Effects of dietary ratio of n-6 to n-3 polyunsaturated fatty acids on immunoglobulins, cytokines, fatty acid composition, and performance of lactating sows and suckling piglets

This experiment was conducted to investigate the effects of dietary ratios of n-6：n-3 polyunsaturated fatty acids （PUFA） on the performance of lactating sows and their piglets. Thirty pregnant Landrace sows were assigned to one of three treatments from d 108 of gestation until weaning （26-29 d） and were fed diets containing different ratios of n-6：n-3 PUFA including 3：1,9：1 and 13：1. The effects on sow and litter production traits were examined together with an assessment of sow body condition. No differences were detected among the treatments for the daily feed intake of sows or changes in sow weight and back-fat levels during lactation （P 〉 0.05）. Litter size at d 14 and d 21 were tended to increase in 3：1 treatment compared with 9：1 and 13：1 treatments （P 〈 0.10）. Litter weight gain （1.77 kg/d） from d 0 to d 14 was tended to increase in 9：1 groups compared with the other two treatments （P 〈 0.10）. A significant difference was observed for the content of a -linolenic acid, total n-3 PUFA, and the ratio of n-6：n-3 PUFA in the colostrum, milk, and piglets plasma （P 〈 0.01）. The effects of different ratios of n-6：n-3 PUFA in sow diets on colostrum, milk and piglet plasma immunoglobulin concentrations are studied. No difference was observed among treatments in the concentrations of IgM, and IgA in colostrum （P 〉 0.05）. A great significant difference for IgG concentration was observed among 3 group in colostrum. A great significant difference for IgA, and IgM （P〈 0.01） concentrations in piglet plasma at d14 and a significant difference for IgG（P 〈 0.05） was observed at d14. Furthermore, at d 21 of lactation, piglet plasma IgG and IgA concentration were greater in 3：1 compared with 13：1 group （P 〈 0.01）. In summary, the current study demonstrated that altering the ratio of n-6：n-3 PUFA in lactating sow diet had an effect on the immune component including immunoglobulin and cytokines, and it tended to increase the litter average daily gain and improve the immune status of piglets when dietary ratio of n-6：n-3 PUFA was 9：1.

Effects of the Ratio of n-6∶n-3 Polyunsaturated Fatty Acids in the Maternal Diet on Immunoglobulins,Fatty Acid Composition,and Performance of Lactating Sows and Suckling Piglets under Conditions of Low Maternal Energy Intake

This experiment was conducted to investigate the effects of different ratios of n-6 ∶ n-3 polyunsaturated fatty acids （PUFA） in sow diets on the performance of lactating sows and their piglets at low digestible energy intakes. Twenty-one pregnant Landrace sows were assigned to one of three diets from day 108 of gestation until weaning （26 to 29 d） ,containing n-6∶n-3 PUFA ratios of 3 ∶1,8 ∶1 and 11 ∶1. The effects on sow and litter production traits and on sow body condition were examined. There were no differences among treatments in daily feed intakes or in changes in sow weight and back-fat levels during lactation. Litter size,litter weight at birth and weaning and litter average daily weight gain were also unaffected by treatment. As expected, large differences were observed in n-6 and n-3 fatty acids in the colostrum and plasma of sows and piglets （P 〈 0. 01） . The ratio of n6 ∶ n-3 PUFA the diet was positively correlated with those in colostrum,sow plasma and piglet plasma （R 2= 0. 55,0. 80 and 0. 80,respectively） . Sow plasma insulin and IGF-I levels at weaning were unaffected by the treatments. Plasma leptin （P 〈 0. 05） concentrations were increased in sows fed the diet with a n-6∶n-3 ratio of 8 ∶ 1. Immunoglobulin concentrations in colostrum were not altered by dietary treatment. Plasma IgG concentrations at d 14 were highest in piglets from sows fed the 8 ∶ 1 ratio of n-6∶n-3. Furthermore,this group had the highest IgA concentrations at day 21 of lactation compared with the other two groups （P 〈 0. 05） . In summary,our study demonstrated that at low digestible energy levels,altering the ratio of n-6 ∶ n-3 PUFA in the diets for lactating sows affected immune components and the fatty acid composition of lactating sows and their piglets. Further studies are needed to examine whether higher levels of fat supplementation than those used in the present study （1. 5%） can successfully enhance performance.

