• Fisheries and Aquatic Sciences
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• 제17권4호
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• pp.455-459
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• 2014

A feeding trial was conducted to determine the optimum dietary protein requirement of young far eastern catfish Silurus asotus. Five isocaloric diets were formulated to contain graded levels of protein (35, 40, 45, 50, and 55%). Triplicate groups of fish (initial body weight of 44 g) were hand-fed to apparent satiation for 9-weeks. Weight gain and specific growth rate of fish fed 55% protein diet were significantly higher than those of fish fed 35 and 40% protein diets, but not significantly different from those of fish fed 45 and 50% protein diets. The feed efficiency of fish fed 50 and 55% protein diets was significantly higher than that of fish fed 35, 40 and 45% protein diets. The protein efficiency ratio of fish fed 40% protein diet was significantly higher than that of fish fed 45, 50 and 55% protein diets, but not significantly different from that of fish fed 35% protein diet. The dietary protein level significantly affected whole body lipid and moisture contents. The results of this study suggest that the 45% protein in the diet is optimal for maximum growth of young far eastern catfish weighing in the range of 44 to 227 g.

• Asian-Australasian Journal of Animal Sciences
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• 제12권3호
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• pp.388-394
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• 1999

Two experiments were conducted to subdivide isoleucine (exp. 1) and valine (exp. 2) requirements for maintenance from the requirements for growth of broilers aged 1 to 3 weeks. Purified diets were used, containing five graded levels of isoleucine and valine. Based on weight gain response, the isoleucine requirement for growth was 7.50 mg/g weight gain and the daily isoleucine need for maintenance (mg) was 0.044 per unit metabolic body size ($(Wg^{0.75})$). Based on the N gain response, the isoleucine requirement for growth was 0.317 mg/mg N gain and the daily isoleucine need for maintenance (mg) was 0.040 per unit metabolic body size $(Wg^{0.75})$. Based on weight gain and N gain response, the total isoleucine requirement was calculated 244 mg/day or 0.59% of the diet, 274 mg/day or 0.66% of the diet, respectively. From the relationship of weight gain and N gain, 5.07% of the retained protein was comprised of isoleucine; the reported isoleucine content of chick muscle was 4.42%. The valine requirement for growth was 9.84 mg/g weight gain and 0.36 mg/mg N gain whereas the maintenance requirement was 0.046 or 0.052 mg per unit of metabolic body size (Wgo.11. According to the model developed to estimate valine requirement, the total requirement was 319 mg/day or 0.77% of the diet, 315 mg/day or 0.76% of the diet, respectively. Previous reported valine requirements for growing chicks of 7~24 days old were in close agreement with these estimates. As a percentage of retained protein, valine was calculated to be 5.81% ; the reported valine concentration of crude protein of chicks' body including feathers was 6.72%.

• Journal of Nutrition and Health
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• 제14권4호
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• pp.209-219
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• 1981

To evaluate long-term metabolic response of free-living Korean subjects consuming local sources adequately or slightly below habitual intake. Subjects, six male medical students aged 23-25 years were free-living, but consumed diets in the metabolic unit. They were healthy as determined from medical laborarory tests. They belong to the Korean middle-class. Temperature of outdoor during study were ranged between -2 to $26^{\circ}C$, whereas the indoor were $18-22^{\circ}C$. Animal protein ranged between 25-30% of total calorie. The three meals and a vitamin supplement to meet recommendation were given daily. Three 50day periods following the design were used to test the protein-energy adequacy of the diet. Urinary nitrogen excretion was measured daily. Fecal samples were pooled for the last 5 days of each week. Nitrogen balance was computed using 5mg N/Kg skin and miscellaneous losses. Body weight was measured daily. The study was covered on 126 metabolic observations weekly. Body weight changes were relatively stable with the energy intake of 37-44Kca1/kg, and N-balances were also relatively stable, but it was influenced by physical and or mental stress somehow. It could be assumed that the mean protein and energy requirement were $190{\pm}10mg$ N/Kg with $41{\pm}2$ Kcal/kg, and the mean digestibility of protein was 81% on these subjects with the experimental conditions. The protein requirement, however, could be cut down somewhat with some limited increaing of energy intake under parameters of N-balance and maintaining body weight. It was also observed a tendency of the requirement were getting smaller with the increase of body size.

