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.     

COMPUTED TOMOGRAPHIC ASSESSMENT OF BODY FAT IN BEAGLES

Obesity is the most common nutritional disorder in small animals. To establish a computed tomographic (CT) method for assessment of visceral and subcutaneous fat content in the dog, CT analysis was performed in normal and obese beagles. Fat area was measured by the level detection method at varied attenuation ranges and compared with body fat content estimated by the deuterium oxide dilution method. Fat area measured at L3 using the attenuation range of -135/-105 Hounsfield unit had the best correlation with body fat content (r = 0.98). Regional fat distribution was almost the same between normal and obese dogs, with more fat accumulation at L1-S1 than T10-T13. Moreover, visceral and subcutaneous fat area could be estimated separately. This CT method may contribute to both the clinical diagnosis and the study of canine obesity, especially for studies in the relationship between body fat distribution and obesity-associated diseases.     

Orosomucoid expression profiles in liver,adipose tissues and serum of lean and obese domestic pigs,Göttingen minipigs and Ossabaw minipigs

The acute phase protein orosomucoid (ORM) has anti-inflammatory and immunomodulatory effects, and may play an important role in the maintenance of metabolic homeostasis in obesity-induced low-grade inflammation. Even though the pig is a widely used model for obesity related metabolic symptoms, the expression of ORM has not yet been characterized in such pig models. The objective of this study was to investigate the expression of ORM1 mRNA in liver, visceral adipose tissue, subcutaneous adipose tissue (SAT) from the abdomen or retroperitoneal abdominal adipose tissue (RPAT) and SAT from the neck, as well as the serum concentration of ORM protein in three porcine obesity models; the domestic pig, Göttingen minipigs and Ossabaw minipigs.No changes in ORM1 mRNA expression were observed in obese pigs compared to lean pigs in the four types of tissues. However, obese Ossabaw minipigs, but none of the other breeds, showed significantly elevated ORM serum concentrations compared to their lean counterparts. Studies in humans have shown that the expression of ORM was unchanged in adipose tissue depots in obese humans with an increased serum concentration of ORM. Thus in this respect, obese Ossabaw minipigs behave more similarly to obese humans than the other two pig breeds investigated.     

Fat depot‐specific effects of body fat distribution and adipocyte size on intramuscular fat accumulation in Wagyu cattle

Ectopic fats have been recognized as a new risk factor for metabolic syndrome. In obese humans, ectopic fat accumulations are affected by body fat distribution. Intramuscular adipose tissue is categorized as one of the ectopic fats. Japanese black cattle (Wagyu) are characterized by the ability to accumulate high amounts of intramuscular adipose tissue. In Japan, the marbling level is indicated by the beef marbling standard number (BMS No.), which reflects the intramuscular fat content of longissimus muscle. We hypothesized that the intramuscular fat accumulation is affected by the body fat distribution in Wagyu cattle. In this study, we showed that the BMS No. was not correlated with the subcutaneous and visceral adipocyte diameter. In contrast, the BMS No. was positively correlated with intramuscular adipocyte diameter. These results indicate that the intramuscular adipocyte diameter of Wagyu is hypertrophied with an increase in the intramuscular fat accumulation. In addition, we showed that the BMS No. was positively correlated with the subcutaneous fat percentage. In contrast, the BMS No. was negatively correlated with the visceral fat percentage. These results indicate that highly marbled Wagyu cattle have a higher percentage of subcutaneous fat and a lower percentage of visceral fat.     

