• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.525-534
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• 2001

A total of 120 pigs were used to investigate the effects of yucca extracts on the growth performance, nutrient digestibility, nutrient excretion and carcass characteristics of finishing pigs fed different levels of dietary protein. Pigs were allotted into $2{\times}3$ factorial design by the supplementation of yucca extracts (YE, 0 and 120 mg/kg) and 3 levels of dietary protein (14, 16, 18% for early finisher and 12, 14, 16% for late finisher for low, medium and high protein diet, respectively). During the early finishing period (51~76 kg BW), no significant difference was found in growth performance regardless of the YE supplementation or dietary protein levels. Growth performance of late finishing pigs (76~101 kg BW) was also not significantly different among treatments. However, ADG of pigs fed YE diet was significantly improved (p<0.05) regardless of the dietary protein levels. For the overall period (51~101 kg BW), although adding YE to the diet and elevating the protein level showed better ADG, there were no significant differences on growth performance among treatments. Early finishers showed significantly higher crude protein, crude ash and crude fat digestibilities when they were fed diets supplemented with YE. Digestibilities of amino acids were not affected by YE. Late finishers did not show any significant differences in proximate nutrient digestibilities regardless of YE supplementation or dietary protein levels. YE tended to slightly improve the CP digestibility, however no significant difference was found with increased dietary protein levels. There was no significant difference in amino acid digestibilities with YE supplementation or dietary CP levels during the late finishing period. Dry matter (DM) and nitrogen (N) excretion in feces did not show any significant difference among treatments. Early finishing pigs also did not respond to the inclusion of YE or dietary protein levels (p<0.05). Fecal N excretion of early finishing pigs seemed to be lowered in pigs fed YE. Pigs fed medium dietary protein diet tended to excrete a higher amount of N during the early finishing period, but not statistically different. A slight increase in fecal N excretion was found with the increased level of dietary protein during the late finishing period. For ammonia nitrogen excretion, although there was no significance, the NH3-N content tended to be increased by the increased dietary protein levels and with YE supplementation. The NH3-N content in manure increased by 24.5% with YE supplementation. There were no significant differences in carcass weight, backfat thickness, carcass grade and loin eye area among treatments. However, pigs fed non-YE with low protein diet showed a significantly (p<0.05) low carcass ratio among treatments and there was significant (p<0.05) difference between the YE-added treatment and non YE treatment in carcass ratio. As for the feed cost, the cost of feeding high level protein was higher than that of medium level protein by 5% and low level protein by 9% (p<0.05). Therefore, based on this study, it could be concluded that environmentally friendly agents might play a role to some extent in finishing pigs from the aspect of pollution control, and that more than 14 and 12% of dietary protein for early finishing and late finishing pigs respectively do not necessarily guarantee high growth performance.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.4
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• pp.583-589
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• 1994

In order to study the interrelationships of calcium (0.45 vs. 0.90%), phosphorus (0.40 vs. 0.70%) and protein (17, 20, 23%), $2{\times}2{\times}3$ factorial design was employed. A total of 480 broilers (Hisex-Hibro) aged 3 days were fed the experimental diets for a period of 28 days. Body weight gain, daily feed intake and feed efficiency were investigated for the simple effects, first order interaction and second order interaction of the dietary factors. These effects were also applied to bone ash retention, percent Ca in bone & ash, percent P in bone & ash, and protein utilizability. Results were as follows. 1) For body weight gain, simple effects of dietary levels of Ca, P, CP were found to be significant (p<0.05). Body weight gain at 0.90% Ca level was improved as the dietary CP levels increased. For the feed intake, single effects of dietary levels of both P and CP were found (p<0.05). Feed efficiency was improved as the dietary CP and P levels increased. Ca $\times$ P interaction was found to be significant for body weight gain, feed intake and feed efficiency (p<0.05), however, Ca $\times$ P $\times$ CP interaction effect was not found. 2) Protein utilizability decreased as the dietary CP level increased (p<0.01). 3) 0.90% Ca in diet showed less bone ash retention than 0.45% Ca level. And, increasing the dietary P level resulted in increased bone ash retention. Increasing the dietary P level resulted in increased bone Ca retention (p<0.01) and increased bone P retention (p<0.05). Dietary CP levels had significant (p<0.01) effect on bone Ca retention except for 23% CP level. Increasing the dietary Ca level resulted in wider Ca:P ratio of bone, but increasing the dietary P level resulted in narrower Ca:P ratio of bone. 4. Ca $\times$ P interaction effects were found to be significant (p<0.01) for bone ash, bone Ca & P, ash P content, and bone Ca:P ratio. Ca $\times$ P $\times$ CP interaction effects were found for bone ash (p<0.01), bone Ca (p<0.05) and bone P content (p<0.01).