• Asian-Australasian Journal of Animal Sciences
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• 제16권12호
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• pp.1777-1781
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• 2003

The lysine requirements of juvenile yellowtail flounder (Pleuronectes ferrugineus) having 19.5 g initial body weight were estimated by feeding six practical-type diets containing graded levels of lysine (1.21 to 2.69% of dry diet). Dietary amino acid profile simulated that of whole body of yellowtail flounder. Most of amino acids in the diets were provided by corn gluten meal, herring meal and gelatin. Protein efficiency ratio (PER) improved significantly until lysine level increased up to 2.1% (4.3% of protein). Same trend was observed in feed:gain ratio (FGR) which maintained constant in fish groups fed diets containing lysine above 2.1%. The highest nitrogen gain (0.34 g/fish) in whole body was found in fish fed 2.1% lysine, though the value was not different from those of fish fed above the level of lysine. Fish fed 2.1% lysine also showed the best nitrogen retention efficiency of 24.6%. The broken-line analysis of protein efficiency ratio and body nitrogen gain against dietary lysine level yielded an estimated lysine requirement of 2.2% (4.5% of protein) and 2.3% (4.7% of protein), respectively.

• Journal of Nutrition and Health
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• 제44권4호
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• pp.338-343
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• 2011

This study assessed the current EAR, RDA, and AMDR for protein, which were set in 2005 and revised in 2010 as the DRIs for Koreans. A classical approach to establish the EAR for protein has been the nitrogen balance method. This method has practical limitations and problems in statistical analysis by giving over estimations of nitrogen balance. Thus, the present EAR for protein might be lower than the true requirement. Recent reevaluations of nitrogen balance studies by bilinear regression analysis and the IAAO method have indicated that the EAR of 0.66 g/kg bw/d should be increased by 39% to give 0.92 g/kg bw/d. The AMDR for protein in the Korean DRIs was set at 7-10%, which covers almost the entire population's protein intake. Since the 5th percentile of Korean protein intake is close to 10% of energy and due to the beneficial effects of protein beyond the maintenance of nitrogen equilibrium, the lower range of 7% needs to be increased up to 10%. For practical meal arrangement, 15% of energy as protein, which is close to the average protein intake of Koreans, seems to be proper, although the value is almost two times the EAR.

• Asian-Australasian Journal of Animal Sciences
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• 제5권2호
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• pp.357-363
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• 1992

The experiment was carried out to estimate the energy and protein requirements of Khaki Campbell $\times$ Thai Native growing ducks. The growing stage was divided into 2: the first was a starting stage from 0 to 4 weeks of age and the second was a growing stage from 4 to 18 weeks of age. In the starting stage, the birds were given diets containing 2.70, 2.75, 2.80, 2.85 and 2.90 Mcal ME/kg and ME/protein ratio of 150/l for the energy requirement trial, and diets containing 17.0%, 18.5%, 20.0% and 21.5% protein and 2.8 Mcal ME/kg for the protein requirement trial. It was found that there were no significant differences in body weight gain of feed efficiency among the energy or protein levels. In the growing stage, no significant differences in body weight gain or feed efficiency were found among the energy levels from 2.70 to 2.90 Mcal ME, or protein levels from 15.5% to 20.0%. The age at first lay was 105-117 days and this is earlier than that observed in purebred Khaki Campbell ducks. The feed cost for raising ducks was lower in the low energy and low protein diets. In conclusion, Khaki Campbell $\times$ Thai native ducks can be raised with a diet low in ME as 2.7 Mcal/kg during the whole growing period. As for the protein. 7.0% in the starting stage and 15.5% in the growing stage is practical.

