• Animal Bioscience
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• 제34권10호
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• pp.1684-1694
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• 2021

Objective: This study investigated the association between feed efficiency, physicochemical properties, flavor precursors and biomolecules in the thigh meat of Korat (KR) chickens. Methods: The feed intake and body weight of individual male KR chickens were recorded from 1 to 10 weeks old to calculate the individual residual feed intake (RFI) of 75 birds. At 10 weeks of age, chickens with the 10 highest (HRFI) and lowest RFI (LRFI) were slaughtered to provide thigh meat samples. The physicochemical properties (ultimate pH, water holding capacity [WHC], drip loss) and flavor precursors (guanosine monophosphate, inosine monophosphate (IMP), adenosine monophosphate and inosine) were analyzed conventionally, and Fourier transform infrared spectroscopy was used to identify the composition of biomolecules (lipids, ester lipids, amide I, amide II, amide III, and carbohydrates) and the secondary structure of the proteins. A group t-test was used to determine significant differences between mean values and principal component analysis to classify thigh meat samples into LRFI and HRFI KR chickens. Results: The physicochemical properties of thigh meat samples from LRFI and HRFI KR chickens were not significantly different but the IMP content, ratios of lipid, lipid ester, protein (amide I, amide II) were significantly different (p<0.05). The correlation loading results showed that the LRFI group was correlated with high ratios of lipids, lipid esters, collagen content (amide III) and beta sheet protein (rg loading >0.5) while the HRFI group was positively correlated with protein (amide I, amide II), alpha helix protein, IMP content, carbohydrate, ultimate pH and WHC (rg loading >0.5). Conclusion: The thigh meat from chickens with different RFI differed in physiochemical properties affecting meat texture, and in the contents of flavor precursors and biomolecules affecting the nutritional value of meat. This information can help animal breeders to make genetic improvements by taking more account of traits related to RFI.

• 한국가금학회지
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• 제45권4호
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• pp.273-283
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• 2018

사료 에너지 수준(고, 저), 깔짚 종류(왕겨, 톱밥), 성별(암 수) 등 세 요인을 각각 달리하여 한협 3호 육계(토종닭)를 대상으로 연구한 결과는 다음과 같다. 깔짚, 사료에너지 수준, 성별 모두 증체량에 영향을 미쳤고, 이들 요인 간 상호효과도 나타났다. 성별에 따라 사료섭취량에 차이가 나타났으나 깔짚이나 사료에너지 수준은 특정 일령의 사료섭취량에만 영향을 미쳤다. 사료요구율은 고 에너지 사료에서 낮았으나, 41~75일령 사료요구율은 차이가 없었다. 지방 이외의 영양소 이용률은 모두 암컷에 비하여 수컷이 높았으며, 지방의 이용률은 성별에 상관없이 저에너지 사료에서 높았다. 가슴육의 색은 사료 에너지 수준과 성별에 따라 달랐고, 다리육의 TBARS가는 암컷에서 높았다. 가슴육의 지방함량은 암컷에서, 다리육의 인과 수분 함량은 수컷에서 높았다. 본 연구로 한협 3호에 대한 사료 에너지 수준, 특히 대부분의 증체가 이루어지는 41~75일령 기간의 사료 에너지 수준을 설정할 때 암 수 간 차이를 두는 것이 바람직하며, 56일령 이후 암컷에는 고 에너지 사료가 오히려 증체량이나 사료요구율에서 불리하다는 점을 알게 되었다.

• 한국가금학회지
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• 제43권4호
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• pp.219-228
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• 2016

