Potential predictive biomarkers of obesity in Burmese cats

Australian Burmese cats are predisposed to diabetes mellitus and, compared to other breeds, have delayed triglyceride clearance that may result in subtle changes within cells and tissues that trigger specific alterations in gene expression within peripheral blood leucocytes (PBLs). Expression of genes involved in energy metabolism (glucose-6-phosphate dehydrogenase and malate dehydrogenase), lipogenesis (ATP citrate lyase [ACL], fatty acid synthase [FAS] and sterol regulatory binding protein-1c [SREBP-1c]), and insulin signalling (insulin receptor substrates 1 and 2, and phosphatidylinositol-3 kinase), as well as cholesterol lipoprotein subfraction profiling were carried out on PBLs from lean Burmese cats and compared with similar profiles of age and gender matched lean and obese Australian domestic shorthaired cats (DSHs) in an attempt to identify possible biomarkers for assessing obesity.For the majority of the genes examined, the lean Burmese cats demonstrated similar PBL gene expression patterns as age and gender matched obese Australian DSH cats. Lean Burmese had increased expression of ACL and FAS, but not SREBP-1c, a main upstream regulator of lipid synthesis, suggesting possible aberrations in lipogenesis. Moreover, lean Burmese displayed a 3- to 4-fold increase in the very low density cholesterol fraction percentage, which was double that for obese DSH cats, indicating an increased degree of lipid dysregulation especially in relation to triglycerides. The findings suggest that Burmese cats may have a particular propensity for dysregulation in lipid metabolism.     

Effects of dietary energy level on lipid metabolism‐related gene expression in subcutaneous adipose tissue of Yellow breed × Simmental cattle

This study was conducted to estimate the effect of dietary energy level on lipid metabolism‐related gene expression of subcutaneous adipose tissue in Yellow breed × Simmental cattle. The experiment was conducted for 60 days. The results showed that final weight, average daily gain, average backfat thickness, (testicles + kidney + pelvic) fat percentage and subcutaneous fat percentage in the high and medium energy groups were significantly higher than in the low‐energy group but that the feed conversion ratio was significantly lower. The glucose, triglycerides, cholesterol, high‐density lipoprotein and low‐density lipoprotein in the high‐energy group were significantly higher than in the low‐energy group. With dietary energy increasing the activities of lipoprotein lipase (LPL), fatty acid synthase (FAS) and acetyl‐CoA carboxylase (ACC) significantly increased, whereas hormone‐sensitive lipase (HSL) and carnitine palmitoyltransferase‐1 (CPT‐1) significantly diminished. Peroxisome proliferator‐activated receptor γ (PPARγ), LPL, FAS, sterol regulatory element binding protein 1 (SREBP‐1), ACC, stearoyl‐CoA desaturase (SCD) and adipocyte‐fatty acid binding proteins (A‐FABP) gene expression were significantly increased by dietary energy increasing, and HSL and CPT‐1 gene expression were significantly decreased. These results indicated that with dietary energy increasing, the subcutaneous fat accumulation mainly increased due to adipose tissue lipogenic gene expression and decreased lipolytic gene expression.     

玉米蛋白多肽对鹅不同组织脂肪酸合成酶定位表达的影响

选用免疫组化技术,探讨玉米蛋白多肽对鹅不同组织脂肪酸合成酶（fatty acid synthase,FAS）定位表达的影响。选取1日龄昌图豁鹅240只,公母各半,随机分为4组,每组设6个重复,每个重复10只。对照组饲喂基础日粮低、中、高剂量组分别于基础日粮中添加玉米蛋白多肽100、300、500 mg/kg。于30和60日龄分别采集动物肝脏和皮下脂肪组织,运用免疫组化法分析两种组织中FAS的表达量及分布。结果表明,鹅两种组织中FAS的表达主要分布在肝脏内皮细胞胞质和胞核及脂肪细胞膜上,且随着鹅日龄增加,FAS含量均增加;玉米蛋白多肽的添加可促进鹅肝脏中FAS的表达,抑制脂肪组织中FAS的表达;高、中、低3个剂量组肝脏中FAS含量,鹅60日龄时分别比30日龄升高47.75%、36.21%、158.74%,增幅均高于对照组（11.00%）;而60日龄时,3个剂量组脂肪组织中FAS含量分别比30日龄降低22.34%、46.43%、49.17%。结果提示,玉米蛋白多肽呈现双重作用,在鹅日粮中较长时间低剂量水平（100 mg/kg日粮）添加,可有效促进肝脏中FAS表达,降低脂肪组织中FAS含量,从而有利于调控机体脂类代谢,提高动物胴体品质。     

