Relationship between the effect of dietary fat on swimming endurance and energy metabolism in aged mice.

AIM: The aim of this study was to investigate the effect of different dietary fats on alterations in endurance, energy metabolism, and plasma levels of interleukin-6 (IL-6) and minerals in mice. METHOD: Male mice (aged 58 weeks) were fed diets containing 6% safflower oil, fish oil, or lard for 12 weeks. Swimming time to exhaustion, energy metabolism, and plasma IL-6 levels were subsequently determined. RESULTS: Mice fed safflower oil exhibited a marked increase in swimming time compared to the baseline level. Mice fed lard exhibited a significant decrease in swimming time, while mice on a fish oil diet exhibited a small decrease in swimming time. The final swimming time of mice fed safflower oil was significantly longer than that of animals fed lard. This improvement in endurance with dietary safflower oil was accompanied by decreased accumulation of lactate and less glycogen depletion during swimming. In the safflower oil group, muscle carnitine palmitoyltransferase activity increased significantly after swimming, while the plasma non-esterified fatty acid concentration decreased significantly. A trend to increased plasma IL-6 levels was observed in sedentary animals on a safflower oil diet compared to those on a lard diet. CONCLUSIONS: These results suggest that dietary safflower oil improves the swimming endurance of aged mice to a greater extent than lard, and that this effect appears to involve glycogen sparing through increased fatty acid utilization.

The effect of methanol extracts of tsao-ko (Amomum tsao-ko Crevost et Lemaire) on digestive enzyme and antioxidant activity in vitro, and plasma lipids and glucose and liver lipids in mice.

Our previous study showed that tsao-ko intake can lower plasma and liver triacylglycerol (TG) concentrations and has hypoglycemic and antioxidant activity in mice. This study involved separating two major fractions (A and B) from the methanol extracts (MeX) of tsao-ko using silica gel column chromatography, and then determining the effect of the fractions in vivo and in vitro to clarify the most effective components of tsao-ko. An intake of MeX and A fraction statistically significantly reduced body lipids and plasma thiobarbitutic acid reactive substances (TBARS) concentrations compared with the control and inhibited lipase and alpha-glucosidase activities. These reductions were not observed in mice fed the B fraction and these inhibitions of B fraction were mild compared with MeX and A fraction. The plasma and liver TG concentrations of each fraction group did not show significant differences compared with the control. The [M-H](+) and maximum UV absorption of the A fraction were 291 m/z and 279 nm, respectively. The peak of A fraction appeared at a similar time to the epicatechin standard in the LC/MS/MS analysis and the MS/MS spectrum of the A fraction was similar to that of the epicatechin standard. It was concluded that the most effective component of tsao-ko for body lipid reduction and hypoglycemic and antioxidant activity was contained in the polar fraction and the evidence suggested that this component could be epicatechin. However, the strongest TG lowering components of tsao-ko may be methanol insoluble.

A comparative study of the effects of erabu sea snake (Laticauda semifasciata) lipids, green tea extract and conjugated linoleic acid on the swimming endurance of mice.

The aim of this study was to assess the interaction between physical and biochemical parameters in mice fed 1 % sea snake lipids (SSL) and compare these with animals fed diets containing 0.2 % green tea extract (GTE) or 0.5 % conjugated linoleic acid (CLA). The swimming times of the SSL group were significantly increased at Weeks 12 and 16 (p<0.001), and those of the GTE group, at Week 12 (p<0.005), but not those of the control or CLA group, compared with those at Week 0. The increase tended to be significant in the SSL group compared with the control group at Week 12 (p=0.09). Both the SSL and GTE groups had significantly longer swimming times than the CLA group at Weeks 12 and 16 (p<0.001). After 5 minutes of swimming exercise, the SSL group exhibited significantly lower levels of plasma and muscle lactates (p<0.01), and plasma non-esterified fatty acid (NEFA) (p<0.001) than the control group. There were no significant differences in any of plasma glucose, muscle and liver glycogens, muscle lactate dehydrogenase (LDH), carnitine palmitoyltransferase (CPT), or monocarboxylate transporter 1 (MCT1) between SSL and control groups. The results suggest that the intake of 1 % SSL improved endurance more than the intake of 0.2 % GTE or 0.5 % CLA in mice. This action may involve the promotion of lactate oxidation for utilization.

Effect of lipid extracted from tsao-ko (Amomum tsao-ko Crevost et Lemaire) on digestive enzyme activity, antioxidant activity, plasma and liver lipids, and blood glucose levels of mice.

Lipids extracted from tsao-ko were separated into three fractions with silica gel column chromatography and fed to mice (3 mo old) for 90 d to clarify their inhibitory activity on digestive enzyme activity. The diets contained the following: control--no tsao-ko, 0.05% total lipid of tsao-ko (TL), 0.0109% chloroform fraction (CF), 0.0245% acetone fraction (AF), or 0.00365% methanol fraction (MeF). Although CF and AF slightly inhibited the activities of alpha-glucosidase, alpha-amylase, and lipase, intakes of these fractions had little influence on plasma and liver lipid concentrations when compared with the control diet. MeF did not inhibit alpha-glucosidase but had DPPH radical scavenging activity and the mice fed this fraction had the most marked reduction in plasma glucose and TBARS concentrations compared with the other diet groups. These results suggest that the fat-soluble polar components of tsao-ko contain an active component that might be associated with decreased plasma glucose and TBARS concentrations in mice.

