• Proceedings of the Korea Society of Poultry Science Conference
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• 2006.11a
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• pp.82-83
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• 2006

생식 세포는 한 세대의 유전 정보를 다음세대에 전달할 수 있는 유일한 세포로서 다양한 특성을 가지고 있다. 기능 유전체 연구를 통해서 새로운 유전자의 기능을 규명함으로써 그 유전자의 생물학적 의미와 상호작용을 설명할 수 있다. 본 실험의 목적은 생식세포에서 특이적으로 발현하는 유전자를 발굴하여 그 유전자가 생식세포의 발달과 분화에 중요한 역할을 수행하는 것을 증명하는 것이다. 이에 본 실험에서는 real-time quantitative RT-PCR 기법을 이용하여 정소에서 특이적으로 발현하는 5개(AGE1, AGE2, AGE3, AGE4, AGE5)를 선발하였고, in situ hybridization 실험을 통하여 정소 조직 내에서의 발현 양상을 확인하였다. AGE1, AGE2는 round spermatid에서 특이적으로 발현하고, AGE3, AGE4, AGE5는 spermatocyte에서 특이적으로 발현하는 것을 확인하였다. 본 실험을 통해 발굴한 유전자들은 닭의 생식선발달에 중요한 기능을 할 것으로 예상되며, 앞으로 닭의 유전육종분야에 큰 도움을 줄 수 있을 것이다.

• Journal of Environmental Science International
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• v.33 no.2
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• pp.179-185
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• 2024

This study aimed to evaluate the differences in canine preferences for pet food terrine according to the processing method. As companion dogs, three male Spitz canines (average age 12 years, average weight 7 kg) and three male Spitz mix canines (average age 12 years, average weight 5 kg) were used in Experiment 1, whereas five male (average age 10 years, average weight 9 kg) and five female Shetland Sheepdogs (Sheltie, average age 10 years, average weight 8 kg) were used in Experiment 2, to evaluate their preferences and intake types. In both experiments, all dog categories mostly preferred 'meat' when it came to their first choice of food consumed, followed by 'vegetables', 'mixed eating', and 'vegetable leftover' last. This confirms means that canines are carnivores, and over time, choosing 'vegetables' or 'vegetable leftovers' as a secondary or alternate food source can be considered a natural process. When provided various terrines, canines in both experiments first ingested 'cooked' rather than 'freeze-dried' duck, chicken, beef, and pork terrines when selecting food at the start of feeding. For both experiments, most of the intake types using duck, chicken, beef, and pork terrine showed a preference for 'after consuming cooked terrine first and then intake freeze-dried' item. In conclusion, the reason for preferring cooked terrine can be attributed to the difference in the preparation cooking method of freeze-dried cooked terrine.

• Journal of the Korean Society of Food Culture
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• v.21 no.5
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• pp.439-445
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• 2006

The purpose of this study was to measure respondent's demographic characteristics, respondent's attitudes toward chicken, and factor influencing on the level of perceived helpfulness of country of origin in predicting the quality of chicken. The data was collected through a consumer survey during the March 2006. A total number of 250 meat consumers living in Suncheon, the eastern part of Chonnam, were randomly selected as respondents. Eleven respondents did not complete the survey instrument, resulting in a final sample size of 239. All estimations were carried out using chi-square, correlation, and logistic procedure of SAS package. The results are as follows. The level of perceived helpfulness of country of origin in predicting the quality of chicken was significantly different by age and occupation of demographic variables, and was significantly correlated with respondent informed of attitude variables. The proportional odds assumption of model was not violated at p<0.05. The effects of income, occupation and respondent informed on the level of perceived helpfulness of country of origin in predicting the quality of chicken. The results from this study could be useful in developing marketing and health promotion strategies, as well as government trade policy.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.5
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• pp.662-669
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• 2011

