• Korean journal of food and cookery science
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• v.23 no.5
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• pp.644-649
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• 2007

In this study a purified protein was prepared from pork meat. The product consisted of 0.5% moisture, 3.0% ash, 5.5% ether extract and 88.7% crude protein. Also, a meat oligopeptide mixture was prepared from a pepsin digest of the protein preparation. The two preparations were colorless and odorless powders with low fat contents. The nutritive values of the pork meat protein and oligopeptide mixture were estimated by two methods, one using biological value(BV) and the other employing net protein utilization(NPU) by the nitrogen balance method. The meat oligopeptide mixture showed an excellent nutritive value by both methods. The true digestibilites of both the pork meat protein and the oligopeptide mixture were more than 98%. The above results indicate that the oligopeptide mixture is an excellent material as a dietary nitrogen source for many purposes.

• Journal of Nutrition and Health
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• v.31 no.3
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• pp.253-262
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• 1998

This study was performed to investigated the effect of dietary fat sources on renal senescence in aged rats. Seventeen month old male Sprague-Dawley rats were divided into 3 groups according to urinary protein excretion. Four month old rats were used as a control group. The rats were fed one of three different experimental diets ; 20% beef tallow, 20% corn oil 20% fish oil diet. They were fed experimental diets ad libitum for 16 weeks . The results are summarized as follows. Serum lipid concentrations were higher in aged rats than in control rats, with the beef tallow group showing the highest level, followed by the corn oil and fish oil groups. Old rats showed higher HDL and lower LDL levels than the control groups. Age and dietary fat had no effect on VLDL. GFR for the both age groups were increased with experimental period with the beef tallow group showing the highest value. Urinary protein excretion was also increased with experimental period in both age groups. There was a large increase in urinary protein in old rats that were fed beef tallow and corn oil, but not in old rats fed fish oil. On the contrary , the effect of dietary fat on urinary protein was not found in control groups. There was individual susceptibility in the effect of dietary fat on urinary protein. Old rats fed beef tallow with high initial urinary protein showed highest increase, but , the change was not significant in rats with a low initial value . It was also found that the increase was kept low in rats of the fish oil group with high initial urinary protein. The corn oil group showed in between values. There were no differences in urine and renal tissue concentrations of TXB2 . Aged rats showed a tendency of having higher urinary PGE2 excretion and lower renal cortex content. Since higher PGE2 excretion was reported to be associated with decreased renal function, this might suggest that the aged rats show renal function reduction. Light microscopic examination showed that glomerular segmental sclerosis, mesangial matrix expansion and tubular atrophy were more frequently present in aged rats, and that these changes were more significant in the beef tallow group, followed by corn oil and fish oil groups. The percentage of urinary protein excretion was increased in aged rats in association with increased glomerular sclerosis and mesangial matrix . This change could be partly due to a change in eicosanoids metabolism . Therefore, modification of dietary fat could affect the eicosanoids metabolism in kidney and renal senescence.

• Journal of the Korean Applied Science and Technology
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• v.3 no.1
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• pp.23-31
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• 1986

Several authors reported that vegetable proteins cause to decrease serum cholesterol and reported the effect of limiting amino acid balance in dietary protein on the blood component. This study was designed to observe growth rate and blood component in 1% cholesterol-fed male rats intake pure isolated soy proteins and methionine for 4 weeks. The diets were supplemented with either 20% casein or isolated soy protein as dietary protein sources and methionine as limiting amino acid of isolated soy protein and casein protein. The results were as follows; 1) The body weight gain was the greatest in casein groups. 2) Serum total cholesterol concentration was significantly increased by casein groups and slightly decreased by isolated soy protein groups. 3) Serum HDL-cholesterol concentration was significantly increased by isolated soy protein groups than control group. 4) Serum total lipid and triglyceride concentrations were significantly decreased by isolated soy protein groups than control group. 5) Serum glucose concentration was significantly increased by isolated soy protein plus 0.8% methionine than control group. 6) Serum total protein and albumin concentrations were significantly increased by all experimental diets groups than control group. Especially, casein groups were the most increased in all experimental diets groups.

