Medium chain triglyceride in early life: Effects on growth of adipose tissue

Effects of feeding early in life a diet high in either long chain (LCT) or medium chain triglyceride (MCT) were studied on the development of adipose tissue in post-weanling rats. The diets were similar in calorie distribution and identical in nutrients except for type of fat. The caloric distribution of the two diets by percent was LCT (corn oil)/protein/carbohydrate, 70/18/12 and MCT/corn oil/protein/carbohydrate, 66/4/18/12. Male littermates with less than 5% weight difference were pair-fed the two diets randomly at age 18–20 days. One-fourth of the rats were killed at 10, 16, 22 and 28 weeks of age and analyzed for adipose depots and adipose tissue cellularity. Results showed that the LCT-fed rats were significantly heavier, with larger epididymal, retroperitoneal, omental and subcutaneous fat pads than the respective pair-fed MCT rats. Also, LCT-fed rats had larger size and number of adipocytes than MCT-fed littermates. It is concluded that the type of fat in the diet, namely LCT or MCT, when fed early in life can influence the development of adipose tissue. MCT appears less lipogenic than LCT. The mechanism for the diminished adiposity of MCT-fed rats is related to extensive oxidation of MCT and its enhancement of thermogenesis leading to lessened energy efficiency. Presented at the symposium on “Specialty Lipids and Their Biofunctionality” at the annual meeting of the American Oil Chemists' Society, Philadelphia, May 1985.     

Nutritional evaluation of medium-chain triglycerides in the rat

Nutritional evaluation of a medium-chain triglyceride (MCT) preparation, containing about 75% octanoic acid and 25% decanoic acid, was carried out in short- and long-term experiments in rats. A casein diet containing 19.6% MCT and 2.5% safflower oil, the latter to supply essential fatty acids, was compared with similar diets containing conventional dietary fats. Data obtained in a 47-week study showed that the MCT diet supported normal growth and development. At autopsy, carcass protein and ash levels, vital organ weights and composition were similar to those in rats fed conventional fats. Histological study showed that intestinal and liver sections were normal after 47 weeks on the MCT-containing diet. In general, rats fed MCT had slightly lower growth rates and caloric efficiency values, less carcass fat and smaller epididymal fat pads than animals fed conventional dietary fats. Little C₈ and C₁₀ were found in depot fat. The MCT diet also supported normal reproducton, as indicated by litter size and number. During lactation the volume of milk secreted by the rats receiving the MCT diet was smaller and contained a lower level of fat than that secreted by the rats receiving an oleo oil diet, resulting in slower gains in weight in the MCT group. After weaning, growth of the rats fed MCT compared favorably with that attained by the animals on the diet containing oleo oil.     

A Low-Protein,High-Carbohydrate Diet Stimulates Thermogenesis in the Brown Adipose Tissue of Rats via ATF-2

The aim of this study was to evaluate thermogenesis in the interscapular brown adipose tissue (IBAT) of rats submitted to low‐protein, high‐carbohydrate (LPHC) diet and the involvement of adrenergic stimulation in this process. Male rats (~100 g) were submitted to LPHC (6 %‐protein; 74 %‐carbohydrate) or control (C; 17 %‐protein; 63 %‐carbohydrate) isocaloric diets for 15 days. The IBAT temperature was evaluated in the rats before and after the administration of noradrenaline (NA) (20 µg 100 g b w^?1 min^?1). The expression levels of uncoupling protein 1 (UCP1) and other proteins involved in the regulation of UCP1 expression were determined by Western blot (Student's t test, P ≤ 0.05). The LPHC diet promoted a 1.1 °C increase in the basal temperature of IBAT when compared with the basal temperature in the IBAT of the C group. NA administration promoted a 0.3 °C increase in basal temperature in the IBAT of the C rats and a 0.5 °C increase in the IBAT of the LPHC group. The level of UCP1 increased 60 % in the IBAT of LPHC‐fed rats, and among the proteins involved in its expression, such as β3‐AR and α1‐AR, there was a 40 % increase in the levels of p38‐MAPK and a 30 % decrease in CREB when compared to the C rats. The higher sympathetic flux to IBAT, which is a consequence of the administration of the LPHC diet to rats, activates thermogenesis and increases the expression of UCP1 in the tissue. Our results suggest that the increase in UCP1 content may occur via p38 MAPK and ATF2.     