猪CRTC3基因表达的品种差异及forskolin对其表达的影响

本试验旨在探究糖脂代谢通路关键基因CRTC3在不同品种猪肌肉和脂肪组织中的表达情况,并通过forskolin处理猪皮下脂肪前体细胞,研究forskolin对脂肪前体细胞分化聚酯和CRTC3基因表达的影响,阐明猪CRTC3基因表达与脂肪沉积的关系。试验选取杜长大猪和莱芜猪各5头,检测肌肉、脂肪组织中CRTC3的mRNA和蛋白表达水平以及脂肪代谢相关基因的mRNA表达水平;选取2头3日龄的杜长大仔猪,分离猪皮下脂肪前体细胞,待完全融合后用MDI诱导培养基诱导4 d,然后用分化培养基继续诱导4 d,完成诱导分化。Forskolin组在诱导分化的第1天即加入forskolin,使其终浓度为10μmol/L,对照组则加入同浓度的二甲基亚砜(DMSO)进行诱导分化。结果表明:在莱芜猪的背最长肌和腰大肌中,CRTC3的蛋白表达水平高于杜长大猪;在莱芜猪的皮下和内脏脂肪组织中,CRTC3及脂肪沉积相关基因过氧化物酶体增殖剂激活受体γ(PPARγ)、脂肪酸结合蛋白4(FABP4)、CCAAT/增强子结合蛋白α(C/EBPα)、围脂滴蛋白(PLIN)和瘦素(LEP)的mRNA表达水平显著或极显著高于杜长大猪(P<0.05或P<0.01),而脂肪棕色化相关基因NF-E2相关因子1(NRF1)、过氧化物酶体增殖物激活受体-γ共激活因子-1α(PGC⁃1α)、PRDM16、解偶联蛋白2(UCP2)、解偶联蛋白3(UCP3)的mRNA表达水平则显著或极显著低于杜长大猪(P<0.05或P<0.01)。进一步的研究发现,猪皮下脂肪前体细胞分化后CRTC3和脂肪沉积相关基因的mRNA表达水平极显著提高(P<0.01),脂肪棕色化相关基因的mRNA表达水平也均极显著升高(P<0.01)。10μmol/L forsko⁃lin处理能抑制猪皮下脂肪前体细胞分化,极显著升高环磷腺苷效应元件结合蛋白(CREB)和脂肪棕色化相关基因的mRNA表达水平(P<0.01),促进CRTC3的进核,极显著降低CRTC3和脂肪沉积相关基因的mRNA表达水平(P<0.01)。上述研究结果表明,CRTC3基因与猪脂肪沉积密切相关,forskolin处理可以调控猪CRTC3及脂质代谢相关基因表达,调控猪皮下脂肪前体细胞分化聚酯。     

Negative hepatic computed tomographic attenuation pattern in a dog with vacuolar hepatopathy and hepatic fat accumulation secondary to cushing's syndrome

This report describes an unusual computed tomographic (CT) hepatic pattern, characterized by negative attenuation values (from –19.59 to –28.85 Hounsfield Units, HU) in a canine patient with severe Cushing's syndrome. Attenuation values of the splenic parenchyma (63.26 HU) and abdominal fat (–118.34 HU) were within normal limits. The negative hepatic attenuation values allowed a CT diagnosis of severe hepatic fatty infiltration that was subsequently confirmed by tissue‐core biopsy and histopathological examination.     

五指山猪皮下脂肪组织lncRNA和mRNA的鉴定与分析

为了鉴定和分析五指山猪背部和腹部皮下脂肪组织中差异表达的长链非编码RNA(long noncoding RNA, lncRNA)和信使RNA(messenger RNA, mRNA),采用RNA-Seq和生物信息学方法对五指山猪皮下脂肪组织中的lncRNA和mRNA进行分析筛选,运用DESeq鉴定背部和腹部皮下脂肪组织中差异表达的lncRNA和mRNA,并对差异表达的lncRNA进行靶基因预测分析。结果显示:在五指山猪皮下脂肪组织中共鉴定出12 875个lncRNA,其中正义型10 155个、反义型278个、内含子型246个、基因间型2 196个;在背部与腹部皮下脂肪间,存在184个差异表达的mRNA,其中前十位分别是ZIC1、ZIC4、HAND2、CCBE1、RPH3A、ISM1、ANXA8、SLITRK4、DSG2、EVPL,存在45个差异表达的lncRNA,其中6个只在背部皮下脂肪中表达、18个只在腹部皮下脂肪中表达;获得差异表达lncRNA的靶基因共109个,包括顺式作用的靶基因和反式作用的靶基因。本试验为进一步研究lncRNA和mRNA调控猪皮下脂肪发育的分子机制提供科学依据。     

Effects of dietary heme iron and exercise training on abdominal fat accumulation and lipid metabolism in high‐fat diet‐fed mice