Different n-6/n-3 polyunsaturated fatty acid ratios affect postprandial metabolism in normal and hypertriglyceridemic rats

Postprandial metabolism plays major roles in many pathological conditions.The n-6/n-3 polyunsaturated fatty acid(PUFA)ratio is closely related to various physiological disorders.This study aimed to investigate the effects of high fat meals with different n-6/n-3 PUFA ratios on postprandial metabolism in normal control(NC)and hypertriglyceridemia(HTG)rats.The postprandial response of triglyceride(TG)in HTG groups was higher than that in NC groups after different n-6/n-3 PUFA ratio meals.The HTG groups showed higher postprandial total cholesterol(TC)responses than NC groups after 1:1 and 20:1 ratio meals.The 5:1 n-6/n-3 PUFA ratio elicited lower postprandial responses of tumor necrosis factorα(TNF-α)than 1:1 and 10:1 ratios in HTG groups.The postprandial malondialdehyde(MDA)response was lower after a 5:1 n-6/n-3 PUFA ratio meal than 1:1 and 20:1 ratio meals in HTG groups.The 1:1 ratio resulted in a lower postprandial reactive oxygen species(ROS)level than 5:1 and 10:1 n-6/n-3 PUFA ratios in NC groups.The results showed that a low n-6/n-3 PUFA ratio improved postprandial dysmetabolism induced by a high fat meal in NC and HTG rats.A high n-6/n-3 PUFA ratio increased the difference in postprandial metabolism between NC and HTG rats.

Beneficial n-3 polyunsaturated fatty acid levels and n6:n3 ratios after 4-week EPA + DHA supplementation associated with reduced CRP: A pilot study in healthy young adults

Chronic systemic inflammation is associated with many conditions of aging such as atherosclerosis. Lowering high n-6:n-3 polyunsaturated fatty acid (PUFA) ratios are commonly found in Western diets aids in preventing inflammatory-related diseases. However, it is not clear whether dietary interventions designed to alter n-6:n-3 PUFA ratios can reduce systemic inflammation in younger adults. Studies that evaluate PUFA intake often use subjective data from food frequency questionnaires or food records rather than more precise physiological measures of PUFAs (e.g. plasma levels). Therefore, the purpose of this pilot study that analyzed data from the experimental parent study of younger adults (n = 18), was to determine whether plasma PUFA levels were associated with levels of C-reactive protein (CRP), an inflammatory marker, and if supplementation with n-3 PUFAs was correlated with rising n-3 PUFA concentrations in plasma and decreasing n-6:n-3 ratios. In the parent study, participants received daily either placebo or n-3 PUFA softgels (1.6 g eicosapentaenoic acid [EPA] and 1.2 g docosahexaenoic acid [DHA]). EPA and DHA are the biologically active components in fish oil. Measures included blood for PUFA quantification at baseline and four weeks later, when blister wounds were created and wound fluid and saliva were collected. The saliva samples were used to measure CRP in the present study. We report that CRP was significantly and negatively correlated with total n-3 PUFAs (tau-β = ?0.373, p = 0.031) and positively correlated with n-6:n-3 ratios (tau-β = 0.320, p = 0.063). Those consuming EPA + DHA supplements had significantly higher concentrations of total n-3 PUFAs and significantly lower n-6:n-3 ratios (p The present study has shown that beneficial levels of n-3 PUFAs and n-6:n3 ratios were achieved with 4-weeks of EPA + DHA supplementation and were associated with reduced CRP in young adults. EPA + DHA supplementation for some young adults may help prevent inflammatory conditions later in life.