• Journal of Nutrition and Health
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• v.27 no.9
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• pp.883-891
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• 1994

The number of diabetics in Korea is about 3 to 5 percent of the population, and the incidence is increasing yearly due to changes of life style and food intake. Diet is a key element in the management of diabetes, yet the appropriate diet for diabetes remains controversial. We have recently shown that a diet rich in protein of animal origin(casein) seems beneficial to controling plasma glucose and lipids in streptozotocin-induced diabetic rats. It therefore seemed desirable to find out whether the beneficial effect of high casein diet in experimental diabetes could also be reproduced with a vegetable source of protein(soy). The purpose of this study is to compare these results with the results of our previous study. In the present study, non-diabetic and streptozotocin-induced diabetic rats were studied in order to examine the effects of altering the level(20% vs 60%) of dietary soy protein on blood glucose, lipids, and hormones. Results of the present study showed that a high soy protein diet decreased triglyceride concentration in diabetic rats. However, diabetic rats fed a high soy protein diet were not hypocholesterolemic compared to rats fed a control diet. Moreover, diabetic rats fed a high soy protein diet had significantly increased plasma glucose concentration compared to rats fed a control diet. This study was not able to discern a specific effect of dietary protein level on insulin, glucagon, or insulin/glucagon ratio. Except for the hypotriglyceridemic effect, the results were not similar to the findings of our previous study which showed a beneficial effect on streptozotocin-induced diabetic rats fed a high casein diet.

• Korean Journal of Poultry Science
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• v.11 no.1
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• pp.1-12
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• 1984

Since a 13% dietary protein level is generally accepted as a standard in evaluating net protein utilization values of protein sources in chicks, limiting amino acids a 13% protein basal diet containing 15% isolated soy-protein as the only source of dietary protein, were identified. Of such amino acids as methionine, lysine, threonine and tryptophan added to the basal diet singly or as a combination, methionine appeared as the only limiting amino acid for optimum growth of the chicks. When the requirement of total sulfur-containing acids (TSAA) was estimated as the point at which the dose-response curve intersected a line representing the plateau for maximum performance, the TSAA requirements for maximum growth and feed intake were 4.73% and 3.73% of dietary protein, respectively. The values, expressed in terms of TSAA intake, required for maximum weight gain, feed intake and gain/feed ratio were 167.1, 136.8 and 159.1 mg/bird/day, respectively.

• Journal of Nutrition and Health
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• v.39 no.2
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• pp.145-159
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• 2006

This study was performed to investigate the stress level, dietary attitudes and nutrient intakes of Food and Nutrition major female students at a university located in Changwon. A total of 122 female students taking the course 'Meal Management' during 2001-2004 participated in this study. The general characteristics, stress level and dietary attitudes of the subjects were surveyed using a self-administered questionnaire. The nutrient intake data collected from 3-day food-record method were analyzed by the Computer Aided Nutritional Analysis Program. The symptoms by stress showed that 'eye strain', 'physically exhausted or get tired' and 'pains on neck or shoulders' were high in 59.4-81.8%. The mean scores of stress in 2001-2004 were 8.5-12.0 out of 30 points and the subjects in 2002 and 2004 scored significantly higher on stress level than the subjects in 2001 did (p < 0.00. The mean scores of dietary attitudes were 58.7-66.6 out of 100 points, most of the subjects are belonged to the 'fair' group in terms of dietary habits level. The stress level had a negative correlation with dietary habits (p < 0.001). About 1/3 of the subjects, the intake of calcium, vitamin $B_2$, vitamin A and iron were less than 75% of Korean RDA, whereas more than half of the subject, protein, vitamin C and phosphorus intake were more than 125% of RDA, and intake ratio of Ca and P showed an unbalance of 1 : 2. The animal protein intake was higher than the plant protein, whereas the animal vitamin A and iron intake were lower than vegetable food source. In 2001-2004, the index of nutritional quality (INQ) of vitamin $B_2$ and niacin was 0.56-0.98, and in 2003, the INQs of vitamin $B_2$ was 0.56, and that of niacin was 0.67, which was extremely low when compared to that of the other nutrients. Therefore, nutritional education is necessary if female university students are to practice optimal nutrition, including well-balanced diets of high nutritional quality.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.78-79
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• 2003

