Evaluation of some biological parameters of Opuntia ficus indica. 1. Influence of a seed oil supplemented diet on rats

Cactus pear (Opuntia ficus indica) is native to Tunisia and the fruit is consumed exclusively as fresh fruit. The seed oil is rich in polyunsaturated fatty acids but the nutritive value of the oil is unknown. The objective of our research was to determine the fatty acid content of cactus pear seed oil and to evaluate the effect of an oil supplemented diet on rats. The main fatty acids of prickly pear seed oil were C16:0, C18:0, C18:1, C18:2 with an exceptional level of linoleic acid, up to 700 g kg(-1), and a total content of unsaturated fatty acids of 884.8 g kg(-1). Feed intake and body weight of rats were measured every two days during the nine weeks of treatment. Digestibility, feed conversion efficiency and protein efficiency ratio were determined. No difference in digestibility was noted for the oil enriched diet. The results indicated a significant decrease in serum glucose concentration (22%) over the control group. However, an increase in the concentration of glycogen was noted in liver and muscle. Blood cholesterol and low density lipoprotein (LDL)-cholesterol decreased in the treated group. High density lipoprotein (HDL)-cholesterol concentration remained unaltered during the treatment. These findings support the nutritional value of cactus pear as a natural source of edible oil containing essential fatty acids and reinforce the possibility of cactus pear as a new crop for Tunisia especially in semi-arid regions, where conventional crops are difficult to establish.     

Effects of leucine and phenylalanine supplementation during intermittent periods of food restriction and refeeding in adult rats

Although many studies have shown that amino acid ingestion acutely stimulates protein anabolism, only few studies have investigated whether long-term supplementation promotes changes in body composition. We therefore tested the hypothesis that l-leucine (LEU) and l-phenylalanine (PHE) supplementation might have a positive impact on the body composition of rats submitted to intermittent periods of food restriction and refeeding (weight cycling or WC). The WC protocol comprised three cycles, each consisting of 1 week of 50% food restriction followed by 2 weeks of ad libitum ingestion. The groups submitted to WC ingested the control diet (WC-CON) or the diet supplemented with LEU+PHE (WC-AA). A pair-fed group receiving the control diet (PF-CON) was used as a reference for the effects of WC. Although food intake was the same in all groups, higher body weight and energy efficiency were observed in the WC-AA group compared to the PF-CON and WC-CON groups although not significantly in relation to the latter. These results were the consequence of a significant increase of lean body mass and body protein content in the WC-AA group compared to the PF-CON and WC-CON groups. The WC-CON and WC-AA groups presented 36.1% and 18.9% more body fat, respectively, than the PF-CON group but this difference was not significant. Neither fasting insulin nor glucose concentration nor postprandial insulin secretion was significantly affected by the supplemented diet. In conclusion, supplementation with LEU+PHE improved the body composition profile of rats submitted to WC, mainly by increasing lean body mass and body protein content.     

Dose dependent accretion of docosahexaenoic acid (DHA) in cardiac membranes of rats fed egg yolk powder enriched in DHA.

We tested the hypothesis that enrichment of the diet with docosahexaenoic acid (DHA) enriched egg yolk powder could modify specifically the (n-3) fatty acids content of rat plasma, red blood cells and heart membranes. Dose-dependent effect of DHA was studied in rats supplemented during 4 weeks. Three groups of adult male rats, DHA10, DHA35 and DHA60 (n = 5 each), had their diet supplemented with 10 mg, 35 mg or 60 mg DHA/kg body weight/day, respectively. Fatty acid composition of membranes and plasma lipids were determined. A significant dose-dependent increase in DHA was observed in all three types of samples. Arachidonic acid (AA) levels did not change in heart and red blood cell membranes whereas it increased significantly in plasma with the DHA35 diet. These results contrast with that previously reported for fish oil supplementation where a decrease in AA levels was reported. Hence, DHA enriched egg yolk supplementation leads to a specific accretion of DHA without competition on AA status.     

The influence of age and sex on selenium distribution and glutathione peroxidase activity in plasma and erythrocytes of selenium-adequate and supplemented rats.

