• Korean Journal of Community Nutrition
• /
• v.27 no.1
• /
• pp.47-60
• /
• 2022

Objectives: This study aimed to evaluate dietary protein intake and its adequacy among Korean adults during recent 10 years. Methods: Based on the 2010 ~ 2019 Korea National Health and Nutrition Examination Survey (KNHANES) data, a total of 51,296 adults aged 19 years old or more who participated in a one-day 24-hr dietary recall were included. Dietary protein intake was estimated as percentages of total energy (% of energy) and grams per body weight (g/kg/day) and compared with the 2020 Dietary Reference Intakes for Koreans to evaluate the adequacy of protein intake. In addition, proportions of people whose protein intakes were less than the estimated average requirement (EAR) and above the upper limit of the acceptable macronutrient distribution range (AMDR) (> 20% of energy) were calculated according to sociodemographic characteristics. Results: Protein intake was increased from 14.7% of energy in 2010 to 15.6% of energy in 2019 among Korean adults. However, there was no increase in protein intake relative to the recommended nutrient intake (% RNI) during the recent 10 years. Protein intake relative to the RNI was decreased from 130.2% in 2010 to 121.1% in 2019 (P for trend < 0.0001) among total participants, and a significant decreasing trend was observed in all age groups except for over 65 years old. However, protein intake relative to the RNI was lowest in the elderly (98.6%). Proportions of low protein intake (< EAR) and high protein intake (> AMDR) increased in the past 10 years (P for trend < 0.0001 for all), and these were associated with socioeconomic statuses, such as education and household income levels. Conclusions: These findings suggest that protein adequacy in Korean adults has not been improved over the past decade compared with recommended levels. Nutritional education and intervention programs should consider different intake levels according to sociodemographic characteristics.

• Journal of Nutrition and Health
• /
• v.21 no.1
• /
• pp.36-46
• /
• 1988

This study was carried out to investigate the effects of different protein and fat levels on the growth and on immune response in rats. In experiment 1, Sprague-Dawly male rats were fed diets containing 6%, 15%, or 30% casein with 2 levels of fat(2% and 30%) at each protein level. In experiment 2 and 3, rats were devided into 8 diet groups ; 4 different sources of proteins(casein, meat protein, fish protein, and gluten) were used at 15% level of the diet with 2% or 30% of dietary fat. The results show as follows 1) The rats in 6% casein group showed lower body weight gain and organ weight than those in 15% and 30% casein groups. There was no significant difference between 15% and 30% casein groups. In experiment 2, the gluten diet group showed the lowest growth rate and epididymal fat pad weight among 4 different dietary protein groups regardless the level of dietary fat. 2) There was no significant difference in immune response according to the sources and levels of dietary protein. However, the rats fed high fat diet showed the lower plaque-forming cell response than those fed low fat diet regardless dietary protein.

• Korean Journal of Poultry Science
• /
• v.14 no.2
• /
• pp.125-135
• /
• 1987

Total 720 brown layers were fed 9 rations differing in metabolizable energy (2500, 2700 and 2900 kcal/kg) and crude protein (13, 15 and 17%) levels for a period of 12 weeks in order to study the effects of dietary energy and protein levels on the performance of brwon layer in summer. As metabolizable energy level increased from 2500 to 2900Kcal/kg of feed egg production, daily feed and protein intake were decreased, but daily energy intake, energy requirement and feed cost per kilogram of egg mass were increased. There were no significant difference in egg weight, feed conversion and motality among dietary energy levels. On the other hand, as dietary Protein level increased from 13 to 17% egg Production, egg weight, daily protein intake and protein requirement per kilogram of egg mass were increased, but feed and energy requirement and feed cost per kilogram or egg mass were decreased. However daily feed intake and mortality were not affected by dietary protein level.

• Journal of Animal Science and Technology
• /
• v.63 no.5
• /
• pp.1126-1141
• /
• 2021

