• Journal of Nutrition and Health
• /
• v.57 no.4
• /
• pp.365-375
• /
• 2024

Purpose: Zinc is involved in regulating homeostasis and metabolism in the body, and understanding these processes is important for estimating intake requirements. This review aimed to assist in setting the standards for Dietary Reference Intakes for Koreans (KDRIs, 2025) for zinc by examining specific factors associated with role of zinc in the body and using the factorial analysis method. Methods: We reviewed the zinc-specific factors that should be considered when setting the required zinc intake to maintain zinc homeostasis in the body and used the factorial analysis method for estimating zinc requirements for different population groups. Results: Factorial analysis involves estimating the required intake based on various factors that affect zinc metabolism and requirements. The key components and steps involved in determining the zinc dietary reference intake (DRI), particularly the estimated average requirement (EAR), include: 1) Estimating basal requirements, which involves calculating the amount of zinc needed to replace natural losses through the intestinal (feces) and non-intestinal (urine, skin and other body secretions) routes, 2) Accounting for the various biomarkers related to metabolic functions of zinc, 3) Considering physiological requirements for zinc, such as those for growth, development, pregnancy, and lactation since zinc is essential for DNA and protein synthesis, and 4) Estimating the dietary absorption rate of zinc. Conclusion: The factorial analysis for zinc requirement is based on scientific evidence and is tailored to meet the requirements of different population groups, ensuring optimal health and preventing deficiency. It includes considerations of physiological needs, dietary absorption, and population-specific characteristics.

• Korean Journal of Poultry Science
• /
• v.14 no.1
• /
• pp.25-31
• /
• 1987

This experiment was conducted to study the most economical and effective dietary protein level and feeding regimes in the performance of broilers. Four kinds of dietary protein level (25, 23, 20 and 18%) were prepared for this experiment. This experiment was carried on for 7 weeks and the results were shown as follows; 1. Increasing the dietary protein level resulted in a significant increase in the body weight gains (P〈0.05). 2. With a higher level of the dietary protein, the feed intake tended to be increased and the feed efficiency had same trends. 3. Increasing the dietary protein level resulted in a significant increase in the protein requirement per kg body weight gains (P〈0.05). 4. Viabilities were not affected by the different dietary protein levels. 5. The highest income had attained in the highest level of protein supplement, and the middle level of protein supplement was not higher than the lowest one. Conclusively, the highest level of protein supplement was considered to be adequate for the broiler's productiveity and income.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.8
• /
• pp.1080-1087
• /
• 2004

A trial with twenty-four newly weaned Awassi lambs (initial body weight=21.5$\pm$0.8 kg) was conducted using a 3$\times$2 factorial design to study the effect of feeding three sources of protein supplements (soybean meal (SBM), sunflower seed meal (SSM), and cottonseed meal (CSM)), either untreated or formaldehyde-treated on the growth performance and carcass traits of Awassi lambs. Lambs were randomly assigned to one of the six diets (4 lambs/treatment diet) and were individually fed for a period of 107 days. Experimental diets were isonitrogenous and isocaloric. Final live weight and average daily gain (ADG) were affected by both source of protein and formaldehyde treatment (undegradable protein). Lambs fed untreated diets had better (p<0.01) daily gain compared to those fed formaldehyde-treated diets. Similarly total feed intake per animal was significantly (p<0.05) affected by protein source and formaldehyde treatment. Formaldehyde treatment caused a significant decrease (p<0.01) in feed intake compared to lambs fed untreated diets. Feed requirement per unit of gain was not affected by formaldehyde treatment during all periods of the experiment except for the second period (the second 28 day period), whereby untreated SBM, SSM and CSM had better feed conversion ratio (FCR) than the treated groups. Source of protein had a moderate effect (p<0.10) on FCR but had a significant effect (p<0.05) on hot and cold carcass weight, digestive tract empty weight and liver weight, with lambs fed SBM having higher values than lambs fed SSM and CSM diets. Supplementation with undegradable protein had a significant effect (p<0.05) on dressing-out percentage (p<0.05), final live weight, and hot and cold carcass weight (p<0.01). The lower values pertain to lambs fed treated diets compared to lambs fed untreated diets. In general, there were no significant differences among all carcass linear dimensions, carcass cut weights and dissected loin tissue weights for both treatments (protein source and formaldehyde treatment). Supplementation with undegradable protein but not the source of protein resulted in significantly higher dissected leg total bone weight (p<0.05), tibia and femur weight (p<0.05), and femur length (p<0.01) at the same carcass weight. Results suggest that the treatment of SBM, SSM and CSM with formaldehyde did not improve efficiency of feed utilization, lamb performance or carcass traits and that the SBM diet resulted in an increase in lamb performance compared to other experimental diets.

