Seong-Koo Hong

Phylogenetic Analysis of a Privately-owned Korean Native Chicken Population Using mtDNA D-loop Variations.

The use of Korean native chicken is increasing, and the discovery of new genetic resources is very important from both economic and genetic conservation points of view. In this study, mtDNA D-loop sequences from 272 privately-owned Korean native chickens from a Hyunin farm were investigated. Seventeen nucleotide substitutions were identified from the sequence analysis and they were classified as 6 haplotypes. Previously investigated haplotypes in five Korean native chicken populations have been compared with the Hyunin chicken population. The results indicated that two haplotypes, H10 and H15, in the Hyunin chicken population were not previously identified in other Korean native chicken populations, representing 33.09% (90/272) and 1.1% (3/272) of the Hyunin population, respectively. On the other hand, four other haplotypes were identical to those of a previous study of Korean native chicken populations. This result is indicative of conservation strategies of Hyunin chicken populations for expanding the genetic diversity in the Korean native chicken population.

Effects of Ad libitum and Restricted Feeding of Concentrates on Body Weight Gain, Feed Intake and Blood Metabolites of Hanwoo Steers at Various Growth Stages

E.G.Kwon,S.K.Hong,H.H.Seong,S.G.Yun,B.K.Park,Y.M.Cho,W.M.Cho,S.S.Chang,K.J.ShinandB.H.PaekNationalLivestockResearchInstitute,R.D.A.ABSTRACTTwo hundred fifty eight Hanwoo steers were used in a completely randomized design experiment todetermine the effects of ad libitum or restricted feeding of concentrates on body weight(BW) gain, feedintake, blood metabolites and hematological parameters. Steers were assigned at 6 months of age tofeeding groups of adlibitum (T1) or restricted(T2)by 18 months of age. Steers in both groups were fedadlibitum from 19 months of age. The restrictive feeding levels were 1.2~1.5% of BW for the growingperiod and 1.7~1.8% of BW for the early fattening period. Average daily gains were significantly higherinT1 thanin T2from 10 to 14 monthsofage,butwere significantly higherinT2 thanin T1from 20to 24 months of age(p<0.05). Total dry matter intake(DMI) was higherin T1 than in T2 at 10, 12 and16 months of age(p<0.05). Total DMI of T2 was higher than that of T1 at 22 months of age(p<0.05).FeedconversionsweresignificantlylowerinT2thaninT1from20to30monthsofage(p<0.05).Bloodalbumin concentrations were significantly higher in T2 than in T1 at 12, 14, 16 and 18 months of age.Blood triglyceride concentrations were significantly higher in T1 than in T2 at14 and 16 monthsof age(p<0.05). Blood inorganic phosphorus concentrations were significantly higher in T2 compared with T1 at8, 10, 16 and 22 months of age(p<0.05). Mean corpuscular volume and mean corpuscular hemoglobinwere significantly lower in T2 than in T1 from 8 to 12 months of age(p<0.05), but those weresignificantly higher in T2 than T1 from 10 months to 12 months of age(p<0.05). Present results mayindicate that the restricted feeding for the growing period does not show adverse effects on body weightgainwithbetterfeedconversionforthefollowinglatefatteningperiod.(Keywords :Hanwoosteers, Adlibitum ,Restricted,Feedconversion,Bloodmetabolites)

Genome-wide Association Study for Warner-Bratzler Shear Force and Sensory Traits in Hanwoo (Korean Cattle).

Significant SNPs associated with Warner-Bratzler (WB) shear force and sensory traits were confirmed for Hanwoo beef (Korean cattle). A Bonferroni-corrected genome-wide significant association (p<1.3×10−6) was detected with only one single nucleotide polymorphism (SNP) on chromosome 5 for WB shear force. A slightly higher number of SNPs was significantly (p<0.001) associated with WB shear force than with other sensory traits. Further, 50, 25, 29, and 34 SNPs were significantly associated with WB shear force, tenderness, juiciness, and flavor likeness, respectively. The SNPs between p = 0.001 and p = 0.0001 thresholds explained 3% to 9% of the phenotypic variance, while the most significant SNPs accounted for 7% to 12% of the phenotypic variance. In conclusion, because WB shear force and sensory evaluation were moderately affected by a few loci and minimally affected by other loci, further studies are required by using a large sample size and high marker density.