Effect of ω-3 Polyunsaturated Fatty Acid on Toll-like Receptors in Patients with Severe Multiple Trauma

This study examined the effects of ω-3 polyunsaturated fatty acid（ω-3PUFA） on the expression of toll-like receptor 2（TLR2）,toll-like receptor 4（TLR4） and some related inflammatory factors in peripheral blood mononuclear cells（PBMCs） of patients with early-stage severe multiple trauma.Thirty-two patients who were admitted to the Department of Traumatic Surgery,Tongji Hospital（Wuhan,China） between May 2010 and November 2010,and diagnosed as having severe multiple trauma with a injury severity score（ISS） no less than 16,were enrolled in the study and divided into two groups at random（n=16 in each）：ω-3PUFA group and control group in which routine parenteral nutrition supplemented with ω-3PUFA or not was administered to the patients in two groups for consecutive 7 days.Peripheral blood from these patients was collected within 2 h of admission（day 0）,and 1,3,5 and 7 days after the nutritional support.PBMCs were isolated and used for detection of the mRNA and protein expression of TLR2 and TLR4 by using real-time PCR and flow cytometry respectively,the levels of NF-κB by quantum dots-based immunofluorescence assay,the levels of TNF-α,IL-2,IL-6 and COX-2 by ELISA,respectively.The results showed that the mRNA and protein expression of TLR2 and TLR4 in PBMCs was significantly lower in ω-3PUFA group than in control group 5 and 7 days after nutrition support（both P0.05）.The levels of TNF-α,IL-2,IL-6 and COX-2 were found to be substantially decreased in PBMCs in ω-3PUFA group as compared with control group at 5th and 7th day（P0.05 for all）.It was concluded that ω-3PUFA can remarkably decrease the expression of TLR2,TLR4 and some related inflammatory factors in NF-κB signaling pathway in PBMCs of patients with severe multiple trauma,which suggests that ω-3PUFA may suppress the excessive inflammatory response meditated by the TLRs/NF-κB signaling pathway.

Transgenic Pigs Carrying a Synthesized Fatty Acid Desaturase Gene Yield High Level of ω-3 PUFAs

Polyunsaturated fatty acids （PUFAs） are essential for normal growth in mammals, especially the ω-3 PUFAs, which play important roles in preventing several life-threatening diseases, such as coronary heart disease and diabetes. In this study, we aimed to investigate whether the sFat-1 gene from Caenorhabditis briggsae could be functionally expressed in transgenic pigs, and whether the transgenic could synthesize high quality ω-3 PUFAs endogenously. In this study, a gene construct consisting of CMV promoter and 1.9 kb cDNA of ω-3 fatty acid desaturase gene （sFat-1） from C. briggsae was injected into the male pronucleus of pig embryos by microinjection. The piglets were screened for the transgene by PCR, Southern blot and reverse transcription-PCR analysis. Pigs that give positive results were mated with wild-type pigs to produce the next generation and the transmission of transgene was examined by PCR analysis. Fatty acids compositions of various tissues in the transgenic pigs were then analyzed by gas chromatograph. A total of 878 embryos were transferred into 42 recipients, among which 29 successfully got pregnant and gave birth to a total of 162 piglets, and 8 of them were identified to be transgenic. Fatty acid compositions in the transgenic pigs were altered, and the levels of ω-6：ω-3 ratios were decreased from 14.53 in the control to 2.62 in Fat-1 transgenic pigs. A number of primary sFat-1-transgenic pigs were bred in this study, which lays the foundation for cultivation of new varieties of transgenic pigs.

Meldonium-induced steatosis is associated with increased delta 6 desaturation and reduced elongation of n-6 polyunsaturated fatty acids

