Identification and characterization of genes that control fat deposition in chickens

Background： Fat deposits in chickens contribute significantly to meat quality attributes such as juiciness, flavor, taste and other organoleptic properties. The quantity of fat deposited increases faster and earlier in the fast- growing chickens than in slow-growing chickens. In this study, Affymetrix Genechip~ Chicken Genome Arrays 32773 transcripts were used to compare gene expression profiles in liver and hypothalamus tissues of fast-growing and slow-growing chicken at 8 wk of age. Real-time RT-PCR was used to validate the differential expression of genes selected from the microarray analysis. The mRNA expression of the genes was further examined in fat tissues. The association of single nucleotide polymorphisms of four lipid-related genes with fat traits was examined in a F2 resource population. Results： Four hundred genes in the liver tissues and 220 genes hypothalamus tissues, respectively, were identified to be differentially expressed in fast-growing chickens and slow-growing chickens. Expression levels of genes for lipid metabolism （SULTIB1, ACSBG2, PNPLA3, LPL, AOAH） carbohydrate metabolism （MGAT4B, XYLB, GBE1, PGM1, HKDCl）cholesttrol biosynthesis （FDPS, LSS, HMGCR, NSDHL, DHCR24, IDI1, MEI） HSD17B7 and other reaction or pro- cesses （CYPIA4, CYP1A1, AKR1BI, CYP4V2, DDO） were higher in the fast-growing White Recessive Rock chickens than in the slow-growing Xinghua chickens. On the other hand, expression levels of genes associated with multicellular organism development, immune response, DNA integration, melanin biosynthetic process, muscle organ develop- ment and oxidation-reduction （FRZB, DMD, FUT8, CYP2C45, DHRSX, and CYP2C18） and with glycol-metabolism （GCNT2, ELOVL d, and FASN）, were higher in the XH chickens than in the fast-growing chickens, fiT-PCR validated high expression levels of nine out of 12 genes in fat tissues. The G1257069A and T1247123C of the ACSBG2 gene were significantly associated with abdominal fat weight. The G4928024A of the FASN gene were significantly associ- ated with fat bandwidth, and abdominal fat percentage. The C4930169T of the FASN gene was associated with ab- dominal fat weight while the A59539099G of the ELOVL 6 was significantly associated with subcutaneous fat. The A8378815G of the DDT was associated with fat band width. Conclusion： The differences in fat deposition were reflected with differential gene expressions in fast and slow growing chickens.

Transcriptome analysis reveals steroid hormones biosynthesis pathway involved in abdominal fat deposition in broilers

Excessive abdominal fat deposition reduces the feed efficiency and increase the cost of production in broilers.Therefore,it is an important task for poultry breeders to breed broilers with low abdominal fat.Abdominal fat deposition is a highly complex biological process,and its molecular basis remains elusive.In this study,we performed transcriptome analysis to compare gene expression profiles at different stages of abdominal fat deposition to identify the key genes and pathways involved in abdominal fat accumulation.We found that abdominal fat weight(AFW)increased gradually from day 35(D35)to 91(D91),and then decreased at day 119(D119).Accordingly,after detecting differentially expressed genes(DEGs)by comparing gene expression profiles at D35 vs.D63 and D35 vs.D91,and identifying gene modules associated with fat deposition by weighted gene co-expression network analysis(WGCNA),we performed intersection analysis of the detected DEGs and WGCNA gene modules and identified 394 and 435 intersecting genes,respectively.The results of the Gene Ontology(GO)functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analyses showed that the steroid hormone biosynthesis and insulin signaling pathways were co-enriched in all intersecting genes,steroid hormones have been shown that regulated insulin signaling pathway,indicating the importance of the steroid hormone biosynthesis pathway in the development of broiler abdominal fat.We then identified 6 hub genes(ACTB,SOX9,RHOBTB2,PDLIM3,NEDD9,and DOCK4)related to abdominal fat deposition.Further analysis also revealed that there were direct interactions between 6 hub genes.SOX9 has been shown to bind to proteins required for steroid hormone receptor binding,and RHOBTB2 indirectly regulates the steroid hormones biosynthesis through cyclin factor,and ultimately affect fat deposition.Our results suggest that the genes RHOBTB2 and SOX9 play an important role in fat deposition in broilers,by regulating steroid hormone synthesis.These findings provide new targets and directions for further studies on the mechanisms of fat deposition in chicken.