Effects of yogurt supplemented with fish oil on plasma lipid and glucose concentrations, and liver lipid contents in mice.

The aim of this study is to clarify the effects of yogurt supplemented with fish oil on plasma lipid and glucose concentrations, and hepatic lipid contents in mice. Male Crlj:CD-1 (ICR) mice were fed five experimental diets for 12 weeks. The experimental diets were as follows: without yogurt and fish oil (control diet); 10% (w/w) yogurt without fish oil [10% FO(-)]; 10% yogurt with fish oil [10% FO(+)]; 30% yogurt without fish oil [30% FO(-)]; 30% yogurt with fish oil [30% FO(+)]. Plasma triacylglycerol concentrations in the 10% FO(+) and 30% FO(-) groups were significantly lower than that in the control diet group (p < 0.05 and p < 0.05, respectively). Plasma total cholesterol and phospholipid concentrations were significantly lower in the 30% FO(+) group than in the control diet group (p < 0.005). Concentrations tended to be lower with supplementation with fish oil. Plasma glucose concentrations in the 10% FO(+) and 30% FO(+) groups were significantly lower than those in the control diet group (p < 0.005 and p < 0.01, respectively). Hepatic triacylglycerol and total cholesterol contents in the 30% FO(+) group were significantly lower than those in the control diet group (p < 0.05 and p < 0.005, respectively). These results suggest that plasma triacylglycerol and glucose concentrations are effectively decreased by supplementation of yogurt with fish oil.

Effects of simultaneous intakes of fish oil and green tea extracts on plasma, glucose, insulin, C-peptide, and adiponectin and on liver lipid concentrations in mice fed low- and high-fat diets.

AIMS: The purpose of this study was to clarify the effects of a simultaneous intake of fish oil and green tea extracts (GTE) on plasma lipids, glucose (Glu), insulin, C-peptide, and adiponectin concentrations and on liver lipids in mice fed low- and high-fat diets. METHODS: Male mice (5 months old) were fed low-fat (5%) or high-fat (20%) diets containing 0% (5 or 20% lard), 1% (4 or 19% lard) or 5% (0 or 15% lard) fish oil with or without 1% GTE for 3 months. RESULTS: Single or combined intakes of fish oil and GTE intakes significantly lowered plasma and liver total cholesterol (T-chol) and triacylglycerol (TG) concentrations in mice on high-fat diets. However, a positive effect of GTE alone was not observed in the plasma T-chol and TG concentrations of mice on low-fat diets. Plasma Glu concentrations were significantly lowered by dietary fish oil in mice on the low- and high-fat diets. A tendency of GTE intake to decrease plasma Glu in mice on both the low- and high-fat diets was not significant. An intake of GTE only minimally influenced plasma insulin, C-peptide, and adiponectin concentrations, but fish oil supplementation increased the adiponectin concentration in mice on the low- and high-fat diets. GTE addition to the diets had no adverse effects on reductions by fish oil. CONCLUSION: These results suggest that a simultaneous intake of fish oil and GTE can improve plasma and liver lipid and plasma Glu profiles in mice fed a high-fat diet without any negative interactions of fish oil and GTE.

Dietary phosphatidylcholine improves maze-learning performance in adult mice.

The effect of phosphatidylcholine (PC) on maze-learning performance was investigated in adult mice. Three-month-old mice were given a semipurified diet of 1%, 2.5%, or 5% PC over a period of 4 months, with their maze-learning ability assessed beginning at 3 months after the start of the experiment and again 4 and 8 days later. This entailed the measurement of the time required by the mice to reach the maze exit and counting the number of times that mice strayed into blind alleys in the maze. During trial 1, mice in the 5% PC diet group required significantly less time to reach the maze exit compared with the control group (P < .05), while mice in the 1% and 2.5% PC dietary groups tended to require a shorter time to find the exit, but the differences were not significant. The number of times that mice strayed into blind alleys in the maze was significantly fewer in the 2.5% and 5% PC diet groups than in the control group during trial 1 (P < .05). The PC diets increased the percentages of docosahexaenoic and arachidonic acids in serum but had a lesser effect on brain fatty acid composition. These results suggest that the intake of 5% PC diet improves learning ability in adult mice and that the improved brain function may be related to the provision of choline.

Levels of plasma insulin, leptin and adiponectin, and activities of key enzymes in carbohydrate metabolism in skeletal muscle and liver in fasted ICR mice fed dietary n-3 polyunsaturated fatty acids.