Background and objective Metabolic associated fatty liver disease(MAFLD)is associated with abnormal lipid metabolism.Mitochondrial dysfunction is considered an important factor in the onset of MAFLD,whereas altered fatty acid composition has been linked to the severity of the disease.Tetradecylthioacetic acid(TTA),shown to induce mitochondrial proliferation and alter the fatty acid composition,was used to delay the accumulation of hepatic triacylglycerol.This study aimed to evaluate how impaired mitochondrial fatty acid beta-oxidation affects fatty acid composition by incorporating meldonium into a high-carbohydrate diet.Methods C57BL/6 mice(n=40)were fed high-carbohydrate diets supplemented with meldonium,TTA,or a combination of meldonium and TTA for 21 days.Lipid levels were determined in liver samples,and fatty acid composition was measured in both liver and plasma samples.Additionally,desaturase and elongase activities were estimated.The hepatic activities and gene expression levels of enzymes involved in fatty acid metabolism were measured in liver samples,whereas carnitines,their precursors,and acylcarnitines were measured in plasma samples.Results The meldonium-induced depletion of L-carnitine and mitochondrial fatty acid oxidation was confirmed by reduced plasma levels of L-carnitine and acylcarnitines.Principal component analyses of the hepatic fatty acid composition revealed clustering dependent on meldonium and TTA.The meldonium-induced increase in hepatic triacylglycerol levels correlated negatively with estimated activities of elongases and was associated with higher estimated activities of delta-6 desaturase(D6D;C18:4n-3/C18:3n-3 and C18:3n-6/C18:2n-6),and increased circulating levels of C18:4n-3 and C18:3n-6(gamma-linolenic acid).TTA mitigated meldonium-induced triacylglycerol levels by 80%and attenuated the estimated D6D activities,and elongation of n-6 polyunsaturated fatty acids(PUFAs).TTA also attenuated the meldonium-mediated reduction of C24:1n-9(nervonic acid),possibly by stimulating Elovl5 and increased elongation of erucic acid(C22:1n-9)to nervonic acid.The hepatic levels of nervonic acid and the estimated activity of n-6 PUFA elongation correlated negatively with the hepatic triacylglycerol levels,while the estimated activities of D6D correlated positively.Conclusion Circulating levels of gamma-linolenic acid,along with reduced estimated elongation of n-6 PUFAs and D6D desaturation activities,were associated with hepatic triacylglycerol levels.

Production of γ-linolenic acid and stearidonic acid by Synechococcus sp.PCC7002 containing cyanobacterial fatty acid desaturase genes

Genetic modifi cation is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be used to modify fatty acid metabolism. S ynechococcus sp. PCC7002, a fast-growing cyanobacterium, does not contain a Δ6 desaturase gene and is therefore unable to synthesize γ-linolenic acid(GLA) and stearidonic acid(SDA), which are important in human health. In this work, we constructed recombinant vectors Syd6 D, Syd15 D and Syd6Dd15 D to express the Δ15 desaturase and Δ6 desaturase genes from Synechocystis PCC6803 in Synechococcus sp. PCC7002, with the aim of expressing polyunsaturated fatty acids. Overexpression of the Δ15 desaturase gene in S ynechococcus resulted in 5.4 times greater accumulation of α-linolenic acid compared with the wild-type while Δ6 desaturase gene expression produced both GLA and SDA. Co-expression of the two genes resulted in low-level accumulation of GLA but much larger amounts of SDA, accounting for as much to 11.64% of the total fatty acid content.

体内ω-6 PUFAs与ω-3 PUFAs比例是影响ω-3 PUFAs发挥健康效应的重要因素

ω-3多不饱和脂肪酸(PUFAs)是人类重要的结构营养素和功能营养素,大量基础实验与人群研究已阐明其降脂、抗炎、防治心脑血管疾病、改善肿瘤微环境等作用。然而,随着ω-3 PUFAs人群干预试验的逐渐增多,部分研究并未发现该类显著效应。这种结果的不一致性阻碍了ω-3 PUFAs在更多医学指南中的应用,也限制了ω-3 PUFAs在临床诊疗和慢病管理中的推广。ω-6 PUFAs是另一类重要的多不饱和脂肪酸,但随着膳食结构的变迁,全球普遍存在ω-6 PUFAs摄入超标和ω-3 PUFAs摄入不足,进而导致体内ω-6与ω-3比例显著上升的问题。ω-6 PUFAs在体内与ω-3 PUFAs存在细胞膜结构占位竞争及代谢竞争的关系,高ω-6/ω-3比例可能会阻碍ω-3 PUFAs发挥其健康效应,并与众多慢病的发生、发展密切相关。本综述通过分析ω-3和ω-6 PUFAs在体内的交互作用及ω-6/ω-3比例对ω-3 PUFAs的影响,提出体内ω-6/ω-3比例是影响ω-3 PUFAs效应发挥的重要因素。同时,本文指出以往部分ω-3 PUFAs研究忽视了ω-6/ω-3比例这一重要指标,在研究终点时仍未恢复平衡的ω-6/ω-3比例可能是导致研究结果不一致的关键原因,提示尽快规范ω-3 PUFAs研究标准、将ω-6/ω-3比例纳入质控监测指标将有助于客观揭示ω-3 PUFAs的健康效应,并最终推动ω-3 PUFAs在慢病管理中的标准化应用。