Identifying the complex genetic architecture of growth and fatness traits in a Duroc pig population

In modern pig breeding programs,growth and fatness are vital economic traits that significantly influence porcine production.To identify underlying variants and candidate genes associated with growth and fatness traits,a total of 1067 genotyped Duroc pigs with de-regressed estimated breeding values(DEBV)records were analyzed in a genome wide association study(GWAS)by using a single marker regression model.In total,28 potential single nucleotide polymorphisms(SNPs)were associated with these traits of interest.Moreover,VPS4 B,PHLPP1,and some other genes were highlighted as functionally plausible candidate genes that compose the underlying genetic architecture of porcine growth and fatness traits.Our findings contribute to a better understanding of the genetic architectures underlying swine growth and fatness traits that can be potentially used in pig breeding programs.

Negative effects of long-term feeding of high-grain diets to lactating goats on milk fat production and composition by regulating gene expression and DNA methylation in the mammary gland

Background： It is well known that feeding a high concentrate（HC） diet to lactating ruminants likely induces subacute ruminal acidosis（SARA） and leads to a decrease in milk fat production. However, the effects of feeding a HC diet for long periods on milk fatty acids composition and the mechanism behind the decline of milk fat still remains poorly understood. The aim of this study was to investigate the impact of feeding a HC diet to lactating dairy goats on milk fat yield and fatty acids composition with an emphasis on the mechanisms underlying the milk fat depression. Seventeen mid-lactating dairy goats were randomly allocated to three groups. The control treatment was fed a low-concentrate diet（35% concentrate, n = 5, LC） and there were two high-concentrate treatments（65% concentrate, HC）, one fed a high concentrate diet for a long period（19 wks, n = 7, HL）; one fed a high concentrate diet for a short period of time（4 wk, n = 5, HS）. Milk fat production and fatty acids profiles were measured. In order to investigate the mechanisms underlying the changes in milk fat production and composition,the gene expression involved in lipid metabolism and DNA methylation in the mammary gland were also analyzed.Results： Milk production was increased by feeding the HC diet in the HS and HL groups compared with the LC diet（P 〈 0.01）, while the percentage of milk fat was lower in the HL（P 〈 0.05） but not in the HS group. The total amount of saturated fatty acids（SFA） in the milk was not changed by feeding the HC diet, whereas the levels of unsaturated fatty acids（UFA） and monounsaturated fatty acids（MUFA） were markedly decreased in the HL group compared with the LC group（P 〈 0.05）. Among these fatty acids, the concentrations of C15：0（P 〈 0.01）, C17：0（P 〈 0.01）, C17：1（P 〈 0.01）, C18：1 n-9 c（P 〈 0.05）, C18：3 n-3 r（P 〈 0.01） and C20：0（P 〈 0.01） were markedly lower in the HL group, and the concentrations of C20：0（P 〈 0.05） and C18：3 n-3 r（P 〈 0.01） were lower in the HS group compared with the LC group. However, the concentrations of C18：2 n-6 c（P 〈 0.05） and C20：4 n-6（P 〈 0.05） in the milk fat were higher in the HS group. Real-time PCR results showed that the m RNA expression of the genes involved in milk fat production in the mammary gland was generally decreased in the HL and HS groups compared with the LC group. Among these genes, ACSL1, ACSS1 ＆ 2, ACACA, FAS, SCD, FADS2, and SREBP1 were downregulated in the mammary gland of the HL group（P 〈 0.05）, and the expressions of ACSS2, ACACA, and FADS2 m RNA were markedly decreased in the HS goats compared with the LC group（P 〈 0.05）. In contrast to the gene expression, the level of DNA methylation in the promoter regions of the ACACA and SCD genes was increased in the HL group compared with the LC group（P 〈 0.05）. The levels of ACSL1 protein expression and FAS enzyme activity were also decreased in the mammary gland of the HL compared with the LC group（P 〈 0.05）.Conclusions： Long-term feeding of a HC diet to lactating goats induced milk fat depression and FAs profile shift with lower MUFAs but higher SFAs. A general down-regulation of the gene expression involved in the milk fat production and a higher DNA methylation in the mammary gland may contribute to the decrease in milk fat production in goats fed a HC diet for long time periods.