• Journal of Life Science
• /
• v.14 no.5
• /
• pp.741-746
• /
• 2004

This study investigated the response of GLUT-4 and GRP-78 protein expression in soleus muscle of Streptozotocin-induced diabetic rats with caffeine oral administration by imposing different exercise intensities. Rats were randomly divided into 5 groups (n=6 in each group): diabetic group (D), diabetic-caffeine group (DC), diabetic-caffeine group with low intensity exercise (DCL), diabetic-caffeine group with moderate intensity exercise (DCM) and diabetic-caffeine group with high intensity exercise (DCH). The rats in DCL, DCM and DCH groups were exercised acutely by treadmill running for 8 meter/m, 16 meter/m and 25 meter/m, respectively. Little difference in GLUT-4 protein expression was shown in DC and DCL compared to D. GLUT-4 protein expression was decreased in DCM and increased in DCH was observed. GRP-78 protein expressions in DCL, DCM and DCH were little lower than that of D. An increase in GRP-78 protein was observed in DC. Improved insulin sensitivity with acute high intensity exercise gives the rats important therapy that lowers insulin requirement. This improvement of insulin sensitivity for glucose transport in skeletal muscle results from translocation of the GLUT-4 protein from the endoplasmic reticilum to the cell surface and increase in total quantity of GLUT-4 protein. It is not clear what mechanism reduced GRP-78 protein level in exercise group. It is merely conjectured that caffeine-induced lipolysis provided cells with energy in abundance and this relieved stress which cells are subjected to receive when performing exercise.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2001.06a
• /
• pp.83-89
• /
• 2001

Recent advances in the structural and molecular biology uncovered that a set of translation factors resembles a tRNA shape and, in one case, even mimics a tRNA function for deciphering the genetic ：ode. Nature must have evolved this 'art' of molecular mimicry between protein and ribonucleic acid using different protein architectures to fulfill the requirement of a ribosome 'machine'. Termination of protein synthesis takes place on the ribosomes as a response to a stop, rather than a sense, codon in the 'decoding' site (A site). Translation termination requires two classes of polypeptide release factors (RFs)： a class-I factor, codon-specific RFs (RFI and RF2 in prokaryotes; eRFI in eukaryotes), and a class-IT factor, non-specific RFs (RF3 in prokaryotes; eRF3 in eukaryotes) that bind guanine nucleotides and stimulate class-I RF activity. The underlying mechanism for translation termination represents a long-standing coding problem of considerable interest since it entails protein-RNA recognition instead of the well-understood codon-anticodon pairing during the mRNA-tRNA interaction. Molecular mimicry between protein and nucleic acid is a novel concept in biology, proposed in 1995 from three crystallographic discoveries, one, on protein-RNA mimicry, and the other two, on protein-DNA mimicry. Nyborg, Clark and colleagues have first described this concept when they solved the crystal structure of elongation factor EF- Tu：GTP：aminoacyl-tRNA ternary complex and found its overall structural similarity with another elongation factor EF-G including the resemblance of part of EF-G to the anticodon stem of tRNA (Nissen et al. 1995). Protein mimicry of DNA has been shown in the crystal structure of the uracil-DNA glycosylase-uracil glycosylase inhibitor protein complex (Mol et al. 1995; Savva and Pear 1995) as well as in the NMR structure of transcription factor TBP-TA $F_{II}$ 230 complex (Liu et al. 1998). Consistent with this discovery, functional mimicry of a major autoantigenic epitope of the human insulin receptor by RNA has been suggested (Doudna et al. 1995) but its nature of mimic is. still largely unknown. The milestone of functional mimicry between protein and nucleic acid has been achieved by the discovery of 'peptide anticodon' that deciphers stop codons in mRNA (Ito et al. 2000). It is surprising that it took 4 decades since the discovery of the genetic code to figure out the basic mechanisms behind the deciphering of its 64 codons.

• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.2
• /
• pp.257-264
• /
• 2019