Additive neurorestorative effects of exercise and docosahexaenoic acid intake in a mouse model of Parkinson’s disease

There is a need to develop interventions to slow or reverse the degeneration of dopamine neurons in Parkinson’s disease after diagnosis.Given that preclinical and clinical studies suggest benefits of dietary n-3 polyunsaturated fatty acids,such as docosahexaenoic acid,and exercise in Parkinson’s disease,we investigated whether both could synergistically interact to induce recovery of the dopaminergic pathway.First,mice received a unilateral stereotactic injection of 6-hydroxydopamine into the striatum to establish an animal model of nigrostriatal denervation.Four weeks after lesion,animals were fed a docosahexaenoic acid-enriched or a control diet for the next 8 weeks.During this period,the animals had access to a running wheel,which they could use or not.Docosahexaenoic acid treatment,voluntary exercise,or the combination of both had no effect on(i)distance traveled in the open field test,(ii)the percentage of contraversive rotations in the apomorphine-induction test or(iii)the number of tyrosine-hydroxylase-positive cells in the substantia nigra pars compacta.However,the docosahexaenoic acid diet increased the number of tyrosine-hydroxylase-positive terminals and induced a rise in dopamine concentrations in the lesioned striatum.Compared to docosahexaenoic acid treatment or exercise alone,the combination of docosahexaenoic acid and exercise(i)improved forelimb balance in the stepping test,(ii)decreased the striatal DOPAC/dopamine ratio and(iii)led to increased dopamine transporter levels in the lesioned striatum.The present results suggest that the combination of exercise and docosahexaenoic acid may act synergistically in the striatum of mice with a unilateral lesion of the dopaminergic system and provide support for clinical trials combining nutrition and physical exercise in the treatment of Parkinson’s disease.

Cytochrome P450 monooxygenase-mediated eicosanoid pathway:A potential mechanistic linkage between dietary fatty acid consumption and colon cancer risk

Human consumption of linoleic acid(LA,18:2ω-6,abundant in vegetable oils)is very high.Animal experiments showed that excessive LA intake increased azoxymethane-induced colon tumorigenesis,however,the impact of excessive LA on colon cancer in human is not conclusive,making it difficult to make dietary recommendations for optimal intake of LA.Understanding the molecular mechanisms of LA on colon tumorigenesis could help to clarify its health effect,and facilitate development of mechanismbased strategies for preventing colon cancer.Recent studies show that the previously unappreciated cytochrome P450 monooxygenase-mediated eicosanoid pathway is upregulated in colon cancer and plays critical roles in its pathogenesis,and could contribute to the effects of dietary LA,as well asω-3 fatty acids,on colon tumorigenesis.In this review,we will discuss recent studies about the roles of cytochrome P450 monooxygenases in fatty acid metabolism and its roles in colonic inflammation and colon cancer,and how this information could help us to clarify the health impacts of dietary fatty acids.