The aim of this study was to clarify the mechanisms related to plasma glucose concentration in mice fed a diet rich in n-3 polyunsaturated fatty acids (n-3 PUFAs). Male Crlj:CD-1 (ICR) mice were fed experimental diets containing 6% lard (LD), 6% fish oil (FO) or 4.1% lard plus 1.5% docosahexaenoic acid ethyl ester and 0.4% eicosapentaenoic acid ethyl ester (DE) for 12 weeks. There were no marked differences in plasma glucose and insulin concentration changes on glucose tolerance test between the three dietary groups. At the end of the feeding trial, plasma glucose concentration was significantly lower in fasted mice in the FO group than in those in the LD group (P<.005). Plasma adiponectin concentration was significantly higher in the FO group than in the LD group (P<.05). Hexokinase, phosphofructokinase, glucose-6-phosphate dehydrogenase and glycerophosphate dehydrogenase activities in skeletal muscle tended to be lower in the FO group than in the LD group, while there were no differences in glucokinase and phosphofructokinase activities in liver between the three dietary groups. However, hepatic glycerophosphate dehydrogenase activity was 53-fold and 4.2-fold higher in the FO group than in the LD and DE groups, respectively (P<.0005 and P<.05, respectively). These results suggest that the reduction in plasma glucose concentration in mice fed n-3 PUFAs is mainly caused by acceleration of glucose uptake and glycerol synthesis in the liver rather than in the skeletal muscle.

Effect of lipids extracted from a salted herring roe food product on maze-behavior in mice.

Male mice (11 mo old) were fed 5% lard, fish oil, or Kazunoko (salted fish roe product) lipids for 4 mo to investigate their effects on maze behavior. The time required and distance traveled to reach the maze exit, and number of times that a mouse strayed into blind alleys in the maze, and the fatty acid compositions of brain lipids after the maze-behavior experiment were measured. The Kazunoko lipid group showed a significant improvement in all three parameters compared with the lard diet group, but the fish oil group showed only a significant decrease in the number of times that a mouse strayed into blind alleys compared with the lard diet group. The mice in the fish oil and Kazunoko lipid groups had significantly lower levels of arachidonic acid and higher percentages of docosahexaenoic acid in brain lipids compared with animals in the lard group. The mice in the Kazunoko lipid group had significantly lower levels of arachidonic acid in brain lipids than those in the fish oil group but the percentages of docosahexaenoic acid were not significantly different between these two diet groups. Our results suggest that an intake of Kazunoko lipids may suppress the percentage of n-6 fatty acids in brain lipids and this diet can be even more effective than fish oil as a supplement to improve learning capacity in mice.

Effects of Western, Vegetarian, and Japanese dietary fat model diets with or without green tea extract on the plasma lipids and glucose, and liver lipids in mice. A long-term feeding experiment.

BACKGROUND/AIMS: The purpose of this study was to investigate the long-term effects of three model diets containing different fats, with or without a small amount of green tea extract (GTE), on plasma lipids and glucose, and liver lipids in mice. METHODS: Male mice (2 months old) fed 10% fat diets with Western (W), Vegetarian (V), and Japanese (J) fat compositions with or without 0.03% GTE for 7 months. RESULTS: The concentrations of plasma and liver total cholesterol in animals fed the W diet were not significantly different from those fed the J diet. Plasma triacylglycerol (TG) concentrations were significantly different from one another in the following order: V > J > W diet groups. GTE supplementation significantly reduced plasma and liver TG content only in V diet group. Plasma glucose (Glu) concentrations were in the following order: W > V > J diet groups, and the GTE supplementation reduced the concentration of Glu in each diet group. The ratios of plasma n-6 to n-3 fatty acids were in the following order: V > W > J diet groups, regardless of GTE supplementation. CONCLUSION: These findings show the possibility that Japanese eating habits combined with drinking green tea might be a factor in preventing the onset of non-insulin-dependent diabetes mellitus.

Effects of rice starch-isoflavone diet or potato starch-isoflavone diet on plasma isoflavone, plasma lipids, cecal enzyme activity, and composition of fecal microflora in adult mice.

The effects of rice starch-isoflavone diet or potato starch-isoflavone diet on plasma concentration of isoflavones, plasma lipids, cecal enzyme activity, and intestinal microflora were studied. Male 15-wk-old mice were fed a rice-starch-based or potato-starch-based diet supplemented with isoflavones for 4 wk, and plasma samples, cecal contents, and feces were collected individually. Plasma equol concentration was significantly higher in the potato-isoflavone diet group than in the rice-isoflavone diet group, but no significant difference was observed in plasma daidzein or genistein concentrations. Plasma total cholesterol concentration was higher in the potato-isoflavone diet group, but no significant difference was observed in plasma triglyceride concentration. Both cecal beta-glucuronidase and beta-glucosidase activities were significantly higher in the rice-isoflavone diet group. The number of bifidobacteria was significantly higher in the potato-isoflavone diet group. These results indicate that different types of starches have different influences on plasma isoflavone and suggest that the influences might be through the change of host physiology and/or the metabolism and composition of intestinal microflora.