• Journal of the Korean Dietetic Association
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• v.7 no.3
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• pp.258-266
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• 2001

The purpose of this study was to investigate the effect of dietary zinc on the carbohydrate metabolism and the serum content of magnesium and chromium in rats fed normal diet. Animals were divided into three groups by different dietary zinc levels which were low(15ppm), normal(30ppm) or high(60ppm). Serum glucose and Insulin concentrations were assessed by the glucose method and the radio immuno assay respectively. Serum zinc. magnesium and chromium contents were measured by Indectively Coupled Plasma(ICP). Results of the study were as follows : 1. Feed intake in a zinc deficiency group was significantly higher than that in other group, but the weight gain in high zinc diet group was significantly lower than in other groups. 2. There were no significant differences in liver, kidney and spleen weight. 3. Serum glucose, insulin and zinc concentrations were not significantly different among different dietary zinc groups, However serum magnesium and chromium concentrations were significantly decreased as the level of dietary zinc was increased.

• Journal of Nutrition and Health
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• v.30 no.4
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• pp.394-405
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• 1997

Endogenous zinc is important for maintaining zinc homeostasis because the size of endogenous zinc pool is almost 3-4 times bigger than that of dietary zinc. The purpose of this study was to examine the phytate effect on the reabsorption of endogenous zinc and the additional Ca effect on the phytate effect. Rats were fed a casein-based diet with added sodium phytate containing either high(1.6%) or low(0.8%) Ca concentrations for 4 weeks to reduce the body zinc pool. After the depletion period, $^{65}$ Zn was given by intraperitoneal injection to label the endogenous zinc pool. Rats were then assigned into phytate or non-phytate group within the same Ca group. feces were collected for 2 weeks of the initial collection period and 1 week after dietary crossover. The ratios of excreted fecal $^{65}$ Zn radioactivity of phytate group non-phytate group were determined as a measure of the phytate effect on the endogenous zinc. Mean fecal $^{65}$ Zn radioactivity was higher in the phytate group than in the non-phytate group during the entire 3 weeks of the collection period in the low Ca group, and during the initial collection period in the high Ca group(p <0.0001). This study showed an adverse phytate effect on endogenous zinc at both high and low dietary Ca levels. Elevated dietary Ca levels showed a synergistic effect on the phytate effect on endogenous zinc(p <0.05). These results imply greater phytate effect on zinc homeostasis rather than on zinc bioavailability through complexing with the endogenous zinc which is larger portion than the dietary zinc on zinc homeostasis.

• Preventive Nutrition and Food Science
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• v.2 no.1
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• pp.35-41
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• 1997

The pancreas is an important organ in the maintenance of zinc homeostasis. Endogenous zinc is con-tinuously secreted via pancreatic exocrine fluid or to a lesser extent in bile. Much of the endogenous secretion must be reabsorbed to sustain zinc homeostasis. The objective of this study was to estimate the relative size of the pancreatic/biliary zinc pool in comparision to the dietary zinc intake, and to study the effect of the phytate and calcium on the zinc homeostasis using a rat model. At the termination of the experiment, pan-creatic/biliary fluid was collected from the rats. Both radioactivity and total zinc were measured and the relative size of the pancreatic/biliary zinc pool was estimated. To determine the effect of phytate and calcium on zinc homeostsis, dietary zinc intake, the amount of zinc in pancreatic.biliary fluid and fecal zinc excretion were measured. The flow rate of pancreatic/biliary fluid, as corrected for tubing constriction, gives the corrected zinc concentration in the pancreatic/biliary fluid was 2.2 times higher than dietary zinc intake. To maintain zinc homeostasis, zinc absorption/reabsorption was very efficient in the current model; 76%, 88% of absorption/reabsorption for low calcium group and high calcium group 81% for phytate group and non-phytate group, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1348-1354
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• 2008

