• Korean Journal of Poultry Science
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• v.35 no.3
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• pp.275-281
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• 2008

This experiment deals with lycopene-enriched egg production in chicken and their effects on egg quality, especially antioxidant status of eggs upon their long term storage. Forty two laying hens(Hyline, 36 weeks of age) were assigned randomly to 1 of 2 diets containing 0 mg and 2 mg lycopene per kilogram feed for 4 weeks. There was a comparable concentration of lycopene in egg yolk($1.57{\mu}g$/1 g yolk) of chickens supplemented with dietary lycopene. No measurable concentration of lycopene was detected in egg yolk of chickens fed the control diet. Dietary lycopene supplementation increased egg yolk color(P<0.01), egg yolk height(P<0.08), egg yolk diameter(P<0.19), egg shell intensity(P<0.19), egg white height(P<0.33), and Haugh unit (P<0.34). After 4 week of storage of eggs in room temperature, lycopene treated eggs were tested for freshness. The ESI, EYH, EWH, HU, and EYC of lycopene treated eggs were comparably higher than those of control groups, even though there was not statistically significant difference between two groups whereas EYD of the control group was smaller than that of lycopene treated group. In conclusion, dietary lycopene supplementation to chickens might be improved egg quality.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.448-458
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• 2009

It has been well documented from animal and human studies that conjugated linoleic acid (CLA) has numerous beneficial effects on health. In chickens, CLA exerts many effects on performance ranging from egg quality and yolk lipids to meat quality. Although there are several CLA isomers available, not all CLA isomers have the same incorporation rates into egg yolk: cis-9,trans-11 and trans-10,cis-12 CLA isomers are more favorably deposited into egg yolk than other isomers investigated, but of the two isomers, the former has a higher incorporation rate than the latter. CLA alters the amounts and profiles of lipids in plasma, muscles and liver. Furthermore, increased liver weight was reported in chickens fed dietary CLA. As observed in egg yolk, marked reduction in intramuscular lipids as well as increased protein content was observed in different studies, leading to elevation in protein-to-fat ratio. Inconsistency exists for parameters such as body weight gain, feed intake, feed conversion ratio, egg production rate and mortality, depending upon experimental conditions. One setback is that hard-cooked yolks from CLA-consuming hens have higher firmness as refrigeration time and CLA are increased, perhaps owing to alterations in physico-chemistry of yolk. Another is that CLA can be detrimental to hatchability when provided to breeders: eggs from these breeders have impaired development in embryonic and neonatal stages, and have increased and decreased amounts of saturated fatty acids and monounsaturated fatty acids (MUFAs), respectively. Thus, both problems can be fully resolved if dietary sources rich in MUFAs are provided together with CLA. Emerging evidence suggests that CLA exerts a critical impact on stress and immune functions as it can completely nullify some of the adverse effects produced by immune challenges and reduce mortality in a dose-dependent manner. Finally, CLA is a key regulator of genes that may be responsible for lipid metabolism in chickens. CLA down-regulates both expression of the gene encoding stearoyl-CoA desaturase-1 and its protein activity in the chicken liver while up-regulating mRNA of sterol regulatory element-binding protein-l.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.986-990
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• 2000

The quality characteristics and proximate composition of the eggs of pheasant, chukar, quail, and guinea fowl were compared. Eggs of the 4 species had a similar ovalish conical shape with blunt and pointed ends, showing the shape indices of 77.30-79.63 with no statistical difference. Egg weight was heaviest in guinea fowl (46.65 g), followed by pheasant (25.79 g), chukar (19.16 g) and quail (10.34 g). Proportion of yolk to the total egg weight was highest in pheasant (35.7%), followed by chukar (33.9%), quail (31.4%) and guinea fowl (30.6%). Albumen content was highest in quail showing 61.2%, while pheasant, chukar and guinea fowl were in the range of 55.6~57.4%. The ratio of yolk to albumen (Y/A) was highest in pheasant (0.65), followed by chukar (0.60), guinea fowl (0.55) and quail (0.52). The portion of shell to the total egg weight was highest in guinea fowl (13.5%) and lowest in quail (7.3%). The shell thickness of the eggs was thickest in guinea fowl ($462.8{{\mu}m}$), followed by pheasant ($241.5{{\mu}m}$), chukar ($231.8{{\mu}m}$) and quail ($174.8{{\mu}m}$). The contents of moisture, crude protein, crude fat and crude ash of whole egg were in the ranges of 74.26-74.50%, 11.98-12.77%, 10.83-11.91% and 1.02-1.10%, respectively, with no statistical difference (p>0.05) among the species. Albumen was high in moisture (87.46-87.99%) and very low in crude fat (0.09-0.13%), which was quite different from yolk. Yolk showed relatively low level of moisture (49.71-50.42%) and high levels of fat (31.48-32.32%), crude protein (15.12-15.99%) and crude ash (1.53-1.86%). No species difference in the proximate compositions of albumen and yolk was found except in crude ash content of albumen.

