• Asian-Australasian Journal of Animal Sciences
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• 제2권2호
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• pp.67-75
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• 1989

Studies were conducted to compare the utilization of dietary calcium between brown laying Tsaiya duck and Leghorn hen. Birds were fed corn-soybean diets containing 1.0, 2.0, 3.0, 4.0 and 5.0% calcium, respectively, with five birds per treatment. The metabolizability of calcium was determined by the indicator method. Experiments were conducted three times each at the age of 27, 31 and 36 weeks. Results appeared that duck eggs were heavier with better shell quality in comparison with hen eggs. Ducks fed 1% calcium diet resulted in severely depressed egg production (19%), but not for hens which still had 56% egg production. The metabolizability of calcium for hens was significantly higher than that for ducks (P<0.05) when both were fed diets containing 1 or 2% calcium. As the dietary calcium level was increased to 3 to 5%, there was no significant difference in calcium metabolizability between ducks and hens. When the dietary calcium was between 2 to 5%, the ducks retained more calcium than did the hens. Plasma calcium content for both hens and ducks fed 1% calcium diet was about the same. When the amount of the dietary calcium was increased to 2-5%, the plasma calcium level of ducks was approximately 7-10 mg/dl higher than that of hens. The calcium content in the egg shell of duck was significantly higher than that of hens, too. As the dietary calcium level was increased, there was a decreased magnesium content in the eggshell of hens, but not for ducks. The magnesium level in the eggshell was higher in hens than that in ducks. It is concluded that ducks could retain significantly more calcium and maintain higher plasma calcium level which might be the reason for larger eggs with better shell quality by ducks.

• Asian-Australasian Journal of Animal Sciences
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• 제5권3호
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• pp.461-464
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• 1992

A survey of the cholesterol content of eggs obtained from commercial sources in Korea was conducted. Eggs from 17 different strain birds were obtained from the Poultry Random Sample Test Station at Ansung, Kyonggi province. Yolk cholesterol contents, determined by the colorimetric procedure, were obtained from three consecutively laid eggs from birds of about 63 weeks of age. The overall mean of cholesterol value was 17.25 mg/g of wet yolk and ranged from 16.40 to 18.18 mg/g yolk. Analysis of t-test between white shell eggs and brown shell eggs showed no difference in cholesterol content: however, the white shell eggs were somewhat high in cholesterol (17.41 vs. 17.08 mg/g yolk). Significant differences (p<0.05) were found in yolk cholesterol contents among strains within the breed.

• 농업과학연구
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• 제45권4호
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• pp.687-694
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• 2018

This study was conducted to investigate the laying performance of six strains of Korean domestic chickens (KDC 1A, 2A, 3A, 1B, 2B and 3B). A total of 288 20-week-old KDC hens were allocated in a completely randomized design to give 12 replicates per each strain (4 chickens per pen). The chickens were fed commercial diets (i.e., week 20 - 32, crude protein [CP] 18.0% and metabolizable energy [ME] 2,850 kcal/kg; week 32 - 40, CP 17.0% and ME 2,800 kcal/kg) ad libitum together with fresh water during the 20-week experiment. Body weight, age of sexual maturity, egg weight, hen-day egg production (HDP) and feed conversion ratio (FCR) were measured during the experiment period (week 20 - 40). Our results show that strain 3B had an improved (p < 0.05) HDP and FCR compared with the other strains on week 24 - 28. However, strain 3A had an improved (p < 0.05) HDP and FCR compared to the other strains on week 28 - 40. Similarly, strain 3A had a higher egg weight (p < 0.05) compared to the other strains on week 28, 32 and 40. In conclusion, the higher laying performance of strain 3A indicates its potential in the development of a KDC strain with improved commercial laying performance.