姬松茸ω-6多不饱和脂肪酸对高血脂鼠的降血脂作用

目的:观察姬松茸ω-6多不饱和脂肪酸(-ω6APFA)对高血脂鼠的降血脂作用。方法:大鼠60只,随机分为空白对照组、模型组、天然大豆磷脂胶囊(NSPC)0.70 g.kg-1剂量组和-ω6APFA 0.28、0.14、0.07 g.kg-13个剂量组(n=10)。除空白对照组外均连续给予高脂饲料14 d,于第14天起开始连续灌胃给药14 d,对照组和模型组给予等容积蒸馏水10 mL.kg-1。实验结束后麻醉大鼠,腹主动脉取血测血清总胆固醇(T-CHO)、甘油三酯(TG)、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)。同时测肝脏超氧化物歧化酶(SOD)活性、肝脏丙二醛(MDA)含量及腹腔脂肪蓄积系数。雄性小鼠72只,随机分为空白对照组、模型组、NSPC 1.0 g.kg-1剂量组、-ω6APFA 0.4、0.2、0.1 g.kg-13个剂量组(n=12),连续给药7 d,末次给药前16 h除空白对照组,均腹腔注射75%蛋黄生理盐水液0.5 mL,并开始饥饿,末次给药后1 h,于眼球采血,测血清T-CHO及TG含量。结果:与模型组比较,NSPC 0.70 g.kg-1和-ω6APFA 0.28 g.kg-1剂量组大鼠血清T-CHO、TG均明显降低,血清HDL-C升高(P<0.001);NSPC 0.70 g.kg-1和-ω6APFA 0.28、0.14 g.kg-1剂量组大鼠肝组织SOD活性升高(P<0.05、P<0.001及P<0.05),MDA降低(P<0.01、P<0.001及P<0.01),大鼠腹腔脂肪系数均降低(P<0.01)。与模型组比较,NSPC 1.0 g.kg-1、-ω6APFA0.4、0.2 g.kg-1组急性高血脂小鼠T-CHO和TG明显降低(P<0.05、P<0.01及P<0.05)。结论:ω-6APFA对高血脂鼠有明显的降血脂作用。

膳食中ω-3和ω-6多不饱和脂肪酸摄入与心血管健康的研究进展

综述了国内外ω–3和ω–6多不饱和脂肪酸摄入推荐标准。介绍了ω–3和ω–6多不饱和脂肪酸摄入量和摄入比对心血管健康影响,为中老年配方奶粉生产企业提供一定的依据。

不同比例ω-3/ω-6多不饱和脂肪酸对DSS诱导大鼠急性结肠炎的影响

目的:探讨不同比例ω-3/ω-6多不饱和脂肪酸对葡聚糖硫酸钠(dextran sulfate sodium,DSS)诱导大鼠急性结肠炎影响及其可能的作用机制.方法:32只1月龄♂SD大鼠随机分为4组,每组8只,A:普通饲料对照组,B:ω-3/ω-6PUFA 1∶1组、C:ω-3/ω-6 PUFA 1∶3组,D:ω-3/ω-6 PUFA 1∶30组.4组大鼠不同饲料喂养6 wk;随后B、C、D组大鼠自由饮用3%DSS溶液7 d,诱发急性结肠炎模型;A组大鼠自由引用普通水7 d.比较各组大鼠结肠炎症状评分、病理炎症评分和结肠组织前列腺素E2(prostaglandin E2,PGE2)、核因子-kB(nuclear factor-kB,NF-kB)、肿瘤坏死因子-α(tumor necrosis factorα,TNF-α)、血清白介素-6(interleukin-6,IL-6)的含量.结果:B组大鼠结肠炎症程度积分显著低于C、D组,分别为2.8±1.2、4.3±1.1、5.6±1.3(P<0.05,P<0.01).B组大鼠结肠炎病理学评分显著低于C、D组,分别为3.2±2.0、35.0±28.8、27.0±25.8(P<0.01,P<0.01).B、C组大鼠结肠组织中PGE2含量低于D组,分别为443.4ng/100g组织±67.3 ng/100g组织、419.5ng/100g组织±52.6 ng/100 g组织、541.2±68.5(ng/100 g组织)(P<0.05,P<0.01).B、C组大鼠结肠组织中TNF-α含量低于D组,分别为189.2 ng/100g组织±27.0 ng/100 g组织、173.2 n g/100g组织±50.2 n g/100 g组织、270.3 ng/100g组织±49.1 ng/100 g组织(P<0.01,P<0.01).B组大鼠血清中IL-6含量低于C、D组,分别为97.1 ng/L±8.2 ng/L、129.1 ng/L±5.5 ng/L、125.4 ng/L±19.6 ng/L(P<0.01,P<0.05).B、C、D大鼠结肠组织中NF-kB含量分别为497.9 ng/100g组织±50.7 ng/100 g组织、569.1 ng/100g组织±121.2 ng/100 g组织、582.5 ng/100g组织±123.1 ng/100 g组织,无统计学差异.结论:提高以ω-3/ω-6 PUFA的比例对于DSS诱导的大鼠急性结肠炎症具有保护作用,尤其是当ω-3/ω-6 PUFA比例提高到1∶1保护作用最明显.随着ω-3 PUFA的比例升高,ω-3/ω-6PUFA1∶1组较ω-3/ω-6 PUFA1:30组大鼠的炎症评分、病理评分以及相关的炎症因子如PGE2、TNF-α、IL-6都有所下降.向饮食中添加适量ω-6 PUFA或可成为治疗炎症性肠病新方向.