The experiment was performed on Sprague-Dawley male rats weighting 203, 103 and 53 g, and female 99 g. Animals were fed for 2 weeks a diet containing 0.1 and 2.0 ppm of Se (Na2SeO3 added). It was observed that the daily Se intake per kg of BW is lowered with an increase in animals body weight. Se-supplementation caused a significant increase of Se content in plasma and red blood cells. The highest concentration of Se in plasma and in RBC was found in females. GSH-Px activity was higher in RBC of all male rats receiving a Se-supplemented diet, but not in females. In plasma these differences between Se-adequate and supplemented rats were significant in youngest male rats and in females. These results suggest that age and sex of rats affect the concentration of Se and GSH-Px activity in plasma and RBC of rats.     

Assessment of protein quality of infant milk food formula supplemented with lactulose

To examine the protein quality of infant food formula supplemented with lactulose (bifidogenic factor), groups of 21 day male weanling rats were fed diet containing lactulose at 0.5% for 4 weeks. The gain in body weight of rats fed lactulose supplemented diet were similar to that of rats fed lactulose free and skim milk powder fed diet as controls. No difference in overall acceptability pattern was also observed in studies conducted with human subjects for organoleptic evaluation. The results suggest that supplementation of lactulose in infant food formula does not affect either the protein quality as indicated by protein efficiency ratio in rats as compared to control formulae or overall acceptability by human subjects.     

Effect of allicin from garlic powder on serum lipids and blood pressure in rats fed with a high cholesterol diet

The use of fresh aqueous garlic extract is known to be effective in reducing thromboxane formation by platelets in both in vivo and in vitro animal models of thrombosis. In the present study, we studied the effect of Lichtwer garlic powder (containing 1.3% alliin equivalent to 0.6% allicin) on the serum cholesterol, triglyceride, glucose, protein, and systolic blood pressure in rats fed with a high cholesterol diet. Experimental rats were fed a 2% high cholesterol diet with and without garlic powder for 6 weeks. Control rats were fed a normal diet. The aqueous garlic powder extract was given orally to rats on a daily basis. It was observed that cholesterol-fed animals had a significant increase in serum cholesterol compared to the control group of rats fed on a normal diet. However, when the rats were fed with a high cholesterol diet mixed with garlic powder, there was a significant reduction in their serum cholesterol levels compared with the group which were on a diet containing high cholesterol without garlic powder. Serum triglyceride levels were also significantly lowered by garlic powder when compared to control and high cholesterol diet group rats. The blood pressure of the high cholesterol diet animals was significantly higher compared to the animals receiving the control diet. The blood pressure of the animals receiving garlic powder and high cholesterol diet was significantly lower as compared to the high cholesterol and control diet group. No significant changes were observed in the serum glucose and protein in all of the rats. These results show that garlic is beneficial in reducing blood cholesterol, triglycerides levels and systolic blood pressure in hypercholesterolemic rats. Our experimental results show that garlic may beneficially affect two risk factors for atherosclerosis--hyperlipidemia and hypertension.     

Anti-obesity property of the brown seaweed,Sargassum polycystum using an in vivo animal model

Obesity has reached epidemic proportions in many countries around the world. Preventing and treating obesity is becoming an increasing priority due to dissatisfaction with high costs and hazardous side effects of anti-obesity drugs. This study was designed to investigate the anti-obesity properties of the Sabah brown seaweed, Sargassum polycystum, on body weight and blood plasma levels of rats fed a high-fat diet supplemented with different doses of the seaweed powder. Male Sprague Dawley rats were divided into five groups, representing control negative (CN) group, control positive (CP) group, low dosage group (LDG), medium dosage group (MDG) and high dosage group (HDG). The study duration was 8 weeks. All groups were fed high-fat diet throughout the study except for CN group, which was fed normal rat chow. LDG, MDG and HDG were supplemented high-fat diet with 2.5, 5.0 and 10.0 % seaweed powder, respectively. By comparing with the CP group, it was found that the HDG (10.0 % seaweed treatment diet) showed the greatest effect in suppressing weight gain, followed by the MDG (5.0 % seaweed treatment diet) and LDG (2.5 % seaweed treatment diet). The HDG decreased the levels of plasma total cholesterol and triglycerides. This finding shows that S. polycystum powder treatment had a positive effect on the inhibition of weight gain and has a promising value in preventing obesity.     