The Effect of a Sustained High-Fat Diet on the Metabolism of White and Brown Adipose Tissue and Its Impact on Insulin Resistance: A Selected Time Point Cross-Sectional Study

(1) Background: studies on the long-term dynamic changes in fat depot metabolism in response to a high-fat diet (HFD) on hepatic lipid deposition and insulin resistance are sparse. This study investigated the dynamic changes produced by HFD and the production of dysfunctional fat depots on insulin resistance and liver lipid metabolism. (2) Methods: mice fed a chow or HFD (45% kcal fat) diet had three fat depots, liver, and blood collected at 6, 10, 20, and 30 weeks. Anthropometric changes and gene markers for adipogenesis, thermogenesis, ECM remodeling, inflammation, and tissue insulin resistance were measured. (3) Results: early responses to the HFD were increased body weight, minor deposition of lipid in liver, increased adipocyte size, and adipogenesis. Later changes were dysfunctional adipose depots, increased liver fat, insulin resistance (shown by changes in ITT) accompanied by increased inflammatory markers, increased fibrosis (fibrosis > 2-fold, p < 0.05 from week 6), and the presence of crown cells in white fat depots. Later, changes did not increase thermogenic markers in response to the increased calories and decreased UCP1 and PRDM16 proteins in WAT. (4) Conclusions: HFD feeding initially increased adipocyte diameter and number, but later changes caused adipose depots to become dysfunctional, restricting adipose tissue expansion, changing the brown/beige ratios in adipose depots, and causing ectopic lipid deposition and insulin resistance.     

Nutritional properties of medium-chain triglycerides

The biological effects of MCT (medium-chain triglycerides) differed from those of conventional fats, and certain of these suggested examination of the fatty acid composition and triglyceride structure of the adipose tissues and other organs of rats which were fed medium- or long-chain triglyceride mixtures with two levels of linoleic acid. Fatty acid compositions and TG patterns varied with the tissue, with the dietary fat, and with the level of linoleate in the diet. Increasing the latter resulted in the deposition of more linoleate at the expense of oleate and in the deposition of more of the dietary fatty acids. The percentage of completely saturated triglyc-erides (S₃), in adipose tissue with the higher linoleate supplement in the rats fed MCT, decreased in those fed LCT and was unchanged in the controls fed a fat-free diet. The increased deposition of the dietary fatty acids was more pronounced in the S₃ band. Supported by Grants U-1347 and U-1510 from the Health Research Council of the City of New York.     

Effect of medium-chain triacylglycerols on anti-obesity effect of fucoxanthin

Dietary effects of medium-chain triacylglycerols (MCT) and fucoxanthin (Fc) on abdominal fat weight were determined using KK-Ay obese mouse. Experimental diet contained MCT(0.9%), Fc (0.1%), or MCT (0.9%) +Fc (0.1%). The abdominal fat weight of mice fed with Fc was significantly lower than that of mice fed with MCT. Uncoupling protein 1 (UCP1), a key molecule for metabolic thermogenesis, was clearly expressed in the white adipose tissue (WAT) of mice fed Fc, but little expression in that of the mice fed MCT. The anti-obesity effect of Fc was increased by mixing Fc with MCT. This increase would be due to the increase in the absorption rate of Fc by MCT.     

Adipocyte fatty acid mobilization in vivo: Effects of age and anatomical location

