Soy germ protein concentrate diet decreased body fat weight and increased hindlimb muscle weight in rats

The purpose of this study was to investigate the effects of soy germ protein intake on body composition. Wistar rats were fed experimental diets for 16 weeks. These consisted of soy germ protein, soy protein, or casein. Abdominal adipose tissue weights significantly lower and hindlimb muscle weights were significantly higher in the soy germ protein group than in the casein group.     

Dietary l-arginine supplementation increases muscle gain and reduces body fat mass in growing-finishing pigs

Obesity in humans is a major public health crisis worldwide. In addition, livestock species exhibit excessive subcutaneous fat at market weight. However, there are currently few means of reducing adiposity in mammals. This study was conducted with a swine model to test the hypothesis that dietary L-arginine supplementation may increase muscle gain and decrease fat deposition. Twenty-four 110-day-old barrows were assigned randomly into two treatments, representing supplementation with 1.0% L-arginine or 2.05% L-alanine (isonitrogenous control) to a corn- and soybean meal-based diet. Growth performance was measured based on weight gain and food intake. After a 60-day period of supplementation, carcass and muscle composition were measured. Serum triglyceride concentration was 20% lower (P < 0.01) but glucagon level was 36% greater (P < 0.05) in arginine-supplemented than in control pigs. Compared with the control, arginine supplementation increased (P < 0.05) body weight gain by 6.5% and carcass skeletal-muscle content by 5.5%, while decreasing (P < 0.01) carcass fat content by 11%. The arginine treatment enhanced (P < 0.05) longissimus dorsi muscle protein, glycogen, and fat contents by 4.8, 42, and 70%, respectively, as well as muscle pH at 45 min post-mortem by 0.32, while reducing muscle lactate content by 37%. These results support our hypothesis that dietary arginine supplementation beneficially promotes muscle gain and reduces body fat accretion in growing-finishing pigs. The findings have a positive impact on development of novel therapeutics to treat human obesity and enhance swine lean-tissue growth.     

Soy protein isolate reduces hepatosteatosis in yellow Avy/a mice without altering coat color phenotype

Agouti (A(vy)/a) mice fed an AIN-93G diet containing the soy isoflavone genistein (GEN) prior to and during pregnancy were reported to shift coat color and body composition phenotypes from obese-yellow towards lean pseudoagouti, suggesting epigenetic programming. Human consumption of purified GEN is rare and soy protein is the primary source of GEN. Virgin a/a female and A(vy)/a male mice were fed AIN-93G diets made with casein (CAS) or soy protein isolate (SPI) (the same approximate GEN levels as in the above mentioned study) for 2 wks prior to mating. A(vy)/a offspring were weaned to the same diets and studied at age 75 d. Coat color distribution did not differ among diets, but SPI-fed, obese A(vy)/a offspring had lower hepatosteatosis (P < 0.05) and increased (P < 0.05) expression of CYP4a 14, a PPARalpha-regulated gene compared to CAS controls. Similarly, weanling male Sprague-Dawley (SD) rats fed SPI had elevated hepatic Acyl Co-A Oxidase (ACO) mRNA levels and increased in vitro binding of PPARalpha to the PPRE promoter response element. In another hepatosteatosis model, adult SD rats fed a high fat/cholesterol diet, SPI reduced (P < 0.05) steatosis. Thus, 1) consumption of diets made with SPI partially protected against hepatosteatosis in yellow mice and in SD rats, and this may involve induction of PPARalpha-regulated genes; and 2) the lifetime (in utero, neonatal and adult) exposure to dietary soy protein did not result in a shift in coat color phenotype of A(vy)/a mice. These findings, when compared with those of previously published studies of A(vy)/a mice, lead us to conclude that: 1) the effects of purified GEN differ from those of SPI when GEN equivalents are closely matched; 2) SPI does not epigenetically regulate the agouti locus to shift the coat color phenotype in the same fashion as GEN alone; and 3) SPI may be beneficial in management of non-alcoholic fatty liver disease.     