Influence of several feeds on bacteria in sheep and goat rumen liquor in vitro

Bacteriological studies were made with in vitro sheep and goat ruminal fluids supplemented with several feeds (alfalfa hay, wheat straw, Agave americana, Opuntia ficus indica and Atriplex nummularia) during anaerobic incubation at 38-39 degrees C. Drastic changes in the bacterial population of sheep ruminal fluids occurred in the presence of different feeds, particularly with addition of feeds of low nutritional quality (wheat straw, A. americana and O. ficus indica). However, the bacterial population in goat rumen liquor was little affected by the addition of the same feeds. These results, which suggest that the rumen bacteria in goats are less affected by different nutritional conditions than the rumen bacteria in sheep, are discussed.     

Effect of dietary cholesterol on erythrocyte peroxidant stress in vitro and in vivo

The effect of dietary variation of plasma cholesterol concentrations on the susceptibility of erythrocytes to in vitro and in vivo peroxidant stress was studied in rats. Malonyldialdehyde, produced in vivo (endogenous malonyldialdehyde) or following in vitro exposure of cells to 10 mM H2O2 (H2O2 malonyldialdehyde), was used as a measure of peroxidant stress. After 5 weeks, the plasma cholesterol concentrations in rats receiving 1.2% cholesterol + 0.6% cholic acid in their diet rose to 6-times that of control rats receiving a diet without added cholesterol; at the same time, erythrocyte H2O2 malonyldialdehyde in the cholesterol-fed rats decreased significantly relative to the control rats. During subsequent exposure of both groups to in vivo peroxidant stress with phenylhydrazine in two separate dose trials, erythrocyte peroxidant stress remained significantly lower in the cholesterol-fed rats: at a dose of 100 mumol/100 g body weight, H2O2 malonyldialdehyde was lower; at a dose of 25 mumol/100 g body weight, both endogenous and H2O2 malonyldialdehyde were lower. Erythrocyte membrane cholesterol concentrations were 12% higher in the cholesterol-fed rats than in controls. The effects of in vivo peroxidant stress on plasma cholesterol were also studied. In vivo peroxidant stress at the higher dose of phenylhydrazine produced a decrease in plasma cholesterol concentrations of control rats. The lower dose had no effect on this group and the plasma cholesterol concentrations were unchanged in the cholesterol-fed rats during both treatments. The data suggest that elevated plasma cholesterol concentrations are protective against erythrocyte peroxidant stress. The mechanism of cholesterol's protective effect is probably mediated through elevated membrane cholesterol concentrations.     

Dietary tyrosine supplementation enhances weight gain in streptozotocin-diabetic rats

The effect of dietary protein concentration and tyrosine supplementation on growth in streptozotocin (65 mg/kg, ip) diabetic rats was evaluated. When rats were fed diets ranging from 15 to 60% protein, weight gain and feed efficiency were greatest in rats fed the 45% protein diet. Adding tyrosine to this diet (8%, incorporated as a percentage of protein) did not promote further weight gain relative to nonsupplemented diabetic animals. In contrast, rats choosing 45% of total calories as protein by selecting from 10 and 60% protein diets supplemented with either 0, 4, or 8% tyrosine demonstrated a 35% (4% tyrosine) to 45% (8% tyrosine) increase in weight gain. Proximate analysis indicated similar body composition in tyrosine supplemented and nonsupplemented diabetic animals. Including tryptophan (1.45%) with tyrosine in the self-selection diet was without effect. Thus, tyrosine supplementation promoted a modest but consistent and specific increase in weight gained by self-selecting diabetic rats.     

Effects of Phytic Acid and Exercise on Some Serum Analytes in Rats Orally Exposed to Diets Supplemented with Cadmium

Cadmium is an environmental pollutant of increasing worldwide concern. It has been reported to be high in the soil where food crops are grown in some parishes of Jamaica. Surprisingly, no adverse effect of cadmium has been reported among the Jamaican population. However, phytic acid has also been shown to be high in some food crops grown in Jamaica. In this study, we evaluated the effects of phytic acid (1 %) and exercise on the metabolism of cadmium (5 mg cadmium/kg body weight) in rats. Five groups of rats were fed as follows: rats fed control diet, control diet supplemented with cadmium and subjected to exercise, control diet supplemented with phytic acid plus cadmium and subjected to exercise, control diet supplemented with cadmium plus phytic acid, and control diet supplemented with cadmium only. The animals were fed for 4 weeks and then sacrificed. Blood samples were collected for some biochemical assays. Percentage weight loss (28.42 %) was greatest in the group that had cadmium supplement only. The group fed control diet supplemented with cadmium only displayed increased liver enzymes and electrolytes except for the significant decrease in bicarbonate compared to other test groups. Similarly, blood urea nitrogen and uric acid were increased in the group fed cadmium supplement only compared to other test groups. Total cholesterol trended downwards in the test groups compared to control. These observations suggest that consumption of diet high in phytic acid with relatively high physical activity may be protective against the adverse effects of cadmium.     