The objectives of the present study were to determine if adipocyte trigly ceride fatty acid (TGFA) mobilization in vivo varied among the different adipose tissue depots and whether these rates were affected by age. In order to accomplish these objectives, two groups of rats were studied. The first group initially weighed 84±1 and the second group 333±2. Both groups were placed on a semisynthetic diet containing 6% corn oil (w/w) and 14% triundecanoin (w/w) for a period of 4 wk. Triundecanoin contains an 11-carbon (C-11) fatty acid (undecanoic acid) that was used to label the adipocyte TGFA. At the end of the 4-wk feeding period, triundecanoin was removed from the diet and replaced with an equivalent amount of corn oil. At this time and at weekly intervals for the next 4 wk, 5 rats from each age group were killed for the determination of TGFA composition in isolated dipocytes from the epididymal (Epi), perirenal (PR), subcutaneous (SC) and mesenteric (M) adipose tissue depots. When the content of C-11 was expressed as mole percent of the total fatty acids, mobilization was significantly more rapid from the PR and M depots than in the other two depots in the young rats. In the older rats mobilization was significantly slower in all depots compared to the younger group. The rates of mobilization were not different between the depots in the older animals. Since fat cell size continued to increase throughout the duration of the study, part of the decrease in C-11 content can be accounted for by dilution by newly acquired TGFA. When data were compared on the basis of the actual pmoles of C-11 per cell, rates of mobilization were not different between the depots nor was mobilization affected by age. These results emphasize again the impact the manner in which adipocyte metabolic data are expressed has on interpretation(s) when comparing adipocytes of different depots or from rats of different age.     

Metformin Reduces Lipogenesis Markers in Obese Mice Fed a Low-Carbohydrate and High-Fat Diet

Lipogenesis is the process by which fatty acids are synthesized. In metabolic syndrome, an insulin resistant state along with high plasma levels of free fatty acids (FFA) and hyperglycemia may contribute to the lipogenic process. The aim of the present study was to investigate the effects of oral administration of metformin on the expression of lipogenic genes and glycemic profile in mice fed with low‐carbohydrate high‐fat diet by evaluating their metabolic profile. SWISS male mice were divided into 4 groups (N = 7) that were fed with standard (ST), standard plus metformin (ST + MET), low‐carbohydrate high‐fat diet (LCHFD) and low‐carbohydrate high‐fat diet plus metformin (LCHFD + MET) (100 mg kg^?1 diet) diets respectively. Food intake, body weight and blood parameters, such as glucose tolerance, insulin sensitivity, glucose, HDL‐c, total cholesterol, triglycerides, ASL and ALT levels were assessed. Histological analyses were performed on hematoxylin and eosin‐stained epididymal adipose tissue histological specimens. The expression levels of peroxisome proliferator‐activated receptor (PPARγ), sterol regulatory element‐binding protein 1 (SREBP1), fatty acid synthase (FAS) and acetyl‐CoA carboxylase (ACC), were assessed by RT‐PCR. This study showed that metformin decreased adipocyte area, body weight and food consumption in obese animals when compared to the standard group. Furthermore, the expression of lipogenic markers in adipose tissue were diminished in obese animals treated with metformin. This data showed that oral administration of metformin improved glucose and lipid metabolic parameters in white adipose tissue by reducing the expression of lipogenesis markers, suggesting an important clinical application of MET in treating obesity‐related diseases in metabolic syndrome.     

