• Journal of Nutrition and Health
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• v.31 no.1
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• pp.5-12
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• 1998

This study was designed to examine how dietary protein levels affect organ growth and protein metabolism in early and normally weaned rats. Early and normally weaned rats separated fro the dam on the 15th and 121st day postpartum, respectively. were fed diets containing three levels of protein : low(10%) , normal (20%),and high(40%) . On the 35th day, the weight and DNA, RNA and protein contents in brain , liver, and kidney were determined to ascertain organ and cellular growth. Furthermore, serum total protein , albumin , $\alpha$-amino N and creatine and urinary urea N, and creatinine were determined in order to ascertain protein metabolism and renal functions. Dietary protein levels were not observed to significantly affect total DNA content, which may represent an index of cell number in the liver, brain and kidney. Fresh weight and protein/DNA ratio, which may represent indices of cell size, significantly increased in proportion to dietary protein in the kidney. As for the early weaned rats , the liver cell size significantly decreased. Dietary protein levels and weaning periods did not affect serum total protein and albumin . However, serum urea-N significantly increased in proportion to dietary protein levels whereas serum $\alpha$-amino N was decreased by early weaning . Nitrogen retention was lower in early weaned rats fed low or high levels of protein than in normally weaned rats. The results demonstrate that low or high levels of dietary protein have less desirable effects on protein metabolism in prematurely weaned rats.

• Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.265-271
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• 2015

A feeding trial of four dietary protein levels (20, 30, 40, and 50%) and two lipid levels (7 and 14%) with a factorial design was conducted to determine the optimal dietary protein and lipid levels for juvenile Israeli carp Cyprinus carpio. Triplicate groups of fish (average body weight, $1.3{\pm}0.02g$) were fed the experimental diets for 9 weeks. Survival of fish was not affected by either dietary protein or dietary lipid level. Weight gain and feed efficiency increased as dietary protein levels increased up to 40 and 50%, respectively. Weight gain was higher in fish fed the high-lipid diets with 20 and 40% protein content. Feeding efficiency increased as the dietary lipid level increased for the 30, 40, and 50% protein diets. Daily feed intake decreased with increasing protein level and the minimum feed consumption was observed in fish fed the 50% protein diet with 14% lipid content. Moisture and lipid contents of the whole body were affected by both dietary protein and lipid levels. The crude lipid content of fish fed the 14% lipid diet was higher than that of fish fed the 7% lipid diet at each protein level. The results of this study indicate that a diet containing 40% protein with 14% lipid content is optimal for the growth and effective protein utilization of juvenile Israeli carp.

• Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.311-316
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• 2009

A 10-week feeding trial with four dietary protein levels (22%, 32%, 42% and 52%) and two dietary lipid levels (8% and 17%) was conducted to investigate the optimum dietary protein and lipid levels for growth of long-nosed barbel fingerlings. Survival rate of fish was not affected by either the dietary protein or the dietary lipid level. Weight gain and feed efficiency were affected by the dietary protein level (P<0.01), but not by the lipid level, and increased with the dietary protein level at the both lipid levels. Weight gain and feed efficiency of fish fed the 52% protein diets with 8-17% dietary lipids were not significantly different from those of fish fed the 42% protein diets with 8-17% dietary lipids and 32% protein diet with 17% dietary lipid. Daily feed intake of fish was not affected by either dietary protein or dietary lipid level. Protein efficiency ratio and protein retention rate of fish fed the 32% protein diet with 17% dietary lipid were significantly higher than those of fish fed the 52% protein diets with 8-17% dietary lipids. Moisture content of fish fed the diets containing 8% lipid were higher than those of fish fed the diets containing 17% dietary lipid at each protein level. Crude lipid content of fish fed the diets containing 17% dietary lipid were higher than that of fish the fed the diet containing 8% dietary lipid at each protein level. The results of this study indicated that 32% protein and 17% lipid could be the optimum dietary level for growth of juvenile long-nosed barbel.