Fenofibrate prevents and reduces body weight gain and adiposity in diet-induced obese rats

Fibrates are hypolipidemic drugs that activate the peroxisome proliferator-activated receptors. Since fibrates may also increase energy expenditure, we investigated whether fenofibrate (FF) had this effect in diet-induced obese rats. A 2-month administration of a high-fat palatable diet to adult rats increased body weight by 25% and white adipose mass by 163% compared with a standard diet. These effects were prevented by FF, both when administered for the 2 months of high-fat feeding and when given for only the second month. Consequently, FF-treated rats had a final body weight and white adipose tissue mass similar to untreated animals on the standard diet. FF also increased resting metabolic rate, hepatic peroxisomal and mitochondrial palmitoyl-dependent oxygen uptake and mRNA levels of acyl-CoA oxidase and lipoprotein lipase. Finally, FF lowered mRNA levels of uncoupling protein-2 and did not affect mitochondrial respiration in skeletal muscle. Therefore, FF seems to act as a weight-stabilizer mainly through its effect on liver metabolism.     

Consumption of pork-liver protein hydrolysate reduces body fat in Otsuka Long-Evans Tokushima Fatty rats by suppressing hepatic lipogenesis

This study was performed to examine the effect of consumption of pork-liver protein hydrolysate (PLH) on body fat accumulation in Otsuka Long-Evans Tokushima Fatty (OLETF) rats as a non-insulin-dependent diabetes mellitus model and in Long-Evans Tokushima Otsuka (LETO) rats as a control. Male 20-week-old OLETF and LETO rats were pair-fed either PLH or casein containing diet for 14 weeks. In the OLETF rats, dietary PLH significantly reduced the growth and weight of fat pad including perirenal and epididymal adipose tissues. Consumption of PLH markedly suppressed hepatic activities of lipogenesis enzymes such as glucose-6-phosphate dehydrogenase and fatty acid synthase and slightly elevated fecal excretion of total fat. In the LETO rats, growth and adipose tissue weight were unaffected by dietary treatment. The results suggest that PLH is a novel ingredient suppressing body fat in genetically obese rats by reducing lipogenesis.     

Amylin blunts hyperphagia and reduces weight and fat gain during recovery in socially stressed rats

During recovery from social stress in a visible burrow system (VBS), during which a dominance hierarchy is formed among the males, rats display hyperphagia and gain weight preferentially as visceral adipose tissue. By proportionally increasing visceral adiposity, social stress may contribute to the establishment of metabolic disorder. Amylin was administered to rats fed ad libitum during recovery from VBS stress in an attempt to prevent hyperphagia and the resultant gain in body weight and fat mass. Amylin treatment reduced food intake, weight gain, and accumulation of fat mass in male burrow rats, but not in male controls that spent time housed with a single female rather than in the VBS. Amylin did not alter neuropeptide Y (NPY), agouti-related peptide (AgRP), or proopiomelanocortin (POMC) mRNA expression in the arcuate nucleus of the hypothalamus as measured at the end of the recovery period, nor did it affect plasma corticosterone or leptin. Amylin exerted most of its effect on food intake during the first few days of recovery, possibly through antagonism of NPY and/or increasing leptin sensitivity. The potential for chronic social stress to contribute to metabolic disorder is diminished by amylin treatment, though the neuroendocrine mechanisms behind this effect remain elusive.     

Exogenous human growth hormone reduces body fat in obese women

The effects of biosynthetic methionyl human growth hormone (met-hGH) on body composition and endogenous secretion of insulin-like growth factor I (IGF-I) were studied in obese women ranging between 138 and 226% of ideal body weight. Following double-blind procedures, 12 subjects were assigned at random to either treatment with met-hGH (n = 6, 0.08 mg/kg desirable body weight) or placebo (n = 6, bacteriostatic water diluent). Treatments were delivered intramuscularly three times per week for a period of 27-28 days. Subjects were instructed to follow a weight-maintaining diet and their pre- and posttreatment kilocaloric intake was monitored for verification. The baseline peak serum GH response to L-dopa/arginine stimulation for the study population as a whole, was in the hyposecretory range (9.6 +/- 1.9 ng/ml), accompanied by a low level of circulating IGF-I (0.56 +/- 0.09 U/ml). Hydrodensitometry revealed that the met-hGH-treated subjects had a significant reduction in body fat, while an observed mean increase in fat-free mass (FFM) approached significance. The percent change in body fat was unrelated to pretreatment levels of body fat, total body weight, or initial endogenous GH status. Changes in circulating IGF-I were similar to those for FFM, with increases approaching significance. There were no significant changes in body composition or IGF-I in the placebo-treated subjects. No significant differences were observed in the self-reported dietary intake of kilocalories during the experimental period between the two groups. We conclude that exogenous GH reduces body fat in obese women in the apparent absence of significant kilocaloric restriction. The effect appears to be unrelated to endogenous GH secretion or body composition.     