Lipid metabolism during cold-exposure and during cold-acclimation

The lipid-containing tissues are important in cold-exposure (exposure to cold of animals not previously living in the cold) and in cold-acclimation (the adaptive state achieved when animals have lived in the cold for several weeks); these are the white adipose tissue and the brown adipose tissue. The white adipose tissue serves as a store of readily mobilized substrate (free fatty acids [FFA]) for calorigenesis in other tissues during cold-exposure, principally for shivering thermogenesis in muscle. The mobilization of the sterol lipid is brought about through activation of the sympathetic nervous system by the cold stress. The brown adipose tissue has two functions in cold-exposure and in cold-adaptation, both quite distinct from the function of the white adipose tissue. These functions are heat production and the maintenance of the adaptationto cold. The triglycerides stored in the brown adipose tissue are mobilized as FFA, also via activation of the sympathetic nervous system, but the FFA are used primarily within the brown adipose tissue itself. The FFA are the agents which switch on the calorigenesis in the brown adipose tissue (via a poorly understood form of “loosening” of the coupling of oxidative phosphorylation); they also serve as the substrate for the calorigenesis. The heat-producing function of the brown adipose tissue occurs in both cold-exposed and in cold-acclimated animals; it is of greater importance in the latter because this tissue normally grows in response to cold. Much of the heat production in cold-acclimated animals (nonshivering thermogenesis) occurs outside the brown adipose tissue itself, most probably in the muscles, and the cold-acclimated animal differs from the cold-exposed animal in being able to switch on nonshivering thermogenesis via activation of the sympathetic nervous system. The maintenance of this adaptation for nonshivering thermogenesis in tissue other than the brown adipose tissue itself depends upon the brown adipose tissue. The adaptation disappears if the brown adipose tissue is removed; the adaptation does not develop if the normal proliferation of mitochondria in the growing brown adipose tissue is inhibited (with oxytetracycline) during acclimation of rats to cold. The mechanism by which the brown adipose tissue exerts this second function is at present unknown. An increased turnover of certain mitochondrial proteins occurs in those tissues (skeletal muscle and brown adipose tissue) in which nonshivering thermogenesis occurs in cold-acclimated rats; no change in turnover of mitochondrial proteins occurs in other tissues (liver and kidney). The relation of this alteration in mitochondrial proteins to the adaptation for nonshivering thermogenesis is at present unknown. However this first demonstration of a biochemical difference between skeletal muscle of cold-acclimated rats and skeletal muscle of warm-acclimated rats opens up a new approach to the study of the nature of both the adaptation for nonshivering thermogenesis and of the role of the brown adipose tissue in the development and maintenance of this adaptation. Presented at the Symposium on “Lipids in Metabolic Stress,” AOCS Fall Meeting, Atlantic City, October 1971. Bond Award paper. Award presented at the AOCS Spring Meeting, Los Angeles, April 1972.     

Male and Female Animals Respond Differently to High-Fat Diet and Regular Exercise Training in a Mouse Model of Hyperlipidemia

Inappropriate nutrition and a sedentary lifestyle can lead to obesity, one of the most common risk factors for several chronic diseases. Although regular physical exercise is an efficient approach to improve cardiometabolic health, the exact cellular processes are still not fully understood. We aimed to analyze the morphological, gene expression, and lipidomic patterns in the liver and adipose tissues in response to regular exercise. Healthy (wild type on a normal diet) and hyperlipidemic, high-fat diet-fed (HFD-fed) apolipoprotein B-100 (APOB-100)-overexpressing mice were trained by treadmill running for 7 months. The serum concentrations of triglyceride and tumor necrosis factor α (TNFα), as well as the level of lipid accumulation in the liver, were significantly higher in HFD-fed APOB-100 males compared to females. However, regular exercise almost completely abolished lipid accumulation in the liver of hyperlipidemic animals. The expression level of the thermogenesis marker, uncoupling protein-1 (Ucp1), was significantly higher in the subcutaneous white adipose tissue of healthy females, as well as in the brown adipose tissue of HFD-fed APOB-100 females, compared to males. Lipidomic analyses revealed that hyperlipidemia essentially remodeled the lipidome of brown adipose tissue, affecting both the membrane and storage lipid fractions, which was partially restored by exercise in both sexes. Our results revealed more severe metabolic disturbances in HFD-fed APOB-100 males compared to females. However, exercise efficiently reduced the body weight, serum triglyceride levels, expression of pro-inflammatory factors, and hepatic lipid accumulation in our model.     

Effect of Peucedanum japonicum Thunb on the expression of obesity-related genes in mice on a high-fat diet

The present study describes the effect of Peucedanum japonicum Thunb (PJT) intake on the expression of obesity-related genes in mice fed a high-fat diet. To explore the mechanism underlying the effect of PJT, This study focused on the expression of genes, especially those related to obesity and metabolism syndrome, in the liver and adipose tissues. In agreement with our previous observations, intake of 10 % PJT for 4 weeks significantly reduced serum triglyceride (TG), leptin, abdominal fat, and adipocyte size. PJT also significantly increased fecal excretion of TG, decreased that of bile acid, and tended to increase the fecal excretion of total cholesterol. Microarray analysis was used to monitor changes in 324 metabolic syndrome-related genes in the liver. Statistically significant upregulation of PPP1R10, RORC, and PBEF1 genes and downregulation of DUSP1, INSIG2, and SERPINA12 genes were noted and confirmed by real-time RT-PCR. These changes were indicative of increased fatty acid oxidation in the maintenance of lipid homeostasis and insulin sensitivity in the livers of PJT-fed mice. PJT increased the expression of PPARγ, FXRα, DGAT1, and ATGL genes, suggesting an enhancement of adipocyte differentiation and normalization of functionality of adipose tissue.     