膳食中高n-6/n-3多不饱和脂肪酸比值对小鼠精子浓度及活度的影响

目的近年来男性精子数量、质量呈下降趋势。文中研究小鼠膳食中高n-6/n-3多不饱和脂肪酸比值对其精子浓度及活度的影响。方法健康的B6小鼠20只,随机数表法分成对照组(基础饲料)和实验组(基础饲料+10%花生四烯酸),每组10只。喂食8周后,取各组小鼠附睾尾检测小鼠精子浓度及活度的变化,观察小鼠附睾组织显微结构的改变。结果实验组小鼠血清中α-亚麻酸、二十碳五烯酸、二十二碳六烯酸、二十二碳五烯酸、亚油酸含量均较对照组明显下降(P<0.01),而花生四烯酸和n-6/n-3 PUFAs明显升高(P<0.01)。实验组精子浓度(7×106个/mL)较对照组(80×106个/mL)显著下降,实验组精子活度(27%)较对照组(86%)显著下降,差异有统计学意义(P<0.01)。附睾组织管腔中精子数目明显减少。结论膳食中高n-6/n-3多不饱和脂肪酸比值对精子数量、质量具有显著损伤作用。

n-6/n-3多不饱和脂肪酸不同比例对乳腺癌细胞脂代谢调控基因的影响

目的探讨不同n-6/n-3多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）构成对乳腺癌细胞脂代谢调控基因及MAPK活性的影响.方法选用MCF-7（ER＋）和MDA-MB-231（ER-）乳腺癌细胞为实验对象,用不同n-6/n-3 PUFA构成（1～10）处理细胞后,MTT法观察细胞增殖能力,RT-PCR分析细胞脂代谢关键性调控基因（COX-2、5-LOX、PPARβ和PPARγ）表达变化,Western blot检测细胞MAPK蛋白磷酸化水平.结果 MCF-7细胞不表达COX-2基因.与对照组相比,单纯n-6和10：1 n-6/n-3 PUFA能明显促进这两种乳腺癌细胞增殖,诱导细胞COX-2、5-LOX、PPARβ和PPARγmRNA表达上调,并促进细胞MAPK磷酸化（P＜0.01）;与之相反的是,单纯n-3和1：1 n-6/n-3 PUFA显著抑制细胞生长,下调细胞COX-2、5-LOX、PPARβ和PPARγ mRNA表达,并抑制细胞MAPK磷酸化（P＜0.01）;但5：1 n-6/n-3 PUFA效果不明显.结论 n-6/n-3 PUFA不同比例对MCF-7和MDA-MB-231乳腺癌细胞脂代谢调控基因及信号转导的影响是不同的.在n-6/n-3比值为1～10范围内,单纯n-3和1：1 n-6/n-3能明显抑制脂代谢基因表达及信号转导,发挥显著抗乳腺癌细胞增殖效应.

n-3多烯脂肪酸对血小板聚集、血栓形成、6-keto-PGF_(1α)/TXB_2比值的影响

国产马面鱼屯鱼油的ｎ－３多烯脂肪酸（ｎ－３ＰＵＦＡｓ）于１～３ｇ／Ｌ浓度能抑制ＡＡ、ＡＤＰ诱导的兔血小板聚集性，ｉｇ０．１５ｇ／ｋｇ能抑制大鼠体外血栓形成，并增加大鼠血浆６－ｋｅｔｏ－ＰＧＦ１α含量，提高６－ｋｅｔｏ－ＰＧＦ１α／ＴＸＢ２比值。