Association of Succinate Dehydrogenase and Triose Phosphate Isomerase Gene Expression with Intramuscular Fat Content in Loin Muscle of Korean (Hanwoo) Cattle

In a previous study, succinate dehydrogenase (SDH) and triose phosphate isomerase (TPI) were detected by 2D gel electrophoresis as differentially expressed proteins in the longissimus thoracis muscles of cattle aged between 12 and 27 months old. In the present study, we investigated the association of SDH and TPI gene expression with intramuscular fat content in 50 Hanwoo steers. The SDH gene was expressed at a 4 times higher level in the 12 month old group than in the 27 month old group (p

Determination of Net Energy and Protein Requirements for Growth in Hanwoo Steers by Comparative Slaughter Experiment

Data from a comparative slaughter experiment with two hundreds of Korean native (Hanwoo) beef steers were utilized to determine net energy and protein requirements for growth (NEg and NPg). Eight randomly selected steers were used in the initial slaughter group of 6 month of age and the remaining steers allocated to treatments within two groups. The restricted groups were fed 1.2 to 1.5% concentrate per kg body weight (BW) in the growing period (6～12 month of age), 1.7 to 1.8% concentrate per kg BW in the early fattening period (13～18 month of age), and concentrate feed ad libitum in the late fattening period (19～30 month of age). Ad libitum groups were fed concentrate ad libitum through the whole period. Rice straw was offered ad libitum for 24 month of two feeding systems. The steers were slaughtered when animals reached every 2 month from 8 to 30 month of age. For all body composition determinations, whole empty body components were weighed, taken each proportional subsample was ground for chemical analysis. Equations developed with the pooled data to predicted NEg and NPg were similar to the equations of Japanese Feeding Standard for Beef Cattle (2000). First equations were developed to predicted NEg; NEg = 0.05332×LBW0.75×DG for restricted treatment and NEg = 0.04912×LBW0.75×DG for ad libitum treatment. Second equations were developed to predicted NPg; NPg = DG × (224.7－0.251×LBW) for restricted treatment and NPg=DG×(210.1－0.214×LBW) for ad libitum treatment.

Genetic Polymorphisms of the Bovine NOV Gene Are Significantly Associated with Carcass Traits in Korean Cattle

The objective of this study was to investigate single nucleotide polymorphisms (SNPs) in the bovine nephroblastoma overexpressed (NOV) gene and to evaluate whether these polymorphisms affect carcass traits in the Korean cattle population. We resequenced to detect SNPs from 24 unrelated individuals and identified 19 SNPs within the full 8.4-kb gene, including the 1.5-kb promoter region. Of these 19 SNPs, four were selected for genotyping based on linkage disequilibrium (LD). We genotyped 429 steers to assess the associations of these four SNPs with carcass traits. Statistical analysis revealed that g.7801T>C and g.8379A>C polymorphisms in the NOV gene were associated with carcass weight (p = 0.012 and 0.008, respectively), and the g.2005A>G polymorphism was associated with the back fat thickness (BF) trait (p = 0.0001). One haplotype of the four SNPs (GGTA) was significantly associated with BF (p = 0.0005). Our findings suggest that polymorphisms in the NOV gene may be among the important genetic factors affecting carcass yield in beef cattle.

Association of Heat Shock Protein Beta 1 (HSPB1) Gene Expression with Tenderness in Loin Muscle of Korean Cattle (Hanwoo)

In a previous proteomic study, heat shock protein beta 1 (HSPB1) was detected as differentially expressed protein in longissimus thoracis between low (grade 3) and high (grade 1++) meat quality groups by 2DE gel electrophoresis. The present study investigated an association of HSPB1 expression at the level of gene and protein with Warner-Bratzler shear force (WBS) measured in 20 Hanwoo steers. An analysis of variance (ANOVA) between expression values and WBS showed that WBS was affected by HSPB1 expression (p<0.05). The expression (at both gene and protein level) of the HSPB1 was 2 times higher in the low WBS group than that in the high WBS group (p<0.01). This result suggests that the HSPB1 gene may be a candidate gene associated with tenderness in longissimus thoracis of Korean cattle.

