,whereas antioxidant supplementation increased the content of C18：2n6c and C18：3n3（P 〈 0.05） but had no effect on the volatiles profile. In regard to PF, dietary soybean oil supplementation increased the C18：0 content（P 〈 0.01）;decreased the C18：1（P = 0.01）, C22：1 n9（P 〈 0.01） and total UFA（P = 0.03） contents; and tended to decrease the E-2-octenal（P = 0.08）, E, E-2, 4-decadienal（P = 0.10）, 2-undecenal（P = 0.14） and ethyl 9-decenoate（P = 0.10） contents.Antioxidant supplementation did not affect either the fatty acid content or the volatiles profile in the PF.Conclusions： Tail SF and PF responded to dietary soybean oil and antioxidant supplementation in different ways. For SF, both soybean oil and antioxidant supplementation increased the levels of unsaturated fatty acids but triggered only a slight change in volatiles. For PF, soybean oil supplementation decreased the levels of unsaturated fatty acids and oxidative volatiles, but supplementation with antioxidants had little effect on PF fatty acids and the volatiles profile.

Free fatty acids, glucose, and insulin in type 2 diabetes mellitus

Xu et al used the HOMA2 model to estimate theβ-cell function and insulin resistance levels in an individual from simultaneously measured fasting plasma glucose and fasting plasma insulin levels.This method is based on the assumption that the glucose-insulin axis is central for the metabolic activities,which led to type 2 diabetes.However,significant downregulation of both the NKX2-1 gene and the TPD52L3 gene force an increase in the release of free fatty acids(FFAs)into the blood circulation,which leads to a marked reduction in membrane flexibility.These data favor a FFA-glucose-insulin axis.The authors are invited to extend their study with the introduction of the saturation index(number of carbon-carbon double bonds per 100 fatty-acyl chains),as observed in erythrocytes.

Effects of Various Foods Intakes on Plasma Levels of Trans Fatty Acids in Japanese Old Men

Background: Trans fatty acids are said to be formed by the partial hydrogenation of vegetable oils. Some amounts are produced in digestive organs of ruminants and present in dairy products or meat. In Japan, use of trans fatty acids in the foods is prohibited, thus trans fatty acids must come from foods or microbes in the digestive organs. Methods: Plasma levels of fatty acids including trans forms of healthy old men are measured by gas chromatography and correlations between various foods intakes and plasma levels of trans fatty acids such as palmitoelaidic, elaidic and linoelaidic acids are examined. Results: No correlations between various foods intakes and trans fatty acids were found except between intake of preference drinks such as tea or coffee and plasma levels of palmitoelaidic and linoelaidic acids. Conclusion: Since palmitoelaidic acid is cardioprotective, increase in plasma levels of palmitoelaidic acid may indicate that intakes of tea and coffee may be beneficial for heath by increasing palmitoelaidic acids.

Correlation of Various Foods Intakes and Plasma Levels of Omega Fatty Acids in Healthy Japanese Old Men

Background: Trans fatty acids are considered to impair health and some ω fatty acids are protective against atherosclerosis and diabetes mellitus. Trans fatty acids are said to be formed by the partial hydrogenation of vegetable oils. Some amounts are produced in digestive organs of ruminants and present in dairy products or meat. It is important how much these intaken fatty acids influence their plasma levels. Methods: Plasma levels of fatty acids including transforms of healthy old men are measured by gas chromatography and correlations between various foods intakes and plasma levels of trans fatty acids, and ω fatty acids are examined. Results: Intake of fish resulted in increase in plasma levels of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) but intake of meat such as beef, cow and chicken meat did not increase plasma levels of arachidonic acid (AA). Intakes of oils increased plasma levels of dihomo-g-linolenic acid significantly and AA to some extent. Conclusion: Plasma levels of EPA and DHA increased upon intakes of fish in Japanese old men. Oil intake but not meat intake increased DGLA significantly. These results may explain low incidence of cardiovascular diseases in Japanese people compared with American people whose plasma levels of DHA and EPA are lower.

Protective role of concomitant administration of flax lignan concentrate and omega-3-fatty acid on myocardial damage in doxorubicin-induced cardiotoxicity