Effect of dietary protein quality and essential fatty acids on fatty acid composition in the liver and adipose tissue after rapid weight loss in overweight cats

OBJECTIVE: To examine effects of dietary protein quality (casein [CA] vs corn gluten [CG]) and dietary lipids (corn oil [CO] vs oil blend [OB] rich in long-chain polyunsaturated fatty acids [LCPUFAs]) on fatty acid composition in liver and adipose tissue after weight loss in overweight cats. ANIMALS: 24 ovariohysterectomized adult cats. PROCEDURE: Cats were allowed ad libitum access to a high-quality diet until they weighed 30% more than their ideal body weight. Cats were then randomly assigned to 1 of 4 weight-reduction diets (6 cats/diet) and were fed 25% of maintenance energy requirements per day. Diets consisted of CG-CO, CA-CO, CG-OB, and CA-OB, respectively, and were fed until cats lost weight and returned to their original lean body mass. Liver biopsy specimens and samples of perirenal, subcutaneous, and abdominal fat were obtained and analyzed for fatty acid content. RESULTS: Following weight loss, fatty acid composition of the liver and adipose tissue was primarily affected by protein quality in that cats fed CA had significantly higher percentages of 20:4(n-6) and 22:6(n-3) fatty acids than those fed CG. Cats fed the CG-CO diet had the lowest concentrations of LCPUFAs, suggesting that dietary lipids and protein quality each influence fatty acid composition in tissues. CONCLUSIONS AND CLINICAL RELEVANCE: These data provide direct evidence that dietary protein quality alters fatty acid composition of tissues during weight loss in cats. The fatty acid patterns observed suggest that protein quality may alter fatty acid composition through modulation of desaturase activity.     

t10,c12-CLA对猪皮下脂肪和背最长肌组织脂类代谢的影响

试验首先建立了30日龄猪皮下脂肪和背最长肌组织块体外培养体系,共设2个处理,处理1为阴性对照（添加0.1mmol/L牛血清白蛋白,BSA）,处理2添加100μmol/L的t10,c12-CLA,每个处理设6个平行,接种时即加入BSA与t10,c12-CLA进行处理至第10天,试验结束后收集细胞保存备用。采用荧光定量PCR技术及试剂盒检测研究t10,c12-CLA对猪皮下和背最长肌脂肪代谢关键酶（FAS、ME、LPL、HSL）和激素（INSR、GHR）及甘油三酯（TG）合成的影响。结果表明：①100μmol/Lt10,c12-CLA显著降低了猪皮下脂肪TG含量并提高了猪背最长肌的TG含量（P〈0.05）;②100μmol/Lt10,c12-CLA显著抑制了猪皮下脂肪FAS、INSR与背最长肌HSL和LPL的基因表达,促进了猪皮下脂肪HSL和背最长肌INSR的基因表达（P〈0.05）;③该研究结果从脂肪代谢关键酶类与调控激素方面揭示了t10,c12-CLA对猪皮下和背最长肌组织脂肪代谢与沉积的差异性调控机制,进一步证实了t10,c12-CLA抑制猪皮下脂肪沉积同时提高肌内脂肪含量。     

t10,c12-CLA对猪皮下脂肪和背最长肌组织脂类代谢的影响

试验首先建立了30日龄猪皮下脂肪和背最长肌组织块体外培养体系,共设2个处理,处理1为阴性对照(添加0.1mmol/l牛血清白蛋白,BSA),处理2添加100μmol/l的t10,c12-CLA,每个处理设6个平行,接种时即加入BSA与t10,c12-CLA进行处理至第10d,试验结束后收集细胞保存备用。采用荧光定量PCR技术及试剂盒检测研究t10,c12-CLA对猪皮下和背最长肌脂肪代谢关键酶(FAS、ME、LPL、HSL)和激素(INSR、GHR)及甘油三酯(TG)合成的影响。结果表明:(1)100μmol/lt10,c12-CLA显著降低了猪皮下脂肪TG含量并提高了猪背最长肌的TG含量(P0.05);(2)100μmol/lt10,c12-CLA显著抑制了猪皮下脂肪FAS、INSR与背最长肌HSL和LPL的基因表达,促进了猪皮下脂肪HSL和背最长肌INSR的基因表达(P0.05);(3)本研究结果从脂肪代谢关键酶类与调控激素方面揭示了t10,c12-CLA对猪皮下和背最长肌组织脂肪代谢与沉积的差异性调控机制,进一步证实了t10,c12-CLA抑制猪皮下脂肪沉积同时提高肌内脂肪含量。     

