• Asian-Australasian Journal of Animal Sciences
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• v.18 no.1
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• pp.113-132
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• 2005

With the demand for free-range products increasing and the pressure on the intensive poultry industry to improve poultry welfare especially in western countries, the number of free-range poultry farms has increased significantly. The USA, Australia and European countries have developed Codes of Practice for free-range poultry farming which detail the minimum standards of husbandry and welfare for birds. However, the performance and liveability of free-range birds needs to be improved and more knowledge is required on bird husbandry, feed supply, disease control and heat wave management. This review examines the husbandry, welfare, nutrition and disease issues associated with free-range poultry systems and discusses the potential of incorporating free-range poultry into a crop-pasture rotation system.

• Korean Journal of Poultry Science
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• v.31 no.4
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• pp.299-306
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• 2004

The objective of this study was to investigate the influence of egg storage, broiler breeder age, and the change of egg weight during incubation on growth rate of chicks and 43-day-old dressing percentage. The trials involved hatching eggs obtained from 27-wk-old hens and stored for 6 d for the Young-EXP group, from 28-wk-old hens and stored for 0 d for the Young-CON group, from 51-wk-old hens and stored for 6 d for the Old-EXP group, and from 52-wk-old hens and stored for 0 d for the Old-CON group, The hens were two commercial broiler breeder flocks of the same strain (Cobb) but of different egg producing stages(early and middle stages of egg production). The chicks were grown on floor pens for 6 wks, The differences of setting egg weights between Old-CON and Old-EXP groups were 1 g, but those between Young-CON and Young-EXP groups were 2.9 g(P<0,05). The loss of egg weight during 18 d incubation did not greatly differ among four groups, but the loss of egg weight during 21 d incubation was significantly (P<0.05) more in the middle stage of egg production groups than in the early stage of egg production groups. The mean birth weights of the middle stage of egg production groups were significantly(P<0,05) heavier by 8,7 g than those of the early stage of egg production groups; however, the differences of 6-wk-old body weight were not significant between egg producing stages. The differences of body weights in both egg producing stages were not significantly influenced by egg storage period in overall wks of ages. Egg storage and hen age did not greatly influence to the 43 d dressing percentages, either, The correlations of the setting egg weight with 18 d egg weight during incubation, growth rate of chicks, or 43 d dressing percentage were not significant.

• Korean Journal of Poultry Science
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• v.43 no.3
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• pp.143-148
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• 2016

This study was conducted to investigate the effect of dietary egg yolk antibody (IgY) powder supplementation on the growth performance, blood component profile, intestinal microflora, and immunoglobulin G in ducks. A total of 300 1-day-old ducks (Cherry Valley) were randomly divided into 5 groups, with 3 replicates of 20 birds. The treatment groups were the negative (NC), positive (PC), egg yolk antibody powder 0.1% (T1), egg yolk antibody powder 0.5% (T2), and egg yolk antibody powder 1.0% (T3) groups. In the growth performance of ducks during the entire experimental period, the IgY groups and positive control group (PC) showed significantly higher (P<0.05) body weights and body weight gains compared to the negative control group (NC). However, no significant differences were observed in the feed intake and feed conversion ratio. The blood component profiles showed that the IgY 0.1 and 1.0% groups decreased in total cholesterol content compared to the NC group. The aspartate aminotransferase (AST) and alanine aminotranferease (ALT) contents were lower in the IgY 1.0% group, but there were no significant differences. Regrading the leukocyte content after feeding IgY, the heterophil: lymphocyte ratio decreased in the IgY groups, especially in the IgY 0.1% group, which had a lower content than the other groups. However, these results showed no significant differences. The Lactobacillus count in the intestines significantly increased (P<0.05) in the IgY 0.1 and 0.5% groups, the level of IgY increased, and the Escherichia coli count decreased. However, no significant difference was observed in the total plate count. The immunoglobulin G content was lower in the IgY groups than in the NC group, and compared with the IgY groups, the IgY 0.5% had a lower content, which was not a significant difference.

