• Genes and Genomics
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• v.40 no.12
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• pp.1373-1382
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• 2018

Hanwoo and Chikso are classified as Korean native cattle breeds that are currently registered with the Food and Agriculture Organization. However, there is still a lack of genomic studies to compare Hanwoo to Chikso populations. The objective of this study was to perform genome-wide analysis of Hanwoo and Chikso populations, investigating the genetic relationships between these two populations. We genotyped a total of 319 cattle including 214 Hanwoo and 105 Chikso sampled from Gangwon Province Livestock Technology Research Institute, using the Illumina Bovine SNP50K Beadchip. After performing quality control on the initially generated datasets, we assessed linkage disequilibrium patterns for all the possible SNP pairs within 1 Mb apart. Overall, average $r^2$ values in Hanwoo (0.048) were lower than Chikso (0.074) population. The genetic relationship between the populations was further assured by the principal component analysis, exhibiting clear clusters in each of the Hanwoo and Chikso populations, respectively. Overall heterozygosity for Hanwoo (0.359) was slightly higher than Chikso (0.345) and inbreeding coefficient was also a bit higher in Hanwoo (-0.015) than Chikso (-0.035). The average $F_{ST}$ value was 0.036 between Hanwoo and Chikso, indicating little genetic differentiation between those two breeds. Furthermore, we found potential selection signatures including LRP1B and NTRK2 genes that might be implicated with meat and reproductive traits in cattle. In this study, the results showed that both Hanwoo and Chikso populations were not under severe level of inbreeding. Although the principal component analysis exhibited clear clusters in each of the populations, we did not see any clear evidence that those two populations are highly differentiated each other.

• Journal of Animal Science and Technology
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• v.52 no.4
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• pp.259-264
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• 2010

This study was carried out to estimate genetic parameters and breeding values of Hanwoo cows for carcass traits. Carcass records were collected from Korean steers raised at the private farms located in rural area of Gangwon-do and slaughtered from December 2004 to June 2008 at the three slaughter houses near fattening farm. The results obtained in this study were summarized as follows; The means and standard deviations of the carcass traits were $5.57{\pm}2.01$ for marbling score (MS), $10.87{\pm}4.06mm$ for backfat thickness (BFT), $87.87{\pm}9.07cm^2$ for eye muscle area (EMA), $426.75{\pm}49.27kg$ for carcass weight (CW), and $65.80{\pm}3.80$ for yield index (YI). Heritability estimates using single trait analyses were 0.36 for MS, 0.35 for BFT, 0.24 for EMA, 0.29 for CW, and 0.40 for YI, respectively. Genetic correlation coefficients of MS with BFT, EMA, CW, and YI were -0.21, 0.30, -0.21 and 0.30, and those of BFT with EMA, CW and YI were -0.12, 0.57 and -0.97, and those of EMA with CW and YI were 0.32 and 0.27, respectively. And genetic correlation of CW with YI was -0.62. Single trait selection for MS might lead to reducing BFT, but might be an obstacle to increase CW due to negative genetic correlations of MS with BFT and CW.

• Journal of Animal Science and Technology
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• v.55 no.1
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• pp.51-59
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• 2013

This study was conducted to investigate the dietary effect of total mixed rations (TMR) containing brewers grain, soybean curd and rice straw, respectively, on growth performance and carcass characteristics of Hanwoo steers. Twenty four Hanwoo steers (average body weight 168 kg) in 6 months age were randomly allocated to 4 experimental groups, which contained 6 animals per group during 22-months feeding trial. The treatment was composed of the group fed concentrate and rice straw separately (T1), the group fed TMR containing brewers grain (T2), the group fed TMR containing soybean curd (T3) and the group fed TMR containing rice straw (T4). Body weight (BW) was not different among treatment groups during the growing and middle fattening period. However, it was significantly greater in T4 group than in T2 group on the final BW (p<0.05). Average daily gain was significantly greater in TMR groups compared to T1 group on the growing and late fattening (p<0.05). However, it was not different in total average. Dry matter intake tended to be increased in TMR groups. The feed conversion ratio was significantly lower in T4 group compare to T2 group (p<0.05). According to the yield traits, carcass weight of T1, T2, T3 and T4 were 389.0, 368.4, 387.5 and 384.3 kg, respectively. The back fat thickness, rib-eye area, and yield index were not different among the groups. Meat color, fat color, texture and maturity were not significantly different among groups. However, marbling score and appearance rate of meat quality grade of over $1^+$ were greater in T2 and T3 groups compare to other groups. Therefore, these results indicated that TMR with brewers grain and soybean curd may be ameliorated the growth performance and carcass characteristics of Hanwoo steers.