Myofibrillar protein turnover and urinary N-tau-methylhistidine output. Response to dietary supply of protein and energy.

The urinary excretion of total N-tau-methylhistidine by the growing rat was measured to evaluate the effects of dietary protein and energy restriction on muscle protein turnover in vivo. 2. Young male rats (about 100 g initial wt.) were fed on one of three diets. Group I (controls) received an adequate 18% lactalbumin diet for 28 days, on which they sustained maximum growth. Group II (protein-depleted) was fed for 14 days on 0.5 lactalbumin diet, which caused loss of weight; this was followed by repletion for 14 days with the control diet. Group III (protein-energy restricted) received a 1% lactalbumin diet at one-half the food intake of group II for 14 days, and this was also followed by 14 days of repletion with the control diet. 3. The controls showed a progressive rise in the daily urinary output of N-tau-methylhistidine, which was proportionally slightly less rapid than the body-weight increase. 4. The protein-depleted group II showed a marked and progressive decrease in N-tau-methylhistidine excretion, which was proportionally greater than the fall in body weight; during repletion, N-tau-methylhistidine output rose in parallel with body-weight increase, but it did not reach the value attained by the control group. 5. Group III, restricted in both dietary protein and energy, showed an initial small increase in daily N-tau-methylhistidine output, which contrasted with the sharp loss of body weight during this period. After 11 days on this restricted diet, group III then underwent a decrease in N-tau-methylhistidine output, which persisted into the first 4 days of the repletion period, after which output of the methylated amino acid became the same as for group II. 6. Creatinine output, used as an additional metabolic measure of muscle metabolism, showed a fairly constant relationship to body weight in groups I and II during depletion and repletion. However, rats with protein-energy deficiency (group III) underwent a marked increase in output of creatinine per unit of body weight, which also persisited into the repletion period before it fell to more normal values relative to body weight. 7. Analysis of the N-tau-methylhistidine content of actin isolated from a group of protein-depleted rats revealed a small (5%) but significance (P less than 0.02) decrease relative to well-nourished controls. 8. Hence, the rate of muscle protein degradation, as indicated by changes in urinary N-tau-methylhistidine output, appears to respond sensitively and in opposite directions to insufficiency of protein of energy in the diet.     

Effect of corticosterone and protein malnutrition on muscle protein breakdown in vivo in rats as measured by the urinary excretion of 3-methylhistidine

The role of corticosterone in regulating the rate of muscle protein breakdown was evaluated by measuring the urinary excretion of 3-methylhistidine (3-Mehis) during the administration of 0.0 (vehicle), 0.8 (physiological dose) and 10 (pharmacological dose) mg of the glucocorticoid/100 g body weight/day to adrenalectomized rats (AdX, AdX 0.8 and AdX 10 respectively). A fourth group of intact rats receiving only vehicle (In) was included as control. Rats were fed on either adequate protein and energy (Co) or low-protein (1-P) diets, for eight consecutive days. No differences were found between AdX and AdX 0.8 groups as compared to the In group in regard to body and liver weights. The AdX 10 group exhibited a significant reduction in body weight and a considerable increase in liver weight; these results were found in rats fed on the Co and 1-P diets, although rats on the 1-P diet showed a proportional decrease in those parameters as compared to the rats fed on the Co diet. Gastrocnemius, tibialis and E.D.L. muscle weights were significantly reduced in AdX 10 group, approximatley at the same extent in the two dietary groups. Soleus muscle weight increased in the AdX 10 group, at the same extent in the two dietary groups, as compared to the In group. Plasma corticosterone levels were significantly greater in the AdX 10 group in both dietary treatments, though restriction of protein in the diet induced a higher plasma hormone level than that of the Co group. Urea-N and creatinine outputs were significantly higher in the AdX 10 group. 3-Mehis excretion underwent an immediate and significant rise in the AdX 10 group, although rats fed on 1-P diet showed a more persistent rise than those fed on the Co diet. No differences were found among the other groups. It is concluded that high plasma corticosterone levels can accelerate muscle protein breakdown and that this action is not seriously affected by the protein content of the diet.     