Animal by‐products can be recycled and used as sources of essential nutrients. Water‐soluble heme iron (WSHI), a functional food additive for supplementing iron, is produced by processing animal blood. In this study, we investigated the effects of dietary supplementation of 3% WSHI and exercise training for 4 weeks on the accumulation of abdominal fat and lipid metabolism in mice fed high‐fat diet. Exercise‐trained mice had significantly less perirenal adipose tissue, whereas WSHI‐fed mice tended to have less epididymal adipose tissue. In addition, total weight of abdominal adipose tissues was significantly decreased in the Exercise + WSHI group. Dietary WSHI significantly increased the messenger RNA (mRNA) levels of lipoprotein lipase and hormone‐sensitive lipase. WSHI‐fed mice also tended to show increased mRNA levels of adipose triglyceride lipase in their epididymal adipose tissue. Dietary WSHI also significantly decreased the mRNA levels of fatty acid oxidation‐related enzymes in the liver, but did not influence levels in the Gastrocnemius muscle. Exercise training did not influence the mRNA levels of lipid metabolism‐related enzymes in the epididymal adipose tissue, liver or the Gastrocnemius muscle. These findings suggest that the accumulation of abdominal fat can be efficiently decreased by the combination of dietary WSHI and exercise training in mice fed high‐fat diet.     

Adipose tissue gene expression in obese dogs after weight loss

Body weight (BW) mainly depends on a balance between fat storage (lipogenesis) and fat mobilization (lipolysis) in adipocytes. BW changes play a role in insulin resistance (IR), the inability of insulin target tissue to respond to physiological levels of insulin. This results in inhibition of lipogenesis and stimulation of lipolysis. Weight gain leads to IR whereas, weight loss improves insulin sensitivity (IS). The aim of this study was to evaluate the effect of weight loss and recovery of IS on the expression of genes involved in lipogenesis and lipolysis in weight losing dogs. Gene expression was studied in both subcutaneous and visceral adipose tissue. Obese dogs received a hypoenergetic low fat high protein diet (0.6 x NRC recommendation). Before and after weight loss, IS was assessed using the euglycaemic hyperinsulinaemic clamp. Gene expression of IRS-2, SREBP, intracellular insulin effectors, ACC, FAS, FABP, ADRP, PEPCK, lipogenesis key proteins, perilipin and HSL, lipolysis key proteins were quantified using real-time RT-PCR in subcutaneous and visceral fat. BW decreased from 15.2 +/- 0.5 to 11.4 +/- 0.4 kg (p < 0.05) over 78 +/- 8 days. When obese, dogs were insulin resistant. After weight loss, IS was improved. In the subcutaneous adipose tissue, the expression of only the IRS-2 was increased. In the visceral adipose tissue, the expression of the genes involved in the lipogenesis was decreased whereas one of the genes implied in the lipolysis did not change. The expression profile of genes involved in lipid metabolism, as measured after weight loss, is indicative for a lower lipogenesis after weight loss than in obese dogs. Our results also confirm dramatic differences in the lipid metabolism of visceral and subcutaneous fat. They should be completed by comparing gene expression during weight losing and normal weight steady state.     

Combining ultrasound and lactobacilli treatment for high‐fat‐diet‐induced obesity in mice

Chronic systemic lipopolysaccharide‐induced inflammation can cause obesity. In animal experiments, lactobacilli have been shown to inhibit obesity by modifying the gut microbiota, controlling inflammation and influencing the associated gene expression. A previous study found that high‐fat‐diet‐induced (HFD) obesity was suppressed by lactobacilli ingestion in rats via the inhibition of parasympathetic nerve activity. This study explored the combined use of lactobacilli ingestion and ultrasound (US) to control body weight and body fat deposition in HFD mice over an 8‐week experimental period. Male C57BL/6J mice received an HFD during treatment and were randomly divided into four groups: (i) control group (H), (ii) lactobacilli alone (HB), (iii) US alone (HU) and (iv) lactobacilli combined with US (HUB). The US was targeted at the inguinal portion of the epididymal fat pad on the right side. At the 8th week, body weight had decreased significantly in the HUB group (15.56 ± 1.18%, mean ± SD) group compared with the HU (26.63 ± 0.96%) and H (32.62 ± 5.03%) groups (p < 0.05). High‐resolution microcomputed tomography (micro‐CT) scans revealed that the reduction in total body fat volume was significantly greater in the HUB group (69%) than in the other two experimental groups (HB, 52%; HU, 37%; p < 0.05). The reductions in the thickness of the subcutaneous epididymal fat pads were significantly greater in the HUB group (final thickness: 340 ± 7 μm) than in the H (final thickness: 1150 ± 21 μm), HB (final thickness: 1060 ± 18 μm) and HU (final thickness: 370 ± 5 μm) groups (all p < 0.05). Combination therapy with lactobacilli and US appears to enhance the reduction in body weight, total and local body fat deposition, adipocyte size and plasma lipid levels over an 8‐week period over that achieved with lactobacilli or US alone in HFD mice. These results indicate that US treatment alone can reduce hyperlipidemia in HFD mice.     