Dietary calcium attenuation of body fat gain during high-fat feeding in mice

Human epidemiological studies have supported the hypothesis that a dairy food-rich diet is associated with lower fat accumulation, although prospective studies and intervention trials are not so conclusive and contradictory data exist in animal models. The purpose of this study was to assess the effects on body weight and fat depots of dairy calcium (12 g/kg diet) in wild-type mice under ad libitum high-fat (43%) and normal-fat (12%) diets and to gain comprehension on the underlying mechanism of dairy calcium effects. Our results show that calcium intake decreases body weight and body fat depot gain under high-fat diet and accelerates weight loss under normal-fat diet, without differences in food intake. No differences in gene or protein expression of UCP1 in brown adipose tissue or UCP2 in white adipose tissue were found that could be related with calcium feeding, suggesting that calcium intake contributed to modulate body weight in wild-type mice by a mechanism that is not associated with activation of brown adipose tissue thermogenesis. UCP3 protein but not gene expression increased in muscle due to calcium feeding. In white adipose tissue there were effects of calcium intake decreasing the expression of proteins related to calcium signalling, in particular of stanniocalcin 2. CaSR levels could play a role in decreasing cytosolic calcium in adipocytes and, therefore, contribute to the diminution of fat accretion. Results support the anti-obesity effect of dietary calcium in male mice and indicate that, at least at the time-point studied, activation of thermogenesis is not involved.     

Raising young reduces body condition and fat stores in black-legged kittiwakes

We conducted a manipulative experiment to investigate how raising chicks affects the body condition (body mass scaled by body size) and body composition (percent fat vs. lean mass) of black-legged kittiwakes (Rissa tridactyla). For 4 consecutive years (1991–1994) we removed eggs from randomly selected nests and then compared adults raising chicks with adults that had their eggs removed. At the end of the chick-rearing period, adults raising chicks were significantly lighter for their size than adults that had their eggs removed. Adults raising chicks also had a significantly lower percent body fat (by 28%) than adults from manipulated nests. The difference in percent body fat between the two groups was apparent at all levels of condition, suggesting that adults that are raising chicks apportion their reserves differently than adults that are working only to meet their own metabolic needs. End-of-season body condition of adults from manipulated and unmanipulated nests varied significantly among 5 years of study, and appeared to reflect differences in local foraging conditions. In all years, females were in worse condition than males at the end of the breeding season. This sex-specific condition difference did not, however, appear to indicate a greater short-term reproductive cost among females. Females were lighter for their size than males in both the manipulated and unmanipulated groups. Our results suggest that adult kittiwakes compromise their body condition and body composition during chick rearing to increase the likelihood of successfully fledging young, even though such adjustments may decrease their own post-reproductive survival probabilities. Prior to estimating the body composition of the experimental birds, we evaluated the usefulness of several noninvasive techniques for predicting fat mass in kittiwakes. We used cross-validation techniques to compare multiple regression models that included total body electrical conductivity (TOBEC), total body water (TBW), and morphometric measurements as independent variables. The most parsimonious model for predicting fat mass was based on TOBEC and mass measurements. TBW and morphometrics were of little utility in predicting fat mass in kittiwakes. Previous studies that have evaluated the usefulness of TOBEC as a predictor of fat mass have shown mixed results. We suggest that the size of the experimental subject relative to the size of the TOBEC measurement chamber may affect the accuracy of this technique. Received: 30 November 1998 / Accepted: 29 April 1999     