An experiment was conducted with broiler (Cobb 400) male chicks (n = 480) to determine the effect of betaine (Bet) supplementation (0 and 800 mg/kg) to diets containing five concentrations (15, 18, 20, 22 and 24 g/kg crude protein, CP) of methionine (Met) in a $2{\times}5$ factorial study for performance, carcass traits, immune responses, and serum parameters. Each diet was fed ad libitum from 1 to 42 d of age to 8 replicates of 6 chicks. Birds were housed in battery brooders placed in an open-sided poultry shed. Body weight gain, feed intake, feed conversion efficiency and slaughter variables were recorded at 21 and 42 d of age. Serum biochemical profile, antibody production against Newcastle disease (ND) and lymphocyte proliferation ratio (LPR) were analysed at 42 d of age. Supplementing Bet to diets containing sub-optimal concentrations of Met (15 g/kg) improved weight gain and breast yield at 21 d of age (p<0.01), and feed conversion efficiency at 42 d of age (p<0.05). Feed efficiency at 21 d of age, body weight gain at 42 d of age, slaughter variables except breast yield at 21 d of age and ND antibody titres were not affected (p>0.05) by the interaction. LPR increased (p<0.05) with Bet supplementation at 20 g Met/kg CP equal to those broilers fed 24 g Met without Bet. Bet supplementation enhanced the concentrations of protein, globulin and cholesterol in serum of broilers fed sub-optimal concentrations of Met. Results suggested that Bet supplementation (800 mg/kg diet) enhanced growth (21 d), feed conversion efficiency (42 d), breast yield and lymphocyte proliferation in broilers fed a diet containing 15 g Met/kg CP.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.6
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• pp.767-777
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• 2014

Characterizing local chicken types and their mostly rural production systems is prerequisite for designing and implementing development and conservation programs. This study evaluated the management practices of small-scale chicken keepers and the phenotypic and production traits of their chickens in Oman, where conservation programs for local livestock breeds have currently started. Free-range scavenging was the dominant production system, and logistic regression analysis showed that socio-economic factors such as training in poultry keeping, household income, income from farming and gender of chicken owners influenced feeding, housing, and health care practices (p<0.05). A large variation in plumage and shank colors, comb types and other phenotypic traits within and between Omani chicken populations were observed. Male and female body weight differed (p<0.05), being $1.3{\pm}0.65$ kg and $1.1{\pm}0.86$ kg respectively. Flock size averaged $22{\pm}7.7$ birds per household with 4.8 hens per cock. Clutch size was $12.3{\pm}2.85$ and annual production $64.5{\pm}2.85$ eggs per hen. Egg hatchability averaged $88{\pm}6.0%$ and annual chicken mortality across all age and sex categories was $16{\pm}1.4%$. The strong involvement of women in chicken keeping makes them key stakeholders in future development and conservation programs, but the latter should be preceded by a comprehensive study of the genetic diversity of the Omani chicken populations.

• Korean Journal of Poultry Science
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• v.50 no.1
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• pp.15-22
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• 2023

This study was to investigate the relationship between chick weight in the growing period and the laying performance of Korean native chicken (KNC) breeders. We measured the body weights of 1,384 KNC breeders at 1-140 days of age at two-week intervals. The age at first egg laying, hen-day and hen-housed egg production, and the egg weights were investigated. Correlation coefficients between the body weight and egg production traits were analyzed. The results showed that the correlation coefficients between body weight and age at first egg laying were significantly positive before 4 weeks, but negative after 8 weeks of age. The correlation coefficients between body weight and egg production rate were estimated to be negative before 8 weeks and positive after 12 weeks of age. Coefficients of hen-day and hen-housed egg production were similar. There was little correlation between body weight and egg weight at 32 weeks of age, whereas a low positive correlation was with egg weight at 50 weeks. In conclusion, there was little correlation between body weight and laying performance before 8 weeks of age, whereas a significant positive correlation was with body weight after 12 weeks. The results suggest that as the chick's weight increases in the late growing stage, sexual maturity is faster, the egg production rate is higher, and the egg weight increases. Therefore, the weight management of KNC female breeders is very important in the late growing stage, and the body weight of chicks must be maintained above the standard weight.

• Korean Journal of Agricultural Science
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• v.44 no.2
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• pp.244-253
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• 2017

This study was conducted to investigate the growth performance indices among male commercial crossbred Korean native chickens from hatch to twelve weeks of age. A total of 312 one-day-old male birds were used for 6 groups of the commercial crossbred Korean native chicken within 1 paternal line and 6 maternal lines (1A, 2A, 3A, 4A, 5A, and 6A). The chickens were allocated to 24 battery cages to give 4 replicates per each crossbreed with 13 chickens per cage. Ad-libitum feeding was practiced throughout the experimental period and fresh water was available via nipple drinkers at all times. Body weight and feed intake were measured at two-week interval. Among six crossbreeds, the 2A group had the greatest (p < 0.05) body weight at week 8 and the greatest average daily weight gain in week 6 - 8. However, crossbreed 2A had the lowest viability (p < 0.05) at week 8 of all crossbreed groups as well as higher uniformity (p > 0.05) at week 2 than the others. No difference (p < 0.05) was found in any crossbreed Korean native chicken's growth performance indices including body weight, average daily gain, average daily feed intake, feed efficiency, uniformity, and viability after week 8. With this in mind, crossbreed 2A had greater bodyweight, average daily gain, average feed intake, and feed efficiency than the other Korean native chickens 84 days after hatch, although they had lower uniformity and viability than the others.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.10
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• pp.1558-1564
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• 2018