猪肌内脂肪沉积相关基因的筛选及其表达特性分析

【目的】 通过分析马身猪和大白猪背最长肌转录组测序数据,筛选肌内脂肪沉积相关基因,并对其表达特性进行分析。【方法】 采集180日龄马身猪和大白猪背最长肌,采用RNA-Seq技术对其进行转录组测序,筛选差异表达基因并进行GO功能和KEGG通路富集分析;采用GeneCards在线查询基因功能,进一步筛选与肌内脂肪沉积相关的差异基因;采用实时荧光定量PCR技术检测差异基因在2个品种猪不同组织以及肌内脂肪细胞成脂分化过程中的表达变化。【结果】 获得2个品种猪背最长肌差异表达基因共280个,其中128个表达显著上调,152个表达显著下调。GO功能富集分析注释到46个条目,其中生物过程24条,分子功能8条,细胞组分14条。KEGG通路分析显著富集到PPAR信号通路、MAPK信号通路和脂肪细胞因子信号等脂肪沉积相关通路。GeneCards功能查询获得TRAF2、DUSP1、ACOT4、NR4A1、SLC27A6、PLIN5共6个与脂肪沉积相关的基因。实时荧光定量PCR分析表明,马身猪和大白猪背最长肌中NR4A1、DUSP1、PLIN5基因表达量差异显著或极显著(P<0.05;P<0.01),TRAF2、ACOT4和SLC27A6基因表达量差异不显著(P>0.05),但表达变化趋势与测序结果一致;马身猪腹部皮下脂肪组织中NR4A1和PLIN5基因表达量极显著高于背部皮下脂肪组织(P<0.01),而大白猪背部皮下脂肪组织中NR4A1和DUSP1基因表达量极显著高于腹部皮下脂肪组织(P<0.01),PLIN5基因表达量显著高于腹部皮下脂肪组织(P<0.05)。在背部皮下脂肪组织中,NR4A1、DUSP1和PLIN5基因在大白猪中的表达量极显著高于马身猪(P<0.01);在腹部皮下脂肪组织中,NR4A1和DUSP1基因在大白猪中的表达量显著高于马身猪(P<0.05),PLIN5基因表达量在2个品种间无显著差异(P>0.05)。体外培养的猪肌内脂肪细胞分析表明,随着成脂天数的增加,NR4A1基因表达量呈下降趋势,DUSP1和PLIN5基因表达量均呈上升趋势。【结论】 本研究获得了NR4A1、DUSP1、PLIN5 3个与猪肌内脂肪沉积相关的候选基因,可为后续进一步探讨猪肌内脂肪沉积调控机制提供一定的参考。     

PLIN2基因在秦川肉牛皮下脂肪组织中的表达规律及基因多态性与肉质性状的关联分析

试验旨在研究围脂滴蛋白2（PLIN2）基因在秦川肉牛皮下脂肪组织中的表达情况及基因多态性与肉质性状的关联分析。采用实时荧光定量PCR检测PLIN2基因mRNA在不同月龄（6~60月龄）秦川肉牛皮下脂肪组织中的表达情况;选取18~24月龄的健康秦川肉牛536头,采集血样并测定肉质性状指标,研究PLIN2基因单核苷酸多态性（SNP）和氨基酸突变,并与秦川肉牛肉质性状进行关联分析。结果发现,PLIN2基因在秦川肉牛皮下脂肪组织中的表达量呈先上升后下降趋势,18月龄时表达量最高。测序共发现9个SNPs位点,其中g.C7919>T位点不同基因型肌内脂肪含量差异显著（P<0.05）,CT基因型显著高于TT和CC基因型;g.C7933>T位点不同基因型背膘厚及肌内脂肪含量均呈显著差异（P<0.05）,CC和CT基因型个体背膘厚显著高于TT基因型,CT基因型个体肌内脂肪含量显著高于TT和CC基因型;g.G8015>C位点CC基因型个体肌内脂肪含量显著高于GG和GC基因型（P<0.05）;3'UTR区域g.T8496>C位点TC基因型个体肌内脂肪含量显著高于CC和TT基因型（P<0.05）;g.C8578>T位点TT基因型个体背膘厚显著高于CT和CC基因型（P<0.05）。综上,PLIN2基因对秦川肉牛肉质性状发育有一定影响,可作为秦川肉牛现代分子选育的候选参考基因。     