Role of dietary calcium and dairy products in modulating adiposity

Dietary calcium plays a pivotal role in the regulation of energy metabolism. High-calcium diets attenuate adipocyte lipid accretion and weight gain during overconsumption of an energy-dense diet and increase lipolysis and preserve thermogenesis during caloric restriction, thereby markedly accelerating weight loss. Our studies of the agouti gene demonstrate a key role for intracellular Ca²⁺ in regulating adipocyte lipid metabolism and TG storage. Increased intracellular Ca²⁺ resulting in stimulation of lipogenic gene expression, and lipogenesis and suppression of lipolysis resulting in adipocyte lipid filling and increased adiposity. Moreover, we recently demonstrated that the increased calcitriol produced in response to lowcalcium diets stimulates adipocyte Ca²⁺ influx and, consequently, promotes adiposity. Accordingly, suppressing calcitriol levels by increasing dietary calcium is an attractive target for obesity intervention. In support of this concept, transgenic mice expressing the agouti gene specifically in adipocytes (a human-like pattern) respond to low-calcium diets with accelerated weight gain and fat accretion, whereas high-calcium diets markedly inhibit lipogenesis, accelerate lipolysis, increase thermogenesis, and suppress fat accretion and weight gain in animals maintained at identical caloric intakes. Further, low-calcium diets impede body fat loss, whereas high-calcium diets markedly accelerate fat loss in transgenic mice subjected to caloric restriction. Dairy sources of calcium exert markedly greater effects in attenuating weight and fat gain and accelerating fat loss. This augmented effect of dairy products is likely due to additional bioactive compounds in dairy that act synergistically with calcium to attenuate adiposity. These concepts are confirmed by both epidemiological and clinical data, which demonstrate that increasing dietary calcium results in significant reductions in adipose tissue mass in obese humans in the absence of caloric restriction and markedly accelerates the weight and body fat loss secondary to caloric restriction, whereas dairy products exert significantly greater effects. These data indicate an important role for dairy products in both the prevention and treatment of obesity.     

The effect of medium and long chain triglyceride on human adipose tissue metabolism

Studies have been performed to assess the effects, in vivo and in vitro, of lipid emulsions on human adipose tissue prostaglandin production. Subcutaneous adipose tissue obtained either during elective surgery or by needle aspiration was studied in tissue culture or by using a perifusion apparatus. Physical mixtures of emulsions of long chain triglyceride (LCT) and/or medium chain triglyceride (MCT) were added to the tissue culture medium so that the final concentration was 400 mg/dl. After a 3-day incubation period the tissue was harvested, placed in buffer and used to determine in vitro production of prostaglandin E₂, prostacyclin I₂ (measured as its stable end product 6-keto PGF_1α) and thromboxane A₂ (measured as TXB₂) by radioimmunoassay. The results demonstrated that samples incubated in 100% MCT had the most significant increase in prostaglandin production, while those incubated in 100% LCT had the most significant decrease in activity of the three prostaglandins assayed. The addition of LCT to MCT caused a stepwise decrease in adipose tissue prostaglandin production. The data suggest a pharmacological rather than a physiological effect of lipid emulsions containing MCT and/or LCT on adipose tissue prostaglandin production. In vivo effects of a 20% safflower oil emulsion, containing high levels of the essential fatty acid linoleate, were assessed in five pediatric patients. Adipose tissue was obtained before and after two and four weeks of treatment. Fatty acid profiles and prostaglandin production were determined. The results demonstrated that intravenous fat infusion increased the concentrations of linoleic and arachidonic acids found in adipose tissue within a short interval. The effect of intravenous fat infusion on human adipose tissue prostaglandin production was less predictable and may have been a function of the patients' disease and subsequent clinical course. These findings suggest that lipid emulsions should not be viewed solely as a source of intravenous energy, because they may have the potential to elicit changes in prostaglandin production as demonstrated by a human adipose tissue model. Presented in part at the symposium on “Specialty Lipids and Their Biofunctionality,” at the annual meeting of the American Oil Chemists' Society, Philadelphia, May 1985.     