• Asian-Australasian Journal of Animal Sciences
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• 제29권9호
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• pp.1256-1264
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• 2016

Adrenergic, alpha-1B-, receptor (ADRA1B) and peroxisome proliferator-activated receptor gamma, coactivator 1 beta (PPARGC1B) genes are involved in regulation of hen ovarian development. In this study, these two genes were investigated as possible molecular markers associated with hen-housed egg production, egg weight (EW) and body weight in Chinese Dagu hens. Samples were analyzed using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique, followed by sequencing analysis. Two novel single nucleotide polymorphisms (SNPs) were identified within the candidate genes. Among them, an A/G transition at base position 1915 in exon 2 of ADRA1B gene and a T/C mutation at base position 6146 in the 3'- untranslated region (UTR) of PPARGC1B gene were found to be polymorphic and named SNP A1915G and T6146C, respectively. The SNP A1915G (ADRA1B) leads to a non-synonymous substitution (aspartic acid 489-to-glycine). The 360 birds from the Dagu population were divided into genotypes AA and AG, allele A was found to be present at a higher frequency. Furthermore, the AG genotype correlated with significantly higher hen-housed egg production (HHEP) at 30, 43, 57, and 66 wks of age and with a higher EW at 30 and 43 wks (p<0.05). For the SNP T6146C (PPARGC1B), the hens were typed into TT and TC genotypes, with the T allele shown to be dominant. The TC genotype was also markedly correlated with higher HHEP at 57 and 66 wks of age and EW at 30 and 43 wks (p<0.05). Moreover, four haplotypes were reconstructed based on these two SNPs, with the AGTC haplotype found to be associated with the highest HHEP at 30 to 66 wks of age and with higher EW at 30 and 43 wks (p<0.05). Collectively, the two SNPs identified in this study might be used as potential genetic molecular markers favorable in the improvement of egg productivity in chicken breeding.

• Asian-Australasian Journal of Animal Sciences
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• 제32권7호
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• pp.1062-1068
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• 2019

Objective: For many generations, most species of farm animals have been subjected to intense and strictly targeted selection for improvement of their performance traits. This has led to substantial changes in animal anatomy and physiology, which resulted in considerable differences between the current animal breeds and their wild ancestors. The aim of the study was to determine whether there is breed-specific variability in behaviour as well as differences in emotional reactivity and preferences of laying hens. Methods: The investigations involved 50 Green-legged Partridge, 50 Polbar, and 50 Leghorn hens. All birds were kept in the same conditions, and the behavioural tests were carried out at 30 weeks of age. We used the tonic immobility test and a modified open-field test including such objects as water, commercial feed, feed enriched with cereal grains, finely cut straw, and insect larvae, a sandpit, a mirror, and a shelter imitating a hen nest. Results: The research results demonstrate that the birds of the analysed breeds differ not only in the excitability and emotional reactivity but, importantly, also in the preferences for environment-enriching elements. Ensuring hens' well-being should therefore be based on environmental modifications that will facilitate acquisition of essential elements of chickens' behaviour. The greatest emotional reactivity was found in the Leghorn breed, which may be a result of correlated selection aimed at an increase in chicken productivity. Conclusion: The differences in the behaviour of the birds from the analysed breeds indicate that laying hens cannot be regarded as one group of animals with the same environmental requirements.

• 한국가금학회지
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• 제39권4호
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• pp.261-267
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• 2012

Different housing systems have considerable influence on performance in poultry production. Therefore, the present study was undertaken to investigate the impact of different housing systems on the performance, bone mineral density and egg yolk fatty acid composition in laying hen. Hy-line brown pullets (n=450) of 12 weeks age were randomly divided into 3 housing systems with 6 replicates of 25 birds in each room. A diet with 2,750 kcal/kg ME and 16.5% CP was assigned to all birds. The pullets provided free access to feed and water. Significantly (P<0.05) higher values for egg production, egg mass and feed conversion efficiency were found in battery cages, however egg weight, egg shell color and breaking strength was remarkably (P<0.05) higher in floor system. The albumin height and Haugh unit were significantly higher (P<0.05) in battery cages which was statistically similar to aviary housing system. The egg yolk fatty acids concentration of linoleic acid and linolenic acids were significantly higher in aviary and in floor system, respectively, however both values were lower in battery cages. Saturated and unsaturated fatty acid content (%) in egg yolk did not influence by any housing systems. Bone mineral density was significantly higher (P<0.05) in floor and aviary housing system than that of battery cage system. It was concluded that in battery cages the egg production and composition maximized, however higher bone mineral density and yolk fatty acids content can be improved in the laying hen reared on floor and aviary housing systems.