Two inorganic (zinc sulfate and zinc oxide) and three organic (zinc acetate, zinc-methionine, and zinc-lysine) zinc sources were evaluated for their effects on the performance and carcass characteristics of broiler chicks. The birds were randomly assigned to one control (non-supplemented) and 15 treatment (supplemented) groups consisting of four replicates of 10 chicks each in a $5{\times}3$ factorial arrangement of treatments (five zinc sources and three supplemental zinc levels). Birds were kept in floor pens in a temperature-controlled room from 1 to 42 d of age and fed a non-supplemented basal diet (control) or the basal diet supplemented with 40, 80 or 120 mg/kg of Zn as mentioned sources. Dietary zinc source had considerable effect on feed intake in all experimental periods. Increasing Zn level from 80 to 120 mg/kg decreased the average feed intake in the growth stage (p<0.01) and also in the entire experimental period (p<0.001). Similarly, the average daily gain during the entire trial period was affected by the type of Zn source (p<0.001) and supplemental level (p<0.01). One degree of freedom contrast comparisons showed that the inclusion of organic zinc sources into the diets caused significant increases in feed intake and body gain when compared with inorganic counterparts. Except in wk 1, dietary supplementation with organic sources improved (p<0.05) feed conversion ratio; FCR values were not affected by dietary Zn source or supplementation level. Breast meat yield increased with supplemental levels of organic Zn sources; however, other carcass parameters were not affected by dietary Zn source. On the other hand, organic versus inorganic zinc supplementation caused a significant increase in liver, breast and carcass weight percentages. The present findings suggest that supplemental levels of organic Zn compounds had beneficial effects on broiler performance, and Zn requirements can be reduced using these feed supplements in poultry rations.

• Korean Journal of Community Nutrition
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• v.3 no.3
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• pp.389-396
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• 1998

This study was intended to examine the zinc status and effect of zinc supplementation on the zinc nutritional status of the elderly living in the Ulsan area. The zinc intake of 207 subjects(male 97, female 110) was measured by a 24-hour dietary recall and food frequency method. Biochemical analysis were conducted from blood and urine samples to evaluate the changes of zinc nutriture with zinc supplementation. The average dietary zinc intake of subjects was $7.7\pm{2.8mg}$ for male and $7.5\pm{2.6mg}$ for female, which were 51.3% and 62.3% of Korean RDA respectively. The first source of zinc was cereal and grain(36%), and the second was eggs and milk group(27%). After 8 weeks of zinc supplementation, the serum zinc content was significantly increased(p<0.01), although the serum copper content was not significantly decrease. Serum HDL- cholesterol level was not significantly decreased with zinc supplementation. Serum alkaline phosphatase(ALP) activity and urinary zinc excretion were significantly increased(p<0.05). The urinary Zn/Cr was not significantly increased. It is suggested from the results that the daily zinc supplementation can be effective to improve zinc nutriture.

• Journal of Nutrition and Health
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• v.22 no.6
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• pp.539-546
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• 1989

This study was carried out to investigate the effect of addition of cellulose in the diet on the metabolism in rat fed high and low level of zinc. The experimental animals were consisted of 24 male weaning rats of Sprague-Dawley strain(mean weight 72.3g), and they were devided into 4 groups of 6 rats and fed experimental diets for four weeks. Dietary zinc levels used were 10 ppm, and 300ppm and cellulose levels were 2.5% and 10% of diet by weight. Throughout the experimental period, feed consumption and body weight gain were measured and feed efficiency ratio was calculated. The weight of live, kidney and spleen were measured, and the contents of zinc in feces, urine, liver, kidney, spleen and serum were determined. The results obtained are summarized as following ; 1. Body weight gain in high zinc-adequate cellulose group was significantly higher than the other groups. Feed consumptions were significantly higher in high zinc groups and no significant difference was found with dietary cellulose levels. 2. Fecal zinc excretions of four groups were not different at the first week, but at the end of fourth week, high zinc groups experince significantly more zinc excretion than low zinc groups, and also high cellulose groups had higher zinc contents in the feces than the adequate ones within the same zinc levels(p<0.05). There was no significant difference in the urinary zinc excretion. 3. The weights of liver, kidney and spleen were heavier in the high zinc groups than the lower ones, and higher in the high cellulose groups(p<0.05). The liver zinc contents were significantly lower in the low zinc and high cellulose groups. However zinc contents in the kidney and serum were not influenced by dietary zinc level but by cellulouse level. High cellulose diet lowered serum and kidney zinc concentrations(p<0.05).

• Journal of Nutrition and Health
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• v.30 no.4
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• pp.406-414
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• 1997

It has been known that dietary phytate decreases the absorption of body zinc pool which is composed of the dietary and endogenous zinc in the body. The purpose of this study was to examine the effect of phytate on the absorption of total bodyzinc in Zn-depleted rats. Rats were Zn-depleted with either low(0.8%) or high(1.6%) Ca diet containing sodium phytate for 4 weeks. After zinc depletion, rats were assigned into phytate or non-phytate dietary groups within each low-or high-Ca dietary group. ant feces were collected for 2 weeks of the initial collection and 1 week after dietary crossover, during which the phytate and the non-phytate diet was switched over within the same Ca group. The content of Zn and Ca measured by atomic absorption spectrophotometer and phytate content was analyzed. food intake was higher in the high Ca group than in the low Ca group(p <0.0001), and was also higher in the non-phytate group than in the phytate group(p <0.0001). Food intake and phytate level affected body weight gain in rats(p <0.0001). Zinc excretion in the total feces was higher in the phytate group than in the non-phytate group at both low and high Ca level(p <0.0001), except during the crossover collection period in high Ca group. Calcium, however, didn't show any synergistic effect on phytate effect(p <0.05). This study showed that phytate decreased the absorption of total body zinc at both low and high Ca levels in Zn-depleted rats. A large portion of total body zinc originated from the endogenous zinc pool in these rats. The results of the present study showed the same effect of phytate on the endogenous zinc in Zn-depleted rats as in a previous study, confirming that phytate adversely affects zinc bioavailability, especially under marginal and poor zinc nutrition.

