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

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.1
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• pp.7-12
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• 1988

Twenty cows, by order of calving, were used in a completely randomized $2{\times}2$ factorial experiment. Variables were tow protein levels (14 and 18% crude protein) and concentration of fat (2 and 6% ether extract) in diets. Fat addition, via unprocessed whole sunflower seed, insured forage utilization in diets to meet energy requirement of cows. A total of 36 wks of lactation was subdivided into three 12-wk stages of lactation. Net energy lactation was set at 1.72, 1.57 and 1.42 Mcal/kg for each stage. Higher protein diets improved the efficiency of energy (FCM/net energy intake) which was particularly noted for diets containing high fat (85.7%). However, diets with low protein-high fat resulted in the lowest efficiency (67.7%). No difference in milk yield and butterfat was due to different levels and combinations of protein and lipid in diets. High protein diets depressed blood cholesterol and glucose compared to low-protein counterparts. Relative decline in milk production was slower for lower fat diets than for higher fat groups, especially mid to later stage of lactation. Results of this experiment tend to support our thesis on the synergistic effect of dietary protein and energy (lipid) upon efficiency of lactation.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.1
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• pp.107-111
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• 1996

Studies on the effects of protein levels on the total sulphur amino acid (TSAA) requirements of chickens were conducted on the starter broilers by feeding four levels of crude protein(16, 18, 20 and 23%) at three levels of TSAA (0.83, 0.93 and 1.03%) and on the grower broilers by feeding three levels of crude protein (16, 18 and 20%) at three levels of TSAA(0.72, 0.79 and 0.86%). The metabolisable energy of the diets was maintained constant at 3,200 kcal/kg and the experiments were carried out for two growing periods: starter (0-3 wk) and grower (3-6 wk). The results showed that there were significant differences in body weight gain, feed intake and feed:gain ratio under different protein levels of the starters. Crude protein, ME and TSAA intake were significantly affected by increasing the CP levels. The TSAA requirement of the starter broilers is recommended at 0.93% and it is not influenced by different protein levels used in the experiment. For the grower period, body weight gain and feed:gain ratio improved significantly at higher protein diets. Birds fed higher protein diet consumed greater quantities of protein. Responses to TSAA supplementation for body weight gain, feed intake and feed:gain ratio were not significant. The present results showed that the TSAA level of 0.79 to 0.86% was required for grower diets and that the protein levels of the diet did not influence the TSAA requirement.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.1
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• pp.57-68
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• 1982

In order to investigate the effect of dietary protein and energy on growing female and male rats, Sprague-Dawley 90 female rats and 54 male rats of 3 weeks old weighing approximately 70-80g and 65-75g, respectively, were subjected to feeding trials for 8 weeks and then subsquently to metabolic trials for 2 weeks. Three dietary energy levels (3200, 3600, 4000 kcal ME/kg) were employed and each energy level contained three protein levels (15, 25, 35% of 3600 kcal ME/kg) and three fat levels (10, 20, 40% of 3600 kcal ME/kg) by addition of an appropriate amount of carbohydrate and the following results were obtained. The body weight gain of female rats was highest for LPHE ration but that of male rats was highest for LPME ration. The weight gains both of female and male rats were not affected by the level of protein. Food efficiencies both of female and male rats was affected by the level of protein, whereas that of male rats was not. Protein efficiencies of female and male rats were highest at low protein level and tended to decrease as the level of protein increased, but that of female rats was highest at high energy level, while that of male rats was highest at medium energy level. The analysis of the body composition after feeding trials for 8 weeks has shown that the contents of body water and protein were not affected by protein level both in female and male rats. The content of body fat increased remarkably as the protein and energy levels increased in case of female rats, but it was not affected by the protein and energy levels in case of male rats. From the above-mentioned experimental results it may be con eluded that the best formula of diet of growing female rats may be composed of low protein (13%) and high energy levels (4000 kcal/kg) whereas that for male rats may be composed of low protein (13%) and medium energy levels (3600 kcal/kg), since all the efficiencies of food, protein and energy have shown to be best at these levels.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.129-138
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• 1992