Effects of dietary lipid level and source (squid liver oil being rich in n-3 HUFA, soybean oil being rich in 18:2n-6, and linseed oil being rich in 18:3n-3) in fishmeal-based diet on growth and body composition of grower sunshine bass raised in seawater were investigated. Fifteen grower (an initial weight of 146.8$\pm$0.23 g) sunshine bass were randomly distributed into 27 of 250 L fiber reinforced plastic flow-through tanks. Fish were hand-fed to satiety twice daily for 6 days a week throughout the feeding trial. Survival was over 97% and not significantly affected by either dietary lipid level or lipid source (n-3 highly unusaturated fatty acid, HUFA). Weight gain of fish tended to improve with dietary n-3 HUFA level up to 2.9%, but sharply decreased at 3.5%. The best weight gain was obtained in fish fed the diet supplemented with 6% squid liver oil and 3% soybean oil. FER and PER were not significantly affected by either dietary lipid level or dietary lipid source. The lowest moisture content of the whole body was observed in fish fed the diet supplemented with 12% squid liver oil and highest for the diet supplemented with 9% linseed oil, respectively. Protein content of fish was not significantly affected by either dietary lipid level or dietary lipid source. However, lipid content of the whole fish tended to increase with an increase of either dietary lipid level or dietary n-3 HUFA level, except for fish fed the diet supplemented with 9% linseed oil. Ash content of fish fed the diet with no supplementation of oil was highest and lowest for the diet supplemented with 9% soybean oil, respectively. Significant differences in saturated fatty acids (16:0, 18:0 and 24:0), monoene (18:1n-9), 18:2n-6, 20:5n-3 and sum of n-3 HFUA of fish were observed. In considering these results, it could be concluded that supplementation of 9% oil combined with 6% squid liver oil and 3% soybean oil into fishmeal-based diet was the most recommendable for growth of grower sunshine bass raised in seawater.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.541-548
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• 2022

Biofloc technology (BFT) systems provides an additional protein source for fish by converting waste in microbial flocs. Therefore, we aimed to determine the difference in the protein levels of the diet of Far Eastern catfish Silurus asotus reared in BFT and FW systems. We applied a two-way (six protein levels × two aquaculture systems) ANOVA design. We formulated six experimental diets to contain different protein levels (CPs)- 20%, 25%, 30%, 35%, 40% and 45%-referred to as the CP20, CP25, CP30, CP35, CP40 and CP45 diets, respectively. We randomly distributed 900 fish into 36 (18 each for BFT and FW), 300 L tanks (25 fish/tank) with three replications of each diet for 4 weeks. The weight gain (WG) and specific growth rate (SGR) considerably improved as the dietary protein level increased in the formulated diets. The BFT fish showed higher growth performance with any experimental diet than the FW fish. The growth performance of the fish fed the BFT-CP35 diet was higher than that of the fish fed the FW-CP45 diet. In conclusion, the cultivation of Far Eastern catfish (S. asotus) in BFTs can be carried out under reduced dietary protein levels.

