The effect of adlay oil on plasma lipids, insulin and leptin in rat.

This study was designed to investigate the effect of dietary adlay oil on plasma lipids, insulin and lipid peroxidation levels in rats. Twenty-four male Wistar rats fed diet containing adlay oil and cholesterol were studied for 4 weeks. The animals were divided into three groups: (1) 10% lard (control) group; (2) 5% lard + 5% adlay oil (5% adlay oil) group; and (3) 10% adlay oil group. Although there was no significant difference in body weight at the end of the feeding study, rats fed a diet containing adlay oil showed a significant decrease in adipose tissue weight and relative adipose weight. In addition, the rats fed the adlay oil showed significantly decreased low-density lipoprotein cholesterol (LDL-C), insulin, leptin and thiobarbituric acid reactive substance (TBARS) concentrations after 4 weeks of the feeding study. Although a significant decrease in total plasma cholesterol was observed in rats fed the 5% adlay oil diet, no significant difference was observed between the 10% adlay oil and control groups, and neither was a significant difference in liver TBARS concentration found between the dietary groups. Results from this study suggest that dietary adlay oil can reduce leptin, adipose tissue and LDL-C levels in rats.     

Lipoprotein lipase and lipogenic enzyme activities in adipose tissue from rats fed different lipid sources

This work was designed to study the effect of different lipid sources on the activities of lipoprotein lipase and lipogenic enzymes in adipose tissue from rats fedad libitum or energy-controlled diets. Male Wistar rats were fed diets containing 40% of energy as fat (olive oil, sunflower oil, palm oil or beef tallow), for 4 wk. Underad libitum feeding no differences were found among dietary fat groups in final body weight, adipose tissue weights and total body fat. Under energy-controlled feeding, despite isoenergetic intake, rats fed the beef tallow diet gained significantly less weight than rats fed the other three diets. Beef tallow fed rats showed the lowest values for adipose tissue weights and total body fat. When rats had free access to food no effect of dietary lipid source on lipogenic enzyme activities was found. In contrast, under energy-controlled feeding rats fed the beef tallow diet showed significantly higher activities of glucose-6-phosphate dehydrogenase and fatty acid synthase than rats fed the other three diets. Heparin-releasable lipoprotein lipase activity in perirenal and subcutaneous adipose tissues was not different among rats fed olive oil, safflower oil, palm oil or beef tallow. When comparing both adipose tissue anatomical locations, significantly higher activities were found in subcutaneous than in perirenal fat pad independently of dietary fat. In conclusion, under our experimental protocol, lipogenesis in rat adipose tissue does not seem to be affected by dietary fat type.     

Selectively hydrogenated soybean oil with conjugated linoleic acid modifies body composition and plasma lipids in rats

The present study examined effects of a selectively hydrogenated soybean oil (SHSO) containing about 21% CLA on body composition, adipose depots and organ weights, and plasma lipid profiles in rats. Male Sprague Dawley rats were fed for 6 weeks a purified diet containing 0%, 1%, 3%, and 5% of SHSO. Different levels of SHSO supplementation did not significantly affect growth performance, although there was a trend toward decreased body weight gain with increasing dietary SHSO levels. The weights of inguinal, epididymal, and retroperitoneal adipose depot, but not mesenteric, were significantly influenced by dietary SHSO supplementation (P < 0.05, P < 0.01 and P < 0.001, respectively). Although the absolute weight of body protein in the control rats was higher in SHSO-fed rats, the effect on absolute weight of body protein is diluted and eliminated when the data are adjusted for eviscerated carcass weight as a percentage base. Therefore, as dietary SHSO level increased, body protein as a percentage of carcass weight increased (P < 0.05), although as dietary SHSO level increased, body fat proportion in carcass decreased (P < 0.01). Plasma triglycerides (TG) and total cholesterol (TC) concentrations were beneficially decreased, and HDL-cholesterol (HDL-C) to TC ratio was also beneficially increased by SHSO supplementation (P < 0.05, P < 0.001, and P < 0.01, respectively). However, plasma HDL-C concentration undesirably decreased with dietary SHSO supplementation (P < 0.05). The present study observed that body composition and plasma lipids were beneficially modulated by SHSO supplementation at least 3% levels (0.6% of CLA), and suggested that SHSO is a useful fat source because of the high level of CLA.     