Reducing effect of feeding powdered scallop shell on the body fat mass of rats

The lipolytic effect of powdered scallop shells was estimated in vitro and in vivo. The scallop shells consisted of 98% calcium carbonate and 2% organic compounds, the extracted organic components promoted lipolysis in 3T3-L1 adipocyte cells. Male Wistar rats were fed on an experimental diet containing either the scallop shell powder or calcium carbonate (control) for 28 d. Feeding the scallop shell powder resulted in a decrease in body weight and in the weight of white adipose tissue. While the organ weights of the liver, kidney, testis, pancreas, and spleen, and of the brown adipose tissue relative to the body weight were no different between the scallop shell powder diet and control diet, the white adipose tissue weight relative to the body weight significantly decreased in the rats fed on the scallop shell powder. The glycerol concentration in the serum increased in the rats fed on the scallop shell powder, suggesting that this promoted lipolysis in the adipose tissue. These results show that the organic components in the scallop shells induced the decrease in weight of the adipose tissue due to the promotion of lipolysis.     

Effect of samh seeds supplementation (Mesembryanthemum forsskalei Hochst) on liver enzymes and lipid profiles of streptozotocin (STZ)-induced diabetic Wistar rats

Thirty streptozotocin (STZ)-induced diabetic of Wistar Albino rats were divided into five groups. The rat groups received different food (natural diet or high fat content diet) supplemented with 10% or 15% of samh seeds for 6 weeks. At the end of the study, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phophatase (ALP) and lactate dehydrogenase (LDH) enzymes have been measured in diabetic rats liver. In addition, liver lipid profile (total cholesterol (TC), triglyceride (TAG), lipid peroxide production malondialdehyde (MDA)) and reduced glutathione (GSH) in have been measured in diabetic rats liver, and the levels of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) were also determined. The samh seeds diet supplemented with cholesterol significantly increase (P < 0.05) the levels of liver peroxide production MDA, TC and TG in diabetic rats comparing to the samh diet not supplemented with the cholesterol. However, the samh seeds significantly decrease (P < 0.05) the level of GSH. These data suggest that the samh seeds diet not supplemented with the cholesterol regulated C and TG metabolism and decrease the lipid peroxidation in the diabetic rats.     

Antioxidant and hypolipidaemic properties of red seaweed,Gracilaria changii

The edible red seaweed, Gracilaria changii, was collected from the coastal area of Sarawak, Malaysia, and evaluated for its hypolipidaemic properties using high cholesterol/high fat (HF) induced male Sprague–Dawley rats. In the in vivo study, the HF diet group showed significantly higher total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), atherogenic index (AI) and body weight gain as compared to other treatment groups. At the end of treatment period, rats fed with a HF diet supplemented with 5 % freeze-dried G. changii powder had significantly reduced plasma TC (?39.19 %), LDL-C (?36.36 %), and triglycerides (TG) content (? 25.45 %). Meanwhile, 10 % seaweed powder significantly lowered the plasma TC, LDL-C and TG content by ?40.34, ?35.95 and ?30.91 % respectively, compared to the HF group. The AI of rats supplemented with 10 % seaweed powder was the lowest among the treatment groups and indicates a lowered risk for cardiovascular diseases. The plasma lipid peroxidation of the seaweed powder-fed groups was also significantly lower than the HF group, while the erythrocyte enzyme antioxidant activities of superoxide dismutase, catalase and glutathione peroxidase of the treatment groups were also improved. Diets supplemented with seaweed powder also decreased plasma aspartate aminotransferase and the alanine aminotransferase levels.     

Dietary supplementation with Agaricus blazei murill extract prevents diet‐induced obesity and insulin resistance in rats

Objective:

Dietary supplement may potentially help to fight obesity and other metabolic disorders such as insulin‐resistance and low‐grade inflammation. The present study aimed to test whether supplementation with Agaricus blazei murill (ABM) extract could have an effect on diet‐induced obesity in rats.

Design and Methods:

Wistar rats were fed with control diet (CD) or high‐fat diet (HF) and either with or without supplemented ABM for 20 weeks.