• Journal of Aquaculture
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• v.21 no.4
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• pp.239-243
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• 2008

A $3{\times}2$ factorial experiment was conducted to investigate the proper dietary protein and lipid levels for the growth of sub-adult flounder Paralichthys olivaceus reared during the summer season. Six experimental diets were formulated to contain three levels of protein (45%, 50% and 55%) and two levels of lipid (9% and 14%). Duplicate groups of fish (initial body weight of 298 g) were hand-fed to apparent satiation during the summer season ($21.8{\pm}1.7^{\circ}C$) for 60 days. Survival of each group was over 83% and there was not significant difference among all groups. Weight gain of fish fed the 45% protein diet with 14% lipid was not significantly different from that of fish fed the 50% and 55% protein diets with 9% and 14% lipids, but weight gain of fish fed the 45% protein diet with 9% lipid was significantly lower than that of fish fed the 55% protein diets with 14% lipid. Feed efficiency tended to increase with increasing dietary lipid level at each protein levels, although no significant differences were observed at 50% and 55% protein levels. Protein efficiency ratio, daily feed intake, condition factor and hepatosomatic index were not significantly affected by dietary protein and lipid levels. Crude lipid content of the liver tended to increase with increasing dietary lipid level at the same protein levels, but the opposite appearance was found for moisture content. The contents of moisture, crude protein and crude lipid of the dorsal muscle were not significantly affected by dietary protein and lipid levels. Based on data obtained form this study, inclusion of dietary protein at level of 45% appears sufficient to support optimal growth, and an increase of dietary lipid level from 9% to 14% has beneficial effects on feed utilization of sub-adult flounder during the summer season.

• Fisheries and Aquatic Sciences
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• v.7 no.4
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• pp.184-191
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• 2004

A 25-week feeding trial of two dietary protein (47 and $52\%$) and three dietary lipid level (7, 12 and $17\%$) factorial design with three replications were conducted to determine effects of dietary protein and lipid levels on growth, feed utilization and body composition of adult starry flounder (Platichthys stellatus), average initial weight 332 g, during the winter season. Survival of fish was not affected by either dietary protein or dietary lipid level. Weight gain, feed efficiency and protein efficiency ratio improved with dietary protein and lipid levels except for those of fish fed the $52\%$ protein diet with $17\%$ lipid. The best growth and feed utilization were observed in the $52\%$ protein diet with $12\%$ lipid, but were not significantly different from those of fish fed the $52\%$ protein diet with $17\%$ lipid or the $47\%$ protein diets with $17\%$ lipid levels. Hepatosomatic and visceral somatic indexes were significantly influenced by dietary protein level, but not by dietary lipid level. None of moisture, crude protein, crude lipid, or glycogen contents of dorsal muscle or liver in starry flounder except for crude lipid in dorsal muscle was significantly influenced by either dietary protein or dietary lipid level. Plasma cholesterol concentration was significantly influenced by both dietary protein and dietary lipid levels. The results of this study suggest that the diets containing $47\%$ protein with $17\%$ lipid or $52\%$ protein with $12-17\%$ lipid are optimal for growth and feed utilization of adult starry flounder under these experimental conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.13-22
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• 1994

This study was designed to investigate the effects of dietary protein and caffeine consumption levels on Ca, P, Na and K metabolism. One hundred twenty rats were divided into twelve groups according to age, protein level and caffeine consumption such as group(120-130g young rat, 250-300g adult rat) , dietary protein group (20% normal protein , 85 low protein) , caffeine consumption group(0, 3.5mg, 7.0mg). Low protein diet containing high caffeine levels caffeine levels increased calcium, phosphorus, sodium and potassium contents of urine and fecal in rats. Young rat has higher level of calcium, phosphorus , sodium and potassium than adult rat. In the serum, calcium contents were not affected by age, dietary protein levels and caffeine consumption . However, phosphorus, sodium and potassium contents of serum in adult rat were higher than young rat. In the liver, potassium decreased with decreasing dietary protein levels. In the kidney, calcium , phosphorus and potassium contents were not different by age group, dietary protein levels and caffeine consumption , but sodium content was significantly reduced in the adult rat.

• Journal of Nutrition and Health
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• v.15 no.4
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• pp.258-267
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• 1982

This study was performed to investigate the effect of different levels of protein and iron in the diet upon Fe, Cu and Zn metabolism in rat during four weeks of growing period. Forty-five male weanling rats of Sprague-Dawley strain weighing $68.5{\pm}1.1g$ were divided into 9 groups and each group was given with one of the 9 different kinds of diets for four weeks. The three dietary protein levels used were 5, 20 and 40% and Fe levels 0, 35, and 350 ppms. The results obtained were summarized as following ; 1) Food intake and body weight gain in 20%(SP) and 40%(HP) dietary protein groups tended to be significantly higher than 5%(LP) protein groups. Protein efficiency ratio (PER) was higher in LP groups than in HP and SP groups. With dietary Fe levels, there were no significant differences among groups in food intake, body weight gain, and PER. 2) In LP groups, the Fe concentrations in liver, kidney, and hind limb muscle were higher than in SP and HP groups. Regarding with dietary protein levels, the liver Cu concentrations in LP groups were slightly higher, but the liver Zn concentrations were lower in LP groups. The Fe concentrations in liver and kidney tended to decrease with decrease in dietary Fe levels, but Cu and Zn concentrations showed no consistent tendency with dietary Fe levels. 3) The Fe, Cu and Zn concentrations in serum were not different from dietary treatments except that the serum Fe concentrations increased slightly in LP groups. 4) The Fe and Cu concentrations in urine tended to be higher in HP groups. Fecal Cu and Zn concentrations showed no significant differences in dietary protein or Fe levels, but the Fe concentrations tended to increase with increase in dietary Fe levels.