Effects of Orlistat on white adipose tissue (WAT) in the γ‐irradiated mouse model

In this study, we showed that γ‐irradiation could trigger biological response like the fat accumulation of gonadal white adipose tissue (gWAT) in mice. The irradiated animal can be used as a useful model for evaluation of anti‐obesity drugs. To induce the fat accumulation by γ‐irradiation, 2‐months‐old female C57BL/6 mice were irradiated at 5 Gy and further raised for 6 months. Subsequently, the mice were i.p. injected daily with Orlistat (25 mg/kg) or vehicle for 3 wk and analyzed for the adipose tissue weight and serum triglyceride and T‐cholesterol levels. The abdominal WAT of the γ‐irradiated mice weighed an average of 3.9/100 g body weight, 1.7‐fold higher than what was seen in normal mice (2.3/100 g body weight), indicating that γ‐irradiation induced the fat accumulation in the adipose tissue. However, the administration of Orlistat, a well‐known anti‐obesity agent, significantly reduced the adipose tissue weight to 1.7/100 g body weight in irradiated mice. In addition, in these Orlistat‐treated mice, a significant reduction of serum triglyceride and T‐cholesterol was observed up to 14% and 27%, respectively.     

BMP7 Drives Human Adipogenic Stem Cells into Metabolically Active Beige Adipocytes

Adult humans have a substantial amount of inducible‐brown (or beige) fat, which is associated with increased energy expenditure and reduced weight gain via thermogenesis. Despite the identification of key regulators of beige adipogenesis, impacts of dietary factors on adaptive thermogenesis are largely unknown, partly due to a lack of validated human cell models. Bone morphogenetic protein 7 (BMP7) is known to promote brown adipogenesis in rodent and human progenitor cells. However, controversy still surrounds the cellular identity in BMP7‐mediated transition of white to brown adipocytes. The aim of this study was to confirm BMP7‐derived human adipocytes as a relevant in vitro model of human beige adipocyte by verifying the cellular lineage and metabolic activity. In this study, we hypothesized that pre‐exposure of the stromal vascular (SV) fraction of primary human adipogenic precursor cells (hASC) to BMP7 would convert metabolically active brown adipocytes. Our results showed that exposure of hASC to human BMP7 was associated with significant escalation of (1) UCP1 gene expression, a signature gene of brown adipocytes, (2) beige specific marker gene expression (i.e., CD137 and TMEM26), (3) glucose and fatty acid uptake, and (4) basal and cAMP‐stimulated oxygen consumption rate compared to white adipocyte control. Taken together, we demonstrated that BMP7 mediates conversion of hASC into metabolically active beige adipocytes. By confirming the cellular identity and metabolic activity, this BMP7‐induced human beige adipocytes from hASC should aid in the discovery and assessment of bioactive molecules to promote adaptive thermogenesis.     

Nutritional properties of the triglycerides of saturated fatty acids of medium chain-length

Summary The influence of a purified rat diet containing 20 or 33% of the saturated medium chain-length triglycerides (MCT) with and without linoleic acid supplements on growth, caloric requirements for weight maintenance and weight increase, fertility, lactation performance, and serum cholesterol levels was compared with that of similar diets containing lard, coconut oil, or no fat. Among male rats maintained on diets containing 20% lard or 20% MCT and .09% linoleic acid for 18 months no differences were observed between the groups other than the depressed body weight and lowered serum cholesterol levels of the group fed MCT. When groups of male rats were kept at constant weight by the daily restricted feeding of diets containing lard, MCT, or coconut oil or no fat plus 2% linoleic acid, the weight-maintenance requirements of the group fed MCT were higher than of those on lard and coconut oil and even somewhat higher than the requirements of the animals fed the fat-free diet. The requirements for weight increase over those for maintenance were 0.9 g. per gram increase for all diets. Additional linoleic acid in the MCT diet decreased the weight and maintenance differences between groups fed MCT and lard. The lactation performance of mothers on MCT plus .09% linoleic acid was poor. The second generation animals initially showed signs of more severe linoleic acid deficiency which however disaappeared without linoleic acid supplements. Some cholesterol levels of animals on MCT were significantly below those of groups on lard. Addition of linoleic acid to the MCT diet did not change the results. Presented at the 48th Annual Meeting, American Oil Chemists’ Society, April 28 to May 1, 1957, New Orleans, La.     