Recent evidence has shown that methionine (Met) supplementation can improve milk protein synthesis under hyperthermia (which reduces milk production). To explore the mechanism by which milk protein synthesis is affected by Met supplementation under hyperthermia, mammary alveolar (MAC-T) cells were incubated at a hyperthermic temperature of 42℃ for 6 h in media with different concentrations of Met. While the control group (CON) contained a normal amino acid concentration profile (60 ㎍/mL of Met), the three treatment groups were supplemented with Met at concentrations of 10 ㎍/mL (MET70, 70 ㎍/mL of Met), 20 ㎍/mL (MET80, 80 ㎍/mL of Met), and 30 ㎍/mL (MET90,90 ㎍/mL of Met). Our results show that additional Met supplementation increases the mRNA and protein levels of BCL2 (B-cell lymphoma-2, an anti-apoptosis agent), and decreases the mRNA and protein levels of BAX (Bcl-2-associated X protein, a pro-apoptosis agent), especially at an additional supplementary concentration of 20 ㎍/mL (group Met80). Supplementation with higher concentrations of Met decreased the mRNA levels of Caspase-3 and Caspase-9, and increased protein levels of heat shock protein (HSP70). The total protein levels of the mechanistic target of rapamycin (mTOR) and the mTOR signalling pathway-related proteins, AKT, ribosomal protein S6 kinase B1 (RPS6KB1), and ribosomal protein S6 (RPS6), increased with increasing Met supplementation, and peaked at 80 ㎍/mL Met (group Met80). In addition, we also found that additional Met supplementation upregulated the gene expression of αS1-casein (CSN1S1), β-casein (CSN2), and the amino acid transporter genes SLC38A2, SLC38A3 which are known to be mTOR targets. Additional Met supplementation, however, had no effect on the gene expression of κ-casein (CSN3) and solute carrier family 34 member 2 (SLC34A2). Our results suggest that additional Met supplementation with 20 ㎍/mL may promote the synthesis of milk proteins in bovine mammary epithelial cells under hyperthermia by inhibiting apoptosis, activating the AKT-mTOR-RPS6KB1 signalling pathway, and regulating the entry of amino acids into these cells.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.4
• /
• pp.723-731
• /
• 1992

Two similar experiments were designed to evaluate the interaction of dietary CP and ME levels on the production performance parameters at the age between 155 and 300 days in Starcross layers. In both experiments, the feed intake and mortality decreased but the egg weight, body weight gain and feed conversion efficiency increased as the dietary CP and ME levels increased. The CP intake was highest CP and lowest ME levels. With the increasing CP and decreasing ME levels, the ME intake decreased significantly (Experiments 1 & 2). The $CP{\times}ME$ interactions were significant only on mean egg weight and egg production in Experiment 2. In both the experiments, the CP levels were positively correlated with CP intake, egg weight, body weight gain and egg production and negative correlation with feed intake, mortality percentage and ME intake. The ME levels showed negative correlation with feed intake, protein intake, mortality percentages and positive correlation with all other parameters in both experiments. The highest values were noted for all the parameters (except mortality percentages) in Experiment 1 than that recorded in Experiment 2.

• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.1
• /
• pp.144-151
• /
• 2019

Objective: Curdlan has been widely used as a gelling agent in various food systems. This study was performed to evaluate the rheological properties of pork myofibrillar protein (MP) with different levels of curdlan (0.5% to 1.5%) and its application to low-fat model sausages (LFS). Methods: MP mixtures were prepared with 0.5%, 1.0%, and 1.5% of curdlan. Cooking loss (%), gel strength (gf), shear stress (Pa), and scanning electron microscopy were measured. Physicochemical and textural properties of LFS containing different levels of curdlan were measured. Results: The shear stress of MP mixtures increased with increasing levels of curdlan. MP gels with increased levels of curdlan decreased cooking loss and increased gel strength (p<0.05). The MPs with 1.0% and 1.5% of curdlan were observed more compact three-dimensional structure than those with 0.5% curdlan. Increased curdlan level in LFS affected redness ($a^{\star}$) and yellowness ($b^{\star}$) values. Although expressible moisture of LFS did not differ among curdlan levels, LFSs with various levels of curdlan decreased cooking loss as compared to control sausages. Hardness values (2,251 to 2,311 gf) of LFS with 0.5% and 1.0% curdlan was increased and differ from those (1,901 gf) of control sausages. Conclusion: The addition of 1.0% curdlan improved the functional and textural properties of LFS.

• Development and Reproduction
• /
• v.23 no.3
• /
• pp.223-229
• /
• 2019

Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance (IR). T2DM is correlated with obesity and most T2DM medications have been developed for enhancing insulin sensitivity. Silk protein fibroin (SPF) from spiders has been suggested as an attractive biomaterial for medical purposes. We generated transgenic rice (TR) expressing SPF and fed it to diabetic $BKS.Cg-m+/+Lepr^{db}$ mice to monitor the changes in blood glucose levels and adipose tissue proteins associated with energy metabolism and insulin signaling. In the present study, the adipocyte size in abdominal fat in TR-SPF-fed mice was remarkably smaller than that of the control. Whereas the adenosine monophosphate-activated protein kinase (AMPK)-activated protein kinase and insulin receptor substrate 1 (IRS1) protein levels were increased in abdominal adipose tissues after TR-SPF feeding, levels of six-transmembrane protein of prostate 2 (STAMP2) proteins decreased. Phosphorylation of AMPK at threonine 172 and IRS1 at serine 307 and tyrosine 632 were both increased in adipose tissues from TR-SPF-fed mice. Increased expression and phosphorylation of IRS1 at both serine 307 and tyrosine 632 in adipose tissues indicated that adipocytes obtained from abdominal fat in TR-SPF-fed mice were more susceptible to insulin signaling than that of the control. STAMP2 protein levels decreased in adipose tissues from TR-SPF-fed mice, indicating that STAMP2 proteins were reducing adipocytes that were undergoing lipolysis. Taken together, this study showed that TR-SPF was effective in reducing blood glucose levels in diabetic mice and that concurrent lipolysis in abdominal adipocytes was associated with alterations of AMPK, IRS1, and STAMP2. Increased IRS1 expression and its phosphorylation by TR-SFP were considered to be particularly important in the induction of lipolysis in adipocytes, as well as in reducing blood glucose levels in this animal model.

