• Journal of Life Science
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• v.10 no.2
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• pp.131-139
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• 2000

Lecithin-free egg yolk protein (EYP), the by-product of lecithin extraction from egg yolk, which is denatured with an organic solvent, would normally be discarded. In this study, the denatured protein was renatured with alkali, and hydrolyzed with Alcalase in order to utilize by-product. The hydrolysate was separated through a series of ultrafiltration membranes with molecular weight cut-off (MWOO) of 10, 5 and 1 kDa, and the antioxidative activities of the hydrolysates was investigated. The 5K hydrolysate, permeate from 5 kDa membrane, showed stronger antioxidative activity than 10 K and 1 K hydrolysate which were permeated from 10 kDa and 1 kDa membrane, in a linoleic acid autoxidation system. In addition, the optimum concentration of antioxidative activity for 5 K hydrolysate was 1%, and the activity was about 37% higher as compared with α-tocopherol. The synergistic effect was also increased by using the hydrolysates with α-tocopherol.

• Korean Journal of Poultry Science
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• v.40 no.4
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• pp.361-368
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• 2013

This experiment was conducted to determine optimum levels of dietary crude protein for productivity and egg quality in laying hens during early stage. A total of seven hundred and twenty 24-wk-old Hy-Line Variety Brown layers were randomly assigned to 4 experimental diets varying with 16%, 17%, 18%, and 19% CP and fed the diets for 12 wks. There were no significant differences in egg production, daily egg mass and feed intake among experimental diets. Although no difference was found on egg weight among experimental diets, decreasing levels of dietary crude protein tended to reduce the egg weight. Haugh unit and egg shell quality were not affected by different levels of dietary crude protein. Although there was no difference on yolk color among experimental diets, increasing levels of dietary crude protein slightly reduced the yolk color. It is concluded that laying hens did not need more than 16% CP to maximize egg production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.2 no.1
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• pp.35-40
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• 1973

Though many papers have reported the nutrition value of Chlorella their results are all different because of the differences in processing method. To investigate its processing and nutrition value we provided the white rats with the Chlorella that were treated with boiling methanol. The results obtained in this investigation are summarized as follows: Two groups. which were fed with 20% Chlorella protein and 10% Chlorella plus 0.37% $_{DL}-methionine$ gained less weight than the 10% egg protein group but equaled the 20% egg protein group in weight gain. The digestion rates calculated from ordinary N-balance method were 83.6% for 20% Chlorella, 81.7% for 10% Chlorella, and 84.9% for 10% Chlorella plus methionine group. This value is lower than 20% Egg (93.8%) and 10% Egg group (89.6%) Biological values from this method were 78.3% for 20% Chlorella and 79.1% for 10% Chlorella group, being lower than 20% Egg (85.2%), 10% Egg (93.2%). But the biological value of 10% Chlorella group was markedly enhanced to 92.2%, a value comparable to that of 10% Egg group, by adding methionine.

• Journal of Aquaculture
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• v.11 no.2
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• pp.271-278
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• 1998

To clarify characteristics of yolk protein of abalone, yolk protein was purified from the ovarian egg extracts of mature female Haliotis discus hannai by a gel chromatography of sepharose CL-4B. From the results of immuno-electrophoresis and Ouchterlony's diffusion test to male and female sera and ovarian egg extracts using antibodies raised against mature female and male sera and male sera and ovarian egg extrascts, it was identified that the mature female serum had female specific serum protein and its antigenecity shared with ovarian egg extracts. A single type of yolk protein was purified from ovarian egg extracts, and it was composed of two subunits. Their molecular weights were estimated to be approximately 166 KDa and 113 KDa by SDSPAGE. The antiserum against yolk proteins cross-reacted with a mature female specific serum protein and extracts of hepatopancreas of vitellogeing females, but did not reacted with extracts of hepatopancreas of mature male.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.101-106
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• 2003

In order to study the optimum daily protein allowance for broiler breeders of 24 to 64 weeks of age on a control-fed basis, an experiment was carried out with 400 hens of Arbor Acres strain. Four levels of protein allowances were used to supply 18 to 24g of protein per day in 2g increments. As the age of hens increased, a same stepwise increase and decrease in daily energy allotment was used in all treatments. Same amount of calcium, phosphorus, methionine and lysine were supplied in all treatments and throughout laying period. Hen-day egg production was highest in hens receiving 20g protein per day(p<0.05), but there was no significant difference among those fed daily protein ranging 18 to 22g, and increasing the daily protein allotment up to 24g resulted in a significant decrease(p<0.05). Average egg weight showed a trend to increase as the daily protein allowance increase(p<0.05), but no significant difference was found among the hens fed daily protein 20 to 24g. Feed and ME conversion was superior in hens receiving 20g daily protein(p<0.05). CP conversion was increased as the daily protein allowance increase(p<0.05), but there was no significant difference between hens receiving 18 and 20g daily protein. Feed cost required per egg or per kg egg was lowest in hens fed 20g daily protein. It could be concluded that the optimum daily protein allowance was 20g in all performances.