Medium-Chain Enriched Diacylglycerol (MCE-DAG) Oil Decreases Body Fat Mass in Mice by Increasing Lipolysis and Thermogenesis in Adipose Tissue

Medium chain fatty acid (MCFA) escapes the formation of chylomicrons in the small intestine, resulting in energy expenditure through beta-oxidation. Diacylglycerol (DAG) is susceptible to oxidation rather than being stored in the adipose tissue. This study was conducted to verify the effect of MCE-DAG oil on body fat mass in vivo. Male C57BL/6 mice were randomly assigned to four groups (n = 12) as follows: (1) normal diet (18% kcal from fat), (2) canola oil as a control (40% kcal from canola oil), (3) MCE-DAG10 (10% kcal from MCE-DAG + 30% kcal from canola oil), and (4) MCE-DAG20 (20% kcal from MCE-DAG + 20% kcal from canola oil). The body weight and fat mass of MCE-DAG20 group mice were decreased relative to those of control mice (P < 0.05 and P < 0.001, respectively). Serum triacylglycerol (TAG) was decreased in both MCE-DAG10 and MCE-DAG20 groups (P < 0.01 and P < 0.05, respectively). Hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) were increased in the MCE-DAG20 group relative to the control in white adipose tissue (WAT) (P < 0.05). Uncoupling protein 1 (UCP1) was also increased in the MCE-DAG20 group relative to the control in brown adipose tissue (BAT) (P < 0.05). In summary, MCE-DAG reduced body fat mass likely by stimulating lipolysis in WAT and thermogenesis in BAT.     

The influence of dietary rumen‐protected linoleic acid on milk fat composition,spreadability of butter and energy balance in dairy cows

The aim of this study was to determine the effects of a diet supplemented with rumenprotected linoleic acids (C18:2) on the composition of milk fat and the energy balance of dairy cattle during the first 15 wk of lactation. The 32 Holstein‐Friesian cows were allotted in two treatment groups; in the experimental group one‐third of the starch (relative to the control group) was substituted with protected fat on an energy basis. Milk samples from all cows were collected weekly from week 2 to 15 postpartum (p.p.). To analyze the milk fat composition milk samples from 16 cows in each group were collected from week 6 and 7 as well as from week 13 and 14 p.p. and were mixed together, respectively. Triglyceride analysis demonstrated an extensive use of depot fat in both cow groups at the beginning of the lactation period. However, calculated energy balance, triglyceride composition and back fat thickness showed that the usual deficit of energy intake in early lactation was significantly shortened in the experimental group by three weeks. In comparison with the control group the content of the saturated fatty acids (FAs) C12, C14 and C16 in the experimental group decreased by 17.3% at 6 to 7 wk and by 19.2% at 13 to 14 wk. The stearic acid content of milk fat was increased by 25.9% at 6 to 7 wk and by 27.7% at 13 to 14 wk in the experimental group. The content of cis Δ9 oleic acid was increased by 21.6% at 6 to 7 and by 30.3% at 13 to 14 wk, while the C18:2 FA content was doubled as compared with the control group. Thus besides the increase of the trans‐C18:1 FA (TFA) content the nutritional value of fats could be improved using the experimental fat supplement. The TFA content still remained within the range of variation of natural milk fats. Additionally the experimental fat intake led to a number of desired effects; an increase in the content of conjugated linoleic acids (cis Δ9, transΔ11) by 55.9% (6 to 7 wk) and by 97.1% (13 to 14 wk p.p.), respectively, and a decrease in the cholesterol level. Further, the butyric acid content increased relatively by more than 20%. The addition of this fat resulted simultaneously in a changed triglyceride composition with increased C50, C52 and C54 contents. Thus a markedly improved spreadability of the resulting butter might be expected.