Papaya improves non-alcoholic fatty liver disease in obese rats by attenuating oxidative stress,inflammation and lipogenic gene expression

BACKGROUND Non-alcoholic fatty liver disease(NAFLD)is a global health issue that is correlated with obesity and oxidative stress.AIM To evaluate the anti-NAFLD effect of papaya in high fat diet induced obesity in rats.METHODS Four-week-old male Sprague-Dawley rats were divided into four groups after 1 wk of acclimatization:Group 1 was the rats fed a normal diet(C);group 2 was the rats fed a high fat diet(HFD);group 3 was the rats fed a HFD with 0.5 mL of papaya juice/100 g body weight(HFL),and group 4 was the rats fed a HFD with 1 mL of papaya juice/100 g body weight(HFH)for 12 wk.At the end of the treatment,blood and tissue samples were collected for biochemical analyses and histological assessment.RESULTS The results of the HFH group showed significantly reduced body weight(HFH vs HFD,P<0.01),decreased NAFLD score(HFH vs HFD,P<0.05),and reduced hepatic total cholesterol(HFL vs HFD,P<0.01;HFH vs HFD,P<0.001),hepatic triglyceride(HFH vs HFD,P<0.05),malondialdehyde(HFL,HFH vs HFD,P<0.001),tumour necrosis factor-α(HFH vs HFD,P<0.05)and interleukin-6(HFH vs HFD,P<0.05)when compared to the HFD group.However,the liver weight showed no significant difference among the groups.The activities of catalase and superoxide dismutase significantly increased in HFH when compared with the HFD group(P<0.05 and P<0.001,respectively).The suppression of transcriptional factors of hepatic lipogenesis,including sterol regulatory elementbinding protein 1c and fatty acid synthase,were observed in the papaya treated group(HFH vs HFD,P<0.05).These beneficial effects of papaya against HFDinduced NAFLD are through lowering hepatic lipid accumulation,suppressing the lipogenic pathway,improving the balance of antioxidant status,and lowering systemic inflammation.CONCLUSION These current results provide experimental-based evidence suggesting papaya is an efficacious medicinal fruit for use in the prevention or treatment of NAFLD.

Impact of dietary fat levels and fatty acid composition on milk fat synthesis in sows at peak lactation

Background Dietary fat is important for energy provision and immune function of lactating sows and their progeny.However,knowledge on the impact of fat on mammary transcription of lipogenic genes,de novo fat synthesis,and milk fatty acid(FA)output is sparse in sows.This study aimed to evaluate impacts of dietary fat levels and FA composition on these traits in sows.Forty second-parity sows(Danish Landrace×Yorkshire)were assigned to 1 of 5 dietary treatments from d 108 of gestation until weaning(d 28 of lactation):low-fat control diet(3%added animal fat);or 1 of 4 high-fat diets with 8%added fat:coconut oil(CO),fish oil(FO),sunflower oil(SO),or 4%octanoic acid plus 4%FO(OFO).Three approaches were taken to estimate de novo milk fat synthesis from glucose and body fat.Results Daily intake of FA was lowest in low-fat sows within fat levels(P<0.01)and in OFO and FO sows within highfat diets(P<0.01).Daily milk outputs of fat,FA,energy,and FA-derived carbon reflected to a large extent the intake of those.On average,estimates for de novo fat synthesis were 82 or 194 g/d from glucose according to method 1 or 2 and 255 g de novo+mobilized FA/d according to method 3.The low-fat diet increased mammary FAS expression(P<0.05)and de novo fat synthesis(method 1;P=0.13)within fat levels.The OFO diet increased de novo fat synthesis(method 1;P<0.05)and numerically upregulated mammary FAS expression compared to the other high-fat diets.Across diets,a daily intake of 440 g digestible FA minimized milk fat originating from glucose and mobilized body fat.Conclusions Sows fed diets with low-fat or octanoic acid,through upregulating FAS expression,increased mammary de novo fat synthesis whereas the milk FA output remained low in sows fed the low-fat diet or high-fat OFO or FO diets,indicating that dietary FA intake,dietary fat level,and body fat mobilization in concert determine de novo fat synthesis,amount and profiles of FA in milk.