• Culinary science and hospitality research
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• v.24 no.2
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• pp.103-111
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• 2018

The objectives of the present study were to examine the antioxidant activity of autofocusing fractions from egg white protein hydrolysates and obtain higher antioxidant peptide fraction, which could be applied to the food model system. Alkaline protease hydrolysate of egg white protein exerted higher antioxidant activities than other protein hydrolysates and were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without toxic solvents and reagents, which is termed autofocusing. Neutral and basic fractions showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than the acidic fractions. The acidic and neutral fractions showed higher hydroxyl (OH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) values than the basic fractions. The acidic fractions showed higher metal chelating activity than basic fractions. Antioxidant activities of some autofocusing fractions except for ORAC showed higher compared to the crude hydrolysate. These results suggest that peptides fractions from egg white protein are effective antioxidant, and that autofocusing could be useful to increase antioxidant activity for application to food system.

• Korean Journal of Agricultural Science
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• v.45 no.3
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• pp.485-492
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• 2018

Two experiments were conducted to investigate the effect of feeding a diet supplemented with swine hair protein (SHP) on the nutrient digestibility of Korean native chickens and their egg production as well as on egg quality. In experiment 1, twenty roosters of the Hanhyup-3 strain were assigned to an individual cage to give 10 replicates per treatment (i.e., 0 and 10% of SHP), and the nutrient digestibility in response to the SHP supplementation was measured. In experiment 2, fifty-four layers of the Hy-Line strain were assigned to an individual cage to give 27 replicates per treatment (i.e., 0 and 10% of SHP), and egg production and egg quality were measured. In experiment 1, no significant difference (p > 0.05) was found in the digestibility of crude protein, crude fat, nitrogen-free extract (NFE), and crude fiber in response to the diet supplemented with SHP. In experiment 2, although no significant difference (p > 0.05) was found with the dietary treatments, the 10% SHP supplemented diet decreased (p < 0.05) the feed intake of laying hens. However, the SHP supplemented diet did not affect (p > 0.05) the laying rate, egg weight and feed conversion ratio of those fed the diet. Eggshell thickness and yolk color decreased (p < 0.05); however, eggshell strength, eggshell color, albumen height and Haugh units increased (p < 0.05) by feeding layers a diet supplemented with SHP. In conclusion, the results suggest that 10% SHP supplemented in a poultry diet could be a useful protein source.

• The Korean Journal of Zoology
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• v.30 no.1
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• pp.10-28
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• 1987

Changes of protein synthesis in the isolated egg chambers were studied during oogenesis of Drosophila melanogaster. Protein synthesis did not change much in quantity except that the activity was slightly enhanced at the stages 11 and 12, when new structures such as vitelline membranes and yolk granules were made, but considerably changed in quality during oogenesis. Protein synthesis was believed to occur mainly in the follicle cells, and a number of stage-specific proteins were found to differ at various stages. The observations suggest that proteins synthesized in the cells within chambers as well as those from the outside of the chambers might be directly required for the growth and maturation of oocytes in Drosophila.

• Journal of Animal Science and Technology
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• v.51 no.6
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• pp.521-526
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• 2009

Irradiation of egg white increased foaming ability significantly. To investigate the protein modification by irradiation responsible for the increase of foaming ability, 3 major egg white proteins were purchased and mixed (7.7 g/L ovalbumin, 1.8 g/L ovotransferrin, 0.5 g/L lysozyme) as a model system and irradiated at 0, 2.5, and 5 kGy. The different protein expressions were evaluated using 2-D electrophoresis and it was found that ovotransferrin was cleaved by irradiation and molecular weight and isoelectric point were changed. In addition, many uncharacterized proteins were found and it indicated that irradiation modified proteins randomly but mainly fragmentation was observed. Therefore, it can be concluded that protein fragmentation of 3 major egg white proteins responsible for foaming ability may be the main reason for the improvement of foaming ability.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.481-488
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• 2003

Insulin-like Growth Factors (IGFs) and IGF-binding protein act as intra-ovarian regulators that modulate the proliferation and differentiation of the granulosa and theca cells. Moreover, the IGF system is involved in metabolism by modulating the synthesis and degradation of glycogen and protein in animals. However the effect of the IGF system on egg productivity or body growth in KNOC has not been studied in depth. Therefore, this study was performed to investigate differences of serum IGFs and binding protein expressions between two groups showing high and low egg production or body weight and to elucidate the relationship of IGFs with egg productivity and body growth. KNOCs were divided into high and low groups depending on their egg productivity or body growth, and sera were collected every 10 wk from 20 till 60 wk. Serum IGF-I and -II concentration were measured by RIA using human and mouse antiserum and chicken standards. IGFBP was detected by Western ligand blotting. IGF-I concentrations were significantly greater in the high egg production group compared with those in the low egg production group (30 wk, p<0.01; 20 and 40 wk, p<0.05). Also, differences in IGF-II amounts between the two groups were detected at 60 wk (p<0.05). But IGFBPs in the low egg production group were more intense than that in the high egg production group through the egg laying period. The correlation between IGF-I concentration and number of egg production is significantly positive (20 wk, r=0.2729: p<0.05; 40 wk, r=0.3500: p<0.01), while IGF-II shows no correlation with egg productivity. In male KNOC, IGF-I and -II concentrations in the high body weight group are lower than that in the low body weight group. Body weight also shows a negative correlation with the serum IGF-II concentration in male chickens (20 wk, r=-0.5901: p<0.01). Consequently, we suggest that IGFs and binding protein are (in)directly involved in the egg productivity and body growth in KNOC.