• Korean Journal of Poultry Science
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• v.47 no.4
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• pp.267-274
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• 2020

This study was conducted to estimate genetic parameters for growth and egg production traits in Black Korean native chicken (L strain) and Korean White Leghorn (F, K strains) using a multi-traits animal model BLUP. Traits used for this study were body weight at 150 days (BW150) and 270 days (BW270), age at first egg (DAY1st), egg weight at first egg (EW1st) and 270 days (EW270), and number of eggs laid by 270 days (EP270), and included 68,688 pedigree and 123,905 performance records collected from 2001 to 2013. In L, F, K strains, heritability estimates of BW150 were high (0.48, 0.52 and 0.50, respectively); of BW270 were high (0.56, 0.57 and 0.56); of DAY1st were medium to high (0.45, 0.39 and 0.31); of EW1st were low (0.15, 0.16 and 0.15); of EW270 were high (0.58, 0.55 and 0.59) and of EP270 were moderate (0.22, 0.21 and 0.20). The genetic and phenotypic correlation of DAY1st with EP270 were highly negative (-0.73 to -0.63 and -0.48 to -0.42). The genetic and phenotypic correlation of EP270 with BW150 and BW270, respectively were low negative (-0.16 to 0.01 and -0.14 to -0.03) and low to moderate positive (-0.08 to 0.07 and -0.13 to 0.04). The genetic and phenotypic correlation of EW270 with BW150 and BW270, respectively were moderate to high positive (0.39 to 0.49 and 0.36 to 0.46) and (0.29 to 0.33 and 0.34 to 0.37). The study showed that there is a potential for genetic improvement of Korean Indigenous chicken through selection program.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2002.11a
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• pp.118-119
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• 2002

This experiment was conduct to determine the influences of different levels of dietary energy and crude protein on growth performances during growing period (2 to 10 wk of age). A total of 360 egg breeder chicks (Hy-Line Brown) was divided into 5 groups with 4 replicates of 18 birds per replicate and fed the experimental diets containing three levels of energy and three levels of protein. With the increase in dietary crude protein levels, body weight significantly increased (P〈0.05). But dietary energy levels did not greatly affect growth performances. There were no significant differences to flock uniformity and tibia strength among treatments.

• Korean Journal of Poultry Science
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• v.26 no.2
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• pp.109-118
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• 1999

Hen's eggs have been regarded as one of the best animal bioreactors to produce biologically active peptides originated from many organisms including human. Despite the last decade's efforts to produce transgenic chicken for any commercial purposes, the results so far reported are very disappointing, indicating that hen's eggs are very difficult to crack for transgenesis. Comparatively large female gamete with enormous amount of yolk may be one of the major obstacles in achieving a similar feat to those of other vertebrate species including mouse, sheep, fish and frog. The delay or less efficiency evidenced may instruct to try an alternative way of gens transfer into chicken egg. Sperm-mediated gene transfer is one of them, and may require a great deal of understanding of mechanisms involved in early fertilization and embryonic development. In other animals where the technique was successful, basic mechanisms have been well studied and established only by painstaking efforts for decades. This paper discusses the accumulated knowledge on early fertilization mechanism in the chicken and how can this information be utilitzed to find the alternative gene transfer in making transgenic chicken.

• Korean Journal of Poultry Science
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• v.27 no.3
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• pp.197-202
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• 2000

Chemical characteristics of the cricket, Gryllus bimaculatus, were investigated in total composition, amino acid composition, fatty acid composition and mineral components. After the treatment of 0.4% of G. bimaculatus in the chicken feed, the changes of fatty acid composition in the chicken meat and egg were also estimated. As the result, saturated fatty acid, especially palmitic acid, decreased 4% and unsaturated fatty acids, linoleic aced and arachidonic acid, increased 12 and 23%, respectively, compared with those of control. In addition, there was a small increase in Eicosapentaenoic acid(EPA). The sensory test of the chicken meat resulted in increased flavor, brightness and yellow color. The sensory scores of G. bimaculatus egg in the point of taste resulted in somewhat better estimate than control. These results are appear to be stemmed from fatty acids of cricket.

