• Journal of Life Science
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• v.31 no.12
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• pp.1079-1087
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• 2021

To analyze gut microbiota of livestock in Korea and compare taxonomic differences, we conducted 16S rRNA metagenomic analysis through next-generation sequencing. Fecal samples from broiler chickens, pigs, and cattle were collected from domestic feedlots randomly. α-diversity results showed that significant differences in estimated species richness estimates (Chao1 and ACE, Abundance-based coverage estimators) and species richness index (OUTs, Operational taxonomic units) were identified among the three groups. However, NPShannon, Shannon, and Simpson indices revealed that abundance and evenness of the species were statistically significant only for poultry (broiler chickens) and mammals (pigs and cattle). Firmicutes was the most predominant phylum in the three groups of fecal samples. Linear discriminant (LDA) effect size (LEfSe) analysis was conducted to reveal the ranking order of abundant taxa in each of the fecal samples. A size-effect over 2.0 on the logarithmic LDA score was used as a discriminative functional biomarker. As shown by the fecal analysis at the genus level, broiler chickens were characterized by the presence of Weissella and Lactobacillus, as well as pigs were characterized by the presence of provetella and cattele were characterized by the presence of Acinetobacter. A permutational multivariate analysis of variance (PERMANOVA) showed that differences of microbial clusters among three groups were significant at the confidence level. (p=0.001). This study provides basic data that could be useful in future research on microorganisms associated with performance growth, as well as in studies on the livestock gut microbiome to increase productivity in the domestic livestock industry.

• Korean Journal of Poultry Science
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• v.45 no.4
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• pp.253-260
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• 2018

The hepatocyte nuclear factor 4 alpha ($HNF4{\alpha}$) gene is related to lipid transport, including abdominal fat and growth, in chickens. Interestingly, the A543G SNP within the $HNF4{\alpha}$ gene has previously been reported to be associated with body weight in both broilers and Korean native chickens (KNCs). However, its exact position within the HNF4 is not yet reported. This study aimed to identify the position of the A543G SNP and to identify additional SNPs that can be used as genetic markers in KNCs. A total of 128 KNCs were used for the sequencing and analysis of these genetic associations. As a result, A543G SNP was located in intron 4 of the $HNF4{\alpha}$ gene; it is reported as rs731246957 in the NCBI database. Fourteen SNPs were detected in the sequenced portion of the $HNF4{\alpha}$ gene; three of these, rs731246957, rs736159604 and new SNP, intron 6 (249), were significantly related with growth in the chickens. In this study, the TT genotype of rs731246957, previously reported as A543G SNP, the GG genotype of rs736159604 and GT of new SNP have are highly associated with body weight from birth to 40 weeks of age in KNCs (P<0.01). These results suggest that rs736159604, rs731246957 and intron 6 (249) SNPs within the $HNF4{\alpha}$ gene could function as growth-related markers in the selective breeding of KNCs.

• Korean Journal of Heritage: History & Science
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• v.44 no.1
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• pp.52-71
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• 2011