• Journal of Nutrition and Health
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• v.22 no.1
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• pp.9-22
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• 1989

The effect of different levels of Zn (0, 30, 300ppm) and protein(7, 20, 40%) in the diet upon lipid metabolism was investigated in Sprague-Dawley male rats weighting 180.54$\pm$29.08g(n=450 fed one of nine diets in a 3$\times$3 factorial design for 5 weeks. The reults obtained were summarized as following. 1) Total lipid contents in serum and liver were tended to be lower in LZn group than CZn and Hzn groups. Those of LP group were higher than CP and HP groups. 2) HDL-cholesterol and total cholesterol contents in serum were significantly affected by dietary Zinc level and were increased as dietary Zinc level increase. 3) Total cholesterol in liver and muscle were tended to be decrease as dietary Zinc level increase. Those in LP group were higher than CP and HP groups. 4) Zinc contents in plasma, liver, muscle and testis were tended to be lower in LZn group than CZn and HZn groups. 5) Protein contents in plasma and liver lower in LZn group than CZn and HZn groups when dietary protein level was 7% and 20%. Those in LP group were lower than those in CP and HP groups. 6) Cu contents in plasma, liver, muscle and testis were tended to be decreased as dietary Zinc level increase.

• Korean Journal of Community Nutrition
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• v.5 no.3
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• pp.484-492
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• 2000

In an attempt to figure out the relationship between zinc status and taste acuity of old and young women, dietary zinc intake, urinary zinc excretion, and taste acuity were determined for 118 women. Zinc intake was measured by 2-day food records and food frequency method. Urinary zinc excretion was measured from urine samples collected for twenty four hours. Body fat, lean body mass (LBM), and total body water were measured by bio-impedence. Average dietary zinc intake by food record was 4.15$\pm$1.33mg (=35% if Korean RDA) for the old women and 5.41$\pm$2.76mg (=25% of RDA) for young women. When zinc intake was measured by a frequency method, the average intakes of the old and young women were 3.5$\pm$1.7mg 4.5$\pm$1.9mg, respectively. It appears that dietary zinc intake of young women was significantly higher than that of the old women. Average urinary zinc excretion of the subjects was 0.27$\pm$0.16mg in the elderly and 0.24$\pm$0.13mg in young women, which indicated a marginal zinc status. However, zinc status was not significantly different between old and young women. Correlation analysis indicated that zinc intake and urinary zinc excretion were positively related to BMI and LBM in young women. The old women (m=49) showed significantly higher taste detection thresholds than young subjects (n=47) for both sweet and salty tastes. Recognition thresholds for sodium chloride and sucrose were not significantly different between old and young women. The lower the taste thresholds for salty taste, the higher the average dietary zinc intake. However, taste perception concentration was not related to the urinary zinc excretion level.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.1
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• pp.80-86
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• 1990

This experiment was conducted to study the effects of dietary zinc and ethanol on the zinc content of serum and tissues. Eight male rats of Sprague-Dawley strain with average weight of 80$\pm$5g were divided into five groups such as C group: ad libitum control diet(100 ppm Zn) plus isocaloric sucrose solution CE group ; ad libitum control diet plus 25% ethanol solution PF group ; pair fed control to zinc deficient diet(5ppm Zn) plus isocaloric sucrose solution ZD grop ; ad libitum zinc deficient diet plus isocaloric sucrose solution and ZDE group ; ad libitum zinc deficient diet plus 25% ethanol solution. The rats were sacrificed after 4 and 7 weeks of feeding periods. The liver weights of ZD and ZDF groups were increased however the weight of testis was decreased in the same groups The content of serum zinc was infiuenced by the dietary zinc level and the amount was significantly decreased in the ZD group. The content of liver zinc was influnced by the dietary zinc level and the amount was decreased by ethanol feeding. The content of testis zinc was significantly low in the ZDE group. The zinc level of feces to be increased by the ethanol feeding.