Effect of vitamin A content in cafeteria diet on the expression of nuclear receptors in rat subcutaneous adipose tissue

The aim of this study was to determine the effects of cafeteria diet containing control or elevated level of vitamin A on the expression of nuclear receptors in adipose tissue. Male Wistar rats were submitted to 3 experimental diets during 8 weeks, a standard diet and two hyper-energetic, hyperlipidic "cafeteria" diets containing normal (Caf) or higher (Caf+) vitamin A level. During the experiment, body weights and energy intakes were measured. At the end of the experimental period, subcutaneous adipose tissue (Swat) and all the fat mass were removed and weighted. Nuclear receptors mRNA levels of RARalpha, RARgamma, RXRalpha, PPARgamma were measured in the Swat by a real-time semi-quantitative RT-PCR method. We observed that energy intake of Caf+ and Caf groups was significantly higher than that of the control group. Despite a higher increase of the energy intake in the Caf group compared to the Caf+ group, no significant difference was observed in the body weight gain of the Caf+ compared to the Caf group. The Caf+ and Caf diets led to a significant increase of adipose tissue in cafeteria groups as observed in the Swat depot. The mRNA levels of PPARgamma and RXRalpha were significantly increased in the Caf+ group as compared to control group, with a significant positive correlation between these two parameters. Expressions of RARalpha and RARgamma were not modified in experimental groups compared to controls. In conclusion, 8-week exposure to cafeteria diets with normal and higher levels of vitamin A led to an increase of adiposity in rats, associated, only in the group fed with the higher vitamin A level cafeteria diet, with an increase of PPARgamma and RXRalpha expressions in subcutaneous adipose tissue.     

Individual severity of dietary obesity in unselected Wistar rats: relationship with hyperphagia

We investigated the relative importance of overeating, thermogenesis, and uncoupling protein (UCP) expression in determining the severity of obesity in male Wistar rats fed a highly palatable diet. After 2 wk of feeding, body weight did not differ significantly from controls (248 +/- 4 vs. 229 +/- 3 g; P > 0.3), but rectal temperature, brown adipose tissue (BAT) mass, UCP3 expression in gastrocnemius muscle, and UCP2 expression in white adipose tissue (WAT) were all elevated in diet-fed animals. In a further study, rats fed a palatable diet for 8 wk exhibited higher energy intake and rectal temperature than controls. Dietary-obese rats were divided into high (427-490 g; n = 8) and low (313-410 g; n = 10) weight gainers. The high gainers ate significantly more than the low gainers, and energy intake was positively correlated with weight gain (r(2) = 0.72, P < 0.01). UCP2 and UCP3 mRNA levels in gastrocnemius muscle were significantly increased above lean controls in all diet-fed animals, whereas UCPs in WAT and BAT did not differ significantly from controls. Whereas rats fed palatable food exhibited a thermogenic response, there was no significant difference in core temperature between high and low gain groups (37. 5 +/- 0.1 vs. 37.6 +/- 0.1 degrees C; P > 0.5). We conclude that a higher energy intake is the critical factor determining susceptibility to dietary obesity in unselected Wistar rats.     

Influence of dietary macronutrient composition on adiposity and cellularity of different fat depots in Wistar rats

The aim of this study was to investigate the role of dietary macronutrient content on adiposity parameters and adipocyte hypertrophy/hyperplasia in subcutaneous and visceral fat depots from Wistar rats using combined histological and computational approaches. For this purpose, male Wistar rats were distributed into 4 groups and were assigned to different nutritional interventions: Control group (chow diet); high-fat group, HF (60% E from fat); high-fat-sucrose group, HFS (45% E from fat and 17% from sucrose); and high-sucrose group, HS (42% E from sucrose). At day 35, rats were sacrificed, blood was collected, tissues were weighed and fragments of different fat depots were kept for histological analyses with the new softwareAdiposoft. Rats fed with HF, HFS and HS diets increased significantly body weight and total body fat against Control rats, being metabolic impairments more pronounced on HS rats than in the other groups. Cellularity analyses usingAdiposoft revealed that retroperitoneal adipose tissue is histologically different than mesenteric and subcutaneous ones, in relation to bigger adipocytes. The subcutaneous fat pad was the most sensitive to the diet, presenting adipocyte hypertrophy induced by HF diet and adipocyte hyperplasia induced by HS diet. The mesenteric fat pad had a similar but attenuated response in comparison to the subcutaneous adipose tissue, while retroperitoneal fat pad only presented adipocyte hyperplasia induced by the HS diet intake after 35 days of intervention. These findings provide new insights into the role of macronutrients in the development of hyperplastic obesity, which is characterized by the severity of the clinical features. Finally, a new tool for analyzing histological adipose samples is presented.     