세 수준(6.3, 9.5, 12.6 수/$m^2$)의 사육밀도와 사료 단백질 수준(19%, 18%)이 저속성장 육계(한협 3호)의 육성성적, 영양소 이용률, 닭고기 저장성, 육색, 계육 성분 및 뼈의 광물질 조성과 혈청 corticosterone 함량에 미치는 영향을 조사하였다. 사육 밀도는 한협 3호 육성성적에 유의적인 영향을 미치는 것으로 나타났다. 증체량은 저 밀도인 6.3 수/$m^2$ 구에서 가장 높았으며, 고밀도(12.6 수/$m^2$) 구에서 가장 낮았다. 특히 고사육 밀도에서는 사료섭취량이 유의적으로 감소한 것으로 나타났다. 그러나 낮은 사료섭취량으로 인하여 고사육 밀도 계군의 사료요구율이 타 사육 밀도 계군의 사료요구율에 비하여 상대적으로 낮았다. 고밀도 계군에서의 사료 섭취량 저하와 낮은 사료요구율은 41~60일 구간보다는 61~75일 구간에 현저하게 나타났는데, 그 영향으로 전 사육기간의 사료섭취량과 사료요구율도 차이가 나타났다. 본 연구에서 사료 단백질 1% 차이는 증체량과 사료요구율에 차이를 나타내지 않았다. 다만 41~75일 구간 사료섭취량은 단백질 19% 구에 비하여 오히려 18% 구에서 낮았다. 저장 중 계육의 TBARS 값은 처리구간에 차이가 없었다. 하지만 계육의 적색도와 명도는 사료 단백질 수준에 따라, 황색도는 사육 밀도에 따라 차이가 나타났다. 가슴육의 단백질 함량과 다리육의 Ca과 P의 함량은 각각 사료 단백질 수준과 사육밀도에 영향을 받았다. 사료의 단백질 수준과 사육밀도는 뼈의 회분함량 및 회분 중 Ca과 P의 함량에는 영향을 미치지 않았다. 혈청 corticosterone 함량은 사육밀도가 낮을수록 낮게 나타났으나, 사료 단백질 수준에 따른 차이는 없었다. 본 연구 결과, 저속성장 육계 한협 3호 사육후기 단계에 고사육 밀도(12.6 수/$m^2$)로 사육하는 것은 생산성을 하락시킬 뿐 아니라, 혈청 corticosterone 함량도 높이므로 바람직하지 않음을 알 수 있었다. 또한 한협 3호 육계의 후기 사료 단백질을 18% 수준으로 설계하더라도 생산성에 차이가 없음을 알게 되었다.

• Animal Bioscience
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• 제34권12호
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• pp.1886-1894
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• 2021

Objective: Growth hormone (GH) and insulin-like growth factor I (IGF-I) play a critical role in animal growth rates. We aimed to investigate the effect of GH and IGF-I genotypes on body weight (BW), dominance, and gene expression in slow-growing chickens at different ages. Methods: A total of 613 Korat chickens (KRs) were bred and divided into three groups by genotype - A1A1, A1A3, and A3A3 for GH and AA, AC, and CC for IGF-I. Chickens were weighed every two weeks, and liver and breast muscle tissues were collected at 10 weeks of age. Genetic parameters of KRs were estimated using ASReml software. The GH and IGF-I mRNA levels were measured by quantitative polymerase chain reaction. Significant differences between traits were analyzed using the generalized linear model. Results: A significant effect of GH genotypes on BW was found at most ages, and the A1A1 genotype had the highest value of BW. Compared with the A3A3 genotype, the A1A1 and A1A3 genotypes showed a higher dominance effect at 0 and 2 weeks, and genotype A1A1 had the highest value of dominance at 8 weeks of age. A difference in GH mRNA levels between genotypes was detected in breast muscle at 6 weeks and in the liver tissue at 2 weeks. In the case of IGF-I gene, the AA genotype had the highest BW at the beginning of life. Significant differences in BW dominance were found at 2 weeks. However, IGF-I mRNA levels were not different among genotypes in both breast muscles and liver tissues. Conclusion: Our results revealed that GH and IGF-I influence growth, but may not be involved in heterosis. GH can be used as a marker gene in selection programs for growth because the homozygous genotype (A1A1) had the highest BW at all ages. The IGF-I is not a useful marker gene for selection programs.

• Asian-Australasian Journal of Animal Sciences
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• 제29권4호
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• pp.479-486
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• 2016

