• Journal of Nutrition and Health
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• v.42 no.8
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• pp.740-749
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• 2009

The objectives of this study was to determine whether a new physically modified cornstarch by ultra-fine- or nanoscale pulverizer to reduce particle size offers better bioactive function than native cornstarch in weanling Sprague-Dawley rats. Male weaning Sprague-Dawley rats were fed diets containing native cornstarch (NAC), ultra fine pulverized cornstarch (UFC) or nano-scale pulverized cornstarch (NSC) for 4 weeks. In vitro rate of starch hydrolysis, growth performance, organ weight, intestine length intestinal proliferation and the fermentation by Bifidobacterium of rat cecum were evaluated. The diet with reduced particle size (UFC or NSC) significantly increased body weight gain and organ weight. Feed efficiency was increased in NSC fed rats and was not affected in UFC fed rats. Intestinal proliferation was decreased in NSC group. Reduction of particle size also increased cecal short chain fatty acid concentration and the growth and acidifying activity of Bifidobacterium. It is concluded that a reduction of particle size of starch granules by physically modification may increase growing performance and gut function.

• Reproductive and Developmental Biology
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• v.34 no.2
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• pp.89-94
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• 2010

Melatonin is induced by light information through the retina and leads to growth factor activation. Thus, we investigated the effects of melatonin by controlling the photoperiod of growing young rats. Male Sprague-Dawley rats (n=6; 4 weeks old) were divided into two experimental groups: the L/D group (normal photoperiod; light/dark: 12/12 h; lights on at 9:00 a.m.) and the L/L group (light/light: 24 h). Rat body weight and food consumption were measured daily for 8 weeks. After 8 weeks, the rats were anesthetized with a mixture of ketamine (50 mg/kg) and xylazine (10 mg/kg) and sacrificed. Tissue was then collected for RNA isolation (from brain, heart, liver, kidney, adrenal gland, testis, tibia, hind limb muscles). Also, serum was isolated from blood using a centrifugal separation. The L/L group had significantly lower body weight than the L/D group from 4 to 6 weeks (p<0.05). The L/D group had increased tissue mass, compared with the L/L group, but the difference was not statistically significant. The L/D group had a significantly higher melatonin concentration than the L/L group between the hours of midnight and 2:00 a.m (p<0.01). These results indicate that photoperiod length may affect the secretion of melatonin from the pineal gland. Also, the reduction of nocturnal melatonin secretion may retard the development of growing young rats. In future studies, we plan to compare exogenous melatonin administration with endogenous melatonin concentration induced by photoperiod control. Moreover, we will confirm whether the effects seen in pathological animal models can be reversed by controlling the photoperiod.

• Korean Journal of Veterinary Research
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• v.39 no.3
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• pp.455-462
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• 1999

This study was designed to investigate the number of the growing and mature follicles in each stage of estrus cycle in mature rats. Eighteen mature rats(Sprague-Dawley, initially 190~230gm) were randomly alloted into 4 groups(proestrus, estrus, metestrus, and diestrus) according to estrus cycles. The uteri and ovaries of rats were collected and then alternative sections of paraffin embedding ovaries were stained with H-E. Numbers of large, middle and small follicles or only large and middle follicles from secondary and tertiary follicles were investigated by LM photography of preparations. Small follicles were defined as secondary follicles with 2~5 cell layers of granulosa cells surrounding the oocyte, and middle follicles were defined as secondary follicles with more than 5 cell layers or with early signs of antral cavity or with more than one small cleft on either side of the oocytes and large follicles were defined as tertiary follicles with a single medium or large antral cavity. The number of follicles in a pair ovary per rat was appeared to be ranged from 207 to 370 and the mean number of these follicles was $270.4{\pm}52.6$ and the mean number of follicles per ovary was $134.9{\pm}32.0$. The mean number of large, middle and small follicles per ovary was appeared to be $16.4{\pm}4.4$($12.2{\pm}3.3%$), $36.2{\pm}8.6$($26.8{\pm}6.4%$), and $82.7{\pm}24.0$($61.3{\pm}17.8%$), respectively. The mean number of large and middle follicles in each stage group of estrus cycle was appeared to be $17.8{\pm}2.1$ and $38.3{\pm}7.4$ at proestrus stage group, $15.7{\pm}5.2$ and $38.0{\pm}10.0$ at estrus stage group, $16.5{\pm}3.5$ and $33.8{\pm}7.0$ at metestrus stage group, $16.7{\pm}5.8$ and $29.7{\pm}5.5$ at diestrus group, respectively. In histological findings of large follicles during each estrus cycle, the large follicles in proestrus group contain single small antrum, thick granulosa cell layers, and were $300{\sim}500{\mu}m$ in diameter and were growing follicles with PCNA-positive cells in the granulosa cell layers, and other luteinizing follicles of proestrus cycle stage were decreased in size and were thicker in wall thickness and more luteinized than those in metestrus and diestrus stage groups. The large follicles in estrus stage group contain thick granulosa cell layers and nonprominent cumulus-oocyte complexes in antrum, and were $400{\sim}700{\mu}m$ in diameter and were growing follicles with PCNA-positive cells in the granulosa cell layers. The large follicles in metestrus and diestrus stage groups contain enlarged antrums, thinner layers of walls and prominent cumulus-oocyte complexes, and were $700-950{\mu}m$ in diameter, and were nongrowing follicles without PCNA-positive cells or another large follicles contain cells with dark stainability and distinct boundary.