• Asian-Australasian Journal of Animal Sciences
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• 제9권1호
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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 Animal Science and Technology
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• 제62권5호
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• pp.628-637
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• 2020

In poultry diets, a requirement of crude protein is one of the most important factors in poultry productivity. Besides, the Pekin duck requirement of crude protein is still not clear. This experiment was conducted to determine the crude protein requirement of Pekin duck on diet formulation by investigation of growth performance, carcass trait, and analysis of blood parameter for a hatch to 21-day (d) of age. A total of 432 male White Pekin ducks were randomly allocated to six levels of crude protein (i.e., 15%, 17%, 19%, 21%, 23%, and 25%) to give six replicate pens per treatment with 12 ducklings per each pen. Body weight and feed intake were measured weekly by calculating feed conversion ratio and protein intake. Two ducklings each pen was euthanized via cervical dislocation for analysis of carcass trait and plasma blood on 21-d of age. Data were applied on both prediction linear-plateau and quadratic-plateau models by estimation of the crude protein requirements. Data were applied on both prediction linear-plateau and quadratic-plateau models by estimation of the crude protein requirements. The level of crude protein requirements of Pekin ducks for 21 days after the hatch was estimated to be 20.63% and 23.25% diet for maximum daily gain, and minimum feed conversion ratio, respectively.

• 한국가금학회지
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• 제14권2호
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• pp.125-135
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• 1987

본 시험은 산란계사료의 에너지 및 단백질 수준이 하절기에 있어서 갈색 산란계의 생산성에 미치는 영향을 구명하기 위하여 대사에너지 3수준(2,500, 2700 및 2900Kcal/kg)과 단백질 3수준(13, 15 및 17%)을 조합한 9개처리에 24주령된 Warren 산란계 720수를 공시하여 1983년 6월 3일부터 동년 8월 25일까지 12주간에 걸쳐 시험을 실시한 바 그 결과는 다음 요약과 같다. 1. 산란율은 에너지 수준이 증가할수록 점차 저하되었고 단백질 수준이 증가할수록 점차 증가하였다. 2. 란중은 에너지 수준에 따라서 큰 차이가 없었으나 단백질 수준이 증가할수록 증가하였다. 3. 사료섭취량은 에너지 수준이 증가할수록 점차 감소하였으나, 단백질 수준에 따라서는 차이가 없었다. 4. 사료요구율은 단백질 수준이 증가할수록 점차 개선되었다. 5. 폐사율은 사료중의 에너지 및 단백질 수준에 영향을 받지 않았다. 6. 1일수당 에너지 섭취량은 사료중의 에너지 수준이 증가할수록 점차 증가하였다. 7. 산란 kg당 대사에너지 요구량은 에너지 수준이 증가할수록 점차 증가하였으며 단백질 수준이 증가할수록 감소하였다. 8. 산란kg당 단백질 요구량은 에너지 및 단백질수준이 증가할수록 점차 증가하였다. 9. 산란kg당 사료비는 에너지 수준이 증가할수록 점차 증가하였고 단백질 수준이 증가할수록 점차 감소하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제10권2호
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• pp.178-184
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• 1997

Purified diets containing five graded levels of lysine were fed to a total of 125 growing chicks (25 chicks per treatment) to evaluate lysine requirements for growth and maintenance. A model was developed to separate lysine requirement for maintenance from requirement for growth. Based on weight gain response, the daily lysine requirement for growth was 12.06 mg/g gain and the daily lysine requirement for maintenance was 0.332 times metabolic body size ($W^{0.75}$). Similarly, the lysine requirement for growth was 0.457 mg/mg nitrogen gain and the daily lysine requirement for maintenance was 0.344 times metabolic body size. The plateau of plasma lysine concentration was reached at 354.75 mg intake/day. The total lysine requirement was 414.27 mg/day or 1.0% of the diet, 420.11 mg/day or 1.01% of the diet based on weight gain response and N gain response, respectively. Previous lysine requirements for growing chicks of 1-28 days old were in close agreement with these estimates. As a percentage of protein, lysine requirement was calculated to be 7.3% and the reported lysine content of chick muscle crude protein of 7.46% was closely related.