• Development and Reproduction
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• v.22 no.3
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• pp.289-295
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• 2018

Large quantity of eggs fail to be fertilized and many of fertilized eggs are unable to hatch in the eel, Anguilla japonica. Larvae of eel absorb egg yolk up to 8 days after hatching but the majority of hatched larvae die before they reach the stage of first feeding in this species. Genes of key enzymes for yolk processing (cathepsin B, D, L and lipoprotein lipase - abbreviated as ctsb, ctsd, ctsl and lpl, respectively) could be associated with egg quality. In this study, we investigated differences in the expression of these genes between floating eggs and sinking eggs, and also the relationship between the gene expressions of the enzymes and fertilization rates in the fertilized eggs obtained from artificially matured female eels. Expressions of yolk processing enzyme genes did not show significant difference between floating and sinking egg groups. Expression of ctsb decreased when fertilization rate was high. Expression of ctsd, ctsl and lpl, however, did not show any significant differences. These results suggest that ctsb expression could be an indicator of egg quality, and that some proteins prone to be digested by ctsb could be very important in the process of fertilization and normal cleavage in this species. Further study should identify these critical proteins to improve our understanding on the quality of fish eggs.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.84-86
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• 2003

An experiment was conducted to determine the effects of dietary supplementation of yeast Rhodotourula glutinis(Glutincus) on the performance and egg quality of layers. A total of 360 ISA Brown layers of 72 weeks old were assigned to one of the following 6 diets ：control, 25 ppm ${\beta}$-carotene. 0.5％, 1％, 2％ and 4％ Glutinicus supplemented diet. Each treatment was replicated three times with 20 birds housed in 2 birds cage units. Glutinicus supplemented at the level of 0.5％ significantly(p＜0.05) improved egg production and FCR. Soft and broken egge production rate decreased as the level of Glutinicus supplementation increased. Eggshell was highest in Glutinicus 4％ supplementation. Egg yolk color increased linearly as the level of Glutinicus supplementation increased up to 2％ of the diet. It was concluded that Glutinicus supplementation at the level of 0.5％ can be recommended for the improvement of egg production while 2.0％ can be recommended for egg yolk pigmentation.

• Korean Journal of Poultry Science
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• v.16 no.4
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• pp.233-238
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• 1989

This experiment was carried out to establish effective egg storage technology by studying the physico-chemical properties of albumen and yolk during the cold storage. The results obtained were summarized as follows：1. Egg Yolk was gelated and whipping quality and whipping stability of albumen was decreased by the freezing storage. 2. NaCl was the best anti-freezer to prevent the gelation of egg yolk among various anti-freezer (NaCl, glucose, sucrose, amides). 3. Viscosity of egg yolk and albumen was increased and color was changed but changes of colorin albumen was slight during the storage at $-5^{\circ}C$ and $-20^{\circ}C$. 4. To store the 5% NaC1 added egg yolk -at $-5^{\circ}C$ was the best way to prevent the gelation of egg yolk and save the energy. 5. Emulsion capacity of egg yolk was decreased by the cold storage with the addition of NaCl.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1769-1774
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• 2005

This experiment was carried out to evaluate the effects of feeding green tea powder on laying performance and egg quality in hens. A total 180 'Tetran Brown' laying hens aged 40 weeks were assigned to 6 treatments in a completely randomized design. Each treatment consisted of five replicates accommodating six layers per replication. The experimental diets were a negative control containing no green tea, a positive control diet containing antibiotics (0.05% chlortetracycline) and diets containing 0.5%, 1.0%, 1.5% and 2.0% green tea powder. Egg production rate of layers fed the diets containing green tea powder did not differ significantly from that of the negative and positive controls (p>0.05). Egg weight was decreased significantly in the group fed the diet containing 0.5% green tea powder (p<0.05). Feed intake of layers was significantly higher for the diet containing 1.5% green tea powder compared to that of negative and positive control diets (p<0.05). The eggshell thickness reduced significantly in the layer group fed the diets containing green tea powder regardless of dietary levels (p<0.05). Green tea powder tended to reduce egg yolk cholesterol in this experiment. Particularly, dietary 2% level of green tea powder significantly suppressed the cholesterol contents of the egg yolk (p<0.05). Thiobarbituric acid value (TBA) of egg yolk was significantly reduced by green tea diets (p<0.05). The yellowness of egg yolk was increased in the layers fed the 2.0% green tea diet compared with that of control diet (p<0.005). The Linoleic and $\alpha$-linolenic acids tended to increase in the group fed diets containing 1.5% green tea powder even though there were no significant differences among treatments (p>0.05). The oleic and docosahexaenoic acid contents of the egg yolk were similar among treatments (p>0.05). Based on the results of the experiment, it is concluded that green tea powder inclusion in the diet for layers at 2.0% level can reduce the cholesterol content and TBA value of the egg yolk, implying its potential effect on egg quality parameters.