• Animal Bioscience
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• v.35 no.2
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• pp.260-271
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• 2022

Objective: We aimed to investigate the effect of the differing amino acid (AA) release dynamics of two protein sources on the growth performance, nitrogen deposition, plasma biochemical parameters, and muscle synthesis and degradation of piglets when included in their diets at normal and low concentrations. Methods: Forty-eight piglets (Duroc×Landrace×Large White) with initial body weight of 7.45±0.58 kg were assigned to six groups and fed one of 6 diets. The 6 dietary treatments were arranged by 3×2 factorial with 3 protein sources and 2 dietary protein levels. They are NCAS (a normal protein content with casein), NBlend (a normal protein content with blend of casein and corn gluten meal), NCGM (a normal protein content with corn gluten meal), LCAS (a low protein content with casein), LBlend (a low protein content with blend of casein and corn gluten meal), LCGM (a low protein content with corn gluten meal). The release dynamics of AA in these diets were determined by in vitro digestion. The digestibility, utilization and biological value of nitrogen in piglets were determined by micro Kjeldahl method. Plasma insulin was measured by enzyme-linked immunosorbent assay kits. The protein expression of mediators of muscle synthesis and degradation was determined by western blotting. Results: Although the consumption of a low-protein diet supplemented with crystalline AA was associated with greater nitrogen digestion and utilization (p<0.05), the final body weight, growth performance, nitrogen deposition, and phosphorylation of ribosomal protein S6 kinase 1 and eIF4E binding protein 1 in the muscle of pigs in the low-protein diet-fed groups were lower than those of the normal-protein diet-fed groups (p<0.05) because of the absence of non-essential AA. Because of the more balanced release of AA, the casein (CAS) and Blend-fed groups showed superior growth performance, final body weight and nitrogen deposition, and lower expression of muscle ring finger 1 and muscle atrophy F-box than the CGM-fed groups (p<0.05). Conclusion: We conclude that the balanced release of AA from CAS containing diets and mixed diets could reduce muscle degradation, favor nitrogen retention, % intake and improve growth performance in pigs consuming either a normal- or low-protein diet.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.962-970
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• 2007

A total of 1,200 LinNan Chinese color-feathered chicks were used to study the effects of methionine source [DL-2-hydroxy-4-methylthio-butanoic acid (HMTBa) or DL-methionine (DLM)] and dietary crude protein (CP) level on growth performance, carcass traits, and whole-body nitrogen and fat retention. The trial was designed as a $2{\times}2$ factorial arrangement, including two CP levels (adequate and low) and two methionine sources (HMTBa and DL-methionine). Diets were formulated for three phases, starter (0-21 d), grower (21-42 d), and finisher (42-63 d). Chicks fed HMTBa had higher daily gain and improved feed efficiency than DLM during the grower phase (p<0.05). A significant two-way interaction was observed for growth performance during the finisher phase and overall (0-63 d). Growth performance was greater for chicks fed HMTBa than DLM on adequate-CP diets (p<0.05), but this was not observed at low-CP level (p>0.05). Chicks fed low-CP diets grew slower, used feed less efficiently during the grower, finisher phase and overall. On d 42, regardless of dietary CP levels, birds fed HMTBa had higher carcass weights, breast and thigh weights than DLM-fed birds (p<0.04). Birds fed low-CP diet had lighter carcass weights and less breast muscle, thigh muscle, and dressing percentage at the end of starter, grower and finisher phases (p<0.05). Whole body composition analyses found that birds fed HMTBa tended to contain more protein and less fat compared to those chicks fed DLM at the end of the starter phase (p<0.10). Low-CP diets increased CP concentration in the whole body at the end of the finisher phase (p = 0.05). HMTBa supplementation increased whole-body N retention rate during the finisher phase and overall (p<0.01), and low-CP diets reduced N intake and whole-body fat retention during the finisher phase and overall (p<0.05). In summary, HMTBa was better than DLM on an equimolar basis for growth performance, carcass traits, and N retention in Chinese color-feathered chicks. Low-CP diets lowered growth performance as well as carcass traits in color-feathered birds, probably due to imbalanced AA profiles.