Emulsion stabilizing properties of various chitosans in the presence of whey protein isolate

The emulsion stabilizing potential of chitosans (CN) with various molecular weights and degrees of deacetylation (CNI=1494 kDa, 78.1%DD; CNHI=694 kDa, 78.5%DD; CNHI2=319 kDa, 78.5%DD; CNHK=749 kDa, 67.7%DD) was compared in the presence of whey protein isolate. Phase separation evolutions revealed minimal stabilizing concentrations against syneresis from 0.1 to 0.125% in most CN preparations, except CNHI2 where it was higher (0.225%). Those stabilizing concentrations are the result of interfacial coadsorption saturation of CN with proteins, favouring interfacial electrostatic and steric stabilizing mechanisms. The emulsion characteristics (droplet size, limiting low-shear viscosity, and surface net charge), mostly distinctive at 0.1%CN, revealed the following order of stabilizing potentials: CNI≈CNHI>CNHK>CNHI2, which is in agreement with respective phase separation evolutions. The lower stabilizing potential of CNHI2 is explained by lower interfacial coadsorption efficiency with protein. In spite of a higher interfacial load of CNHK vs. CNI and CNHI, its lower stabilizing potential is essentially explained by a lower surface net charge.     

Directness of resource use metrics affects predictions of bear body fat gain

Many North American ursids rely on an annual hyperphagic period to obtain fat reserves necessary for winter survival and reproduction. Identifying causes of variation in body fat gain may improve understanding of how bear resource use affects body condition. We used data from southcentral Alaska to model changes in percentage body fat of adult female American black bears (Ursus americanus) in 1998 and 2000 and brown bears (Ursus arctos) in 2000. We used year, proportion of radio locations in different habitats, distance to streams containing salmon (Onchorynchus spp.), and degree of radio location clustering as predictors for black bears and elevation, distance to streams containing salmon, and degree of radio location clustering as predictors for brown bears. Degree of location clustering was the only predictor variable supported by parameter coefficients in black bear models, supporting our hypothesis that metrics of energetics perform better as predictors of body condition than habitat use. With every unit increase in location clustering black bear body fat increased 2 %. No predictor variables influenced variation in brown bear change in body fat. Some variables previously found useful for predicting bear presence (e.g., habitat) were not useful in predicting changes in body fat, an important biological outcome for these species. Rather than assuming fitness benefits of habitat-level selection, we recommend including metrics of energetics that might more directly influence biological outcomes.     

Lipoic acid prevents body weight gain induced by a high fat diet in rats: Effects on intestinal sugar transport

Several studies have suggested that oxidative stress might cause and aggravate the inflammatory state associated with obesity and could be the link between excessive weight gain and its related disorders such as insulin resistance and cardiovascular diseases. Thus, antioxidant treatment has been proposed as a therapy to prevent and manage obesity and associated complications. Therefore, the aim of the present study was to investigate the effects of supplementation of a standard or high fat diet with the antioxidant lipoic acid (LA) during 56 days, on body weight gain, adiposity, feed efficiency and intestinal sugar absorption, in male Wistar rats. LA supplementation induced a lower body weight gain and adipose tissue size in both control or high fat fed rats accompanied by a reduction in food intake. The group fed on a high fat diet and treated with LA (OLIP group) showed a lower body weight gain than its corresponding Pair-Fed (PF) group (P<0.05), which received the same amount of food than LA-treated animals but with no LA. In fact, LA induced a reduction on feed efficiency and also significantly decreased intestinal α-methylglucoside (α-MG) absorption both in lean and obese rats. These results suggest that the beneficial effects of dietary supplementation with LA on body weight gain are mediated, at least in part, by the reduction observed in food intake and feed efficiency. Furthemore, the inhibitory action of LA on intestinal sugar transport could explain in part the lower feed efficiency observed in LA-treated animals and therefore, highlighting the beneficial effects of LA on obesity.     