犊牦牛肾周棕色脂肪组织的发育及其产热相关基因的表达分析

棕色脂肪组织(BAT)作为非震颤性产热(NST)的主要产热器官,在新生动物的寒冷适应中发挥重要的作用。为探究犊牦牛肾周BAT的发育及其产热相关基因的表达,本试验采集1日龄、7日龄和30日龄犊牦牛肾周脂肪组织,利用苏木精-伊红染色观察脂肪细胞,利用透射电子显微镜观察脂滴和线粒体的超微结构,利用免疫组织化学染色、实时荧光定量PCR和蛋白质免疫印迹(Western blot)检测解偶联蛋白1(UCP1)在脂肪细胞的定位、mRNA和蛋白表达水平,以及脂肪转化因子过氧化物酶体增殖激活受体α(PPARα)和过氧化物酶体增殖物受体γ共激活因子1α(PGC-1α)基因mRNA表达水平。结果显示,犊牦牛肾周存在2种类型的脂肪细胞,即含有小脂滴和大量线粒体的棕色脂肪细胞以及含有大脂滴和少量线粒体的白色脂肪细胞;与1日龄犊牦牛相比,7日龄和30日龄犊牦牛肾周白色脂肪细胞的面积和密度均显著增加(P<0.05),棕色脂肪细胞的面积和密度均显著降低(P<0.05);不同日龄犊牦牛肾周棕色脂肪细胞和白色脂肪细胞质膜上均有UCP1阳性表达,与1日龄犊牦牛相比,7日龄和30日龄犊牦牛肾周脂肪细胞中UCP1阳性表达强度均显著降低(P<0.05);与1日龄犊牦牛相比,30日龄犊牦牛肾周脂肪组织中BAT产热相关基因(UCP1、PPARα和PGC-1α)mRNA表达水平均显著降低(P<0.05);与1日龄犊牦牛相比,7日龄和30日龄犊牦牛肾周脂肪组织中UCP1蛋白表达水平均显著降低(P<0.05)。结果表明,出生后犊牦牛肾周棕色脂肪细胞数量逐渐减少而白色脂肪细胞数量逐渐增加,且产热相关基因表达水平逐渐降低。该结果为深入探究犊牦牛寒冷适应机制提供了参考资料。