Objective: Dairy cattle nutrient requirement systems acknowledge amino acid (AAs) requirements in aggregate as metabolizable protein (MP) and assume fixed efficiencies of MP used for milk protein. Regulation of mammary protein synthesis may be associated with AA input and milk protein output. The aim of this study was to evaluate the effect of nanoemulsified methionine and cysteine on the in-vitro expression of milk protein (casein) in bovine mammary epithelial cells (MAC-T cells). Methods: Methionine and cysteine were nonionized using Lipoid S 75 by high-speed homogenizer. The nanoemulsified AA particle size and polydispersity index were determined by dynamic light scattering correlation spectroscopy using a high-performance particle sizer instrument. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the cytotoxicity effect of AAs with and without nanoionization at various concentrations (100 to $500{\mu}g/mL$) in mammary epithelial cells. MAC-T cells were subjected to 100% of free AA and nanoemulsified AA concentration in Dulbecco's modified Eagle medium/nutrient mixture F-12 (DMEM/F12) for the analysis of milk protein (casein) expression by the quantitative reverse transcription polymerase chain reaction method. Results: The AA-treated cells showed that cell viability tended to decrease (80%) in proportion to the concentration before nanogenesis, but cell viability increased as much as 90% after nanogenesis. The analysis of the expression of genetic markers related to milk protein indicated that; ${\alpha}_{s2}$-casein increased 2-fold, ${\kappa}$-casein increased 5-fold, and the amount of unchanged ${\beta}$-casein expression was nearly doubled in the nanoemulsified methionine-treated group when compared with the free-nanoemulsified methionine-supplemented group. On the contrary, the non-emulsified cysteine-administered group showed higher expression of genetic markers related to milk protein ${\alpha}_{s2}$-casein, ${\kappa}$-casein, and ${\beta}$-casein, but all the genetic markers related to milk protein decreased significantly after nanoemulsification. Conclusion: Detailed knowledge of factors, such nanogenesis of methionine, associated with increasing cysteine and decreasing production of genetic markers related to milk protein (casein) will help guide future recommendations to producers for maximizing milk yield with a high level of milk protein casein.

• Asian-Australasian Journal of Animal Sciences
• /
• v.25 no.1
• /
• pp.98-103
• /
• 2012

This study was conducted to re-evaluate the dietary vitamin C requirement in juvenile eel, Anguilla japonica by using L-ascorbyl-2-monophosphate (AMP) as the vitamin C source. Five semi-purified experimental diets were formulated to contain 0 ($AMP_0$), 30 ($AMP_{24}$), 60 ($AMP_{52}$), 120 ($AMP_{108}$) and 1,200 ($AMP_{1137}$) mg AMP $kg^{-1}$ diet on a dry matter basis. Casein and defatted fish meal were used as the main protein sources in the semi-purified experimental diets. After a 4-week conditioning period, fish initially averaging $15{\pm}0.3$ g (mean${\pm}$SD) were randomly distributed to each aquarium as triplicate groups of 20 fish each. One of five experimental diets was fed on a DM basis to fish in three randomly selected aquaria, at a rate of 3% of total body weight, twice a day. At the end of the feeding trial, weight gain (WG) and specific growth rate (SGR) for fish fed $AMP_{52}$ and $AMP_{108}$ were significantly higher than those recorded for fish fed the control diet (p<0.05). Similarly, feed efficiency (FE) and protein efficiency ratio (PER) for fish fed $AMP_{52}$ were significantly higher than those for fish fed the control diet (p<0.05). Broken-line regression analysis on the basis of WG, SGR, FE and PER showed dietary vitamin C requirements of juvenile eel to be 41.1, 41.2, 43.9 and 43.1 (mg $kg^{-1}$ diet), respectively. These results indicated that the dietary vitamin C requirement could range from 41.1 to 43.9 mg $kg^{-1}$ diet in juvenile eel when L-ascorbyl-2-monophosphate was used as the dietary source of vitamin C.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.1
• /
• pp.39-45
• /
• 2004

Despite higher fecundity, Black Bengal goat generally has lower milk production, which is often insufficient for their multiple kids. However, milk requirement of Black Bengal kids is poorly defined. Present trial was thus designed to determine the requirement and intake of milk of pre-weaned Black Bengal kids in relation to their growth rate age and sex. Thirty, one month old Black Bengal kids of either sex divided into two groups were allocated to two groups, suckling alone (T1) or suckling along with teat-bottle feeding of milk (T2). Ten kids were allocated for the T1 and 20 kids were allocated for the T2. Digestibility of milk was also determined in T2 animals. Average daily consumption of milk, milk energy and milk N were 773 and 722 g, 1,170 and 1,093 kJ/kg $W^{0.75}/d$ and 1,552 and 1,462 mg N/kg $W^{0.75}/d$, respectively. During 9 weeks trial period, male kids had significantly higher live weight (4.32 vs. 4.20 kg; p<0.01) and intake of milk (773 vs. 722 g/d; p<0.05), energy (117 vs. 1,093 kJ/kg $W^{0.75}$/d; p<0.01) and N (1,552 vs.1,462 mg/k $W^{0.75}/d$; p<0.01) than the female. Milk consumption and the corresponding milk energy and milk N intake increased linearly up to 5th week of the trial, which, then decreased quadratically up to 9th week i.e., up to the weaning. Overall milk DM intake during this period was 2.58% (range 1.5-3.0%) of live weight or about 36 g/kg $W^{0.75}/d$ (range 29-45 g/kg $W^{0.75}/d$). Pre-weaned Black Bengal kids of about 4.5 kg weight, growing at the rate of 60 g weight daily requires at least 750 g milk daily. Daily live weight gain, estimated as the regression between the live weights over time, was 60 g ($r^2$=0.99) and 55 g ($r^2$=0.99), respectively, for the male and female kids. Efficiency of milk energy utilization for weight gain ranged from 0.67 to 0.84 (mean 0.81) for the male kid and 0.75 to 0.91 (mean 0.82) for the female kids. Efficiency of milk protein utilization for weight gain ranged from 0.46 to 0.70 (mean 0.61) for the male kid and 0.51 to 0.81 (mean 0.64) for the female kids. Additional teat-bottle feeding of suckling kids had no significant effect on their growth rate (54vs. 57 g/d). Average digestibility of milk DM, OM and N was 98.85, 98.99 and 98.69%, respectively and they were slightly (p>0.05) higher in the male than the female kids. Results suggest that the requirement of energy and protein and their utilization efficiency in Black Bengal kids is not different from that of the other breeds of goat.