Fenofibrate prevents orotic acid--induced hepatic steatosis in rats

The experiments performed in this report were designed to investigate the mechanisms involved in the metabolic alterations associated with orotic acid-induced hepatic steatosis and the effect of fenofibrate, a stimulant of peroxisome proliferators-activated receptor alpha (PPARalpha), on these alterations. Male Wistar rats were divided into three experimental groups: 1) fed a balanced diet (C); 2) fed a balanced diet supplemented with 1% orotic acid (OA); 3) fed OA diet containing 100 mg.kg(-1) bw.day(-1) fenofibrate (OA+F), for 9 days. Administration of OA to rats induced significant increase in the hepatic total lipids content, marked microvesicular steatosis and decrease in plasma lipids concentrations compared to control group. Fenofibrate treatment prevented fatty liver induction, caused an additional reduction on plasma lipids concentrations and caused a 40% decrease in the lipogenic rate in adipose tissue. The results also showed a 40% increase in lipoprotein lipase (LPL) activity in adipose tissue from OA treated group and fenofibrate administration induced a 50% decrease in LPL activity. The liver mRNA expression of PPARalpha and ACO (acyl CoA oxidase) were 85% and 68% decreased in OA group when compared to control, respectively. Fenofibrate treatment increased the PPARalpha and ACO expressions whereas the CPT-1 (carnitine palmitoyl transferase-1) expression was not altered. Our results have shown that fenofibrate treatment decreases the hepatic lipid content induced by OA which is mediated by an important increase in fatty acid oxidation consequent to an increase in hepatic mRNA expression of PPARalpha and ACO.     

Effects of ω3 Polyunsaturated Fatty Acids on Growth and Tissue Fatty Acid Compositions of Maternal Rats and Their Progeny

The effects of ω3 polyunsaturated fatty acids [PUFA; mainly eicosapentaenoic acid (20: 5, ω3) and docosahexaenoic acid (22:6, ω3)] on the growth, tissue weights and fatty acid compositions of tissue total lipids in female rats and their progeny were investigated. Female rats of the Wistar strain, weighing 77~94g, were fed a 25% casein diet containing 5% of either corn oil (control), sardine oil or PUFA ethyl ester for 8 ~ 9 weeks prior to mating, and during gestation and lactation, and then for a further 2 weeks. The progeny were weaned to the maternal diet and then the latter was administered for a further 2 weeks. Dietary changes in the body weights of the dams were not generally seen, but the body weights at birth and growth of the offspring from the females supplied with the PUFA diet were inferior compared to those of the other groups. The fertility did not differ among the dietary groups. The weights of several tissues in the dams and the progeny increased in proportion to their body weights but not that of the progeny brain, which remained ' almost unchanged by the dietary fats. As to the fatty acid compositions of total lipids in the tissues, on the whole, decreased levels of ωβ fatty acids and increased percentages of ω3 fatty acids were found in the sardine and PUFA groups, the changes being greater in the PUFA group than in the sardine one. Such findings due to the feeding of PUFA were more remarkable in the progeny compared with in the dams. Eicosatrienoic acid (20: 3, ω9) was almost completely undetectable in the tissue total lipids of all the dietary groups.     