断尾对兰州大尾羊脂肪细胞结构和脂肪代谢相关基因表达的影响

旨在观察断尾对兰州大尾羊尾部脂肪细胞数量、结构以及皮下脂肪、大网膜脂肪、尾部脂肪、肾周脂肪和背最长肌脂肪代谢相关基因表达的影响,明确断尾引起脂肪沉积重新分布后,脂肪细胞和各脂肪沉积部位脂肪代谢相关基因表达的变化,为阐明断尾对脂尾型绵羊脂肪代谢调控的分子机理提供参考。选择5日龄[(3.79±0.12)kg]单羔兰州大尾羊羔羊18只,随机分为对照组(C组)和试验组(T组),每组9只羔羊,试验组羔羊采用橡皮圈结扎法断尾。试验羊2月龄断奶后饲喂配合日粮,两组羊日粮相同。试验期240 d。试验结束后,采集样品进行分析。1)相对于背最长肌肌内脂肪和内脏脂肪,断尾对尾部脂肪、皮下脂肪基因表达影响较大,断尾组尾部脂肪SCD、LEP、PLIN1的mRNA表达量显著升高,LPL、FAS、PEPCK的表达量显著降低(P<0.05);皮下脂肪中SCD显著升高,LEP、ADPN、FABP4、PLIN1显著降低(P<0.05);肾周脂肪中LPL、ADPN、PEPCK、UCP1和大网膜脂肪中的PEPCK显著降低(P<0.05);背最长肌中SCD显著升高,PEPCK、PLIN1显著降低(P<0.05)。2)断尾组背最长肌的肌内脂肪含量(6.96%和6.05%)、脂滴面积比(4.28%和3.04%)显著增加(P<0.05),脂滴面积比增加了约1%,而尾部脂肪中脂滴面积比例降低了约10%(87.43%和97.58%),尾部脂肪细胞直径显著降低(P<0.05);3)兰州大尾羊尾部脂肪细胞被融合的大脂滴填充,细胞核、细胞质等被大脂滴挤到细胞边缘,细胞边缘的细胞质薄层中含有线粒体、内质网、高尔基体、自噬小体等细胞器和小脂滴,断尾组尾部脂肪细胞质中单个脂滴体积较小,周围糖原颗粒较多。综上所述,长脂尾型绵羊兰州大尾羊早期断尾后,背最长肌的脂滴面积比增加,尾部脂肪中脂滴面积比降低,尾部脂肪细胞直径减小,各部位脂肪代谢相关基因表达也发生变化,断尾后脂肪沉积分布改变可能是在SCD、PLIN1、LPL、FAS、PEPCK等一系列脂肪代谢相关基因的调控下实现的。

德昂酸茶水提物对高脂饮食小鼠肠道病理及脂肪代谢相关基因表达的影响

通过灌胃不同剂量的德昂酸茶水提物,研究德昂酸茶对高脂饮食诱导肥胖小鼠的生理指标、肠道病理及脂肪代谢等相关基因的影响。结果表明:与高脂对照组相比,德昂酸茶可显著降低高脂饮食小鼠的体质量、腹脂比(P<0.05),对高脂饮食造成的小鼠小肠组织肠黏膜损伤具有一定的改善和保护作用;同时德昂酸茶中剂量组能显著上调高脂饮食小鼠肝脏组织、脂肪组织中PPARα、AOX、CPT-1的基因表达水平,并有效下调肝脏组织中脂肪酸合成酶的基因表达水平。

饲养方式对滩羊肌内脂肪沉积影响及相关基因表达差异研究

本试验基于转录组学技术探讨舍饲与放牧条件下,滩羊脂肪沉积的差异及相关表达基因的筛选及分析。试验采用随机区组的试验设计方法,将体况相近的12只4月龄滩羊羯羊随机分为2组,每组6只,分别采用放牧和舍饲的饲养模式。于6月龄屠宰取背最长肌与股二头肌。试验结果表明:舍饲滩羊背最长肌肌内脂肪(IMF)含量显著高于放牧组(P <0.05),放牧组滩羊背最长肌IMF含量为(1.4567±0.0987)%,舍饲组滩羊背最长肌IMF含量为(2.0700±0.1493)%。股二头肌IMF含量舍饲组较放牧组高,但差异不显著。与舍饲组滩羊相比,放牧组滩羊背最长肌与股二头肌饱和脂肪酸含量均低,其中背最长肌己酸(C6:0)、癸酸(C10:0)、肉豆蔻酸(C14:0)、十五烷酸(C15:0)、棕榈油酸(C16:1)、十七烷酸(C17:0)、十七碳烯酸(C17:1)、硬脂酸(C18:0)含量显著低于舍饲组(P <0.05),股二头肌十五烷酸(C15:0)、棕榈油酸(C16:1)、十七烷酸(C17:0)显著低于舍饲组(P <0.05),碳原子数≥18的长链脂肪酸和不饱和脂肪酸含量以放牧组滩羊较高,其中背最长肌二十一烷酸(C21:0)和股二头肌十七碳烯酸(C17:1)含量显著低于舍饲组(P <0.05)。基于转录组学分析得知,与舍饲组相比,放牧组滩羊背最长肌脂肪代谢基因表达量显著下调的有酰基辅酶A硫酯酶7(ACOT7)、脂肪细胞分化转录因子(ADIG)与酰基辅酶A氧化酶2(ACOX2)(P <0.05),显著上调的有溶质载体家族7成员8(SLC7A8)、游离脂肪酸受体4(FFAR4)与胰岛素样生长因子2(IGF2)(P <0.05)。放牧组滩羊股二头肌脂肪代谢基因表达显著下调的有ACOT7、ADIG、脂肪酸结合蛋白4(FABP4)与脂肪酶A(LIPA)(P<0.05),显著上调的有花生四烯酸15-脂加氧酶(ALOX15)与二酰基甘油O-酰基转移酶2(DGAT2)(P <0.05)。