• Journal of Animal Science and Technology
• /
• v.51 no.2
• /
• pp.155-162
• /
• 2009

This study was conducted to determine the protein requirement level in adult Jindo dog (Korea Jindo Dog) through nitrogen balance experiments. 12 female dogs aged 36~38 weeks old (for early stage) or aged 45~49 weeks old (for late stage) were fed one of 3 diets containing 17, 19 and 21% of crude protein. Body weight of dogs were measured during the 12 days of feeding trial, and feces and urine were collected last 3 days of the trial period. In early stage of Jindo dog, average daily gain of dogs fed experimental diets containing 17, 19 and 21% of crude protein were -38.33, -16.25 and -12.71g/d, respectively. There was a significant differences between 17 and 21% of crude protein treatments (p<0.05) and calculated retained nitrogen were -0.29, -0.04 and -0.03g/kg$BW^{.75}$/d, respectively. In late stage of Jindo dog, average daily gain of dogs fed experimental diets containing 17, 19 and 21% of crude protein were -34.05, -28.71 and -28.28g/d, and calculated retained nitrogen were -0.33, -0.06 and 0.09g/kg$BW^{.75}$/d, respectively, and were significantly higher (p<0.05) in dogs fed 21% of crude protein diet than those of other dogs. In early stage and late stage of adult Jindo dog, a calculated linear regression equation for nitrogen intake (x) and nitrogen retention (y) were y = 0.7484x-1.18 ($R^2$ = 0.9923) and y = 0.88231x-1.0894 ($R^2$ = 0.9982) and the requirement of crude protein were estimated as 9.85g/kg$BW^{.75}$/d and 7.72g/kg$BW^{.75}$/d from above equation.

• Journal of Animal Science and Technology
• /
• v.58 no.10
• /
• pp.37.1-37.10
• /
• 2016

Background: Providing of insufficient nutrients limits the potential growth of pig, while feeding of excessive nutrients increases the economic loss and causes environment pollution. For these reasons, phase feeding had been introduced in swine farm for improving animal production. This experiment was conducted to evaluate the effects of dietary energy levels and phase feeding by protein levels on growth performance, blood profiles and carcass characteristics in growing-finishing pigs. Methods: A total of 128 growing pigs ([Yorkshire ${\times}$ Landrace] ${\times}$ Duroc), averaging $26.62{\pm}3.07kg$ body weight, were assigned in a $2{\times}4$ factorial arrangement with 4 pigs per pen. The first factor was two dietary energy level (3,265 kcal of ME/kg or 3,365 kcal of ME/kg), and the second factor was four different levels of dietary protein by phase feeding (1growing(G)-2finishing(F) phases, 2G-2F phases, 2G-3F phases and 2G-3F phases with low CP requirement). Results: In feeding trial, there was no significant difference in growth performance. The BUN concentration was decreased as dietary protein level decreased in 6 week and blood creatinine was increased in 13 week when pigs were fed diets with different dietary energy level. The digestibility of crude fat was improved as dietary energy levels increased and excretion of urinary nitrogen was reduced when low protein diet was provided. Chemical compositions of longissimus muscle were not affected by dietary treatments. In backfat thickness ($P_2$) at 13 week, pigs fed high energy diet had thicker backfat thickness (P = 0.06) and pigs fed low protein diet showed the trend of backfat thinness reduction (P = 0.09). In addition, water holding capacity was decreased (P = 0.01) and cooking loss was increased (P = 0.07) as dietary protein level reduced. When pigs were fed high energy diet with low subdivision of phase feeding, days to 120 kg market weight was reached earlier compared to other treatments. Conclusion: Feeding the low energy diet and subdivision of growing-finishing phase by dietary protein levels had no significant effect on growth performance and carcass characteristics. Also, phase feeding with low energy and low protein diet had no negative effects on growth performance, carcass characteristics but economical profits was improved.