Intracerebroventricular interleukin-6 treatment decreases body fat in rats

Recently we found that interleukin-6 (IL-6) knockout mice develop mature-onset obesity and that a single intracerebroventricular (ICV) injection of IL-6 increases energy expenditure. In the present study we investigated if chronic ICV treatment with IL-6 can suppress body fat mass. IL-6 was injected ICV daily for two weeks to rats fed a high-fat diet. IL-6 treatment but not saline treatment decreased body weight by 8.4% and decreased the relative weights of mesenteric and retroperitoneal fat pads. Consistent with this, circulating leptin levels were decreased by 40% after IL-6 treatment but not after saline treatment. Average food intake per day was decreased in the IL-6 treated group compared to the saline treated rats. IL-6 treatment did not change hepatic expression of the acute-phase protein haptoglobin, serum levels of insulin or insulin-like growth factor-I, or the weights of the heart, liver, kidneys, adrenals, and spleen. We conclude that centrally administered IL-6 can decrease body fat in rats without causing acute-phase reaction.     

Effect of sequential bleeding on body weight gain in rats.

Monthly withdrawal of a total of 1.25--2.0 ml of blood from young, mature, inbred Fischer 344 rats produced no noticeable effects on common hematologic parameters, but it did cause a decrease in the rate of body weight gain. The difference in body weight between rats bled and not bled was evident 3 weeks after the study began, and the difference persisted throughout the 23-week study.     

Identification of 30-kDa fat body protein of Sarcophaga peregrina larvae selectively phosphorylated in the presence of 20-hydroxyecdysone as ribosomal protein S6

Previously, we showed that 20-hydroxyecdysone induces selective phosphorylation of a fat body protein of Sarcophaga peregrina with a molecular mass of about 30,000 (30-kDa protein) (Itoh, K., Ueno, K., & Natori, S. (1985) Biochem. J. 227, 683-688). This paper describes the identification of this 30-kDa protein. From the electrophoretic profile of 40S ribosomal proteins on two-dimensional polyacrylamide gel electrophoresis, the 30-kDa protein was identified as S6.     

Green tea reduces body fat accretion caused by high-fat diet in rats through beta-adrenoceptor activation of thermogenesis in brown adipose tissue

The aim of the present study was to investigate body fat-suppressive effects of green tea in rats fed on a high-fat diet and to determine whether the effect is associated with beta-adrenoceptor activation of thermogenesis in brown adipose tissue. Feeding a high-fat diet containing water extract of green tea at the concentration of 20g/kg diet prevented the increase in body fat gain caused by high-fat diet without affecting energy intake. Energy expenditure was increased by green tea extract which was associated with an increase in protein content of interscapular brown adipose tissue. The simultaneous administration of the beta-adrenoceptor antagonist propranolol(500 mg/kg diet) inhibited the body fat-suppressive effect of green tea extract. Propranolol also prevented the increase in protein content of interscapular brown adipose tissue caused by green tea extract. Digestibility was slightly reduced by green tea extract and this effect was not affected by propranolol. Therefore it appeared that green tea exerts potent body fat-suppressive effects in rats fed on a high-fat diet and the effect was resulted in part from reduction in digestibility and to much greater extent from increase in brown adipose tissue thermogenesis through beta-adrenoceptor activation.     

Chronic stress reduces body fat content in both obesity-prone and obesity-resistant strains of mice

Unpredictable stressors have been used to assess the effect of stress on energy metabolism in obesity-prone (C57BL6J) and obesity-resistant (AJ) mice. Mice were exposed for 25 days to a stress protocol. Both strains of mice were divided into groups of control and stressed mice, which had access to either a high-fat or a high-carbohydrate diet. Twenty-four hours after the last session of stress, mice were sacrificed for blood and brain collections. Insulin, corticosterone, and glucose concentrations in plasma were measured, and expressions of corticotropin-releasing factor (CRF) in the paraventricular hypothalamic nucleus (PVH) and the central amygdala (CeA) were determined by in situ hybridization. Stressed mice in all groups had lower body fat contents than control mice, and all mice fed with the high-fat diet had heavier retroperitoneal and inguinal fat pads than mice fed with carbohydrate. CRF mRNA level in the CeA was lower in B6 mice than in AJ mice. Stressed mice had a lower expression of CRF in the CeA than control mice. In conclusion, chronic stress reduces body fat content in obesity-prone as well as in obesity-resistant mice.