调控肉牛肌内脂肪沉积的分子机制研究进展

肉牛肌内脂肪(intramuscular fat,IMF)是指存在于肌纤维内的脂肪组织,含量与牛肉的多汁性、嫩度和适口性呈正相关关系,是决定牛肉质量等级的重要因素之一。明确肉牛IMF沉积的产生和调控机制是提高牛肉IMF含量的有效途径。文章对肉牛IMF沉积过程及调控IMF沉积的候选基因、转录因子和非编码RNA(non-coding RNA,ncRNA)进行综述,旨在为进一步解析肉牛IMF沉积的分子机制和推动肉牛肉质性状选育进程提供参考。

时钟基因调控低氧训练肥胖大鼠白色脂肪组织棕色化

背景:低氧训练可以促进机体脂肪的降解,外界环境变化可影响动物昼夜节律,但昼夜节律变化对脂肪组织棕色化及脂肪降解的调控机制尚不明确。目的:阐明时钟基因对低氧训练大鼠附睾脂肪组织棕色化的调控机制。方法:喂养高脂饲料构建肥胖大鼠模型,造模成功后抽取40只肥胖大鼠随机分为4组,即常氧安静组、低氧安静组、常氧训练组、低氧训练组,每组10只,进行4周的干预。安静组大鼠不实施干预;低氧组大鼠全天生活在氧浓度为13.6%的低氧仓中;训练组第1周为适应性训练,后3周训练速度和时长保持不变。测量肥胖大鼠体质量、体长和肾周脂肪质量;并使用血脂生化检测试剂盒检测肥胖大鼠血清中三酰甘油、总胆固醇、低密度脂蛋白胆固醇以及高密度脂蛋白胆固醇水平;油红O染色观察肝脏脂肪含量变化;苏木精-伊红染色评价各组大鼠附睾脂肪组织棕色化变化;转录组测序技术结合生物信息学分析脂肪组织中转录组水平变化;采用qRT-PCR检测附睾脂肪组织中PGC-1α、Beclin1、KLF2、Perilipin1 mRNA的表达变化情况。结果与结论:①低氧训练干预使营养性肥胖大鼠体质量、脂体比、Lees’s指数、血清总胆固醇、三酰甘油以及低密度脂蛋白胆固醇浓度显著降低(P<0.01),高密度脂蛋白胆固醇浓度显著升高(P<0.01);②油红O染色和苏木精-伊红染色显示,相比于常氧安静组、低氧安静组和常氧训练组,低氧训练更能有效促进大鼠肝脏组织中脂肪动员和附睾旁脂肪组织棕色化;③转录组测序结果显示,低氧训练时钟基因Dbp、Nr1d1、Sik1以及脂肪组织棕色化基因Ppargc1a(PGC-1α)等表达显著上调(P<0.05),而Arntl(Bmal1)显著下调(P<0.05),同时伴随物质代谢相关基因的表达增强;④qRT-PCR结果证实低氧训练时脂肪组织棕色化基因PGC-1α和脂代谢基因Perilipin1表达量均显著升高(P<0.01);⑤结果证实时钟基因在低氧训练促进脂肪组织棕色化过程中起到重要作用。