This study was initiated with the intent to consider the features of Gugokwonlim and to compare Gabsagugok(甲寺九曲) to Yongsangugok(龍山九曲) against the backdrop of Mt. Gyeryong by revealing their nature and confirming the names and exact locations. A literature review, interviews with local people and field studies confirmed that Gabsagugok and Yongsangugok are each composed of 9 seasonal features. The former is made up of Yongyuso(龍遊沼) - Iilcheon(二一川) - Baengnyonggang(白龍岡) - Dalmuntaek(達門澤) - Geumgyeam(金鷄?) - Myeongwoldam(明月潭) - Gyemyeongam(鷄鳴巖) - Yongmunpok(龍門瀑) - Sujeongbong(水晶峰) while the latter is made up of Simyongmun(尋龍門) - Eunnyongdam(隱龍潭) - Waryonggang(臥龍剛) - Yuryongdae(遊龍臺) - Hwangnyongam(黃龍岩) - Hyeollyongso(見龍沼) - Ullyongtaek(雲龍澤) - Biryongchu(飛龍湫) - Sillyongyeon(神龍淵). Both Gabsagugok and Yongsangugok are part of Gugokwonlim built in the valleys of Mt. Gyeryong in the late Joseon Dynasty by Byeoksu Yun Deok-yeong (1927) and Chwieum Gwon Jun-myeon (1932), respectively, with a 5 year difference. Gabsagugok was supposedly designed to reflect an individual taste for the arts and to admire principles of Juyeok (ch. Zhouyi) and the beauty of nature. On the contrary, Yongsangugok appears to be the builder's expression of his longing for independence day, likened to the life of a dragon after receiving the sad news of Japan's annexation of Korea. Such differences show that these two builders had very different intentions from one another. The letters of Gabsagugok have a semi cursive style and were deeply engraved on the rock in a square shape. Consequently they have not been worn away except for those in Yongyuso, the first Gok. In contrast, the letters in Yongsangugok have an antiquated, cursive-Yija style but because they were engraved relatively lightly, serious wear and damage occurred. In terms of location, Gabsagugok was built around Ganseongjang adjacent to the 5th Gok while Yongsangugok was set up around the 5th Gok, Hwangnyongam. Meanwhile, the important motif which forms the background of Gabsagugok seemingly highlights the geographic identity of Mt. Gyeryong using the dragon and the chicken as themes. It also appears to symbolize the principles of Juyeok focusing on Kan of the Eight Trigrams for divination; this requires an in-depth study for confirmation. The main motif and theme of Yongsangugok is the dragon. It infuses the builder's intentions in Sangsinri Valley by communicating with nature through a story of a dragon's life from birth to ascension. It is assumed that he tried to use this story to express his hope for restoring the national spirit and reconstructing the country.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.740-748
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• 2018

This study was conducted to investigate the effects of dietary supplementation of enzyme complex (metalloprotease and xylanase) on growth performance, carcass characteristics and meat storability of broiler chickens. The experiment utilized a 2 (basal and low spec diets) ${\times}$ 3 (0, 0.5 or 1 g/kg of enzyme supplementation) factorial arrangement. A total of 360 male Ross broilers were randomly assigned into the following six groups: BD-T0 (basal diet + enzyme complex 0 g/kg), BD-T1 (basal diet + enzyme complex 0.5 g/kg), BD-T2 (basal diet + enzyme complex 1 g/kg), LD-T0 (low spec diet + enzyme complex 0 g/kg), LD-T1 (low spec diet + enzyme complex 0.5 g/kg), LD-T2 (low spec diet + enzyme complex 1 g/kg). Feed and water were provided ad libitum for 42 days, during which time feed intake and body weight were measured at one-week intervals. After the feeding trial, chickens were slaughtered by exsanguination and samples were collected. Feed intake was lower in the enzyme supplemented groups than the non-supplemented groups (p<0.05), as were body weight and gain (p<0.05). Thus, the feed conversion ratio improved in the enzyme supplemented groups relative to the non-supplemented groups (p<0.05). The carcass rate and production index were also significantly improved by supplementation with enzyme complex (p<0.05). Finally, the thiobarbituric acid reactive substances (TBARS) values were lower in the enzyme supplementation groups after 6 storage days (p<0.05). In conclusion, dietary supplementation with enzyme complex including metalloprotease and xylanase improved growth performance, carcass characteristics, and storability of broiler chicken meat.

• Korean Journal of Poultry Science
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• v.48 no.2
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• pp.91-100
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• 2021

The study determined the effects of stock density (SD) and energy level (EL) on growth performance, serum biochemistry, and meat quality in Korean native chickens. A total of 240 chickens were randomly assigned to one of the four treatments including two stock density (low, 14, and high, 16 chickens per m²) and two energy level (low, 2,950, 3,000, 3050 ME kcal/kg, and high 3,150, 3,200, 3,250 ME kcal/kg, for starter, grower, and finisher, respectively). During the whole period of the experiment, the chickens were fed ad libitum. The greater final body weight and weight gain were achieved in chickens fed high energy diet, whereas the final body weight and weight gain were significantly reduced in high-density treatment compared with the low density. Chickens in low-density groups had a higher feed intake compared with high-density treatment, however, the energy level did not affect the feed intake. An improved overall feed conversion ratio was detected in the high energy treatment. There was a significant interaction between stock density and energy level on cholesterol concentration. The concentration of aspartate transaminase in serum was increased by higher stock density. There was a significant treatment interaction on IgM levels. Moreover, the carcass rate was significantly increased in the high energy level treatment. Based on the findings, we suggest that rearing chickens in low density with high dietary energy levels could be beneficial by improving the growth performance.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.181-188
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• 2022

