• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.117-125
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• 2024

This study aimed to find genetic markers for breed-independent identification of early- and late-feathering chickens. We explored the novel sequences of the ev21-K locus associated with late-feathering and investigated its characterization. Additionally, the genetic transmission pattern of the identified sequences were investigated to understand its potential application in auto-sexing lines. A total of 707 chickens from 5 chicken breeds were employed for the study. The ev21-K locus was identified through a comparative analysis of the ev21 gene and the K gene related to feather development. For analysis of identified loci, specific primers for the target sequences were prepared and polymerase chain reaction (PCR) was performed to obtain the products, and then their nucleotide sequences were analyzed. Crossbreeding tests of early-feathering and late-feathering chickens were conducted to examine the genetic transmission patterns of the identified sequences. The results showed that the identified 230 bp ev21-K locus, which named as ev21-related K specific sequences were 99% homology with the ev21 gene. PCR analysis confirmed its presence exclusively in late-feathering chickens. Comparative analyses across tissues, breeds, and ages demonstrated the sequences consistency in identifying late-feathering chickens. Genetic transmission patterns were investigated through crossbreeding tests, revealing sex-linked inheritance and consistent segregation with feathering phenotypes. The inheritance patterns of the ev21-related K specific sequences demonstrated that this locus follows the typical Mendelian inheritance pattern as a dominant gene. In conclusion, the novel sequences of ev21-K locus were a reliable molecular marker for identifying early- and late-feathering chickens across breeds.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1531-1535
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• 2002

It has been known that the sex of chicken cells can be most accurately identified by fluorescence in situ hybridization (FISH). However, the presently available FISH has not been widely used for sex identification, because the procedures for cell preparation and FISH itself are complicated and time-consuming. The present study was undertaken to test a rapid FISH procedure for sexing chicken. A FISH probe was simultaneously synthesized and labeled with digoxigenin by polymerase chain reaction (PCR) targeting a 416 bp segment of the 717 bp XhoI family fragment which is repeated over 10 thousand times exclusively in the W chromosome. Sexing by FISH was performed on cytological preparations of early embryos, adult lymphocytes and feather pulps of newly hatched chicks. The DNA probe hybridized to all types of uncultured interphase as well as metaphase female but not male cells that had been examined. Moreover, consistent with the known site of the XhoI family, the hybridization signal was localized to the pericentromeric region of the W chromosome. We, therefore, conclude that the present PCR-based FISH can be used as a rapid and reliable sex identification procedure for chicken.

• Animal Bioscience
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• v.34 no.3_spc
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• pp.393-404
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• 2021

Objective: This study compared the catechin composition of different tea byproducts and investigated the effects of dietary supplementation with green tea byproducts on the accumulation of abdominal fat, the modulation of lipid metabolism, and the inflammatory response in red feather native chickens. Methods: Bioactive compounds were detected, and in vitro anti-obesity capacity analyzed via 3T3-L1 preadipocytes. In animal experiments, 320 one-day-old red feather native chickens were divided into 4 treatment groups: control, basal diet supplemented with 0.5% Jinxuan byproduct (JBP), basal diet supplemented with 1% JBP, or basal diet supplemented with 5×106 colony-forming unit (CFU)/kg Bacillus amyloliquefaciens+5×106 CFU/kg Saccharomyces cerevisiae (BA+SC). Growth performance, serum characteristics, carcass characteristics, and the mRNA expression of selected genes were measured. Results: This study compared several cultivars of tea, but Jinxuan showed the highest levels of the anti-obesity compound epigallocatechin gallate. 3T3-L1 preadipocytes treated with Jinxuan extract significantly reduced lipid accumulation. There were no significant differences in growth performance, serum characteristics, or carcass characteristics among the groups. However, in the 0.5% JBP group, mRNA expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) were significantly decreased. In the 1% JBP group, FAS, ACC and peroxisome proliferator-activated receptor γ levels were significantly decreased. Moreover, inflammation-related mRNA expression levels were decreased by the addition of JBP. Conclusion: JBP contained abundant catechins and related bioactive compounds, which reduced lipid accumulation in 3T3-L1 preadipocytes, however there was no significant reduction in abdominal fat. This may be due to a lack of active anti-obesity compounds or because the major changes in fat metabolism were not in the abdomen. Nonetheless, lipogenesis-related and inflammation-related mRNA expression were reduced in the 1% JBP group. In addition, dietary supplementation with tea byproducts could reduce the massive amount of byproducts created during tea production and modulate lipid metabolism and the inflammatory response in chickens.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.11
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• pp.1523-1528
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• 2013