• Journal of Nutrition and Health
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• v.36 no.10
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• pp.1030-1035
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• 2003

This study was conducted to evaluate the safety of herbicide-resistant rice, a genetically modified organism (GMO) developed by the Rural Development Administration, in Sprague-Dawley rats. The nutrient content of herbicide-resistant polished and brown cooked rice was compared with that of conventional Ilpum polished and brown cooked rice to assess composition equivalence. Compositional analysis was performed to measure proximates, fiber, and minerals before animal feeding. Growing male rats were fed one of the following four diets for six weeks: Ilpum polished cooked rice (IP) and Ilpum brown cooked rice (IB) as a non-GMO and herbicide-resistant polished cooked rice (GP) and brown cooked rice (GB) as a GMO. We checked clinical symptoms (anorexia, salivation, diarrhea, polyuria, anuria, fecal change) every day, food intake, change of body weight twice a week, and serum biochemistry and organ weights after 6 weeks of experimental feeding among the four groups. Nutrient content of the herbicide-resistant rice was similar to that of the non-transgenic control and was within the published range observed for non-transgenic rice. We could not find any significant difference in the above-mentioned items as the index to be checked in the animals fed the GMO. These results suggest that the nutrient content of genetically modified herbicide-resistant rice is compositionally equivalent to that of conventional Ilpum rice and that growing male rats fed herbicide-resistant rice are no different from those fed Ilpum rice, non-GMO for 6 weeks.

• Journal of Nutrition and Health
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• v.9 no.4
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• pp.11-18
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• 1976

In this third report influence of vibration on growth and on some metabolism of young growing rats fed on varying levels of protein was investigated. Forty eight (48) young growing male rats weighing about 60 grams were used, grouping to four (4) groups, twelve (12) rats each group. They were fed on 8%, 13%, 19%, and 26% casein diet respectively (See the table 1) for the period of 10 weeks experiment. During the experimental period the half number of the rats of each group were subjected to a given degree of vibration for two (2) hours daily. Observations for growth rate, food and protein efficiency ratios, organs development, cholesterol levels in aorta, total nitrogen, urea nitrogen and creatinine levels in urine may be summarized as follows 1. Growth was impaired by the vibration in all groups including 26% easein diet. 2. There is tendeney that in higher protein diets, the organs (See table 3) developed more well. And also the impairment of the organs development by the vibration revealed less in higher protein diets. 3. Food and protein efficiency ratios were generally decreased under vibration and the food efficiency was improved by increasing the protein level in diet. 4. Total and free cholesteral levels in aorta were increased by the vibration. Ester from/tatal ratio was 17.7% and 17.3% respectively at 8% and 13% protein diets and 54.8% and 54.2% at 19% and 26% protein diets. These show that, in higher protein diets, the vibration doesn't influence the cholesterol ratio. 5. Total nitrogen, urea nirogen and creatinine levels in urine were increased by increasing the protion level in diet and also increased by the vibration. 6. It seems that, according to the above observations, the vibration used in this experiment influenced, in certain extent, on physical development, physiological availability of nutrients, and on body metabolism. And it is also thought that higher protein diets act some good role in protecting body from suffering from vibration.