• 한국가금학회지
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• 제17권4호
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• pp.318-326
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• 1990

본 시험은 산란계에 대한 경제적인 케이지 사육밀도를 구명하여 계사 및 케이지의 이용성을 높이고자 실시하였고 백색계로는 ISA Babcock 산란계 600수와 유색계로는 ISA Brown 산란계 450수를 공시계로 하여 수당 사육밀도에 따라 백색계, 6처리, 유색계 5처리 4반복 시험을 1987년 5월 11일부터 1988년 6월 27일(14~72주령)까지 시험을 실시한 결과는 다음과 같다. 1. 사육밀도에 따를 육성기간(14－20주령) 동안의 증체고은 백색곡에서는 사육밀도가 272$\textrm{cm}^2$, 수당 급이기 길이 8m에서 381g으로 가장 적었고, 유색계에서는 사육밀도 306$\textrm{cm}^2$에서 554g으로 가장 적었으나 처리간에 통계적인 유의차는 인정되지 않았다. 2. 육계기간(14~20주) 동안에 사육밀도간의 육성율은 백색곡와 유색계 모두 97.63% 이상으로 높은 편이었고 처리간 통계적 유의차는 인정되지 않았다. 3. 산란기간(21－72주) 동안의 사육밀도별 성계생존율은 백색계는 453$\textrm{cm}^2$ 구에서만 89.31%로 통계적유의차(P＜.05)가 인정되었고, 유색계에서는 306$\textrm{cm}^2$의 고밀도 구에서만 80.94%로 유의차(P＜.05)가 인정되었다. .4. 전 산란기간(21－72주령) 동안의 산란율은 백색계에서는 초고밀도인 272$\textrm{cm}^2$/수당 구에서 62.11%로 가장 낮았으며 사육밀도가 증가할수록 산란율도 증가하는 경향을 보였고, 유색계에서도 고밀도인 306$\textrm{cm}^2$/수당구에서 65.01%로 가장 낮았고 사육밀도가 증가할수록 산란율도 증가하는 순향을 나타내었다. 5. 사육밀도가 평균난중에 미치는 영향은 백색석와 유색계 모두 전 산란기간 동안 처리간의 특별한 경향치를 나타내지 않았으며 통계적 유의성도 인정되지 않았다. 6. 1일 산란양은 백색계의 경우 산란말기(63~72주령)에 고밀도 사육구(272~306$\textrm{cm}^2$/수)에서 떨어지는 경향이었고, 유상무에서는 산란 전기간(21~72주령)동안 사육밀도에 따라 산란양은 감소하는 경향이었고 처리간 통계적 유의성(P＜.05)이 인정되었다. 7. 산란전기간 동안(21－72주)의 사료섭취양은 백색계에서는 사육밀도간에 통계적 유의성이 인정되지 않았으나 유색계에서는 사육밀도와 수당 급이기의 길이가 증가할수록 사료섭취양도 증가하는 경향이었고 처리간의 유의성도 인정되었다. 8. 사료요구율은 백색계에서는 초고밀도(272$\textrm{cm}^2$/수)에서 2.94로 가장 많았으나 다를 처리구 사이에서는 유의성이 인정되지 않았으며, 유색계에서도 306$\textrm{cm}^2$/수의 고밀도 구에서 2.87로 가장 높았으나 다른 처리구 사이에서는 일정한 경향치가 없었고 통계적 유의차도 인정되지 않았다. 이상의 결과에서 산란계의 케이지 사육 적정 밀도는 백색계의 경우 초고밀도인 272$\textrm{cm}^2$/수를 제외한 수당면적 306~453$\textrm{cm}^2$, 유색계의 경우 수당면적 340~453$\textrm{cm}^2$ 일 때 경제능력을 제대로 발휘할 수 있고 경제성이 있는 것으로 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제6권2호
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• pp.243-248
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• 1993