The severe cardiotoxicity incurred due to doxorubicin limits the use of their therapeutic potential.The current study aims to investigate the cardioprotective effect of concomitant administration of flax lignan concentrate(FLC)and omega-3-fatty acid(ω-3-FA)on myocardial damage in doxorubicin-induced cardiotoxicity in Wistar rats.Cardiotoxicity was induced by intraperitoneal injection of doxorubicin(4 mg/kg)on day 7th,14th,21st and 28th day in normal saline.Concomitant administration of FLC(500 mg/kg)andω-3-FA(1 mL/kg)lowered TNF-αlevel,normalized ST,QT and mean arterial blood pressure,elevation in endogenous enzymes levels such as glutathione and lowering in malondialdehyde,super oxide dismutase followed by normalized lipid profile and reduced the mortality rate.The treatment had antiapoptotic potential at cellular level also histopathology of heart tissue(light and electron microscopical).Thus concomitant action of FLC andω-3-FA may be antioxidant,antihyperlipidemic,anti-inflammatory and anti-apoptotic actions seem to the probable mechanisms in doxorubicin induced cardiotoxicity.It can be concluded that FLC andω-3-FA both have distinct mechanism for cardioprotection and hence the additive effect was observed in the present study due to concomitant administration of FLC andω-3-FA.©2013 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

养殖与野生鮻营养成分和挥发性物质比较

为探究养殖与野生鮻肌肉营养成分的差异,采用常规方法检测并分析“跑道”养殖鮻和野生鮻肌肉基本营养成分、氨基酸、脂肪酸和挥发性成分等指标。试验结果显示,“跑道”养殖鮻肌肉水分含量显著低于野生鮻(P<0.05),粗脂肪含量显著高于野生鮻(P<0.05),灰分和粗蛋白含量差异不显著(P>0.05);“跑道”养殖鮻肌肉中大部分氨基酸含量显著高于野生鮻(P<0.05),必需氨基酸、非必需氨基酸以及氨基酸总量差异显著(P<0.05)。依据氨基酸评分、化学评分,鮻肌肉中第一限制氨基酸均为甲硫氨酸+胱氨酸,第二限制氨基酸均为缬氨酸。必需氨基酸指数为“跑道”养殖鮻(101.39)>野生鮻(82.79)。“跑道”养殖鮻不饱和脂肪酸含量、脂肪酸不饱和度显著高于野生鮻(P<0.05),而饱和脂肪酸含量、二十碳五烯酸+二十二碳六烯酸含量低于野生鮻(P<0.05)。“跑道”养殖鮻和野生鮻分别检测出18种和29种挥发性化合物,野生鮻肌肉中关键风味物质的种类和数量更多,风味更丰富,而“跑道”养殖降低了鮻肌肉中部分呈现不愉悦气味的化合物含量。试验结果表明,“跑道”养殖模式改善了鮻肌肉氨基酸和挥发性化合物的组成。

鲤上皮瘤细胞两种转染试剂的条件优化及应用

鲤上皮瘤细胞是常用的鱼类细胞系,广泛使用在各种病毒学和基因功能研究中。利用细胞转染技术在鲤上皮瘤细胞进行基因功能研究时,转染试剂和DNA的剂量以及取样时间没有统一的数据支持。为解决该问题,选取两种常用转染试剂Lipofectamine®2000和FuGENE®HD,分别对荧光蛋白标记的多种质粒进行多配组转染试验,多温度、多时间节点追踪记录转染效率。28℃,以35 mm培养皿铺板,16μL Lipofectamine®2000和4μg DNA在转染后48 h达到最高转染效率(5.92±0.52)%;12μL FuGENE®HD和4μg DNA在转染72 h后转染效率达到(9.81±0.33)%。为验证该条件,构建一个鲤高不饱和脂肪酸合成相关转录因子过氧化物酶体增殖物激活受体蛋白α(PPARα)的EGFP标签载体,该载体利用两种转染试剂分别获得了约4%和约8%的转染效率。以实时荧光定量PCR检测该转录因子对下游脂肪酸去饱和酶2(fads2)基因的转录调控效应,虽然两种转染试剂本身可导致下游基因的上调,但与空载质粒组相比,两种转染试剂高表达转录因子均对下游靶基因产生了转录激活效应。本试验获得了常用转染试剂Lipofectamine®2000和FuGENE®HD在鲤上皮瘤细胞细胞转染时的最适转染试剂和DNA剂量和最优取样时间,并在一转录调控实例中进行了验证,试验结果为后续充分利用鲤上皮瘤细胞进行基因功能研究提供了数据支持,有助于更好地服务于渔业种质资源育种创新。

不饱和脂肪酸在反刍动物饲粮中的应用研究进展

不饱和脂肪酸主要存在于植物种子、植物油及含油量多的海鱼中,在自然界含量丰富,对人体具有补脑健脑、调节免疫功能、抵抗心血管疾病等重要作用。在反刍动物生产上,富含不饱和脂肪酸的饲粮具有改善反刍动物生产性能、减少甲烷排放和改善产品质量的功能。本文主要针对不饱和脂肪酸对反刍动物生产性能、瘤胃发酵、甲烷排放等方面的影响进行综述,旨在为不饱和脂肪酸在反刍动物营养方面的研究和应用提供参考。