• Journal of Life Science
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• v.30 no.1
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• pp.58-63
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• 2020

This study was conducted to examine association between melanocortin-4-receptor (MC4R) genotypes and fatty acid (FA) composition in an F₂ intercross between Duroc and Jeju (South Korea) Native pigs (JNP). Fourteen FA composition traits were measured in more than 290 F₂ progeny population produced between Duroc and JNP. All experimental pigs were successfully genotyped for the MC4R c.1426A>G (p.Asp298Asn) single nucleotide polymorphism (SNP) by using Taq I PCR-RFLP methods. We detected three MC4R genotypes, AA, AG, and GG with 0.299, 0.542, and 0.159 genotype frequencies, respectively. The MC4R AA genotype animals showed higher levels in palmitic acid (C16:0, p<0.05), stearic acid (C18:0, p<0.01), eicosenoic acid (C20:1n9, p<0.05), saturated fatty acid (SFA, p<0.01) than GG homozygotes, respectively. Whereas MC4R GG genotype showed higher values in linoleic acid (C18:2n6, p<0.001), linolenic acid (C18:3n3, p<0.001), linolenic acid (C18:3n6, p<0.001), arachidonic acid (C20:4n6, p<0.001) and unsaturated fatty acid (USFA, p<0.01) than AA pigs, respectively. The MC4R GG genotype was associated with increasing USFA and decreasing SFA in the F₂ progeny population produced between Duroc and JNP. Our finding suggests that the MC4R polymorphisms can be used as a valuable genetic marker for Duroc and JNP breeding programs to improve meat quality and to control FA compositions.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.279-286
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• 2019

Currently, feather-sexing, which is based on differences in feather development at hatching, is a widely used chick sexing method in the poultry industry. For effective chicken feather-sexing, paternal early-feathering (EF) chickens and maternal late-feathering (LF) chickens must be bred. Therefore, it is critical to identify the effect of EF and LF patterns on production traits in chickens. Thus, the purpose of this study is to analyze and compare the production performances between 522 EF and 232 LF chickens in order to establish the Korean native chicken feather-sexing lines. The results showed that the survival rate of the LF group was significantly higher than that of the EF group from hatching to 52 weeks of age (P<0.05). Body weight, however, was not significantly different between the two groups at all ages. LF and EF groups did not significantly differ in age at first egg laying. However, the hen-day and hen-housed egg production of the LF group were significantly higher than those of EF group (P<0.01). No significant differences were found between the EF and LF groups in all egg quality indicators such as egg weight, eggshell color, albumin height and Haugh unit. Because the breeding target of Korean native commercial chicken is meat-type chicken, feather-sexing strains of Korean native chicken should be established using weighing-based paternal EF lines and laying-based maternal LF lines. Therefore, these results are critical for establishing desirable and effective feather-sexing strains.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.455-462
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• 2003