• Korean Journal of Poultry Science
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• v.42 no.1
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• pp.87-100
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• 2015

It is well known that dietary protein affects the growth performance and carcass composition of poultry. Over the last several decades, numerous studies have been carried out to investigate to optimize the level of dietary protein since the protein is an important and expensive constituent in poultry feed. It is generally accepted that dietary protein should represent a balance of amino acids supporting the requirements for growth and maintenance of birds. A protein with balanced essential amino acids that matches a bird's requirement and sufficient non-essential amino acid nitrogen to enable the synthesis of all of the non-essential amino acids, is referred to as an 'ideal protein'. Feeding of excess protein or amino acids may result in an amount of nitrogen emission. Most common method to reduce nitrogen emission is using diet formulation which has lower dietary crude protein level and higher concentration of amino acid supplements. However, there are conflicting reports whether low protein diets supplemented with synthetic amino acids can obtain the growth performance equal to high protein diets. Excessive nitrogen excretion caused by amino acid imbalance also may influence the environment of poultry house due to ammonia production from uric acid. These environmental conditions may increase the incidence of skin problem or respiratory diseases of chickens. Various strategies based on comprehensive understanding should be tested to optimize nitrogen utilization and reduce nitrogen emission while maintaining the performance in poultry production.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.3
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• pp.261-271
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• 2006

To study the correlation with increasing body fat mass for the Standard Guideline for Korean Dietary Life, a nationwide, cross-sectional survey was performed with 178 male college students in december 2005. Among the student subjects, 76 were analyzed for body protein mass, body mineral mass, body fat mass, percent body fat, waist-hip ratio(WHR), body mass index(BMI) and obesity degree using Inbody 3.0(Biospace Co, Seoul, Korea). Body protein mass was at a high level of 92.1%, body mineral mass was at a low level of 94.7%. Body fat mass was at a high level of 28.9%, percent body fat was at a high level of 37.3%, WHR was at a high level of 31.6%, and obesity degree was at a high level of 38.2%, BMI was at a high level of 24.3% and BMR was observed at a high level of 41.8%. WHR was correlated with '7. Prepare food proper amount sanitarily.' and obesity degree, while BMl was were correlated with '4. Increase movement and eat proper amount.' positively. BMR was correlated with '6. Enjoy 3 meal a day regularly.' ArmCircle was correlated with '4. Increase movement and eat proper amount.' and fitness score was corrected with '4. Increase movement and eat proper amount', and '8. Enjoy Korean rice food style.' positively. Body protein mass and body mineral mass were negatively correlated with fruit, ArmCircle was positively correlated with fish, obesity degree was positively correlated with soup and BMI and ArmCircle were positively correlated with sweet. '8. Enjoy Korean rice food style.' was negatively significantly correlated with overweight, over percentage body fat, obesity degree > 120 and BMI. Male students were not practicing the Standard Guideline for Korean Dietary Life well with an average score of 37.7%. However, male students who are within the normal range of body composition analysis value have to notice that over range of weight, protein, percentage body fat, WHI and obesity degree was observed above average score of 30%.

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

• Journal of Aquaculture
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• v.6 no.1
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• pp.47-53
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• 1993

Feeding trials were conducted for a test of the optimum dietary protein levels for the fingerling Korean catfish, Parasilurus asotus. The growth response was examined in terms of weight gain, feed coefficient. protein efficiency ratio and net protein utilization for 8 weeks at $23\~27^{\circ}C$. Within a range of 25 to 55\%$ crude protein levels in the diet, the body weight increased while the dietary protein level increased. Accumulation of protein in the body reached the maximum when the crude protein level in the diet was at $45\%$. These results indicate that the optimum dietary protein level of fingerling Korean catfish was about $45\%$ when anchovy meal was used as the protein source.

