• Proceedings of the Korean Nutrition Society Conference
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• 2004.05a
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• pp.103-103
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• 2004

• Korean Journal of Poultry Science
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• v.14 no.2
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• pp.109-111
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• 1987

Three experiments were conducted to show effects of adding amino acids to a broiler starter diet (0-3 weeks of age) low in protein. A diet of 22% protein with adequate levels of all essential amino acids was used as a reference diet. Supplementing an 18% protein diet with adequate amounts or methionine and lysine significantly improved performance of chicks. However, adding excessive amounts of these amino acids was detrimental, indicating that the excess aggravated deficiency or the third amino acid. Supplemental arginine tended to alleviate this aggravating effect.

• Journal of Nutrition and Health
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• v.7 no.4
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• pp.1-5
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• 1974

Forty weaning albino rats were used to find the effects of alternate feeding of high protein diet with different intervals on growth, feed efficiency, protein efficiency ratio, weight of some internal organ, protein digestibility and nitrogen balance. Results obtained are summarized as follows: 1. The growth rate and feed efficiency of group B fed high protein and low protein alternately in every other day was equal to that of A group fed medium protein diet daily. However, the rats fed high protein diet once every three days or every four days could not result in same growth that obtained by group A. 2. The protein efficiency ratio of each group was the same without significant difference. 3. The liver weight appeared to be in proportion to final body weight, but intestine weight and length appeared not to be affected by treatments. 4. The protein digestibility in each group was insignificant. However, urinary nitrogen loss of intermittent high protein feeding group was lower than that of control group and the nitrogen retention ratio decreased with increased nitrogen intake.

• Journal of Nutrition and Health
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• v.43 no.4
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• pp.342-350
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• 2010

This study was aimed to investigate whether soy protein hydrolysates had beneficial effects on serum and tissue lipid contents and appetite-related hormones as compared with intact soy protein. Four-week-old male Sprague-Dawley rats were fed AIN-93M diet containing high fat (18% w/w) with low protein (10% w/w). After four weeks, the rats were divided into four groups (n = 8/group) and fed experimental diets with different nitrogen sources and levels, respectively; 10% soy protein isolate (10SPI), 25% soy protein isolate (25SPI), 25% soy protein hydrolysates (25SPH) and 25% soy macro-peptide fractions (25SPP, MW $\geq$ 10,000) for six weeks. Weight gain was significantly higher in 25% nitrogen sources-fed groups than in 10% group (10SPI). In 25SPP, perirenal fat mass and serum total lipid were significantly lower than in other groups. As for appetite-related hormones, serum ghrelin concentration was not shown to be different among groups but leptin concentration was significantly decreased in 25SPP. It can be concluded that soy macro-peptide fractions as compared with intact soy protein may have beneficial effects on reducing fat mass and serum lipid.

• 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.

• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.117-123
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• 2010

This work was carried out to investigate the effect of the induced molting with low-protein and energy diet on the postmolt performance of layers. Eighty White Leghorn layers (61-old-wk) with over 80% egg production were used for 12 weeks in this work. Treatments were non-molt control (CO), fasting treatment for 10 days (FW), molt treatment with low-protein and low-energy molting diet for 3 weeks (LO), and molt treatment with standard molting diet for 3 weeks (ST) as 4 treatments (2 replications/treatment and 10 birds/replication). Body weight (BW) loss was 26.5% of initial BW at 2 week in FW treatment, and was 17.3% and 14.2% in both LO and ST treatments (P<0.05). Layers in molting treatments were fed with commercial layer diet after completion of molting since BW of layers was recovered for 7 weeks. Heart weight ratio was shown as 0.47, 0.43, 0.46 and 0.46% at CO, FW, LO and ST treatments, respectively, and liver weight ration of body weight was shown as 2.56, 1.30, 1.47 and 1.52%, respectively. Thus, those of molting treatments decreased compared to non-molt control (P<0.05). Oviduct weight ratio were shown as 3.95, 1.17, 1.54 and 1.67%, respectively, and similar with the results of liver (P<0.05). Feed intake decreased at LO and ST treatments during molting period and increased from the 5th week compared to control. Egg production decreased at 1 week in molt treatment and stopped at 2 week in FW, 3 week in LO, and 4 week in ST treatments. The birds started to lay egg at 4 week in FW and at 5 week in LO and ST treatments. Egg production was recovered until 50% at 6 week in FW and was recovered as 66.1 and 71.6% at 8 week in LO and ST treatment, respectively. Egg weights were similar among all treatments. Eggshell thicknesses were 0.41, 0.47, 0.46 and 0.46 mm at CO, FW, LO and ST treatment, respectively, but the higher in molt treatments than control (P<0.05). Eggshell breaking strength was 3.83 and 3.81 kg/$cm^2$ in FW and LO treatment, respectively, and high compared to control. However, eggshell breaking strengths were 3.54 and 3.78 kg/$cm^2$ and were not statistically different. Haugh units were 75.6, 81.1, 80.6 and 79.9 in 4 treatments and high in molt treatment. Finally, dietary low-protein and low-energy may induce molt as few effect on performance of layers.