• The Journal of Korean Medicine
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• v.24 no.1
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• pp.1-8
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• 2003

Purpose : Nowadays, there are many studies of growth retardation treatment by oriental medical therapy. This study was performed to evaluate the effect of Hwalhyulsungjang-san (Huoxuechengzhang-san) and KC101 on physical development in growth, Methods : 60 young (3 weeks old) male rats, whose mean weight was $46.8{\pm}0,7g$, were divided into 5 groups : groups A, B, C, and D were fed an experimental diet containing respectively Hwalhyulsungjang-san 2.5%, Hwalhyulsungjang-san 7.5%, KC101 5.0%, and KC101 10.0%, and the other group were fed an AIN-diet containing neither Hwalhyulsungjang-san nor KC101 as a control. Study of each group used 2 rats and was repeated in 6 times. Body weight, daily weight gain, dietary intake, body length, femur length, backbone length and serum concentration of IGF-I and hemoglobin were measured. Result : 1. Body weight and daily weight gain of group D (KC101 10%) were highest; dietary intake of group D was also increased by 13% over the control group. 2. Average body length of group D was increased to 1.69cm, which was 3.2% over the control group. Backbone length of group D was also increased 4% compared to control group. 3. Serum concentration of IGF-I of group D increased 17% compared to control group. 4. Serum concentration of hemoglobin of group B (Hwalhyulsungjang-san 7.5%) increased 8% compared to control group. Conclusion : This study showed that Hwalhyulsungjang-san and KC101 composed of oriental medicinal stuffs have effect on physical development in growing rats. There were not any statistical meaning compared to control group, but this study suggests that intake of these compounds from a young age may lead to increase physical development in growth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.2
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• pp.131-136
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• 1985

This study was intended to observe some nutritional effects of the boiling water extracts of mugwort powder in albino rats. Forty young male albino rats of Sprague-Dawley strain, body weight of $77{\pm}5g$ were employed for the experiment. They were divided into 5 dietary group, 0 (control), 1, 2, 4, and 8g% mugwort powder extract supplemented into the control diet, and fed each corresponding diet to the rats for 4 weeks. They were observed on intake of food and protein, efficiencies of food and protein, amount of energy intake, growing rate, and levels of hematocrit and hemoglobin in the blood. The amount of intakes of food, protein and energy was the highest in the group fed on 4g% mugwort extracts supplemented diet than any other groups studied. The efficiencies of food and protein in the groups fed on mugwort extracts supplemented diets were all lower than that of the control group. The growing rate of the group fed on 1g% mugwort extracts supplemented diet was the highest, however, there was no significant difference among them. The levels of hemoglobin of the groups fed 4g% or 8g% mugwort extracts supplemented diet was higher than that of the control, but not significant.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.263-272
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• 2007

This experiment was conducted to examine the effects of cage type (CT) and cage density (CD) on physiological variables in growing rats. Sprague Dawley rats (n=108) weighing an average of 46 g were housed in metallic cage with woodchip bedding (MCWB), metallic cage with wire mesh (MCWM), and plastic shoebox with woodchip bedding (PCWB) separately by sex at normal ($160-cm^2/rat$, ND) and high ($80-cm^2/rat$, HD) CD from 3 to 10 wks of age. All cages were in dimension of $24{\times}40{\times}20$ cm ($W{\times}D{\times}H$). At the end of the experiment, blood samples were collected and 6 rats from each cage were sacrificed. No death was observed among rats at ND, whereas mortality rate at HD was 22.3% for males and 13.9% for females. Heart weight was affected by CT. Doubling CD caused 23, 11.8, 17.9, 8.6, 6.9, and 16.4% decreases in BW and weights of heart, liver, kidney, testis, and ovary, respectively. Except for adrenal gland, other organs for males were heavier than for females. Liver weight of males and females responded differently to CT and CD. Comparing with females, males had 7.3 and 5.2% heavier and 9.9% lighter liver weights in MCWB, MCWM, and PCWB, respectively. As CD doubled, liver weight for males and females decreased by 22.4 and 13.1%, respectively. Mean adrenal gland weight increased by 8.4% and decreased by 9.7% for males and females, respectively, with doubling CD. CT affected glucose, TG, Ca, and ALP levels. However, CD did not alter blood chemistry. Rats housed in metallic cages had greater neutrophil count and neutrophil:lymphocyte ratio than rats housed in plastic cages. Doubling CD caused a 24.2% increase in lymphocyte count. There were CT by CD, CT by sex, and CD by sex interaction effects on lymphocyte count. Doubling CD caused 0.1% decrease and 49.8 and 26.7% increases in lymphocyte count for rats housed in MCWB, MCWM, and PCWB, respectively. Comparing with females, lymphocyte count for males housed in MCWB, MCWM, and PCWB had 8.9 and 12.9% greater and 30.3% less lymphocyte counts, respectively. Lymphocyte count decreased by 4.12% for males, whereas it increased by 61.0% for females as CD doubled. Doubling CD resulted in 2.5 and 2.3% increases in erythrocyte count and hematocrit value. These data suggest that animals perform better in metallic cages than in plastic cages and that cage density had pronounceable effects on physiological parameters in a cage type and sex dependent-manner.

