• The Korean Journal of Community Living Science
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• v.15 no.4
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• pp.89-96
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• 2004

This study is to investigate the effect of dietary mixed protein and L-carnitine supplementation on lipid metabolism in the rats fed high fat diet. Six experimental groups were organized and each group had eight Sprague-Dawley male white rats with the initial weight of around 180g. The six experimental groups were CO(supplemented with casein), CC(supplementedwith casein and cartinine), ISO(supplemented with isolated soy protein), ISC(supplemented with isolated soy protein and cartinine), CIM(supplemented with casein and isolated soy protein), and CIC(supplemented with casein, isolated soy protein and cartinine). Each group was supplemented with the experimental diet for four weeks, and carnitine contained 3efo of the diet. The results were as follows; 1. There was no significant difference in food intake among the experimental groups. The weight increased more significantly in the group supplemented with the mixed protein than in the group supplemented with casein(p<0.05).2. There was weight reduction effect by the supplementation of carnitine(p<0.05), however no weight reduction effect by the supplementation of carnitine was observed in the group supplemented with the mixed protein and isolated soy protein. 3. Food efficiency was lower in the group supplemented with the mixed protein than in the group supplemented with casein (p<0.05), however it was similar in the group supplemented with isolated soy protein.4. Serum total lipid and se겨m total cholesterol were lower in the group supplemented with mixed protein than in the group supplemented with casein(p<0.05). 5. There was no significant difference of serum triglyceride, HDL-cholesterol, and LDL-cholesterol among the experimental groups. 6. Liver triglyceride was the highest in the group supplemented with mixed protein (p<0.05), and there was no significant difference of liver total lipid and total cholesterol among the experimental groups. 7. In the groups supplemented with mixed protein, the level of liver TBARS showed the lowest when casein was supplemented(p<0.05), and there was no significant difference of GSH-Px activities among the experimental groups. In summary, when mixed protein was supplemented to the rats weight gain and food efficiency were similar with those in the group supplemented with isolated soy protein, however they were lower than those in the group supplemented with casein. The effect of carnitine on weight was not observed in the group supplemented with mixed protein and isolated soy protein, however it was observed in the group supplemented with casein. Serum Total lipid and total cholesterol were lower than those in the group supplemented with casein. Liver total triglyceride was high in the group supplemented with mixed protein, and the antioxidant effect was observed in the group supplemented with mixed protein.

• Korean Journal of Rural Living Science
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• v.6 no.1
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• pp.31-39
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• 1995

This study was performed to observe how soy protein and calcium in rats fed unsaturated fat-enriched diet affect the total lipid and cholesterol contents of blood and tissues male Sprague-Dawley rats weighing approximately 220g were fed four purified diets which contained 18% (w/w) corn oil, 1% (w/w) cholesterol, two sources of protein : casein or isolated soy protein (ISP) and two levels of dietary calcium : 0.1% or 1.0%, first for four weeks (Expt. 1) and second for eight weeks (Expt. 2). The contents of total lipid, cholesterol and triglyceride in blood, liver, heart and feces were determined. After four weeks feeding, the serum lipid and cholesterol concentration was not significantly different among the groups. After eight weeks feeding, these concentrations were significantly lower in ISP-High calcium group. The serum lipid concentration was influenced by dietary protein sources and calcium levels. These results indicated that the hypolipidemic effects of soy protein and high calcium intake were partly due to decrease in lipid absorption and these effects were not detected at 4 weeks feeding but 8 weeks feeding.

• Journal of Community Nutrition
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• v.6 no.1
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• pp.48-54
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• 2004

The purpose of this study was to examine the effects of dietary protein and exercise on bone mineral density and bone mineral content of growing male rats. Forty male, Sprague-Dawley rats(age 21 days) were assigned to four groups that underwent 9 weeks of experimental treatment. Animals were assigned to one of two exercise treatments (treadmill running or sedentary). The exercise and nonexercise group were fed a diet containing casein or soy with rich isoflavones (3.4mg/g protein). The exercise group ran on a rodent treadmill(speed of 15m/min for 30min) three days per week during the 9-week study period. All rats were fed an experimental diet and deionized water ad libitum for 9 weeks. Total bone mineral density (BMD), total bone mineral content (BMC), total body calcium, spine BMD and BMC, and femur BMD and BMC were determined by using dual energy x-ray absorptiometry (FIXI-mus, GE Lunar Radiation Cooperation, Madison, WI, USA). The soy diet group appears to have a significantly higher total BMD/weight and total BMC/ weight, spine BMD/weight, spine BMC/weight, femur BMD/weight and femur BMC/weight compared to the casein group in nonexercise and exercise. The exercise group had significantly greater total BMD/weight and BMC/ weight, spine BMD/weight and BMC/weight, femur BMD/weight and BMC/weight compared to the nonexercise group when the protein source was casein. The exercise combined soy group had significantly greater total BMD/weight and BMC/weight, spine BMD/weight and BMC/weight, femur BMD/weight and BMC/weight, compared to the exercise combined casein group. The results indicate that exercise had a positive influence on bone mineral density and bone mineral content and soy significantly affect on bone mineral density and bone mineral content for the 9 weeks experimental period. It can be concluded that exercise combined with a soy diet is most beneficial for acquisition of spine bone mineral density in young growing male rats. This convincing evidence suggests that a change in life style such as increasing exercise and consumption of soy protein is a practical strategy for significantly reducing the incidence of osteoporosis.