Cholesterol-induced stimulation of platelet aggregation is prevented by a hempseed-enriched diet

Hypercholesterolemia indirectly increases the risk for myocardial infarction by enhancing the ability of platelets to aggregate. Diets enriched with polyunsaturated fatty acids (PUFAs) have been shown to reduce the detrimental effects of cholesterol on platelet aggregation. This study investigated whether dietary hempseed, a rich source of PUFAs, inhibits platelet aggregation under normal and hypercholesterolemic conditions. Male New Zealand white rabbits were fed one of 6 dietary interventions: regular control diet (RG); control diet + 10% hempseed (HP); control diet + 10% partially delipidated hempseed (DHP); control diet + 0.5% cholesterol (OL); control diet + 0.5% cholesterol + 10% hempseed (OLHP); control diet + 5% coconut oil (CO). After 8 weeks, blood was collected to measure ADP- and collagen-induced platelet aggregation and plasma levels of fatty acids, cholesterol, and triglycerides. The hempseed-fed animals (HP and OLHP) displayed elevated plasma levels of PUFAs and a prominent enhancement in 18:3n-6 (gamma-linolenic acid, GLA) levels, a unique PUFA found in hempseed. The cholesterol-supplemented groups (OL and OLHP) had significantly elevated plasma levels of cholesterol and triglycerides, but platelet aggregation was significantly augmented only in the OL group. The addition of hempseed to this diet (OLHP) normalized aggregation. The direct addition of GLA to the OL platelet samples blocked the cholesterol-induced stimulation of platelet aggregation. The results of this study demonstrate that when hempseed is added to a cholesterol-enriched diet, cholesterol-induced platelet aggregation returns to control levels. This normalization is not due to a reduction in plasma cholesterol levels, but may be partly due to increased levels of plasma GLA.     

Effect of dietary calcium: Phosphorus ratio on bone mineralization and intestinal calcium absorption in ovariectomized rats

We investigated the effect of dietary calcium:phosphorus (Ca:P) ratio on bone mineralization and intestinal Ca absorption in ovariectomized (OVX) rat models of osteoporosis and sham-operated rats. Thirty 12-wk-old female Wistar rats were divided into three groups of OVX rats and three groups of sham rats. Thirty days after the adaptation period, OVX rats and sham rats were fed a diet formulated Ca:P, 1:0.5, 1:1 or 1:2 (each diet containing 0.5% Ca), respectively for 42 d. In both sham and OVX rats, serum osteocalcin, a marker of bone turnover, was increased by decreasing Ca:P ratio (1:2). In contrast, rats fed the Ca:P = 1:0.5 diet (dietary P restriction) suppressed the increased serum parathyroid hormone, osteocalcin and urinary deoxypyridinoline, and increased Ca absorption in both sham and OVX rats compared to the Ca:P = 1:1 and 1:2 diets. Especially, in OVX rats, the decreased bone mineral density of the fifth lumbar was also suppressed when rats were fed the Ca:P = 1:0.5 diet. These results indicated that the elevation of dietary Ca:P ratio may inhibit bone loss and increase intestinal Ca absorption in OVX rats.     

Effects of dietary fat content on adiposity during energy restriction in genetically obese rats.

The effects of the amount of fat provided in a restricted diet on weight loss and body composition were studied in this work. Lean male (Fa/?) Zucker rats were fed a control diet ad libitum. Obese (fa/fa) Zucker rats were divided into three groups: one group was fed a control diet ad libitum and the other two groups were fed 75% energy-restricted diets, which provided 10 or 50% of calories as fat. After 4 weeks, energy restriction normalized body weight but not body composition in the genetically obese rats. Reductions in adipose tissue weights and adipocyte size, without changes in the cellularity, were observed. Differences only reached statistical significance in subcutaneous adipose tissue. A standard fat content in the diet induced the same fat-free mass reduction as a higher amount of this macronutrient, but a greater body fat reduction. This suggests that the restriction of dietary fat, as well as energy, is necessary to achieve dietary management in obesity.     

Effects of maternal leptin treatment during lactation on the body weight and leptin resistance of adult offspring

We investigate whether leptin treatment to lactating rats affects food intake, body weight and leptin serum concentration and its anorectic effect on their adult offspring. Lactating rats were divided into 2 groups: Lep-single injected with recombinant rat leptin (8 microg/100 g of body weight, daily for the last 3 consecutive days of lactation) and control group (C) that received the same volume of saline. After weaning all pups had free access to the control diet, their body weight and food intake were monitored at each 4 days until 180 days of age, when they were tested for its food intake and response to either leptin (0.5 mg/kg body wt, ip) or saline vehicle. The offspring of the leptin-treated dams gained more weight and had higher food intake from day 37 onward (p<0.05), higher amount of retroperitoneal white adipose tissue (RPWAT) (37%, p<0.05) and higher leptin serum concentration (40%, p<0.05) at 180 days of age compared to control group. The food intake at 2, 4, 6 and 24 h was unaffected after acute injection of leptin in these animals, suggesting resistance to the anorectic effect of leptin. The maternal leptin treatment during lactation makes their adult offspring more susceptible to overweight with resistance to the anorectic effect of leptin.     