不同年龄梅花鹿肌内脂肪沉积规律及其对风味品质影响

旨在揭示不同年龄段梅花鹿肌内脂肪沉积规律,研究肌内脂肪含量对风味品质的影响。分别选取2、3、4岁梅花鹿母鹿,检测不同年龄段梅花鹿肌肉组织特性,并根据肌内脂肪(intramuscular fat, IMF)含量将样品分为高IMF组(IMFH组)和低IMF组(IMFL组),分析其对肌苷酸、脂肪酸含量以及脂肪酸结合蛋白4(FABP4)、脂肪酸合成酶(FASN)、甾醇调节元件结合转录因子1(SREBF1)和乙酰辅酶A羧化酶(ACACA)4种基因表达量。结果表明,梅花鹿肌内脂肪含量随年龄增长逐渐增加(P<0.001),里脊肌内脂肪含量最高(P<0.001),前腱子含量最低(P<0.001);梅花鹿年龄越长,肌纤维密度显著降低(P<0.05),肌苷酸、棕榈油酸(C16:1)、C18脂肪酸、饱和脂肪酸和单不饱和脂肪酸含量显著增高(P<0.05);高肌内脂肪样本肌纤维面积显著高于低肌内脂肪样本(P<0.05),IMFH组4岁龄梅花鹿肌束内肌纤维根数和肌苷酸以及3岁龄梅花鹿C16:1、C18:1和C18:3含量高于IMFL组(P<0.05),肌纤维密度高于IMFL组。油酸(C18:1)和亚麻酸(C18:3)含量高于低肌内脂肪样本(P<0.05);FABP4和SREBF1基因表达量显著高于低肌内脂肪样本(P<0.05),肌内脂肪与多不饱和脂肪酸呈负相关(P<0.05),与单不饱和脂肪酸呈正相关(P<0.05)。综上所述,梅花鹿随年龄增长,肉质嫩度降低,风味物质含量增加,高肌内脂肪组肉质更嫩,FABP4、FASN、SREBF1和ACACA四种基因高效表达和单不饱和脂肪酸含量对肌内脂肪沉积有促进作用。

牦牛皮下脂肪组织miRNA的鉴定与分析

为鉴定不同饲养方式下牦牛皮下脂肪组织中差异表达的微小RNAs(miRNAs),本试验采用高通量测序对不同饲养方式下牦牛皮下脂肪组织中的miRNAs进行筛选,运用DESeq分别鉴定出自然放牧18月龄(G18) vs (从自然放牧18月龄开始舍饲育肥6个月至24月龄)F24、G18 vs (自然放牧至24月龄)G24和F24 vs G24皮下脂肪组织中差异表达的miRNAs,对差异表达的miRNAs进行靶基因预测分析。在9个牦牛皮下脂肪组织中共鉴定出1158个miRNAs,其中已知miRNAs 731个,新预测miRNAs 427个。在G18 vs F24中有43个差异miRNAs,预测到的靶基因2436个;在G18 vs G24中有68个差异miRNAs,预测到的靶基因3559个,在F24 vs G24中有31个差异miRNAs,预测到的靶基因1456个。对预测到的基因进行GO和KEGG富集分析,其主要富集到了脂肪酸代谢过程、脂肪酸生物合成过程、脂肪酸生物氧化、不饱和脂肪酸代谢过程和脂肪细胞分化调节等。因此,枯草期对牦牛进行补饲有利于牦牛皮下脂肪组织沉积。

猪FATP1基因5'调控区多态性及其与脂肪性状的相关分析

脂肪酸转运蛋白1(Fatty acid transport protein 1,FATP1)是脂肪酸转运蛋白家族(FATPs)的一员,具有促进脂肪细胞吸收利用长链和极长链脂肪酸的功能,在脂肪沉积过程中发挥着重要的作用。采用直接测序法寻找FATP1基因5'调控区+64～-723 bp片段的单核苷酸多态性,在-586 bp处发现了一个T→C突变SNP(单核苷酸多态性)座位,利用PCR-RFLP的方法检测它在3个试验猪群体中的基因型,发现该座位在皮特兰和金皮F2代猪群中存在多态性,而在金华猪中仅表现为FATP1g-586TFATP1g-586T基因型。建立混合模型方程组分析该座位对188头金皮F2代猪脂肪性状的效应,结果显示,猪FATP1基因第-586座位的不同基因型与肩背膘厚、6～7肋背膘厚、最后一根肋骨处背膘厚、平均背膘厚和板油重显著相关(P<0.05),表明FATP1基因5'调控区的第-586位上的T→C突变对猪脂肪沉积有一定的影响。