To increase plumage color uniformity and understand the genetic background of Korean chickens, we performed a genome-wide association study of different plumage color in Korean native chickens. We analyzed 60K SNP chips on 279 chickens with GEMMA methods for GWAS and estimated the genetic heritability for plumage color. The estimated heritability suggests that plumage coloration is a polygenic trait. We found new loci associated with feather pigmentation at the genome-wide level and from the results infer that there are additional genetic effect for plumage color. The results will be used for selecting and breeding chicken for plumage color uniformity.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.50-56
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• 2003

An experiment was carried out to compare the body weight, shank length, rectal temperature, comb area, abdominal fat, blood parameters and bone traits of capon, slip and intact birds in Taiwan country chicken cockerels. One hundred and sixty-six Taiwan country chicken cockerels were randomly assigned to caponized or intact male groups. Caponized birds were surgically altered at 10 weeks old and raised to 28 weeks old. At 28 weeks of age, the capons were separated into capon and slip groups, depending on the atrophy of the comb and wattle in size. The results showed that body weight and shank length in slips were significantly (p<0.05) greater than in intact birds. Intact birds had the highest (p<0.05）feather scores and the lowest (p<0.05) rectal temperature. Compared with intact birds and slips, capons had a significantly (p<0.05) smaller comb area. Bone percentage, stress and cortical thickness, and bone and ash calcium content and plasma testosterone concentration, in intact birds were the highest (p<0.05) followed by slips and capons. However, intact birds had the lowest (p<0.05) plasma ionized calcium and phosphorus concentrations. Bone and ash manganese contents in capons were significantly (p<0.05)lower than those in others. These findings support the hypothesis that androgenic effects on secondary sexual characteristics are stronger than anabolic growth promoting response. Androgens can directly influence calcium fluxes in male chickens. Caponized caused a reduction in the bone percentage, stress, cortical thickness and bone calcium content.

• Korean Journal of Poultry Science
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• v.20 no.1
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• pp.1-9
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• 1993

This study carried out to build up new synthetic egg production lines which had sex-linked gene for feather color sexing and also superior combining ability for producing the best commercial chicks. The closed flock breeding method was utilized to improve the general performances in the first experiment and combining ability for heterosis was tested for new synthetic line in the second experimental year. In order to test for the egg production ability in cross breeds synthetic lines, the crossing of B$\times$4 B$\times$C, two imported strains and two domestic strains as controls were compared for the general performances. There was on difference in mortality, body weight to 56 weeks of age. Sexual maturity was delayed about 10 days by comparing with other reports, except 153 days of the Manina White, but no difference among mating systems in this experiment. The hen housed egg production in B$\times$A, B$\times$C was 186.3, 191.3 respectively and it was better than the other controls, except ISA imported lines. The hen-day egg production of B$\times$A, B$\times$C was better than other controls, with 75.7%, 76.8% respectively. In the average egg weight, the B$\times$C cross breed was highest with 64.5g. As the sex of hatching chicks was identified by difference of feather color, the genetic composition of synthetic lines must be homogenized. The feather color of female chicks was brown and that of male was silver (99%), In conclusion, the egg production ability of B$\times$A, B$\times$C cross breeds was superior to the imported and domestic lines. Therefore, it suggest that the synthetic lines with sex-linked gene might be utilized for improving egg production performances.

• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.126-138
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• 2017

This study was conducted to investigate the potential of chicken feather (CF), which is a by-product in poultry industry, as a raw material of wood adhesives. For the purpose, adhesive resins were formulated with NaOH- and $H_2SO_4$-hydrolyzed CF as well as crosslinkers, and then the properties and water resistance of the adhesive resins against hot water were measured. CF was made of mainly keratin-type protein, and no or very low content of heavy metals was detected. Hydrolysis rate of CF increased as NaOH concentration in hydrolysis solutions increased. However, in order to minimize the loss of adhesive property of protein itself by the severe hydrolysis of CF and to seek its proper hydrolysis conditions, NaOH concentrations in hydrolysis solution determined to adjust to 5%, 7.5% and 10%. In the NaOH-hydrolyzed CF, $H_2SO_4$-hydrolyzed CF as a hardener and crosslinker were added to formulate CF-based adhesive resins. Solid content of the resins ranged from 28.3% to 44.8% depending on hydrolysis conditions and type of crosslinker. Viscosity of the resins at $25^{\circ}C$ was very high. However, when the temperature of the resins was increased to $50^{\circ}C$, the viscosity decreased greatly and thus the resins could be applied as a sprayable resin. Retention rate measured to evaluate the water resistance of adhesive resins was the highest in the cured resin formulated with 5% NaOH-hydrolyzed CF and 5% $H_2SO_4$-hydrolyzed CF of 10% based on the solid weight as a hardener. Retention rate depending on crosslinkers added into adhesive resins was the highest phenol-formaldehyde (PF) followed by melamine-urea-formaldehyde (MUF) and formalin. The retention rate of CF-based adhesives formulated with 5% NaOH-hydrolyzed CF, PF and $H_2SO_4$-hydrolyzed CF of 10% and over did not differ statistically from that of commercial MUF resins. All of CF-based adhesives formulated with PF as a crosslinker and one with 5% NaOH-hydrolyzed CF of 55%, 5% $H_2SO_4$-hydrolyzed CF of 15%, and MUF of 30% on the basis of solid weight could be substituted for commercial urea-formaldehyde resins, From the results, CF can be used as a raw material of wood adhesives if hydrolyzed in proper conditions.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.385-394
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• 2017