Whole-genome bisulfite sequencing of abdominal adipose reveals DNA methylation pattern variations in broiler lines divergently selected for fatness

The methylation status of pivotal genes involved in fat deposition in chickens has been extensively studied. However, the whole-genome DNA methylation profiles of broiler abdominal adipose tissue remain poorly understood. Using whole-genome bisulfite sequencing, we generated DNA methylation profiles of chicken abdominal adipose tissue from Northeast Agricultural University broiler lines divergently selected for abdominal fat content. We aimed to explore whether DNA methylation was associated with abdominal fat deposition in broilers. The whole-genome DNA methylation profiles of fat- and lean-line broilers abdominal adipose tissue were constructed. The DNA methylation levels of functional genomic regions in the fat broiler were higher than those in the lean broiler, especially in the 3′ untranslated regions (UTRs) and exons in the non-CG contexts. Additionally, we identified 29,631 differentially methylated regions and, subsequently, annotated 6,484 and 2,016 differentially methylated genes (DMGs) in the gene body and promoter regions between the two lines, respectively. Functional annotation showed that the DMGs in promoter regions were significantly enriched mainly in the triglyceride catabolic process, lipid metabolism-related pathways, and extracellular matrix signal pathways. When the DMG in promoter regions and differentially expressed genes were integrated, we identified 30 genes with DNA methylation levels that negatively correlated with their messenger RNA (mRNA) expression, of which CMSS1 reached significant levels (false discovery rate < 0.05). These 30 genes were mainly involved in fatty acid metabolism, peroxisome-proliferator-activated receptor signaling, Wnt signaling pathways, transmembrane transport, RNA degradation, and glycosaminoglycan degradation. Comparing the DNA methylation profiles between fat- and lean-line broilers demonstrated that DNA methylation is involved in regulating broiler abdominal fat deposition. Our study offers a basis for further exploring the underlying mechanisms of abdominal adipose deposition in broilers.     

Capsosiphon fulvescens extracts improve obesity‐associated metabolic disorders and hepatic steatosis in high‐fat diet‐induced obese mice

Herbal dietary supplements have attracted more and more attention owing to their relative effectiveness in obesity ‐related metabolic disorders and diseases. This study investigated the therapeutic effects and underlying mechanisms of Capsosiphon fulvescens (CF) extracts on obesity, their associated metabolic disorders and hepatic steatosis in high‐fat diet (HFD)‐induced obese mice. Male C57BL/6 mice were fed with normal, HFD/Vehicle and HFD/CF (orally 300 mg/kg/day for CF). After 12 weeks, CF blocked HFD‐induced body weight, food intake, liver weight, hepatic triglyceride (TG), fat mass (weight of abdominal subcutaneous fat and epididymal adipose tissue) and biochemical parameters (total cohlesterol, glucose, TG, creatinine, high‐density lipoproteins cholesterol and low‐density lipoprotein cholesterol) of serum. CF also had improved serum levels of adiponectin, leptin and insulin‐like growth factor‐1 in HFD/CF mice. Moreover, CF ameliorated the hepatic steatosis‐reducing size of white adipose tissue. These results indicate that CF have anti‐obesity effects and are effective for reducing metabolic risk and hepatic steatosis.     