N-6/N-3多不饱和脂肪酸不同比例对乳腺癌细胞缝隙连接细胞通讯的影响

目的观察n-6／n-3多不饱和脂肪酸（polyunsaturated fatty acid，PUFA）不同比例对乳腺癌细胞缝隙连接细胞通讯的影响。方法n-6／n-3PUFA不同比例（1～10）处理MCF-7（ER^＋）和MDA-MB-231（ER^-）乳腺癌细胞，采用免疫细胞化学观察细胞核Ki-67表达，Western blot检测细胞膜和细胞质缝隙连接蛋白Cx26、Cx43表达，划痕负载染料迁移法分析细胞缝隙连接通讯功能。结果免疫组化结果显示，单纯n-6和10：1n-6／n-3 PUFA增强两种乳腺癌细胞Ki-67表达（P〈0．05），5：1 n-6／n-3 PUFA虽无明显变化，但单纯n-3和1：1n-6／n-3 PUFA抑制细胞Ki-67表达（P〈0．01）。免疫印迹发现，单纯n-3和1：1n-6／n-3 PUFA能明显上调MCF-7细胞膜和细胞质的Cx26、Cx43蛋白表达，单纯n-6 PUFA却下调两种蛋白表达；在MDA-MB-231细胞，n-6／n-3 PUFA不同比例对膜和细胞质的Cx43蛋白表达与MCF-7细胞具有相同趋势，但对Cx26蛋白则无明显作用。用划痕负载染料迁移法却发现，n-6／n-3 PUFA不同比例对细胞缝隙连接通讯功能均无明显影响。结论单纯n-3和1：1n-6／n-3PUFA对MCF-7和MDA-MB-231乳腺癌细胞增殖活性的抑制作用，可能是Cx26和Cx43蛋白通过独立于缝隙连接细胞通讯功能的调节所致。

n-6多不饱和脂肪酸生理功能及其在肉牛生产中的应用

n-6多不饱和脂肪酸是动物的必需脂肪酸,与机体脂代谢、免疫机能和繁殖性能密切相关。研究发现,饲粮补充n-6多不饱和脂肪酸不仅可促进母牛妊娠建立而提高受胎率,且有利于胎儿发育、子代健康和生长发育,并改善育肥牛生产性能和胴体品质。鉴于此,本文综述了n-6多不饱和脂肪酸的生理功能,并详细阐述其在肉牛生产中的应用,为生产上科学合理地应用n-6多不饱和脂肪酸改善肉牛繁殖机能、提升健康和生产性能提供理论基础。

n-6／n-3多不饱和脂肪酸不同比例对乳腺癌细胞胰岛素样生长因子受体表达的影响

目的探讨n-6／n-3多不饱和脂肪酸（polyunsaturated fatty acid，PUFA）不同比例对乳腺癌细胞株MCF-7（ER^＋）及MDA-MB-231（ER^-）胰岛素样生长因子受体一1（insulin—like growth factor receptor-1，IGF-1R）表达的影响。方法用不同比例的n-6／n．3PUFA（1～10）处理细胞，MTF法检测细胞增殖能力变化；RT—PCR检测细胞IGF-1RmRNA表达变化；Westem blot检测IGF-1R蛋白在细胞膜的表达变化。结果单纯n-6PUFA和10：1n-6／n-3 PUFA能够明显促进MCF-7细胞和MDA—MB-231细胞增殖，诱导细胞IGF-1 RmRNA及蛋白表达上调（P〈0．01）；单纯n-3PUFA和1：1n-6／n-3PUFA则显著抑制细胞增殖，并降低细胞IGF-1RmRNA及蛋白表达水平（P〈0．01）；但5：1n-6／n-3PUFA效果不明显（P〉0．05）。结论不同n-6／n-3PUFA构成能差异性调节乳腺癌细胞IGF-1R表达，其中单纯n-3PUFA和1：1n-6／n-3PUFA能明显降低其表达并抑制乳腺癌细胞增殖。