• Korean Journal of Poultry Science
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• v.29 no.3
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• pp.195-204
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• 2002

Two experiments were conducted to study the effects of nutrient level and feeding method of split diets for a.m. and p.m. on laying hen performance, feed cost and eggshell quality. In experiment 1, 384 ISA Brown layers of 30∼38wk of age were assigned to four treatments which comprise of three replicates each containing 32 birds. The control(C) was fed a conventional single diet throughout the day and split diet groups(T1, T2 and T3) were offered high energy/protein-low Ca diets, and low energy/protein-high Ca diets in a.m.(04:00∼15:00) and p.m.(15:00∼21:00), respectively. In the split diet groups, daily ME and CP consumption, and feed cost were significantly reduced(P<0.05) compared to the C, while the hen-day egg production, average egg weight and daily feed intake were not different among treatments. Due to the reduced daily ME and CP intakes and feed cost, the conversions of feed, ME, CP and feed cost required per day and per kg egg mass were also significantly improved(P<0.05) in the split diet groups. Eggshell qualities (egg specific gravity, egg breaking strength and eggshell thickness) were improved(P<0.05) by split diet feeding. As the Ca level of the p.m. diet increased. In Experiment 2, 384 ISA Brown layers of 50∼58 wk of age were used in three treatments and each treatment was represented by four replicates each containing 32 birds. The control(C) was fed a conventional single diet throughout the day and split diet group(T1) was offered high energy/protein-low Ca diets, and low energy/protein-high Ca diets in a.m.(04:00∼l5:00) and p.m.(15:00∼21:00), respectively. T2 group was fed the diet mixed (50:50) with the a.m. diets in mash and p.m. diet in pellet used T1 group. In T1 and T2 groups, daily feed intake and average egg weight were significantly reduced(P<0.05) compared to the C, while the hen-day egg production was not influenced by the feeding system. Daily ME and CP consumption, and feed cost were reduced(p.0.05), and the conversions of ME, CP and feed cost required per egg were also significantly improved(P<0.05) in T1 and T2, while the conversions of feed, ME, CP and feed cost required per kg egg mass were not different to the C. Eggshell qualities of T1 and T2 were improved(P<0.05) compared to the others. It was concluded the feed and nutrients consumption, feed cost per day or per kg egg mass could be reduced by introducing split diets for a.m. and p.m. and the feeding method of mixed diet of split diets were also convenient and effective for sparing feed cost and improvement of eggshell quality.

• Journal of Aquaculture
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• v.18 no.2
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• pp.122-129
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• 2005

Ammonia is the major limiting factor in intensive aquaculture production systems. Therefore, quantification of ammonia excretion is important for the water quality management in aquaculture systems. Ammonia excretion is known to be affected by many factors such as body weight and dietary protein level (DPL). In this study, experiments were carried out to investigate the effects of body weight and DPLs on the rates of ammonia excretion of Nile tilapia Oreochromis niloticus. Three sizes of fishes (mean initial weight; 4.8 g,42.7 g and 176.8 g) were fed each of two dietary protein levels (30.5% and 35.5%). Daily feeding levels for the three fish sizes of 4.8 g, 42.7 g and 176.8 g were 6%, 3%, and 1.5% body weight per day, respectively. Each group of fish was stocked in a 17.1-L aquarium and all treatments were triplicated. Following feeding, the weight-specific ammonia excretion rate of O. niloticus increased, peaked at 4 to 8 h, and returned to pre-feeding levels within 24 h. Total ammonia nitrogen (TAN) excretion.ate per unit weight decreased with the increase of fish weight for each diet (P<0.05). The TAN excretion rate increased with increasing dietary protein content for each fish size (P<0.05). TAN excretion rates (Y) for each diet with different fish weights were described by the following equations: low DPL diet (30.5%): $Y\;(mg\;kg^{-1}\;d^{-1})=955.69-147.12\;lnX\;(r^2=0.95)$, high DPL diet (35.5%): $Y\;(mg\;kg^{-1}\;d^{-1})=1362.41-209.79\;lnX\;(r^2=0.99)$. Where: X=body weight (g wet wt.). The TAN excretion rates ranged 28.5%-37.1% of the total nitrogen ingested for the low DPL diet (30.5%) and 37.4-38.5% for the high DPL diet (35.5%). Total nitrogen losses of fish fed the high DPL diet $(35.5%;\;0.26\sim0.91g\;kg^{-1}\;d^{-1})$ were higher than those fed the low DPL diet $(30.5%;\;0.22\sim0.68g\;kg^{-1}\;d^{-1})$. The losses decreased per kg of fish as fish size increased. Results will provide valuable information fer water quality management and culture of Nile tilapia in recirculating aquaculture systems.

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

• The Korean Journal of Zoology
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• v.39 no.3
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• pp.307-316
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• 1996

A persistent major haemolyruph protein (MHP) was confirmed, and its ontogeny and physicochemical charadedstics were investigated in Helicoverpa assulta. The MHP existed continually during larval-pupal-adult development, and its ontogeny was similar to that of total haemolymph protein concentration during development. Its content increased with larval growth, and kept to high level during pupal-adult development except for temporary decrease at the early pupal and adult stages. The MHP was purified by ammonium sulfate precipitation, gel filtration and ion exchange chromatography. The purified MHP was determined to be hexamer glycolipoprotein (pI 5.9, M.W. 414kDa) consisted of single type subunit (69kDa). Amino acid analysis suggested that the MHP contained a relatively high content of aromatic amino acids (18.27 mole % of tryptophan, 7.47 mole % of tyrosine and 6.51 mole % of phenylalanine) compared to storage proteins from other insects. Immunodiffusion test and electrophoretic analysis of the organ proteins (gut, fat body, and Malphigian tubule) suggested that the major haemolymph protein was present in the fat body.