甘草提取物对绵羊皮下脂肪沉积与代谢相关酶活性的影响

作者旨在探讨添加不同水平甘草提取物(LE)对绵羊皮下脂肪沉积及代谢相关酶活性的影响。采用单因素试验设计,选用健康、断奶后20~30 d、初始体重相近的宁夏滩羊公羔50只,随机分为5组,每组10只,其中对照组饲喂基础日粮,不添加LE;试验Ⅰ~Ⅳ组分别在基础日粮中添加1000、2000、3000、4000 mg/kg LE。试验期120 d,试验结束后进行屠宰并测定滩羊皮下脂肪重、血清脂质代谢相关指标及皮下脂肪代谢相关酶活性。结果表明,与对照组相比,试验Ⅰ~Ⅳ组的皮下脂肪重分别降低了20.16%、14.40%、18.11%、20.16%;添加3000 mg/kg LE降低血清总胆固醇的效果最明显,LE对总甘油三酯(TG)和高密度脂蛋白(HDL-C)含量均无显著影响(P>0.05);LE显著降低皮下脂肪组织葡萄糖-6-磷酸脱氢酶(G6PDH)活性(P<0.05),其中添加3000 mg/kg LE降低G6PDH活性的效果最佳,对脂肪酸合成酶(FAS)、苹果酸脱氢酶(MDH)、异柠檬酸脱氢酶(ICDH)和6-磷酸脱氢酶(6PGDH)活性的影响均未达到显著水平(P>0.05)。提示,LE有降低血清总胆固醇和皮下脂肪重的趋势,其中添加3000 mg/kg LE的降脂作用最好,甘草提取物主要通过下调脂肪合成途径的关键酶活性来抑制绵羊皮下脂肪沉积,但甘草提取物调控滩羊皮下脂肪代谢关键酶的机制,尚需进一步研究。     

硫酸特布他林—β肾上腺素能兴奋剂对肉仔鸡生长和脂肪沉积的影响

在艾维茵商品代肉仔鸡日粮中（８～５２日龄）添加１和５ｍｇ／ｋｇ硫酸特布他林（ＴｃｒｂｕｔａｌｉｎｃＳｕｌｐｈ，简称特布他林）。结果：①５２日龄鸡的平均体重和饲料效率处理组均优于对照组，而按处理比较鸡的存活率较对照组高了４．３个百分点（９６．２％对９１．９％）（Ｐ＜０．０５）；②试验组公鸡，每公斤净体重（活重减去全消化道内容物重）含腹脂、皮下脂和肠脂的总量（以下称合计量）由４９．４６ｇ降低到４３．７５ｇ，减少了５．７１ｇ（Ｐ＜０．０５），其中皮下脂肪减少６．１３ｇ。与此相反，试验组母鸡脂肪合计量较对照组增加２１．７８ｍｇ／ｋｇ净体重。③日粮添加特布他林致母鸡内脏器官重（心、肝、脾、肺、肾和胰脏）增加了９．１１ｇ／ｋｇ净体重，对公鸡内脏影响不明显。     

The relationship between plasma leptin concentrations and the distribution of body fat in crossbred steers

The objective of the present study was to examine the relationship between plasma leptin levels and fat distribution in crossbred steers. Twenty-four crossbred steers (Japanese Black × Holstein) were used in this study. Six steers belonged to the growing phase (11 months of age), and 18 steers to the finishing phase (from 21 to 28 months of age). Plasma leptin levels correlated positively with body fat weight ( r  = 0.807, P  < 0.01), body fat percentage ( r  = 0.802, P  < 0.01), visceral fat weight ( r  = 0.807, P  < 0.01), visceral fat percentage ( r  = 0.780, P  < 0.01), subcutaneous fat weight ( r  = 0.745, P  < 0.01), subcutaneous fat percentage ( r  = 0.734, P  < 0.01), intermuscular fat weight ( r  = 0.793, P  < 0.01), intermuscular fat percentage (0.775, P  < 0.01), renal fat weight ( r  = 0.694, P  < 0.01), renal fat percentage ( r  = 0.642, P  < 0.01), subcutaneous fat thickness ( r  = 0.755, P  < 0.01), intermuscular fat thickness ( r  = 0.721, P  < 0.01), beef marbling score ( r  = 0.706, P  < 0.01) and the crude fat content of Musculus longissimus thoracis ( r  = 0.592, P  < 0.01). The location of fat deposits did not affect the correlation values. However, when steers were divided into growing ( n  = 6) and finishing ( n  = 18) groups, there was no significant correlation between plasma leptin levels and the carcass characteristics related to fat deposition (fat weight, fat percentage, carcass traits) in either group. These results suggest that plasma leptin levels in crossbred steers positively correlate with body fat content and carcass traits when these parameters vary widely.