Ergogenic effect of dietary L-carnitine and fat supplementation against exercise induced physical fatigue in Wistar rats

L-carnitine (LC) plays a central role in fatty acid metabolism and in skeletal muscle bioenergetics. LC supplementation is known to improve physical performance and has become widespread in recent years without any unequivocal support to this practice. A scientific-based knowledge is needed, to understand the implications of LC supplementation on physical fatigue. In current study, we have explored synergistic effects of dietary LC and fat content against physical fatigue in rats. Ninety male Wistar rats were supplemented with different concentrations of LC (0.15, 0.3, and 0.5 %) and fat content (5, 10, and 15 %) through diet in different combinations. Our results elucidated that LC (0.5 %) along with 10 and 15 % fat diet supplemented rats showed significant ergogenic effect. The swimming time until exhaustion was increased by ~2- and ~1.5-fold in rats fed with 10 and 15 % fat diet containing LC (0.5 %). LC supplementation improved the energy charge by increasing the levels of ATP, tissue glycogen, reduced GSH, plasma triglyceride, plasma glucose levels, and enzymatic antioxidant status, i.e., superoxide dismutase, catalase, and glutathione peroxidase. LC supplementation also significantly reduced lipid peroxidation, lactic acid, plasma urea nitrogen, creatinine, creatinekinase, and lactate dehydrogenase levels in various tissues compared to its respective control group. Thus the present study indicates that LC ameliorates the various impairments associated with physical endurance in rats.     

Regulation of glucose transport and transporter 4 (GLUT-4) in muscle and adipocytes of sucrose-fed rats: effects of N-3 poly- and monounsaturated fatty acids.

The goal of this study was to compare the short-term effects of dietary n-3 polyunsaturated (fish oil) and monounsaturated (olive oil) fatty acids on glucose transport, plasma glucose and lipid controls in a dietary insulin resistance model using sucrose-fed rats. The underlying cellular and molecular mechanisms were also determined in the muscle and adipose tissue. Male Sprague-Dawley rats (5 weeks old) were randomized for diets containing 57.5 % (w/w) sucrose and 14 % lipids as either fish oil (SF), olive oil (SO) or a mixture of standard oils (SC) for 3 weeks. A fourth control group (C) was fed a diet containing 57.5 % starch and 14 % standard oils. After three weeks on the diet, body weight was comparable in the four groups. The sucrose-fed rats were hyperglycemic and hyperinsulinemic in response to glucose load. The presence of fish oil in the sucrose diet prevented sucrose-induced hyperinsulinemia and hypertriglyceridemia, but had no effect on plasma glucose levels. Insulin-stimulated glucose transport in adipocytes increased after feeding with fish oil (p < 0.005). These modifications were associated with increased Glut-4 protein (p < 0.05) and mRNA levels in adipocytes. In the muscle, no effect was found on Glut-4 protein levels. Olive oil, however, could not bring about any improvement in plasma insulin, plasma lipids or Glut-4 protein levels. We therefore conclude that the presence of fish oil, in contrast to olive oil, prevents insulin resistance and hypertriglyceridemia in rats on a sucrose diet, and restores Glut-4 protein quantity in adipocytes but not in muscle at basal levels. Dietary regulation of Glut-4 proteins appears to be tissue specific and might depend on insulin stimulation and/or duration of dietary interventions.     