• Journal of Nutrition and Health
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• v.15 no.2
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• pp.119-128
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• 1982

The effect of dietary protein on growth and lipid levels of plasma and liver was studied in weanling male rats fed diets differing protein sources and amino acid balance. Rats were devided into 9 experimental diets which were grouped into 3 categories ; 1) Simple protein category includes gluten-, soy protein isolate-, and casein-containing diet groups, 2) Supplemented category includes casein supplemented with methionine, soy protein isolate supplemented with methionine, and gluten supplemented with lysine and methionine, 3) Mixed protein category includes diet groups containing gluten (2/3), casein (1/3), soy protein isolate (2/3) and casein (1/3), and casein (1/3), soy protein isolate (1/3) and gluten (1/3). The experimental diets composed of 15% protein, 65.8% carbohydrate, 10% fat and 1% cholesterol. The body wt. gain and P.E.R. were greater in rats of supplemented and mixed protein groups than simple protein groups. No statistical differences were found in plasma cholesterol among gluten, soy protein isolate and casein groups. Consumption of diets supplemented with limiting amino acid to gluten or soy protein isolate reduced the plasma cholesterol level by 23.2% and 34.2% respectively. However there was no difference between casein and the supplemented casein groups. The mixed protein groups shows relatively high plasma cholesterol concentration and low liver cholesterol levels. On the other hand gluten group showed low plasma cholesterol and high liver cholesterol levels, which means body cholesterol pool may not have been changed by the dietary protein. Feeding soy protein meal and the supplemented soy protein isolate resulted in lower plasma cholesterol, plasma triglycerides, liver cholesterol and liver triglycerides levels. This hypolipidemic effect is considered to see unique to soy protein isolate. Rats in gluten and the supplemented gluten groups showed lower plasma protein levels and a tendency of fatty liver.

• Preventive Nutrition and Food Science
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• v.7 no.3
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• pp.278-281
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• 2002

The objective of the current study was to determine the influences of dietary proteins and methionine on plasma lipid concentrations. Thirty growing male Sprague-Dawley rats were fed diets similar in all respects except that dietary protein was from either casein, soy protein isolate, or soy protein isolate supplemented with L-methionine (0.24 %). The animals were fed experimental diets ad libitum for nine weeks. Plasma total-cholesterol concentrations were unaffected by the protein source or methionine supplementation. Plasma triglyceride concentrations were lower in rats of methionine supplemented soy protein diets (76 mg/dL) than in the rats fed casein or soy diet (120 mg/dL, 109 mg/dL, respectively). These results indicate that soy protein reduces plasma triglycerides relative to casein in rats fed cholesterol free diets, and that methionine-supplemented soy diets decrease plasma triglyceride concentrations more than soy protein alone.

• Journal of Nutrition and Health
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• v.22 no.6
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• pp.516-530
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• 1989

A 44-day metabolic study was conducted to compare the effects of soy protein and meat protein on N, Ca, P, and Mg metabolism in young Korean males. Meat protein diet(MPD) and soy protin diet(SPD) were provided for 3 weeks each. For MPD, meat protein Supplied 50.3% of total protein and mean daily suplies of Ca, P, and Mg were 33.28mg, 1013.01mg, 226.81mg respectively. For SPD, soy protein supplied 51.8% of total protein and mean contents of Ca, P and Mg were 737.86mg, 1261.76mg, and 451.3mg. Mean daily fecal and urinary excretions of Ca were 350.6mg and 113.3mg for MPD and 515.0mg and 118.3mg for SPD. Apparent absorption rates in MPD and SPD were 4.2mg in MPD and 700.4mg and 475.1mg SPD. Apparent absorption rates were 65.6% in MPD and 44.5% in SPD(p<0.01). For Mg, fecal and urinary excretions were 144.8mg and 81.2mg in MPD and 292.4mg and 65.5mg in SPD. Apparent absorption rates were 37.5% in MPD and 35.2% in SPD. The correlations between urinary Ca, P, and their balance were significant (p<0.001) in MPD, but not in SPD. Urinary Ca was significantly correlated with urinary N, P, Mg(p<0.001) in MPD, but not in SPD. From these results, meat protein seems to increase the excretions of major minerals compared to soy protein.