• Korean Journal of Poultry Science
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• v.2 no.1
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• pp.4-6
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• 1975

Field trials and research works have shown that the sexually retarded pullets are better equipped to lay larger eggs at the commencement of lay than the pullets grown under the natural conditions with no control over the rate of maturity. The method of delaying the sexual maturity by restricting the nutrient intake is receiving a considerable attention from the research workers, since the nutrient restriction can be a method of reducing the rearing cost. Many experiments were carried out to study the effect of different methods of restricting the nutrient intake of the chicken. But the comparisons between these experiments are difficult because of the differences in the environment, management, type of breed and feed, and in the length of the time during which the feed intake was restricted. In addition the comparisons were not made on an economic basis in these experiments. This experiment was designed to provide information on the reproductive responses to three different methods of restricting the nutrient intake in a egg type stock and to establish which methods are economically profitable. (omitted)

• Journal of Animal Environmental Science
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• v.6 no.3
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• pp.141-151
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• 2000

Over-grown seaweeds in Donghae(east sea of Korea peninsula) may impedes ocean environment, however, they can be a good nutrient resources for poultry feeds if they are utilized properly. In this study, seaweeds powder were tested for laying hens\` ration to investigate the effects on egg production rate, egg quality and calcium phosphorus excretion. One hundred 65wks-old brown layers were fed for 5 weeks alotted with seaweeds powder addition to experimental diet by 0(control), 0.5, 1.0 and 2.0%, respectively, and obtained following results; 1. Seaweeds proved a mid-protein low-energy feed resources with planty of K, Na, Ca, Mg, Sr and Fe. 2. Seaweeds addition by 0.5% and 1.0% improved egg production rate and egg-mass output markedly(p<0.05) than control. Seaweeds addition did not alter cholesterol level of yolk and yolk index, however egg shell thickness showed increasing trend by increasing seaweeds addition level. 3. Protein absorption and digestibility in seaweed addition treatments were significantly higher(p<0.05) than control group and protein contents of excreta in 0.5% and 1.0% treatments were reduced(p<0.05), which suggests effective protein metabolism for egg production. Increasing seaweeds addition reduces Ca and P contents in rectum and excreta, suggesting Ca and P utilization improvement in laying hens and lessening soil pollution. 4. In conclusion, seaweeds addition in layers' diet by 1.0% level improves egg-mass production and might be egg quality by increasing metabolism of protein, calcium and phosphorus.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1546-1552
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• 2002

Proliferation and differentiation of ovarian cells are regulated by gonadotrophins and various intraovarian factors, with many of their actions dependent on growth factors. Transforming growth factor-$\beta$ (TGF-$\beta$) has been reportedly involved in the regulation of ovarian follicular development. The overall objectives of the present study were to examine the influence of TGF-$\beta$1 expression in ovarian follicular development or yolk formation and to investigate the association of egg weight with ovarian TGF-$\beta$1 expression at 60 wk. Egg weights of 70 Korean Native Ogol Chicken (KNOC) were recorded from 20 to 60 wk. Ovaries were taken at 60 wk, and TGF-$\beta$1 was measured with ELISA, respectively. Based on egg weight up to 60 wk and TGF-$\beta$1 expression in ovary, the chickens were divided into high and low groups. Egg weights and follicle weight in the high TGF-$\beta$1 group were higher than those in the low groups. Also, TGF-$\beta$1 expression and follicle weight in high egg weight group were higher than those in the low groups. Taken together, the results indicate that TGF-$\beta$1 is associated with egg weight in KNOC. This association of TGF-$\beta$1 with egg weight in KNOC supports the report that TGF-$\beta$ is mainly involved in the development and differentiation of follicles in the poultry. Further studies about other endocrine factors related to yolk formation are required to fully understand the endocrine mechanism of egg weight in Korean Native Ogol Chickens.