• Korean Journal of Poultry Science
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• v.34 no.3
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• pp.223-229
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• 2007

This study was conducted to evaluate effects of dietary pine cone meal on egg production, egg quality, serum cholesterol and cholesterol content and fatty acid composition of egg yolk in laying hens. The total of 252 (51-wks) Hy-line brown commercial hens were used for 5 weeks. Dietary treatments included 1) T1 (basal diet + 1% cottonwood sawdust), 2) T2 (basal diet + 0.5% cottonwood sawdust + 0.5% pine cone meal) and 3) T3 (basal diet + 1% pine cone meal). During the overall period, there was no significant difference in egg production, egg weight and egg quality among the treatments. Lipids profile(total, HDL, LDL cholesterol and triglyceride) in serum was not affected by treatments. Egg yolk cholesterol was not significantly different among the treatments. In fatty acid contents of yolk, C18:3 was higher in T1 treatment than T3 treatment(P<0.05). Total SFA, PUFA, MUFA and UFA/SFA were not significantly different in experimental period. In conclusion, dietary supplementation of pine cone meal affected C18:3 fatty acid content of yolk in laying hens, without any adverse effect on egg production.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.10
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• pp.1458-1463
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• 2016

A 42-d study with 384 Hy-line brown laying hens was conducted to assess the effects of dietary octacosanol supplementation on laying performance, egg quality and blood metabolites of laying hens. Hens were randomly allocated into 4 dietary groups of 8 cages each, which were fed basal diet supplemented with 0 (Control), 9 (OCT9), 18 (OCT18), and 27 (OCT27) mg/kg diet of octacosanol isolated from rice bran, respectively. The experiment was conducted in an environmental controlled house and hens were fed twice daily for ad libitum intake. Laying performance was determined over the 42-d period, and egg quality as well as blood metabolites were estimated on d 21 and d 42. Diets in OCT18 and OCT27 increased (p<0.05) laying rate, egg weight, egg mass, egg albumen height, Haugh unit and eggshell strength on d 42, but decreased (p<0.05) feed conversion rate and levels of total cholesterol, triglyceride and low density lipoprotein cholesterol in the serum as compared to those of Control. Feed intake, yolk color, yolk diameter, eggshell thickness and high density lipoprotein cholesterol were similar (p>0.05) among treatments. Results demonstrate that supplementing 18 to 27 mg/kg diet of rice bran octacosanol can improve laying rate and egg quality and reduce blood lipid of laying hens.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.279-284
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• 2011

The objective of this study was to evaluate the effects of storage temperature and time on the quality parameters of eggs from laying hens at peak production. A total of 576 eggs were obtained from Lohmann Light-Brown hens, which were collected 3 times when the hens were 26, 27, and 28 weeks old. The fresh eggs were collected and measured within 2 h of being laid. Samples of 48 eggs each were stored in chambers for 2, 5, or 10 d inside a refrigerator ($5^{\circ}C$), at room temperature ($21^{\circ}C$), and at a high temperature ($29^{\circ}C$). As the storage temperature and time increased, egg weight, percentage of albumen, Haugh unit (HU), and yolk color significantly (p<0.001) decreased. In addition, egg shell weight, shell percentage, and albumen weight significantly (p<0.001) decreased with storage time. Yolk weight, yolk percentage, and albumen pH significantly (p<0.001) increased with increasing storage temperature, and yolk pH significantly (p<0.001) increased with increasing storage time. When the storage temperature was increased to $29^{\circ}C$, egg weight loss dramatically increased from 1.74 to 3.67% at 5 and 10 d of storage time, respectively. With the exception of the $5^{\circ}C$ storage temperature, HU dramatically decreased according to storage time and temperature, decreasing from 91.3 to 72.63 at $21^{\circ}C$ and from 87.62 to 60.92 at $29^{\circ}C$ during 10 d of storage; however, this decline was not found at $5^{\circ}C$. A rapid increase in albumen alkalinity was observed even after just 2 d of storage regardless of the storage temperature. Interactions between storage time and temperature were significant (p<0.001) with respect to egg weight loss, egg shell weight and percentage, albumen weight and percentage, yolk weight and percentage, albumen and yolk pH, HU, and yolk color. The results of the current study indicated that eggs from laying hens at peak production had significant deterioration of internal quality with increasing storage temperature and time. The results suggest that egg weight loss, albumen pH, and HU are parameters that are greatly influenced by the storage temperature and time of eggs from hens at peak laying.