• Korean Journal of Exercise Nutrition
• /
• v.25 no.4
• /
• pp.54-58
• /
• 2021

[Purpose] Deleted in breast cancer 1 (DBC1) ablation causes obesity, and stearoyl-CoA desaturase 1 (SCD1) induces the biosynthesis of monounsaturated fatty acids. This study examined whether voluntary wheel running (VWR) alters SCD-1 and DBC1 protein levels in the liver of leptin-deficient ob/ob mice. [Methods] Twenty-five Ob/Ob mice were divided into two groups (ob/ob-Sed and ob/ob-Ex). The expression of DBC1 and SCD1 in the mouse liver was determined using western blotting. [Results] After 10 weeks, VWR significantly reduced body weight without affecting the fatty acid synthase and CD36 protein levels. The average daily running distance was 4.0±1.0 km/day. This improvement was associated with changes in the hepatic SCD1 and DBC1 levels. Hepatic SCD-1 protein levels increased significantly, and DBC1 protein levels decreased in ob/ob-Sed animals. On the other hand, VWR inhibited the obesity-induced increase in SCD1 expression and impaired the obesity-induced decrease in DBC1 expression in the liver of leptin-deficient ob/ob mice. [Conclusion] This is the first study showing that VWR has strong effects on hepatic SCD1 and DBC1 in ob/ob mice, and provides key insights into the effects of exercise on obesity.

• Asian-Australasian Journal of Animal Sciences
• /
• v.6 no.4
• /
• pp.527-539
• /
• 1993

To investigate the effects of crude protein and thyroxine on growth performance, nutrient utilizability, carcass composition, the content of total fat and cholesterol in leg muscle, breast muscle and liver, and caloric efficiency in broiler chicks. The experiment involved 3 levels of dietary crude protein (1-3 weeks: 20, 23, 26%; 4-6 weeks: 17, 20, 23%) and 3 levels of thyroxine (0.0, 1.5, 3.0 mg/kg). In the starting period (1-3 weeks), body weight gain of chicks fed diets containing 26% crude protein and 1.5 mg/kg thyroxine was higher than any other groups, and among thyroxine levels, 3.0 mg/kg thyroxine groups were lower. The best feed efficiency was obtained at 26% crude protein with no thyroxine supplemented or 1.5 mg/kg thyroxine supplemented groups. In the finishing period (4-6 weeks) the highest body weight gain was obtained at 23% crude protein with no thyroxine supplemented group. Feed intake of 17% crude protein with 1.5 mg/kg thyroxine supplemented group was higher than those of the other groups. It was found that the utilizability of crude protein in the starting period, showed the best utilizability at 20% crude protein with 1.5 mg/kg thyroxine group. Increasing crude protein level from 17 to 23%, utilizability of crude fat was decreased. The carcass composition was significantly (p<0.05) influenced by crude protein and thyroxine. Increasing thyroxine level from 0.0 to 3.0 mg/kg, crude protein content was increased whereas, crude fat content was decreased. Chicks fed diet containing 1.5 mg/kg thyroxine showed the lowest total fat content in liver tissue. In breast muscle, it was significantly (p<0.05) affected by crude protein and thyroxine. Present data revealed that the cholesterol content was increased for the chicks fed 3.0 mg/kg thyroxine. It the caloric efficiency, chicks fed a diet containing 20% crude protein with no thyroxine supplementation showed the highest caloric efficiency and the lowest efficiency was from 23% crude protein group with 1.5 mg/kg thyroxine. From this study it may be concluded that crude fat content of carcass could be successfully reduced by dietary supplementation of thyroxine, whereas crude protein content was increased.

• Asian-Australasian Journal of Animal Sciences
• /
• v.11 no.3
• /
• pp.245-248
• /
• 1998

The influence of refeeding either protein, carbohydrate or fat on hepatic insulin-like growth factor-I (IGF-I) mRNA level in chicks which had been fasted for 2 days was examined. The hepatic IGF-I mRNA was measured by ribonuclease protection assay. Fasting reduced hepatic IGF-I mRNA levels to less than half of those in the fed control. When chicks were refed either a control, protein or carbohydrate diet, IGF-I mRNA levels significantly increased to those in the fed control until 2 hours of refeeding. Refeeding of fat did not alter hepatic IGF-I mRNA levels. The significant correlation between liver weight and hepatic IGF-I gene expression suggests that when chicks are refed after 2-d fasting, the acute increase in hepatic IGF-I gene expression brought about after refeeding may be partly regulated by the increase in liver protein metabolism.