A previous genome-wide association study (GWAS) exposed histone deacetylase 2 (HDAC2) as a possible candidate gene for breast muscle weight in chickens. The present research has examined the possible role of HDAC2 in skeletal muscle development in chickens. Gene expression was measured by quantitative polymerase chain reaction in breast and thigh muscles during both embryonic (four ages) and post-hatch (five ages) development and in cultures of primary myoblasts during both proliferation and differentiation. The expression of HDAC2 increased significantly across embryonic days (ED) in breast (ED 14, 16, 18, and 21) and thigh (ED 14 and 18, and ED 14 and 21) muscles suggesting that it possibly plays a role in myoblast hyperplasia in both breast and thigh muscles. Transcript abundance of HDAC2 identified significantly higher in fast growing muscle than slow growing in chickens at d 90 of age. Expression of HDAC2 during myoblast proliferation in vitro declined between 24 h and 48 h when expression of the marker gene paired box 7 (PAX7) increased and cell numbers increased throughout 72 h of culture. During induced differentiation of myoblasts to myotubes, the abundance of HDAC2 and the marker gene myogenic differentiation 1 (MYOD1), both increased significantly. Taken together, it is suggested that HDAC2 is most likely involved in a suppressive fashion in myoblast proliferation and may play a positive role in myoblast differentiation. The present results confirm the suggestion that HDAC2 is a functional gene for pre-hatch and post-hatch (fast growing muscle) development of chicken skeletal muscle.

• Asian-Australasian Journal of Animal Sciences
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• 제29권7호
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• pp.987-997
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• 2016

The objective of the study was to compare the carcass characteristics, meat quality, and blood parameters of slow and fast grown female broiler chickens fed in organic or conventional production system. The two genotypes tested were medium slow-growing chickens (SG, Hubbard Red JA) and commercial fast-growing chickens (FG, Ross 308). Both genotypes (each represented by 400 chickens) were divided into two sub-groups fed either organic (O) or conventional (C) systems. Chickens of each genotype and system were raised in a semi environmentally controlled poultry house until 21 d of age and were assigned to 5 pens of 40 chickens each. Then, O system chickens were transferred into an open-side poultry house with an outdoor run. At 81 d of age, 10 female chickens from each genotype and from each production system (n = 40) were randomly chosen to provide material for analysis, and were weighed and brought to the slaughterhouse to assess carcass characteristics and meat quality. The blood parameters were determined by using 5 female chickens from each genotype and from each production system (n = 20). FG had the higher live weight, along with carcass, breast, and thigh-drumstick weights compared to SG (p<0.05). FG had the higher breast yield, whereas SG had the higher thigh-drumstick yield (p<0.05). The O system resulted in a higher amount of abdominal fat (p<0.05). In addition, the O system values were higher for dry matter, crude ash, crude protein, and $pH^{15}$ values in breast meat, and for crude ash, crude protein, and $pH^{15}$ values in drumstick meat (p<0.05). In addition, total saturated fatty acids, total mono-unsaturated fatty acids, and total omega 3 were significantly higher in the O system than in the C system. Thus, the O system showed a positive advantage compared to the C system regarding female chicken meat quality, primarily within the ash, protein, and total omega 3 fatty acid profiles. In conclusion, the present study indicated that the main factor affecting the carcass characteristics of female chickens was genotype, whereas the organic system contributed to enhanced meat quality. These findings provide a better understanding of the relative roles of genotype and production systems in female broiler characteristics, and might aid producers in designing their facilities to optimize yield and quality while maintaining acceptable animal welfare standards.

• Asian-Australasian Journal of Animal Sciences
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• 제24권5호
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• pp.603-609
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• 2011

Telomeres are special structures at the ends of eukaryotic chromosomes. Vertebrate telomeres consist of tandem repeats of conserved TTAGGG sequence and associated proteins. Birds are interesting models for molecular studies on aging and cellular senescence because of their slow aging rates and longer life spans for their body size. In this longitudinal study, we explored the possibility of using telomeres as an age-marker to predict age in Single Comb White Leghorn layer chickens. We quantified the relative amount of telomeric DNA in isolated peripheral blood lymphocytes by the Quantitative Fluorescence in situ Hybridization technique on interphase nuclei (IQ FISH) using telomere-specific DNA probes. We found that the amount of telomeric DNA (ATD) reduced significantly with an increase in chronological age of the chicken. Especially, the telomere shortening rates are greatly increased in growing individuals compared to laying and old-aged individuals. Therefore, using the ATD values obtained by IQ FISH we established the possibility of age prediction in chickens based on the telomere theory of aging. By regression analysis of the ATD values at each age interval, we formulated an equation to predict the age of chickens. In conclusion, the telomeric DNA values by IQ FISH analyses can be used as an effective age-marker in predicting the chronological age of chickens. The study has implications in the breeding and population genetics of poultry, especially the reproductive potential.