The effect of dietary lipid factors (plant and animal oil, cholesterol and ${\beta}$-sitosterol) on the liver, serum, and egg yolk cholesterol levels of the laying hen was studied. Single Comb White Leghorn laying hens, at 28 weeks of age, were fed two basal diets containing 8.0% soybean oil or 8.0% fish oil, with or without supplemental cholesterol (1.0%), ${\beta}$-sitosterol (2.0%) or combinations of both. Restricting caloric intake resulted in significantly (p<.05) decreased egg production and the total amount of cholesterol excreted via the egg was significantly (p<.05) different among treatment groups. Cholesterol supplementation to the two basal diets resulted in a significant elevation of liver, serum and egg yolk cholesterol levels. The addition of ${\beta}$-sitosterol lowered the cholesterol levels in liver and serum, while increased in the egg yolk (SO + ST, FO + ST). The anticholesterogenic effect of dietary ${\beta}$-sitosterol was not clearly exhibited in this study.

• 대한수의학회지
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• 제48권4호
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• pp.469-472
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• 2008

Necropsy was performed on a total of twenty three either white leghorn or ogol chickens which were more than 150 weeks of age. Among twenty three chickens examined, fifteen chickens were laying and the rest eight chickens were non-laying. On necropsy, neoplastic mass in the five chickens among non-laying chickens was found. These neoplastic masses were present mostly in the ovaries and one case in the liver and characterized by multifocal to coalescing 1 to 5 mm tan firm nodular formation. On histopathology, ovarian adenocarcinoma with widespread abdominal seeding and hepatic metastasis was diagnosed in the three chickens. Oviductal leiomyoma was also found in two chickens that had a focal well-demarcated nodules in the oviduct. Taken together, the number with ovarian adenocarcinoma among non-laying chickens over 150 week old was 37.5%. As most animal species do rarely develop ovarian tumors, the high rate of spontaneous ovarian adenocarcinoma in non-laying hen suggest that the hen is a proper model for human ovarian cancer study.

• Asian-Australasian Journal of Animal Sciences
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• 제32권7호
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• pp.930-938
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• 2019

Objective: Estimate genetic parameters, the rate of inbreeding, and the effect of inbreeding on growth and egg production traits of a Thai native chicken breed Lueng Hang Kao Kabinburi housed under intensive management under a tropical climate. Methods: Genetic parameters were estimated for weight measured at four weekly intervals from body weight at day 1 (BW1D) to body weight at 24 weeks (BW24) of age, as well as weight at first egg, age at first egg (AFE), egg weight at first egg, and total number of eggs (EN) produced during the first 17 weeks of lay using restricted maximum likelihood. Inbreeding depression was estimated using a linear regression of individual phenotype on inbreeding coefficient. Results: Direct additive genetic effect was significant for all traits. Maternal genetic effect and permanent environmental hen effects were significant for all early growth traits, expect for BW24. For BW24, maternal genetic effect was also significant. Permanent environmental hen effect was significant for AFE. Direct heritabilities ranged from 0.10 to 0.47 for growth traits and ranged from 0.15 to 0.16 for egg production traits. Early growth traits had high genetic correlations between them. The EN was lowly negatively correlated with other traits. The average rate of inbreeding for the population was 0.09% per year. Overall, the inbreeding had no effect on body weight traits, except for BW1D. An increase in inbreeding coefficient by 1% reduced BWID by 0.09 g (0.29% of the mean). Conclusion: Improvement in body weight gain can be achieved by selecting for early growth traits. Selection for higher body weight traits is expected to increase the weight of first egg. Due to low but unfavorable correlations with body weight traits, selection on EN needs to be combined with other traits via multi-trait index selection to improve body weight and EN simultaneously.