The effects of dietary levels of lysine and energy on growth performance, the content of DNA, RNA and protein in liver, thigh muscle composition and nutrient utilization in broiler chicks were investigated in an experiment involvies with 2 levels of dietary energy : 3,200 (2900) 2,900 (2700) kcal ME/kg) and 6 levels of lysine : 0.6(0.5), 0.8(0.7), 1.0(0.9), 1.2(1.1), 1.4(1.3), and 1.6(1.5)% was carried out. A total number of 384 male broiler chicks was used for a period of 7 weeks. Body weight gain of 1.0(0.9)% lysine level group was significantly (p < 0.01) higher than that of any other groups. Interaction between lysine and energy in the feed intake was observed (p < 0.05). Present data indicate that the content of DNA in liver tissues was significantly (p < 0.05) different by the levels of lysine, namely, 1.0(0.9)% or 1.2(1.1)% lysine level groups showed higher content than other groups (p < 0.01). Dietary levels of 1.2(1.1)% or 1.6(1.5)% lysine groups showed the highest protein content in thigh muscle tissues than that of any other groups (p < 0.05). Interaction between energy and lysine in the content of protein of thigh muscle tissues was shown (p < 0.01). The level of 0.6% lysine group showed the highest fat content in thigh muscle tissues than any other groups. Interaction between lysine and energy in the content of crude ash and crude fat of thigh muscle tissues was observed (p < 0.01). Apparent amino acid availability of arginine, glycine and threonine (p < 0.01), phenylalanine (p < 0.05) were significantly affected by the levels of lysine and interaction between lysine and energy was found only in arginine (p < 0.01).

• Korean Journal of Poultry Science
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• v.14 no.1
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• pp.39-53
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• 1987

A total of 1,440 White Leghorn pullets hatched in summer and winter, aged 20 to 72 weeks were fed 9 rations differing in dietary protein (13, 15 and 17%) and energy (2,500, 2,700 and 2,900 kcal/kg) levels for a period of 52 weeks in order to evaluate the optimum dietary energy and protein levels for laying hens. As metabolizable energy level increased from 2,500 to 2,900 kcal/kg of feed egg production, daily feed and protein intake and egg shell quality decreased, but reverse was true for the daily energy intake, energy requirement and feed cost per kg egg, body weight gain, nutrients utilizability and abdominal fat accumulation, Egg weight, viability and egg yolk Pigmentation were not affected by the dietary energy level. On the other hand, as dietary protein level increased from 13 to 17%, egg production, egg weight, daily protein intake, protein requirement per kg egg and body weight gain icreased, but daily feed and energy intake, feed and energy requirement per kg egg, egg yolk pigmentation and dry matter utilizability decreased, and no significant difference in the feed cost per kg egg, viability and egg shell quality was observed among dietary protein levels. However: the hens fed 15% and 17% Protein diets did not show significant differences in egg production, egg weight and body weight gain. For the entire laying period of 52 weeks, metabolizable energy level of 2,500 kcal/kg of feed and 15% dietary protein level were considered to be adequate to support the optimum productivity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.308-313
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• 2015

A $3{\times}3$ factorial study was conducted to investigate the effects of dietary protein and lipid levels on the growth, feed utilization and innate immunity of red seabream Pagrus major. Nine diets consisting of three protein levels (42%, 46% and 50% crude protein) and three lipid levels (10%, 14% and 18% crude lipid) were formulated. Triplicate groups of red seabream were fed the experimental diets to apparent satiation (5-6 times a day, from 08:00 to 18:00 h at 2-h intervals) for 10 weeks. At the end of the feeding trial, the weight gain and specific growth rate of fish fed P46L14 (46% protein and 14% lipid), P50L10 (50% protein and 10% lipid) and P50L14 (50% protein and 14% lipid) were significantly (P<0.05) higher than those of fish fed P42L18 (42% protein and 18% lipid). The feed conversion ratios (FCR) of the fish were affected by dietary lipid levels (P<0.039), but not dietary protein levels. The FCR tended to increase with increasing dietary lipid levels from 10% to 18% with the 46% and 50% protein levels. The weight gain, protein efficiency ratio, specific growth rate, feed intake and survival of fish were not affected by either dietary protein or lipid levels. Myeloperoxidase activity in the group fed P50L14 (50% protein and 14% lipid) was significantly higher than that in the group fed P42L10 (42% protein and 10% lipid) or P50L18 (50% protein and 18% lipid). However, the myeloperoxidase activity of fish was not affected by either dietary protein or lipid level. The fish fed P46L14 (46% protein and 14% lipid) and P46L18 (46% protein and 18% lipid) showed significantly higher superoxide dismutase activity than did the fish fed P46L10 (46% protein and 10% lipid), P50L10 (50% protein and 10% lipid) of P50L18 (50% protein and 18% lipid). In conclusion, the optimum protein and lipid levels for the growth and feed utilization of juvenile red seabream were 46% and 14%, respectively, and the optimum dietary protein to energy ratio was 27.4 g/MJ.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.207-212
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• 1994