Determination of Maintenance Energy Requirements for Growing Hanwoo Steers

Present experiment was carried out to determine maintenance energy requirements for growing Hanwoo steers. Six Hanwoo steers (BW = kg) were used in two 3 3 latin square design with three different energy intake levels; TDN 1.70 kg (Low), 2.05 kg (Medium), 2.80 kg (High), respectively, based on the Korean Feeding Standards. Each period lasted 18 days including a 14-day adaptation and a 4-day measuring period. The steers were in the head hood chamber system (one cattle per chamber) during each measuring time to measure heat and methane production for 1 day. Dry matter intake was 2,058, 3,256 and 3,881 g/day for Low, Medium and High TDN, respectively. Increase in energy intake did not affect digestibilities of dry matter, crude protein, crude fiber, crude fat, NDF, ADF and nitrogen-free extract. Gross energy intake averaged 180.21, 292.74 and 337.15 kcal/ for Low, Medium and High TDN, respectively. Energy loss was 28.7% in feces and 2.1% in urine of gross energy intake. Further, energy loss from methane produced during rumen fermentation was 6~8.3%, while body heat loss averaged 34~60%. Intercept of regression equation between ME intake and retained energy indicated that the energy requirement was 109.84 kcal ME/.

Association of Microsatellite Marker in FABP4 Gene with Marbling Score and Live Weight in Hanwoo

The bovine fatty acid binding protein 4 (FABP4) plays an important role to uptake intracellular fatty acid. It has been previously reported as a positional candidate gene for marbling score in livestock. The re-sequencing of FABP4 gene detected a polymorphic AT repeated sequence in intron II of FABP4 gene. Allelic distribution for this microsatellite marker was examined in other cattle breeds. A total of 8 alleles were detected with diverse repeat units (14 to 21 AT repeat) in Hanwoo and 7 breeds. Of the 8 alleles, the predominant alleles were (AT)16, (AT)18 and (AT)19 in the Hanwoo and 7 cattle breeds. The linear mixed model for genotypic effect (3237AT) on carcass traits showed a significant effect on marbling score (MAR P=0.025) and live weight (LWT; P=0.04) in the 583 Hanwoo cattle population. Live weight (LW) was highest in the homozygous (AT)17 genotype (557.5 ± 6.94) and lowest in the heterozygous (AT)16/17 genotype (521.7 ± 7.70). On the other hand, the homozygous (AT)17 genotype (3.0 ± 0.15) has the highest effect on marbling score and the lowest effect was in homozygous (AT)18 genotype (2.2 ± 0.15). The marbling score difference between both groups was 0.8 which is around two times higher than SNP genotype effect on marbling score in Limousin × Wagyu crosses. (Key words : Fatty acid binding protein 4 (FABP4), Microsatellite marker, Marbling score (MAR))

Effects of a Mixture of Eugenol, Thymol and Malate on Growth Performance, Beef Quality and Liver Function in Hanwoo Finishing Steers Fed a High-Concentrate Diet

ABSTRACT Thirty six Hanwoo steers (average BW, 564.5± 25.7 kg; average age, approximately 23 months) were used to evaluate the effects of a mixture of eugenol (14%), thymol (1%) and malate (85%) on growth performance, beef quality and liver function in Hanwoo finishing steers fed ahigh-concentrate diet. A feeding trial was conducted for 7 months in National Agricultural Cooperative Federation farm located in Anseong, Korea. Steers were assigned randomly to one of three treatments: control (without additive supplementation), treatment 1 (0.05% additive of concentrate), treatment 2 (0.1% additiveof concentrate). The results of this study showed that initial and final BW averaged 564 and 755 kg, respectively, and BW gain was significantly higher (P<0.05) for steers fed the additive mixture than for those fed no mixture (0.78 and 0.79 vs. 0.69 kg/d, respectively). Serum aspartate aminotransferase in the T2 treatment was decreased during the 24 to 31 months of age. Although supplementation of additives resulted in no substantial effect on carcass characteristics, it had a potential effect to improve feed efficiency and AST concentration in Hanwoo finishing steers fed a high-concentrate diet. In conclusion, a mixture of eugenol, thymol and malate has shown promise in improving feed efficiency and liver function in the finishing phase of Hanwoo steers.(