有氧运动同时补充玉米肽对肥胖大鼠脂肪分解关键酶的影响

目的：研究有氧运动同时补充玉米肽对高脂饮食诱导的肥胖大鼠减脂的作用及其与脂肪分解关键酶甘油三酯脂肪酶（ATGL）和脂蛋白酯酶（LPL）关系。方法：4周龄健康雄性SD大鼠150只,体重160~180 g,随机选取15只作为普通膳食不运动组,给予普通饲料喂养。剩余135只大鼠进行8周的高脂饲料喂养建立肥胖大鼠模型,以体重超过普通膳食不运动组大鼠平均体重的20%作为肥胖大鼠建模成功的标准。将建模成功的肥胖大鼠40只随机分为5组（n=8）：肥胖对照组、酪蛋白组、玉米肽组、运动组和运动+玉米肽组。除酪蛋白组、玉米肽组喂养自制饲料外,其余各组均用普通饲料喂养,运动组每天进行15 m/min,持续时间60 min的跑台运动,每周6天。4周运动和玉米肽干预后取血,检测大鼠血浆中TG、TC、HDL、LDL的含量;取大鼠肾周、附睾脂肪和肝,检测肾周和附睾脂肪的重量,Western blot检测大鼠肝ATGL、脂肪LPL的蛋白表达水平。结果：与肥胖对照组大鼠相比：①运动组、运动+玉米肽组大鼠的体重、附睾和肾周脂肪含量明显降低（P<0.05）,且运动+玉米肽组比运动组下降得更明显（P<0.05）,而其它组大鼠无显著差异。②运动组大鼠血浆TG显著降低,运动+玉米肽组的血浆TG、TC显著降低（P<0.05）,其它组大鼠的TG、TC无显著差异;血浆HDL和LDL各组间均无显著性差异。③运动组和运动+玉米肽组大鼠的肝ATGL、脂肪组织LPL的蛋白水平明显增加（P<0.01）,且运动+玉米肽组比运动组的更显著（P<0.05）;其他两组无显著差异。结论：有氧运动、有氧运动同时补充玉米肽都可以明显降低大鼠的体脂和血脂水平,且后者的作用更强,这可能与其更显著地增加肥胖大鼠肝ATGL和脂肪LPL的蛋白水平有关。而仅仅补充玉米肽不能降低大鼠的体脂和血脂水平。     

Defense of body weight against chronic caloric restriction in obesity-prone and -resistant rats

Half of Sprague-Dawley rats develop and defend diet-induced obesity (DIO) or diet resistance (DR) when fed a high-energy (HE) diet. Here, adult male rats were made DIO or DR after 10 wk on HE diet. Then half of each group was food restricted for 8 wk on chow to maintain their body weights at 90% of their respective baselines. Rate and magnitude of weight loss were comparable, but maintenance energy intake and the degree of sympathetic activity (24-h urine norepinephrine) inhibition were 17 and 29% lower, respectively, in restricted DR than DIO rats. Restricted DIO rats reduced adipose depot weights, plasma leptin, and insulin levels by 35%. Restricted DR rats reduced none of these. When fed ad libitum, both DR and DIO rats returned to the body weights of their respective chow-fed phenotype controls within 2 wk. This was associated with increased adipose mass and leptin and insulin levels only in DIO rats. Thus DR rats appear to alter primarily their lean body mass, whereas DIO rats primarily alter their adipose mass during chronic caloric restriction and refeeding.     

Obesity induced by a high-fat diet downregulates apolipoprotein A-IV gene expression in rat hypothalamus

Apolipoprotein A-IV (apo A-IV) is an anorectic protein produced in the intestine and brain that has been proposed as a satiety signal. To determine whether diet-induced obesity alters apo A-IV gene expression in the intestine and hypothalamus, rats were fed a high-fat (HF), low-fat (LF), or standard chow (CHOW) diet for 2, 4, 6, 8, or 10 wk. Rats fed the HF diet had significantly greater body weights than rats given the LF and CHOW diets. Intestinal and plasma apo A-IV levels were comparable across dietary groups and time. LF and CHOW rats had comparable hypothalamic apo A-IV mRNA across the course of the experiment. However, HF rats had a slow and progressive diminution in hypothalamic apo A-IV mRNA over time that became significantly lower than that of LF or CHOW rats by 10 wk. Intragastric infusion of lipid emulsion to animals that were fasted overnight significantly stimulated hypothalamic apo A-IV mRNA in LF and CHOW rats but had no effect in HF rats. These results demonstrate that chronic consumption of a HF diet significantly reduces apo A-IV mRNA levels and the response of apo A-IV gene expression to dietary lipids in the hypothalamus. This raises the possibility that dysregulation of hypothalamic apo A-IV could contribute to diet-induced obesity.     