Objective: We report monitoring conservation effect for a Chinese indigenous chicken (Langshan) breed using major histocompatibility complex (MHC) and DNA barcords. Methods: The full length of MHC B-G gene and mitochondrial cytochrome oxidase I (COI) gene in generations 0, 5, 10, 15, 16, and 17 was measured using re-sequencing and sequencing procedures, respectively. Results: There were 292 single nucleotide polymorphisms of MHC B-G gene identified in six generations. Heterozygosity (He) and polymorphic information content (PIC) of MHC B-G gene in generations 10, 15, 16, and 17 remained stable. He and PIC of MHC B-G gene were different in six generations, with G10, G15, G16, G17 >G5>G0 (p<0.05). For the COI gene, there were five haplotypes in generations 0, 5, 10, 15, 16, and 17. Where Hap2 and Hap4 were the shared haplotypes, 164 individuals shared Hap2 haplotypes, while Hap1 and Hap3 were the shared haplotypes in generations 0 and 5 and Hap5 was a shared haplotype in generations 10, 15, 16, and 17. The sequence of COI gene in 6 generations was tested by Tajima's and D value, and the results were not significant, which were consistent with neutral mutation. There were no differences in generations 10, 15, 16, and 17for measured phenotypic traits. In other generations, for annual egg production, with G5, G10, G15, G16, G17>G0 (p<0.05). For age at the first egg and age at sexual maturity, with G10, G15, G16, G17>G5>G0 (p<0.05). Conclusion: Combined with the results of COI gene DNA barcodes, MHC B-G gene, and phenotypic traits we can see that genetic diversity remained stable from generations 10 to 17 and the equimultiple random matching pedigrees conservation population conservation effect of Langshan chicken was effective as measured by these criteria.

• Journal of Animal Science and Technology
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• v.64 no.4
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• pp.752-769
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• 2022

Wheat gluten is an increasingly common ingredient in poultry diets but its impact on the small intestine in chicken is not fully understood. This study aimed to identify effects of high-gluten diets on chicken small intestines and the variation of their associated transcriptional responses by age. A total of 120 broilers (Ross Strain) were used to perform two animal experiments consisting of two gluten inclusion levels (0% or 25%) by bird's age (1 week or 4 weeks). Transcriptomics and histochemical techniques were employed to study the effect of gluten on their duodenal mucosa using randomly selected 12 broilers (3 chicks per group). A reduction in feed intake and body weight gain was found in the broilers fed a high-gluten containing diet at both ages. Histochemical photomicrographs showed a reduced villus height to crypt depth ratio in the duodenum of gluten-fed broilers at 1 week. We found mainly a significant effect on the gene expression of duodenal mucosa in gluten-fed broilers at 1 week (289 differentially expressed genes [DEGs]). Pathway analyses revealed that the significant DEGs were mainly involved in ribosome, oxidative phosphorylation, and peroxisome proliferator-activated receptor (PPAR) signaling pathways. These pathways are involved in ribosome protein biogenesis, oxidative phosphorylation and fatty acid metabolism, respectively. Our results suggest a pattern of differential gene expression in these pathways that can be linked to chronic inflammation, suppression of cell proliferation, cell cycle arrest and apoptosis. And via such a mode of action, high-gluten inclusion levels in poultry diets could lead to the observed retardation of villi development in the duodenal mucosa of young broiler chicken.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2002.11a
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• pp.140-142
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• 2002

This study was conducted to obtain some genetic information for developing superior Korean native chickens. Heterosis and combining ability effects were estimated with 1,080 progenies of full diallel crosses of 3 strains in Korean Native Chicken. The traits of egg productivity were Investigated, and heterosis effect, general combining ability, specific combining ability and reciprocal effect were analyzed model I of the Griffing's method 1. The general performance were 147.0 days in age at first egg laying, 71.8 eggs in egg numbers to 270 days, 50.1g in egg weight at 270 days, 75.6 in egg shape index, 356$\mu\textrm{m}$ in egg shell thickness, and 4.27kg/$\textrm{cm}^2$ in egg shell strength, respectively. According to result, heterosis effect revealed comparatively high in age at first egg laying, egg numbers, egg weight, and egg shell strength. The effects estimated highly in general combining ability for age at first egg laying, egg numbers, egg weight, egg shape Index and egg shell thickness, and in specific combining ability were egg numbers, egg weight and egg shell thickness, and in reciprocal effects for egg numbers, egg shape index, and egg shell thickness. This result could be used for developing Korean native chicken.