This study was conducted to investigate the effects of the metabolic energy levels of Korean native chicken breeder diets on laying performance, egg quality, fertility and hatchability. On the basis of dietary metabolic energy values (2,800, 2,700, and 2,650 kcal/kg), 168 twenty-week-old 'Woorimatdag' breeders (maternal line) were divided into three treatment groups (four replications per treatment with each replicate containing 14 birds) and reared until 32 weeks of age. We found that the body weight of hens increased with age, although there were no significant differences among treatments with respect to body weight or egg weight. Egg production ratio at 20-24 and 24-28 weeks of age tended to be low in birds fed the 2,700 and 2,650 kcal/kg diets, although the differences among treatments were none significant. Feed intakes was significantly decreased as the metabolic energy level reduced (P<0.05). There were no significant differences among treatments with respect to feed conversion ratio or the strength and thickness of eggshell. Similarly, we detected no significant differences among the three metabolic energy levels with regards to fertility, hatchability, or chick weight. In conclusion, our findings indicate that during the initial phase of laying, the metabolic energy level of 'Woorimatdag' breeder diets could be lowered to 2,700 kcal/kg without significantly influencing the laying performance of breeders or egg quality, fertility and hatchability, and chick weight.

• Journal of Food Hygiene and Safety
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• v.37 no.3
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• pp.136-142
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• 2022

The research aims to develop a rapid and easy analytical method for methoprene using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A simple, highly sensitive, and specific analytical method for the determination of methoprene in livestock products (beef, pork, chicken, milk, eggs, and fat) was developed. Methoprene was effectively extracted with 1% acetic acid in acetonitrile and acetone (1:1), followed by the addition of anhydrous magnesium sulfate (MgSO₄) and anhydrous sodium acetate. Subsequently, the lipids in the livestock sample were extracted by freezing them at -20℃. The extracts were cleaned using MgSO₄, primary secondary amine (PSA), and octadecyl (C₁₈), which were then centrifuged to separate the supernatant. Nitrogen gas was used to evaporate the supernatant, which was then dissolved in methanol. The matrix-matched calibration curves were constructed using 8 levels (1, 2.5, 5, 10, 25, 50, 100, 150 ng/mL) and the coefficient of determination (R²) was above 0.9964. Average recoveries spiked at three levels (0.01, 0.1, and 0.5 mg/kg), and ranged from 79.5-105.1%, with relative standard deviations (RSDs) smaller than 14.2%, as required by the Codex guideline (CODEX CAC/GL 40). This study could be useful for residue safety management in livestock products.

• Journal of Animal Science and Technology
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• v.65 no.2
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• pp.336-350
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• 2023