番鸭脂肪酸合成酶基因的克隆及填饲对其mRNA水平的影响简

本研究以番鸭肝脏为试验材料,通过RT-PCR扩增出番鸭脂肪酸合成酶（fatty acid synthase,FAS）部分CDS序列,利用相关分子生物学软件对其进行分析,同时采用实时荧光定量PCR技术检测FAS基因在成年番鸭各组织中的表达特性及填饲对番鸭肝脏和腹脂中该基因表达的影响。结果表明,克隆出的番鸭FAS基因CDS片段大小为1122 bp,编码374个氨基酸,与近缘物种禽类核苷酸同源性为92%～99%;实时荧光定量PCR结果表明,番鸭FAS基因在肝脏和腹脂中高表达,说明FAS具有组织表达特异性;填饲导致肝脏中FAS基因表达显著升高（P＜0.05）。本试验结果可为进一步研究FAS基因在番鸭肝脏脂质代谢中的作用奠定基础。     

Assessment of feline abdominal adipose tissue using computed tomography

Obesity is a common nutritional disorder in cats and it increases the risk factors for various diseases. The aim of this study is to suggest a method for the evaluation of feline obesity using computed tomography. The attenuation range from -156 to -106 was determined as the range of feline abdominal adipose tissue. With this range, total (TAT), visceral (VAT) and subcutaneous (SAT) adipose tissues were measured. The best correlation between the adipose tissue in cross-sectional image and entire abdomen volume was obtained at the L3 and L5 levels. The mean VAT/SAT ratio was 1.18±0.32, which was much higher than in humans. The cats with an overweight body condition had a significantly lower VAT/SAT ratio than cats with an ideal body condition. This technique may contribute to both the clinical diagnosis and the experimental study of feline obesity.     

Characterization of key genes of the renin–angiotensin system in mature feline adipocytes and during in vitro adipogenesis

Obesity is a growing health problem in humans as well as companion animals. In the development and progression of obesity‐associated diseases, the members of the renin–angiotensin system (RAS) are proposed to be involved. Particularly, the prevalence of type 2 diabetes mellitus in cats has increased enormously which is often been linked to obesity as well as to RAS. So far, reports about the expression of a local RAS in cat adipocytes are missing. Therefore, we investigated the mRNA expression of various RAS genes as well as the adipocyte marker genes adiponectin, leptin and PPAR‐γ in feline adipocytes using quantitative PCR. To characterize the gene expression during adipogenesis, feline pre‐adipocytes were differentiated into adipocytes in a primary cell culture and the expression of RAS key genes measured. All major RAS components were expressed in feline cells, but obvious differences in the expression between pre‐adipocytes and the various differentiation stages were found. Interestingly, the two enzymes ACE and ACE2 showed an opposite expression course. In addition to the in vitro experiments, mature adipocytes were isolated from subcutaneous and visceral adipose tissue. Significant differences between both fat depots were found for ACE as well as AT1 receptor with greater expression in subcutaneous than in visceral adipocytes. Visceral adipocytes had significantly higher adiponectin and PPAR‐γ mRNA level compared to the subcutaneous fat cells. Concerning the nutritional status, a significant lower expression of ACE2 was measured in subcutaneous adipocytes of overweight cats. In summary, the results show the existence of a potentially functional local RAS in feline adipose tissue which is differentially regulated during adipogenesis and dependent on the fat tissue depot and nutritional status. These findings are relevant for understanding the development of obesity‐associated diseases in cats such as diabetes mellitus.     

siRNA特异性抑制犊牛原代肝细胞SREBP—1c基因的表达

固醇调节元件结合蛋白-1c（SREBP-1c）是脂肪合成基因的重要转录调节因子,又称脂肪细胞决定和分化因子1。SREBP-1c主要在动物肝脏和脂肪细胞中表达,是脂肪代谢中重要的核转录因子,它可以通过调节脂肪代谢相关酶基因的表达来调控动物体内的脂肪合成。本试验设计合成了SREBP—1c的siRNA,通过脂质体转染将siR...     