Effects of dietary cellulose and protein levels on nutrient utilization in chickens were investigated. Four experimental diets containing 5% (low cellulose) or 20% (high cellulose) cellulose in combination with 10% (low protein) or 20% (high protein) protein of 70 g/day were alternatively forced-fed to eight colostomized White Leghorn cockerels once a day to make $4{\times}4$ Latin-square design. The digestibilities of DM and energy decreased with the increase in cellulose level, but not affected by dietary protein level. Ether extract digestibility was higher in the high cellulose diets than in the low cellulose protein level. Ether extract digestibility was higher in the high cellulose diets than in the low cellulose diets. The digestibility of nitrogen free extract had the same trend with the digestibility of DM and energy. The digestibility of acid detergent fiber was not so much different among the diets, but the NDF digestibility was lower in the high cellulose diets than in the low cellulose diets, due to the low hemicellulose digestibility. The true digestibility of protein was influenced by both of the dietary protein and cellulose levels, and their interaction was found. The dietary protein level affected the biological value of protein but the dietary cellulose level did not, and consequently the biological value of protein in the low protein diets was lower than in the high protein diets.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.3
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• pp.330-339
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• 2002

Fifty one Nili-Ravi dairy buffaloes in their last two months of gestation were selected. After parturition, rectal examination of reproductive organs was carried out until the occurrence of the first oestrus (PEI). Milk samples were analyzed for milk progesterone levels (MPL). Ovulation (POI) was confirmed by rectal palpation and MPL. Feed and blood samples were collected fortnightly and analyzed. Body condition score (BCS) was recorded on a scale of 0 to 5. Crude protein (CP) intake varied among different seasons and correlated positively with serum urea levels, POI (p<0.01) and PEI (p<0.05). Excess CPI was lower in the group showing oestrus as compared to those remaining as anoestrus (p<0.05). The dietary ratio of crude protein - metabolizable energy (CP:ME) in the oestrus animals was narrow and constant, while the anoestrus animals had a widely fluctuating one. In normal breeding season (NBS) calvers, mean serum urea level (SUL) was lower than the low breeding season (LBS) calvers. SUL was positively correlated with PEI and POI (p<0.01). Up to six months postpartum, SUL were constantly higher in anoestrus than oestrus buffaloes. Mean metabolizable energy (ME) intake was lower in the NBS calvers than the LBS calvers (p<0.01). BCS and postpartum ovulation interval were correlated with ME intake (p<0.01). Prepartum ME intake was higher in oestrous as compared to anoestrous animals (p<0.05). Higher and lower ME intakes were associated with anoestrus, while a moderate energy intake was associated with a PEI of less than 75 days. Buffaloes with poor BCS belonged to the LBS calving group and most of the NBS calving buffaloes had good BCS. BCS was negatively correlated with PEI (p<0.01) and was higher in oestrous buffaloes than anestrus. It was concluded that excess intake of crude protein, associated with higher serum urea levels and low energy intake, associated with poor body condition, are the key factors for low reproductive efficiency. It may be corrected by adopting a proper feeding strategy.

• Journal of Animal Science and Technology
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• v.61 no.3
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• pp.154-162
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• 2019

This experiment was conducted to evaluate the effect of dietary energy and crude protein (CP) levels on reproductive performance, litter performance, milk quality, and blood profiles in gestating sows. A total of 59 multiparous sows (Yorkshire ${\times}$ Landrace) with similar body weights (BW), backfat thickness (BF), and parity were assigned to one of six treatments with 9 or 10 sows per treatment using a $2{\times}3$ factorial arrangement and completely randomized design. The first factor was two levels of dietary metabolizable energy (ME) density (13.40 or 13.82 MJ/kg) and the second factor was three dietary protein levels based from 35 day in gestating phases (10.5%, 12%, and 13.5%). Backfat thickness change in lactating sows decreased linearly as CP level increased (p = 0.03). Increased energy level in the gestating sow diet tended to increase the total number of piglets born (p = 0.07), but piglet weight decreased (p = 0.02). Dietary CP level had a negative effect on colostrum quality. Casein, protein, total solid, and solids-not-fat concentrations decreased linearly and lactose level increased linearly as CP level in the gestating sow diet increased (casein%: p = 0.03; protein%: p = 0.04; lactose%: p = 0.06; total solids: p = 0.03; solid-not-fat: p = 0.03, respectively). However, improving ME by 0.42 MJ/kg had no significant effect on the chemical composition of sow colostrum. There were no significant differences in blood glucose concentration in gestating sows when sows were fed different levels of energy during gestation, but blood glucose increased at 21 day of lactation when energy increased by 0.42 MJ/kg (p = 0.04). Blood urea nitrogen concentration increased linearly when dietary CP levels increased at 110 day in gestation, 24-hours postpartum, and 21 days of lactation (linear, p < 0.05, p < 0.05, and p < 0.05, respectively), and it also increased when dietary energy increased at 110 days of gestation and 24-hours postpartum (p < 0.01, and p < 0.01, respectively). A gestating sow diet containing 13.82 MJ/kg ME and 10.5% CP can improve reproductive performance, litter performance, and colostrum quality.