• Korean Journal of Poultry Science
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• v.22 no.1
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• pp.43-54
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• 1995

Effects of dietary protein sources and their amino acid compositions on the liver and plasma cholesterol levels in growing Single Comb white Leghorn male chicks were studied. A diet containing isolated soy protein (21% cp) was supplemented with 0.5% DL-methionine and 0.3% L-glycine. and another diet containing casein(21% cp) was supplemented with 1.5% L-arginine HCl, 0.4% DL-methionine. and 1.0% L-glycine. Plasma cholesterol level was markedly lower in groups force-fed the diets containing either soy protein or casein supplemented with amino acids compared to those found in birds fed corresponding diets without amino acids supplementation. The cholesterol lowering effect of the casein diet. when balanced with various supplemental amino acids appeared to be due to arginine instead of methionine or glycine. It is likely that amino acid balance rather than the composition of a specific amino acid is one of the major factors determining the effect of dietary protein sources on the blood cholesterol levels in chicks.

• The Korean Journal of Community Living Science
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• v.15 no.3
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• pp.113-120
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• 2004

This study is to investigate the effect of dietary L-carnitine supplementation on lipid metabolism in rats fed with isolated soy protein and casein for their source of protein. Four experimental groups were organized and each group had eight Sprague-Dawley male rats with the initial weight of around 180g. The four groups were CO (casein only supplemented group); CC (casein and 3% L-carnitine supplemented group); ISO (isolated soy protein only supplemented group); ISC (isolated soy protein and 3% L-carnitine supplemented group). All groups were supplemented with the experimental diet for four weeks and carnitine comprised 3% of. their diet. The results were as follows; 1. There was no significant difference in food intake among the groups. 2. Final weight gain was significantly lower in the groups supplemented with isolated soy protein than in the groups supplemented with casein (P<0.05). The groups with supplemented casein and carnitine showed the effect of weight reduction (p<0.05). 3. Food efficiency ratio was lower in the groups supplemented with isolated soy protein than in the groups supplemented with casein (p<0.01). The groups supplemented with casein and carnitine showed low food efficiency ratio. 4. The serum total lipid was higher in the groups supplemented with casein than in the groups supplemented with isolated soy protein (p<0.05). 5. Serum total cholesterol was higher in the groups supplemented with casein than in the groups supplemented with isolated soy protein. 6. There was no significant difference in triglyceride, HDL-cholesterol, and LDL-cholesterol in serum among the groups. 7. Out of the groups supplemented with isolated soy protein the total cholesterol level in liver was low in the groups to which carnitine was supplemented (p< 0.05). However, there was no significant difference of liver total lipid and triglyceride among the groups. 8. There was no difference in TBARS levels and GSH-Px activities in liver among the groups.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.2
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• pp.156-162
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• 1984

The objective of this study was to investigate the influence of three types of protein source in a basal diet during the prenatal and lactating periods on the cellular growth and development of organs in rate. Twenty four pregnant Sprague-Dawley rats weighing 187.7${\pm}$18.5 g were fed ad libitum diets containing casein, soy protein, or corn gluten. The weight of organ and the contents of DAN, RNA, and protein of organs in pups were determined at 0, 3, 7, 14, and 21 days after the birth. Dietary intake of rats during trimester of pregnancy and lactation were significantly higher in the rats fed case in containing diet than those of rats fed the corn gluten diet. Body weight of the progeny fed casein diet at birth and after 7 days were significantly higher than those of rats fed the corn gluten diet. The weight of brain, liver, and kidney of pups which fed corn gluten diet were significantly lower than those fed the casein diet. DNA contents in the brain of pups fed the casein and the soy protein were slightly higher than those fed the corn gluten diet. RNA and protein contents of the brain, and DNA, RNA and protein contents of the liver of the corn gluten treated group were significantly lower than those of the others.

• Journal of Nutrition and Health
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• v.38 no.4
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• pp.279-288
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• 2005

The purpose of this study was to examine whether soybean protein isolate with rich isoflavones which was the same amount as used for earlier study prevents bone induced by ovarian hormone deficiency. Forty female Sprague-Dawley rats (body weight 210 $\pm$ 5 g) were divided into two groups, ovariectomy (OVX) and sham surgery groups, which were each randomly divided into two subgroups that were fed casein and soybean protein isolate with rich isoflavones (isoflavones 3_4 mg/g protein). The diets were fed for 9 weeks after operation. The results of this study indicate that body weight gain and food intake were higher in OVX groups than in SHAM groups regardless of diets. Weight gain were higher in soy isolate groups than in casein groups. Serum Ca concentration was lower in OVX rats than in SHAM rats when fed casein diet. Within the OVX groups, serum Ca concentration was higher in rats fed soy isolate diet than in rats fed casein diet. Serum ALP were higher in OVX groups than in SHAM groups. Within the OVX, soy isolate groups, indices of serum osteocalcin, were a trend for greater than those of the OVX casein group. Crosslink value were increased in ovariectomy groups. Spine BMD and femur BMD of ovariectomy groups were significantly lower than SHAM groups. However, soy isolate with rich isoflavones group in ovariectomy groups, spine BMC and femur BMC were significantly increased after 9 weeks. In conclusion, the soy protein with rich isoflavones was beneficial for bone in ovareiectomized rats and the results were similar to the findings of our previous study which showed a beneficial effect on bone in growing rats.