不同日龄猪腹脂中脂肪酸合成酶(FAS)基因表达规律的研究

从猪腹脂中提取总RNA，用RT-PCR扩增脂肪酸合成酶基因（FAS），获得一条206bp的片段，以pGEM-TEasyvector为载体，将该基因片段克隆到大肠杆菌E.coli DH5α，筛选阳性克隆并测序。测序结果表明，得到的片段为FAS基因的部分序列，与GenBank中登录的猪FAS基因（AY183428）494～699之间序列同源性达到100％。以FAS基因片段的克隆为基础，构建了优化的半定量RT-PCR法，以18S rRNA为内标，研究从1日龄到28周龄杜长大腹脂中FAS基因表达的规律。结果显示，从1日龄到28周龄，FAS基因在腹脂mRNA水平呈逐渐升高的趋势；统计分析发现，1日龄与28周龄FAS在腹脂中mRNA水平存在显著性差异（P〈0．05）。     

日粮蛋白质水平对乌金猪肝脏组织脂类代谢相关基因表达的影响

为探讨日粮蛋白质水平对乌金猪肝脏组织脂类代谢相关基因表达的影响,试验选取体重约15 kg的乌金猪54头,随机分为3组,每组18头,为低、中和高蛋白质组,其在15～30、30～60及60～100 kg生长阶段的蛋白质水平分别为14%、12%、10%,16%、14%、12%和18%、16%、14%。猪在体重为30、60和100 kg时屠宰,取其肝脏组织,Real-time PCR定量检测脂类代谢相关基因的表达水平。结果显示,在30、60和100 kg时,乌金猪肝脏组织中ACC、FAS、SREBP-1C基因的表达水平均随着蛋白质水平的升高而降低;CPT-Ⅰ和PPARα基因的表达水平则随着蛋白质水平的升高而升高。由此表明,日粮高蛋白质水平显著降低肝脏脂肪酸合成代谢基因(ACC、FAS和SREBP-1C)的表达(P<0.05),提高脂肪酸分解代谢基因(CPT-Ⅰ和PPARα)的表达水平(P<0.05);脂肪酸合成减少,且被氧化的量增加,两者共同作用导致用于合成甘油三酯(TG)的脂肪酸含量降低,从而减少了从肝脏组织被运输到各个组织的TG含量,使机体沉积TG的能力降低。     

Copper and lipid metabolism in beef cattle: a review

Results from experiments investigating Cu metabolism in ruminants indicate that Cu is involved in lipid metabolism. Copper supplementation ranging from 10 to 40 mg of Cu/kg of DM to high-concentrate finishing diets decreased subcutaneous adipose tissue deposition and decreased cholesterol concentrations but increased unsaturated fatty acid composition of LM. Serum norepinephrine tended to be greater in Cu-supplemented steers after a 24-h feed withdrawal and at 2 h postfeed consumption, potentially explaining the reduction in subcutaneous adipose tissue deposition. However, when exogenous norepinephrine was administrated, serum NEFA concentrations were less in Cu-supplemented steers, possibly due to the nonsupplemented control steers having a greater subcutaneous adipose tissue depth at slaughter relative to Cu-supplemented steers. Furthermore, in vitro basal and epinephrine-stimulated lipolytic rates of subcutaneous adipose tissue were greater in Cu-supplemented steers relative to controls. These data indicate that that Cu may influence lipogenic or lipolytic function in subcutaneous adipose tissue. In an attempt to further investigate the effect of Cu on lipid metabolism, lipogenic, lipolytic, and homeostatic mechanisms related to Cu are currently being studied. Recent data indicate that genes involved in bovine liver Cu homeostasis are correlated with Cu transporter protein gene expression in the bovine liver. Therefore, the overall intent of this review is to discuss possible mechanisms whereby Cu may affect lipid metabolism in ruminants.     

氨氮胁迫下饥饿与复投喂对黄颡鱼肝脏中脂质代谢相关酶活性及相关基因表达的影响

为了研究氨氮胁迫下饥饿与复投喂对黄颡鱼脂质代谢的影响,将360尾黄颡鱼幼鱼[初始体重为(14.95±0.03)g]随机分配到12个养殖桶中,每桶30尾.对照组人工饱食投喂42 d,试验组饥饿14 d后恢复投喂28 d.对照组和试验组分别被暴露到总氨氮浓度为0(低氨氮处理,正常养殖环境)和5.70 mg/L(高氨氮处理,...