畜禽肌内脂肪沉积的基因调控及其作用机制

肌内脂肪含量与肉的系水力、嫩度和风味等指标密切相关,是影响肉质的关键因素之一。近年来随着基因测序技术的不断更新发展,调控肌内脂肪沉积的基因被不断挖掘,但其发挥作用的分子机制还需要进一步完善。因此文章主要从影响肌内脂肪沉积的非编码RNA和候选基因两方面进行综述,以期为畜牧生产中提高肌内脂肪的沉积提供一定借鉴和参考。

fat-1基因对结肠癌HT-29细胞增殖的抑制作用

目的探讨fat-1基因在结肠癌HT-29细胞凋亡、增殖以及细胞周期中所起的作用。方法构建真核表达载体(pEGFP-fat-1),用脂质体介导的方法转染到结肠癌HT-29细胞,通过荧光显微镜观察及RT-PCR检测fat-1基因的表达,气相色谱分析检测fat-1基因对HT-29细胞n-6/n-3多聚不饱和脂肪酸(PUFAs)比例的影响,MTT法分析fat-1基因对HT-29细胞增殖的影响,流式细胞术检测fat-1基因对HT-29细胞凋亡和细胞周期的影响。结果成功构建了真核表达载体pEGFP-fat-1,并在HT-29细胞内有效表达。fat-1基因通过降低HT-29细胞内n-6/n-3PUFAs的比例抑制HT-29细胞的增殖,促进其凋亡,细胞增殖主要被阻滞在S期。结论fat-1基因改变HT-29细胞n-6/n-3PUFAs比例后,通过一定的信号转导途径促进大部分HT-29细胞在S期凋亡,抑制了其增殖。

线虫fat-1基因密码子优化设计

本研究旨在优化线虫fat-1基因,使其在牛肌肉组织中高效表达,为进一步生产fat-1转基因肉牛提供目的基因。试验在不改变fat-1基因编码氨基酸序列的基础上,参考了11个牛肌肉蛋白相关基因的密码子使用频率,对fat-1基因进行了密码子优化。结果发现,共改变了65个碱基,涉及65个密码子、7个氨基酸,约占fat-1基因总碱基数的5.38%,G+C含量从45.08%上升到50.04%,且分布均匀利于基因的表达。结构预测结果显示,该优化后的基因能够在牛肌肉中高效表达。

fat-1转基因小鼠的构建与鉴定

目的构建和鉴定携带有外源fat-1基因的转基因小鼠。方法将fat-1基因的cDNA与动物表达载体pEF-neo连接,构建pEF-fat-1重组质粒,酶切、测序鉴定正确后,以显微注射法把线性化重组质粒注射到小鼠受精卵的雄原核中,并将受精卵移植到受体鼠的输卵管中产出转基因小鼠,通过PCR、Southern blot杂交等方法确立阳性整合有目的基因的G0代小鼠。结果成功构建了pEF-fat-1重组质粒,将其显微注射到小鼠受精卵中,得到G0代小鼠,PCR、Southern blot杂交确立了4只整合有fat-1基因的首建鼠。结论fat-1基因可整合到小鼠体内,得到的转基因小鼠为研究fat-1基因的生物学功能提供了动物模型。

fat-1转基因动物研究进展

转染秀丽隐杆线虫fat-1基因后的哺乳动物具备了将n-6多不饱和脂肪酸(PUFAs)转化为n-3 PUFAs的能力,可降低动物机体的n-6/n-3 PUFAs比例。n-3 PUFAs有益于人类健康,可减少多种相关疾病发生的风险,但人体内不能合成n-3 PUFAs,其必须依赖于富含n-3 PUFAs的食品,fat-1转基因动物将成为人类必需的n-3 PUFAs的重要来源。对fat-1及其转基因动物的研究现状进行综述。