In this study, reaction mechanism and curing characteristics of adhesives formulated with NaOH- and $H_2SO_4$-hydrolyzed chicken feather (CF) and formaldehyde-based crosslinkers were investigated by FT-IR and DSC. In addition, adhesive properties and formaldehyde emission of medium-density fiberboards (MDF) applied with the adhesives were measured. CF-based adhesives having a solid content of 40% and over were very viscous at $25^{\circ}C$, but the viscosity reduced to $300{\sim}660m{\cdot}Pa{\cdot}s$ at $50^{\circ}C$. Consequently, the adhesives could be used as a sprayable resin. Through the FT-IR spectra of liquid and cured CF-based adhesives, addition reaction of methylol group and condensation reaction between the functional groups with the use of formaldehyde-based crosslinkers were identified. From the analysis of DSC, it was elucidated for CF-based adhesives to require a higher pressing temperature or longer pressing time comparing to commercial urea-formaldehyde (C-UF) resin. MDF bonded with CF-based adhesives, which was formulated with 5% NaOH-hydrolyzed CF (CF-AK-5%) and PF of formaldehyde to phenol mole ratio of 2.5 (PF-2.5), and pressed for 8 min had higher MOR and IB than those with other CF-based adhesives. MOR and IB of MDF bonded with the CF-based adhesives regardless of formulation type and pressing time were higher than those with C-UF resin. When the values compared with the minimum requirements of KS standard, IB exceeded the KS standard in all formulations and pressing time, but MOR of only MDF bonded with CF-AK-5% and PF-2.5 and pressed for 8 min satisfied the KS standard. What was worse, 24-TS of MDF bonded with all CF-based adhesives did not satisfied the KS standard. However, MOR and 24-TS can be improved by increasing the target density of MDF or the amount of wax emulsion, which is added to improve the water resistance of MDF. Importantly, the use of CF-based adhesives decreased greatly the formaldehyde emission. Based on the results, we reached the conclusion that CF-based adhesives formulated under proper conditions had a potential as a sprayable resin for the production of wood panels.

• Korean Journal of Poultry Science
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• v.20 no.4
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• pp.209-216
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• 1993

This study was conducted to classify Korean native chicken(KNC) and imported chicken by phenotypic performances and DNA fingerprinting. Two lines, KNC and White Leghorn(WL) , of chicken were maintained in the laboratory of Yeungnam University. Economic traits (body weight, sexual maturity, hen-day egg production, egg weight) and phenotypic characteristics (body-type, head, feather, shank) were checked. The DNA fingerprinting was analyzed for both breeds. The growth rate of the KNC was similar to WLS and sexual maturity of the KNC came later than WL. Hen-day egg production of the KNC was also slightly lower than the WL. The egg weight was about 10g lighter than WL. There was no difference in body weight of female KNC compared to the WL after 28 weeks. The study confirms difference between KNC and WL in DNA fingerprinting as well as its outlook. Thus, we suggest that these should be tested in nationwide districts about chickens known as the KNC using DNA fingerprinting. Then, the confirmed KNC populations should be maintained and used for the genetic improvement. Finally, only confirmed KNC should be in market which induce consumer to seek the KNC by its favorite.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.10
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• pp.1504-1510
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• 2013

Native chickens hold a significant share of the market in China. In response to the huge demand from the market, the productivity of Chinese native chickens needs to be improved. Cross breeding is an effective method to increase productivity, although it might affect meat quality. In this study, two pure lines (SD02 and SD03) of Erlang mountainous chickens were hybridized with a yellow feather and faster growing line (SD01). The effect of hybridization on carcass and meat quality (physiochemical and textural traits) was measured in the $F_1$ population at d 91 of age. The hybrids exhibited higher body weight and dressed weight, and amount of semi-eviscerated, eviscerated, breast muscle and abdominal fat (p<0.05). Abdominal fat yield also increased (p<0.05) compared to the offspring of the two pure-lines. Meanwhile, there was no significant difference in meat quality traits except for the myofiber diameter and density and the shear force of the breast muscle. Overall, the offspring of cross-lines were similar to pure lines in meat color, pH value, inosinic acid, crude protein, crude fat, dry matter, moisture content and amino acid composition in the breast muscle. These results suggest that productivity can be improved via cross-breeding while maintaining meat quality of the Erlang mountainous chicken.