Copper modulates sex-specific fructose hepatoxicity in nonalcoholic fatty liver disease (NALFD) Wistar rat models

This study aimed to characterize the impact of dietary copper on the biochemical and hepatic metabolite changes associated with fructose toxicity in a Wistar rat model of fructose-induced liver disease. Twenty-four male and 24 female, 6-week-old, Wister rats were separated into four experimental dietary treatment groups (6 males and 6 females per group), as follows: (1) a control diet: containing no fructose with adequate copper (i.e., CuA/0% Fruct); (2) a diet regimen identical to the control and supplemented with 30% w/v fructose in the animals' drinking water (CuA/30% Fruct); (3) a diet identical to the control diet but deficient in copper content (CuD/0% Fruct) and (4) a diet identical to the control diet but deficient in copper content and supplemented with 30% w/v fructose in the drinking water (CuD/30% Fruct). The animals were fed the four diet regimens for 5 weeks, followed by euthanization and assessment of histology, elemental profiles and identification and quantitation of liver metabolites. Results from ¹H nuclear magnetic resonance metabolomics revealed mechanistic insights into copper modulation of fructose hepatotoxicity through identification of distinct metabolic phenotypes that were highly correlated with diet and sex. This study also identified previously unknown sex-specific responses to both fructose supplementation and restricted copper intake, while the presence of adequate dietary copper promoted most pronounced fructose-induced metabolite changes.     

Effects of structured lipids containing eicosapentaenoic or docosahexaenoic acid and caprylic acid on serum and liver lipid profiles in rats

The physiological activity and effect on lipid metabolism of four types of structured lipids (SLs), that contain caprylic acid (C8) and either eicosapentaenoic (EPA) or docosahesaenoic acid (DHA), were evaluated in male Wistar rats fed experimental diets containing 7% (wt %) of each SL and 3% (wt %) soybean oil for 28 days. Control rats were fed a diet containing 10% (wt %) soybean oil. The relative perirenal adipose tissue weights of rats fed D-8-8 and 8-D-8 diets were significantly lower than those of other groups. We observed significantly lower serum cholesterol concentrations in rats fed SLs than those of control group over experimental period. The serum lipids concentrations in rats fed diets containing SLs were significantly lower P < 0.05) than those of soybean oil group. The fatty acid compositions of WAT did not reflect the structural differences in the triglyceride. These results suggest that the physiological effects of the SLs used in this study were due to the fatty acids rather than the structural specificity. Therefore, further study will be needed to ascertain the most desirable structural configuration.     

The modifying effects of fish oil on fasting ghrelin mRNA expression in weaned rats

Ghrelin expression and secretion seem to be influenced by the fat content of the diet. However, data on the probable adverse effect of high fat diet (HFD) with different dietary fats and saturation level of fatty acids is inconclusive. This study aimed at investigating the effects of HFDs on fasting total and acyl-ghrelin plasma levels, gastric fundus and duodenum ghrelin mRNA expressions. Weaned Wistar rats (n=50) were randomly divided to five groups of HFDs with fish oil (HF-F), olive oil (HF-O), soy oil (HF-S), butter (HF-B) and the controls. After 8weeks, blood samples were collected. While the animals were fasting for 24h, their blood and tissue samples were obtained. Plasma parameters of total and acyl ghrelin and ghrelin mRNA expression level in stomach and duodenum were measured. The HF-B fed group had lower fasting plasma acyl ghrelin level than the control, HF-F and HF-O groups (P<0.05); furthermore, the HF-F group had significantly higher acyl ghrelin level than the HF-S one (P<0.05). After feeding, all the groups, except for the HF-B one, had a significantly lower plasma acyl ghrelin levels (P<0.05), compared with the fasting state. Ghrelin mRNA expression levels in the gastric fundus and duodenum were significantly lower in the HF-B as compared to the control group. Furthermore, the HF-F group had significantly higher mRNA level in the duodenum, in comparison with the HF-B and HF-S groups. As HF-F and HF-O diets had the highest stimulatory effect on fasting ghrelin expression and plasma level, consumption of these dietary oils can play an important role in ghrelin regulation, which might affect feeding behavior and energy intake.