Results:

HF diet‐induced body weight gain and increased fat mass compared to CD. In addition HF‐fed rats developed hyperleptinemia and insulinemia as well as insulin resistance and glucose intolerance. In HF‐fed rats, visceral adipose tissue also expressed biomarkers of inflammation. ABM supplementation in HF rats had a protective effect against body weight gain and all study related disorders. This was not due to decreased food intake which remained significantly higher in HF rats whether supplemented with ABM or not compared to control. There was also no change in gut microbiota composition in HF supplemented with ABM. Interestingly, ABM supplementation induced an increase in both energy expenditure and locomotor activity which could partially explain its protective effect against diet‐induced obesity. In addition a decrease in pancreatic lipase activity is also observed in jejunum of ABM‐treated rats suggesting a decrease in lipid absorption.

Conclusions:

Taken together these data highlight a role for ABM to prevent body weight gain and related disorders in peripheral targets independently of effect in food intake in central nervous system.     

Effect of a Low-Protein Diet Supplemented with Ketoacids on Skeletal Muscle Atrophy and Autophagy in Rats with Type 2 Diabetic Nephropathy

A low-protein diet supplemented with ketoacids maintains nutritional status in patients with diabetic nephropathy. The activation of autophagy has been shown in the skeletal muscle of diabetic and uremic rats. This study aimed to determine whether a low-protein diet supplemented with ketoacids improves muscle atrophy and decreases the increased autophagy observed in rats with type 2 diabetic nephropathy. In this study, 24-week-old Goto-Kakizaki male rats were randomly divided into groups that received either a normal protein diet (NPD group), a low-protein diet (LPD group) or a low-protein diet supplemented with ketoacids (LPD+KA group) for 24 weeks. Age- and weight-matched Wistar rats served as control animals and received a normal protein diet (control group). We found that protein restriction attenuated proteinuria and decreased blood urea nitrogen and serum creatinine levels. Compared with the NPD and LPD groups, the LPD+KA group showed a delay in body weight loss, an attenuation in soleus muscle mass loss and a decrease of the mean cross-sectional area of soleus muscle fibers. The mRNA and protein expression of autophagy-related genes, such as Beclin-1, LC3B, Bnip3, p62 and Cathepsin L, were increased in the soleus muscle of GK rats fed with NPD compared to Wistar rats. Importantly, LPD resulted in a slight reduction in the expression of autophagy-related genes; however, these differences were not statistically significant. In addition, LPD+KA abolished the upregulation of autophagy-related gene expression. Furthermore, the activation of autophagy in the NPD and LPD groups was confirmed by the appearance of autophagosomes or autolysosomes using electron microscopy, when compared with the Control and LPD+KA groups. Our results showed that LPD+KA abolished the activation of autophagy in skeletal muscle and decreased muscle loss in rats with type 2 diabetic nephropathy.     

Serum and gene expression levels of leptin and adiponectin in rats susceptible or resistant to diet-induced obesity

The aim of the present study was to identify the role of leptin and adiponectin in the development of resistance or susceptibility to diet-induced obesity in rats. For this purpose, male Wistar rats were fed with standard laboratory diet (control group) or cafeteria diet. After 15 days, two groups of rats with different response respect to the cafeteria diet were identified, and were assigned as diet-induced obesity (DIO) and diet resistant (DR) rats. The high-fat diet induced a very significant increase in both body and fat mass weight in DIO group. However, DR rats, gained even less weight than control-fed animals. Food intake was increased in cafeteria-fed rats (both DIO and DR) in comparison to control group; but hyperphagia was higher in DIO rats. In addition, feed efficiency (the ratio of weight gained to calories consumed) was significantly decreased in DR as compared to DIO rats. Regarding leptin, a significant increase in both adipose tissue gene expression and serum levels was observed in DIO rats in comparison with other groups (control and DR). A significant increase in both adiponectin circulating levels and adipose tissue mRNA expression was also observed in DIO animals as compared with the other groups. These data suggest that the susceptibility to obesity of DIO rats might be secondary, at least in part, to an earlier development of leptin resistance, which could lead to alterations in food intake (hyperphagia) and energetic metabolism. However, neither changes in leptin or adiponectin seem to be involved in the adaptive mechanisms that confer resistance to high fat intake.     

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.