• Journal of the Korean Home Economics Association
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• v.29 no.3
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• pp.47-59
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• 1991

This study wa performed to investigate the effects of dietary protein and fiber on the lead and protein metabolism in lead poisoning rats. Seventy male rats of Sprague-Dawley strain weighing 172$\pm$2g were blocked into 14 gropus according to body weight. Protein(casein) was given at levels of 15 or 40%, and fibers(pectin, cellulose and CMC) were given at levels of 0, 4 or 10%. The results are summarized as follows: 1. Food intake, weight gain and food efficiency ratio(FER) in groups fed high protein diets were higher than those in low protein groups. Liver weight in groups fed no dietary fiber was higher than that of animals fed fiber. Kidney and femur weights were greater in high protein groups. Tibia and femur lengths, and tibia weight were not significantly different among groups. 2. Hemoglobin content and hematocrit values showed no significant differance with dietary factors. 3. Total protein contents of serum and liver showed no significant difference, but tended to increase with increasing dietary protein level. Both daily urinary and fecal nitrogen excretions in high protein groups were higher than those in low protein groups. Especially daily fecal nitrogen excretions in high dietary fiber groups were significantly high. Body nitrogen absorption rate was the highest in animals fed no fiber. 4. Pb levels in blood, liver, kidney and bone tended to decrease with high dietary protein and fiber levels. Especially Pb level of kidney was high in all groups. Daily urinary Pb excretion showed no significant difference with dietary factors, but fecal Pb excretion increased significantly in high protein and fiber groups.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.4
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• pp.399-405
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• 1991

The interaction of 4 dietary crude protein (13, 16, 19 or 22%) and 4 metabolizable energy (2600, 2800, 3000 or 3100 kcal ME/kg) levels on egg quality performances of Starcross layers were assessed between 245 and 275 days of age. The egg weight increased significantly with the increasing dietary protein and energy levels. But egg shape index, albumen index, yolk index, yolk dry matter, yolk protein, yolk fat, albumen protein and shell tickness were similar at all dietary protein and/or energy levels. The egg specific gravity and albumen weight increased but the yolk, weight, Haugh unit and albumen drymatter decreased with the increase of dietary protein levels and showed irregular trend with energy levels. The albumen dry matter and egg shell weight, however, were not affected by energy and protein levels. Simultaneous increase of protein and energy increased specific gravity, albumen index and shell thickness at a greater rate than that increased by the increase of protein or energy alone.

• Journal of Nutrition and Health
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• v.21 no.6
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• pp.410-420
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• 1988

This study were performed to investigate effect of dietary cadmium(Cd) and protein levels on growth, body protein metabolism and Cd toxicity in growing rats. Forty eight male rats of Sprague-Dawley weighing 113$\pm$2g were blocked into 6 groups accoridng to body weight. Dietary protein were given at the levels of 7, 15 and 40% of diet and Cd (200ppm)were either added or not. The result obtained were summerized as follow; 1) Food intake, weight gain, FER PER, liver and kidney weight, weight and length of bones, hematocrit, and hemoglobin content in Cd-added groups were low than those in Cd-free groups. 2) Serum total protein showed no significant difference with Cd addition, but it was significantly lower in low protein diet groups. Liver protein in Cd-added groups was lower than Cd-free groups, and was tend to be increased with increasing dietary protein level. 3) Daily urinary and fecal nitrogen excretions in Cd-added groups were lower than Cd-free groups, and were increased with increasing dietary protein level. 4) Cadmium contents in blood, liver, kidney, and femur were tend to be decreased with increasing dietary protein level. Especially, Cd content in kidney of Cd-added groups was significantly decreased with increasing dietary protein level. 5) Daily urinary and fecal Cd excretions were tend to be increased with increasing dietary protein level, and Cd-added-high protein diet group showed the highest Cd excretion among the Cd-added groups, Cd absorption ration and Cd retention ratio were tend to be decreased with increasing dietary protein level.