Two experiments were conducted in this research. Experiment 1 investigated the spatial expression characteristics of calcium (Ca) and phosphorus (P) transporters in the duodenum, jejunum, and ileum of 21-day-old broilers provided with adequate nutrient feed. Experiment 2 evaluated the effects of dietary vitamin D₃ (VD₃) concentration (0, 125, 250, 500, 1,000, and 2,000 IU/kg) on growth performance, bone development, and gene expression levels of intestinal Ca and P transporters in 1-21-day-old broilers provided with the negative control diet without supplemental VD₃. Results in experiment 1 showed that the mRNA levels of calcium-binding protein 28-kDa (CaBP-D28k), sodium-calcium exchanger 1 (NCX1), plasma membrane calcium ATPase 1b (PMCA1b), and IIb sodium-phosphate cotransporter (NaPi-IIb) were the highest in the broiler duodenum. By contrast, the mRNA levels of inorganic phosphate transporter 1 (PiT-1) and 2 (PiT-2) were the highest in the ileum. Results in experiment 2 showed that adding 125 IU/kg VD₃ increased body weight gain (BWG), feed intake (FI), bone weight, and percentage and weight of Ca and P in the tibia and femur of 1-21-day-old broilers compared with the negative control diet (p < 0.05). The rise in dietary VD₃ levels from 125 to 1,000 IU/kg further increased the BWG, FI, and weights of the bone, ash, Ca, and P (p < 0.05). No difference in growth rate and leg bone quality was noted in the broilers provided with 1,000 and 2,000 IU/kg VD₃ (p > 0.05). Supplementation with 125-2,000 IU/kg VD₃ increased the mRNA abundances of intestinal Ca and P transporters to varying degrees. The mRNA level of CaBP-D28k increased by 536, 1,161, and 28 folds in the duodenum, jejunum, and ileum, respectively, after adding 1,000 IU/kg VD₃. The mRNA levels of other Ca and P transporters (PMCA1b, NCX1, NaPi-IIb, PiT-1, and PiT-2) increased by 0.57-1.74 folds by adding 1,000-2,000 IU/kg VD₃. These data suggest that intestinal Ca and P transporters are mainly expressed in the duodenum of broilers. Moreover, the addition of VD₃ stimulates the two mineral transporter transcription in broiler intestines.

• Korean Journal of Poultry Science
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• v.50 no.2
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• pp.101-108
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• 2023

This study was conducted to investigate the appropriate levels of crude protein (CP) and phytase in the diet of broiler chicks in order to reduce nitrogen and phosphorus contents in feces while maintaining performance of broilers. Six hundred forty-eight 1-day-old male broilers (41.9±0.91 g) had a total of 3 × 3 complex factor of 3 levels of CP (22%, 21%, 20%) and 3 levels of phytase (1,000, 800, 500 FTU/kg) in the diet. Divided into 9 treatments, 4 replications per treatment, 18 birds per replication, were completely randomly assigned and reared in a metabolic cage for 7 days. Seven-day-old body weight (BW) and body weight gain (BWG) of broilers were significantly lower at CP 20% treatment (P<0.05), and feed conversion ratio (FCR) was significantly lower at CP 21% and phytase 800 FTU/kg treatment (P<0.05). Nitrogen and phosphorus contents in chicken excreta were significantly lower in CP 20% and phytase 500 FTU/kg treatment, respectively (P<0.05). Interactions between CP and phytase in the feed were shown for nitrogen and phosphorus in feces (P<0.05). In conclusion, considering the broiler performance and excretion contents of nitrogen and phosphorus, it is thought that CP and phytase levels of broiler chicks diet can be reduced by 21% and 800 FTU/kg, respectively.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.213-229
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• 2023

This study aimed to investigate the effects of beak trimming and crossbreeding-combinations on the productive performance and stress response levels of Korean native chickens. The study divided 248 individuals from six crossbreeding-combinations into two groups: one underwent beak trimming, and the other did not. The survival rate, body weight, egg production rate, egg quality, feather damage score, HSP-70 gene expression level, H/L ratio, and intracellular DNA damage rate were measured and analyzed. The results showed that the beak-trimmed group had significantly higher survival rates and hen-housed egg production compared to the non-beak-trimmed group (P<0.05). Feather damage and DNA damage rates were significantly lower in the beak-trimmed group (P<0.05). On the other hand, there were no significant differences between the two groups in adult body weight, hen-day egg production, egg quality, HSP-70 gene expression level, and H/L ratio. Among the crossbreeding-combinations, there were significant differences in survival rate, body weight, feather damage score, egg quality, and DNA damage rate (P<0.05), while egg production rate, HSP-70 gene expression level, and H/L ratio showed no significant differences. There was an interaction between beak trimming and crossbreeding-combinations in some traits. In conclusion, beak trimming in Korean native chickens has a positive impact on productive performance, and in terms of stress response, beak trimming may not act as a stress factor or may even reduce stress after the growing period. Furthermore, there were differences in productive performance and stress response levels among crossbreeding-combinations, but the effects of beak trimming were similar across these combinations.