• Korean Journal of Veterinary Research
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• v.36 no.2
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• pp.417-428
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• 1996

In order to know the toxic effect and carcinogenic activity in rats and mice fed with juice of Korean native Petasites japonicus Maxim of its pellet(4% or 8%) which were dried, milled and mixed with basal diet, the investigations were carried out by macroscopy and histopathology. Macroscopically, although remarkable changes were not observed in the liver of mice, there were slight to moderate swelling of rat livers in the whole groups at 12 to 14 weeks after feeding and milky spots in rats fed with its juice and 8% pelleted Petasites japonicus Maxim diet and a normal diet for 1 week alternatively for 14 weeks. Moreover, moderate to severe swelling and milk spots were recognized in livers of all rats fed with its juice and 8% pellet or 8% pelleted Petasites japonicus Maxim for 16 weeks. But, in cases of rats fed with its juice and 4% pellet or 4% pelleted Petasites japonicus Maxim, only swelling of livers was recognized moderately or severely. Histopathologically, major lesions were found in livers of both rats and mice. There were congestion, hemorrhage, fatty change, focal necrosis, megalocytosis and hyperplasia of endothelial cell in livers of mice and rats, the additional lesions such as proliferation of bile duct and nodular regeneration with diffuse regenerating cells were seen in livers of rats. In addition, preneoplastic lesions, the areas of milky spots macroscopically, were observed in livers of rats fed with Petasites japonicus Maxim for 14 to 16 weeks. In a few cases, haemangioendothelial sarcoma in livers was detected in rats fed with Petasites japonicus Maxim for 16 weeks. Petasites japonicus maxim growing naturally in Korea seem to exhibit toxic effect especially in liver and it contained a causative agent of primary liver tumors.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.375-382
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• 1999

Growing evidence indicates that enhanced generation or actions of nitric oxide (NO) are implicated in the pathogenesis of hypertension in spontaneously hypertensive rats and diabetic nephropathy in streptozotocin (STZ)-induced diabetic rats. We investigated whether inducible nitric oxide synthase (iNOS) expression in STZ-induced diabetic rats is responsible for the alterations of vascular reactivity. Diabetic state was confirmed 28 days after injection of STZ (i.p) in rats by measuring blood glucose. In order to evaluate whether short term (4 weeks) diabetic state is related with altered vascular reactivity caused by iNOS expression, isometric tension experiments were performed. In addition, plasma nitrite/nitrate (NOx) levels and expression of iNOS in the lung and aorta of control and STZ-treated rats were compared by using Griess reagent and Western analysis, respectively. Results indicated that STZ-treated rats increased the maximal contractile response of the aorta to phenylephrine (PE), and high $K^+,$ while the sensitivity remained unaltered. Endothelium-dependent relaxation, but not SNP-mediated relaxation, was reduced in STZ-treated rats. Plasma nitrite/nitrates are significantly increased in STZ-treated rats compared to controls. The malondialdehyde (MDA) contents of liver, serum, and aorta of diabetic rats were also significantly increased. Furthermore, nitrotyrosine, a specific foot print of peroxynitrite, was significantly increased in endothelial cells and smooth muscle layers in STZ-induced diabetic aorta. Taken together, the present findings indicate that enhanced release of NO by iNOS along with increased lipid peroxidation in diabetic conditions may be responsible, at least in part, for the augmented contractility, possibly through the modification of endothelial integrity or ecNOS activity of endothelium in STZ-diabetic rat aorta.