A study was conducted to determine the effects of feeding a diet containing no Ca supplement (limestone) during the late finishing period on growth, marbling and serum 1,25-dihydroxy vitamin $D_3$ level in Korean native cattle. Twenty-four steers (20${\sim}$24 mo of age) were divided into two groups of 12 each: one group assigned to a control diet (concentrates containing 2.5% limestone) and the other to a diet containing no calcium supplement. They were allowed to have free access to diets (concentrates and orchard grass hay) and water during the entire feeding period (223 d). Serum $Ca^{2+}$, Ca and P concentrations were not influenced by diets, but serum 1,25-dihydroxy vitamin $D_3$ concentrations determined 2 or 6 mo after the beginning of feeding the experimental diets were higher (P<0.01) in steers fed the diet without Ca supplement than in those fed the control diet (78.3 vs 51.7 and 80.3 vs 51.1 pg/mL, respectively). Steers fed the diet without Ca supplement tended to have a higher intake of concentrates, but a lower intake of hay, compared to those fed the control diet. Average daily gain was higher (P<0.05) in steers fed the diet without Ca supplement than in those fed the control diet. Feeding the diet without Ca supplement remarkably (P<0.01) increased the marbling score (5.1 vs 2.2) and the muscle (M. longissimus dorsi) fat content (10.2 vs 6.7%) with a concomitant decrease in moisture content (67.6 vs 70.4%), compared to feeding the control diet. Ribeye area was increased (77.2 vs 82.8 $cm^2$) with the diet without Ca supplement, compared to the control diet (P<0.05). Meat color, pH and water-holding capacity in longissimus muscle were not different between the two groups. The Warner-Brazler Shear (WBS) force of the longissimus muscle was slightly (P=0.08) lower in steers fed the diet without Ca supplement than in steers fed the control diet (2.9 vs 3.2 kg/1.27-cm diameter core). Sensory evaluation showed that feeding the diet without Ca supplement slightly (P<0.05) improved tenderness (4.9 vs 4.5) and flavor (4.9 vs 4.6), compared to feeding the control diet, but juiciness was not affected by diets. Results showed that deletion of Ca supplement from finishing diets is beneficial, increasing growth and marbling partly through an increased energy intake and induced 1,25-dihydroxy vitamin $D_3$ synthesis that may increase intracellular $Ca^{2+}$ concentration and in turn fat synthesis.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.105-115
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• 2019

In this study, viability, growth performance and egg production performance were investigated to determine the productive characteristics of 12 Korean domestic chicken varieties which have been collected and conserved for over 25 years in National Institute of Animal Science, Rural Development Administration, Korea. The 1,134 hens were tested and their production traits including survival rate, body weight, age at first egg laying, hen-day and hen-housed egg production, egg weight, and egg quality were measured. Survival rate was the highest in Korean Rhode-D and Korean Native Chicken (KNC) White and the lowest in Korean Cornish Brown (92.2% and 54.3%, respectively). Body weights from 4 to 50 wks were consistently high in the order of Korean Cornish, Korean Rhode, KNC, Korean Ogye, and Korean Leghorn breeds. There was no significant difference in weight between varieties within a breed. Age at first egg laying was the shortest in Korean Leghorn, while it was the longest in Korean Cornish. The hen-day egg production from $1^{st}$ egg to 57 wks was the highest in Korean Leghorn-K, and the lowest in Korean Cornish Brown. Egg weight was the heaviest in Korean Leghorn-F and the lightest in KNC White. The Haugh unit was the highest in Korean Rhode-C and the lowest in Korean Ogye. Taken together, these results suggest that it is desirable that the Korean Cornish variety is improved as the Korean meat breed because of its excellent growth ability, the Korean Leghorn variety is improved as the Korean layer breed because of its good laying performance, and the Korean Rhode and KNC varieties are improved as strong viable breeds because of their good survival rate.

• Korean Journal of Poultry Science
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• v.49 no.1
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• pp.1-8
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• 2022

We investigated the effects of stunning methods and gas treatments during slaughter on the quality characteristics of chicken breast and small intestine. Broilers (Ross 308) were stunned and slaughtered using halal, CO₂, or N₂ gas stunning methods (for 10 birds). After slaughter, the pH, proximate composition, color, water-holding capacity, cooking loss, and shear force of chicken breast muscle and small intestine were determined. Compared with the halal treatment, CO₂ treatment resulted in higher pH and lower cooking loss (P<0.05), and the pH, color, and shear force of chicken breast muscle with N₂ treatment were similar to those of the halal treatment (P>0.05). Compared with the halal treatment, the gas treatments resulted in lower pH and lightness and higher redness, yellowness, thickness, and shear force of the small intestine (P<0.05). However, compared with the CO₂ treatment, the N₂ treatment resulted in lower pH, redness, and yellowness, and higher lightness, thickness, and shear force. Overall, compared with the halal method, our results suggest that the use of N₂ gas suppresses the discoloration and deterioration of the texture of chicken meat and small intestine caused by CO₂ gas treatment in the gas stunning method.