• Journal of Nutrition and Health
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• v.29 no.5
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• pp.461-471
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• 1996

This study was performed to investigate the effect of dietary protein and cysteine levels on cadmium toxicity in rats. Seventy-two male rats of Sprague-Dawley strain weighting 171$\pm$3g were blocked into 12 groups according to body weight, and were raised for 30 days. cadmium chloride was given at levels of 0 or 400ppm, protein at levels of 7, 15 and 40%, and cysteine was added(total dietary cysteine contents : 0.45%) to diet or not. The results are summarized as follow. Food intake, weight gain, food were lower than those of cadmium free group. But, these were increased with increasing dietary protein level and cysteine addition. Fecal cadmium excretion was remarkably increased in high protein (40%) groups. Thus, cadmium retention rates were decreased in high protein groups. Metallothionein concentrations in liver and kidney were increased in cysteine addition, and cadmium administration. Especially, these were remarkably increased in cadmium and cysteine added groups. Urinary calcium excretion was increased with cadmium administration, but urinary protein excretion and creatinine clearance were not changed in these animal. In conclusion, food intake, weight gain and organ weights were decreased with administration. Cadmium toxicity was alleviated by increasing fecal cadmium excretion, while cysteine addition increased metallothionein concentrations in liver and kidney. From these results, it was shown that cadmium toxicity was alliviated by synergistic effect of high protein level and cysteine addition.

• 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.

• Journal of Nutrition and Health
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• v.27 no.1
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• pp.90-99
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• 1994

This study was carried out to examine how dietary protein and calcium levels in rats fed fat-enriched diet affect the total lipid and cholesterol contents of blood and tissues. Male Sprauge-Dawley rats weighing approximately 200g were fed six purified diets which contained 18%(w/w) beef tallow, 1% (w/w) cholesterol, two source of protein, casein or isolated soy protein (ISP) and three levels of dietary calcium, 0.1%, 0.4% and 1.0%, first, for four weeks, and second, for eight weeks. The contents of the total lipid, cholesterol and triglyceride in blood, liver, heart and feces were determined. After four weeks feeding serum lipid and cholesterol concentrations significantly decreased in rats fed 1.0% (w/w) level calcium, regardless of dietrary protein sources. After eight weeks, these concentrations were significantly lower in the rats fed soy protein than in casein-fed rats. As dietary calcium level increased serum and tissue lipid and cholesterol contents were decreased and fecal lipid excretion increased. It is concluded that hypolipidemic and/or hypocholesterolemic effects of soy protein and calcium were partly due to decrease in lipid absorption.

• Journal of Nutrition and Health
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• v.26 no.3
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• pp.231-247
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• 1993

This study was designed to confirm the effect of dietary protein level and oral administration of tryptophan on brain serotonin metabolism. Two animal experiments were conducted. The objectives and results of research were as follows : In the first experiment, it was investigated whether administration of reserpine to Sprague-Dawley rats fed 6% or 20% casein diet induced decrease in serum tryptophan and large neutral amino acid(LNAA) concentrations, tryptophan/LNAA concentration ratio, brain tryptophan, serotonin and 5-hydroxyindoleacetic acid(5-HIAA) contents. Brain serotonin content of 6% casein diet group was lower than those of 20% casein diet group. Both 6% and 20% casein diet groups administered with reserpine to induce the analogous depression, showed the notable decrease in brain serotonin content when they were compared with 20% casein diet group not administered with reserpine. Serum tryptophan/LNAA ration and brain 5-HIAA content showed a tendency similar to the change of serotonin content, but the mean difference among all groups was not significant. From these results, it could be said that when the dietary protein level was low, brain serotonin content was decrease. The second experimnt was to see the change in serum tryptophan concentration and tryptophan/LNAA ratio and brain tryptophan, serotonin and 5-HIAA content when tryptophan was administered orally to the animals treated with reserpine. Serum tryptophan concentration tended to increase in both reserpine-treated 6% and 20% casein diet groups administered with tryptophan, especially in the 6% casein diet group. Serum tryptophan/LNAA concentration ratio tended to incrase in reserpine-tteated 6% casein diet group, while decrease in reserpine-treated 20% casein diet group. Brain tryptophan content was increased in both reserpine-treated 6% and 20% casein diet groups. However, brain serotonin content of reserpine-treated 6% casein diet group showed a tendency to decrease, while that of reserpine-treated 20% casein group increase. Consequently, the effect of tryptophan administration on increase of brain tryptophan and serotonin content in animals treated with reserpine was far more excellent in 20% casein diet groups. It was concluded that dietary protein intake and tryptophan administration increase brain serotonin level. Accordingly, it was possible to confirm that brain function, particularly in aspect of behavior related to the serotonin, was changed with manipulation of dietary composition.