• Journal of Microbiology and Biotechnology
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• 제30권8호
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• pp.1180-1183
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• 2020

The prevalence and characterization of plasmid-mediated quinolone resistance (PMQR) determinants in ciprofloxacin-resistant Escherichia coli isolated from a Korean commercial layer farm were studied. A total of 45 ciprofloxacin-resistant E. coli isolates were recovered and all isolates were multidrug-resistant. Eight isolates have the PMQR genes aac(6')-Ib-cr, qnrS1, and qnrB4, and seven isolates exhibited double amino acid exchange at both gyrA and parC, and have high fluoroquinolone minimum inhibitory concentrations. Five transconjugants demonstrated transferability of PMQR and β-lactamase genes and similar antimicrobial resistance. Because PMQR genes in isolates from commercial layer chickens could enter the food supply and directly affect humans, control of ciprofloxacin resistance is needed.

• Asian-Australasian Journal of Animal Sciences
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• 제18권9호
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• pp.1221-1225
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• 2005

The peroxisome proliferator-activated receptors (PPARs) are members of a superfamily of nuclear hormone receptors. Lots of studies in rodents and humans have shown that PPARs were involved in lipid metabolism and adipocyte differentiation. The main objective of this work was to detect the single nucleotide polymorphisms (SNPs) in whole coding regions of peroxisome proliferator-activated receptor alpha (PPAR-$\alpha$) and gamma (PPAR-$\gamma$) genes with approach of single strand conformation polymorphism (SSCP) in the chicken population of Arber Acres broiler, Hyline layer and three Chinese native breeds (Shiqiza, Beijing You, Bai'r). Two SNPs of C1029T and C297T were found in chicken PPAR-$\alpha$ and PPAR-$\gamma$ genes respectively and each SNP found three genotypes in the experimental populations. The results showed that the distribution frequency of 3 genotypes in Arber Acres broiler, Hyline layer and Chinese native breeds had significant differences on the PPAR-$\alpha$ and PPAR-$\gamma$ gene respectively (p<0.01). Furthermore, in the PPAR-$\alpha$ gene, the results of least square estimation for genotypes and body composition traits showed the BB genotype birds had higher abdominal fat weight (AFW) and percentage of abdominal fat (AFP) than AA genotype birds (p<0.05). From these we conjecture the PPAR-$\alpha$ and PPAR-$\gamma$ genes were suffered intensive selection during the long term commercial breeding and the PPAR-$\alpha$ gene may be a major gene or linked to the major genes that impact chicken fat metabolism and the SNPs could be used in molecular assistant selection (MAS) as a genetic marker for the chicken fatness traits.

• 한국가금학회지
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• 제47권2호
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• pp.115-119
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• 2020

Fowl cholera is an infectious disease caused by Pasteurella multocida that contributes to high economic loss in the commercial chicken industry. Three Pasteurella multocida strains were isolated from outbreaks of acute fowl cholera in the Korean layer farms from 2018 to 2019. One strain was identified and serotyped using capsular PCR typing. This strain was also genotyped by lipopolysaccharide (LPS) PCR typing as A: L3, whereas other strains were non-typable. The multilocus sequence typing (MLST) result showed that the A: L3 strain is sequence type (ST) 134; the non-typable strains were recorded as the following new STs: ST 366 and ST 374. Using phylogenetic tree analysis based on MLST sequences, we determined that ST 366 and ST 374 are closely related to the reference strains that were previously isolated from duck and chicken in Korea, and they were highly prevalent within the Korean cluster. In conclusion, Pasteurella multocida strains were identified and isolated in this study. Furthermore, this is the first report of using MLST to determine the prevalence of fowl cholera in Korea.

• Asian-Australasian Journal of Animal Sciences
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• 제14권7호
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• pp.979-985
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• 2001

Two experiments on commercial broiler chickens (3-37 d) and WL layers (252-364 d) were conducted to study the relative bioavailability of phosphorus (P) from different P supplements in comparison to tricalcium phosphate (TCP), at constant dietary calcium (Ca):P ratio. The P sources tested were dicalcium phosphate (DCP), steam sterilized bone meal (SSBM), commercial mineral mixture (CMM), phosphoric acid (PA) and a combination of CMM + PA. Fluorine (F) content in CMM and SSBM was 13.12 and 0.14 g/kg, respectively. In commercial broiler diets, DCP, SSBM or PA could be used as supplemental P sources without affecting (p<0.05) weight gain, feed intake, tibia ash and, P and Ca contents in tibia ash when compared to TCP. Severity of leg abnormality and deposition of F in bone were higher (p<0.05) in group fed CMM. P retention and serum inorganic P content was significantly reduced (p<0.05) in CMM fed birds compared to those fed TCP, SSBM, PA or CMM+PA. Among other P sources (TCP, SSBM, PA and CMM+PA) the serum inorganic P levels did not vary significantly (p<0.05). The P retention also significantly reduced in CMM fed groups compared to those fed DCP or PA. The P retention significantly increased from 0.183 to 0.216 units by supplementation of PA to CMM diet. In layers, egg production was not affected by replacing TCP with DCP, SSBM, PA or CMM+PA, but significantly (p<0.05) reduced with CMM. Feed (kg)/kg egg mass, egg weight, shell quality (shell weight and shell thickness) and serum Ca levels were not influenced by dietary variation in P source. The poor performance of both broilers and layers fed on CMM based diets could be attributed to the presence of hlgher levels of F (647.8 and 630.1 mg/kg, respectively) and low P utilization. Based on growth, bone mineralization and P retention it is concluded that DCP, SSBM or PA can be used as alternatives to TCP in broiler diets. In WL layer diets, in addition to above P sources, CMM can also be used as supplemental P source by replacing one half of P from CMM with PA without affecting egg production and shell quality.

• 한국가금학회지
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• 제10권2호
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• pp.113-121
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• 1983

국내에서 발생하고 있는 ILT의 역학적인 사항을 파악하기 위하여 1982년 6월부터 1983년 8월까지 ILT가 발생된 5개 종계농장과 1개 산란계농장의 총56개 계군을 대상으로 계군간 및 계군내 전파속도와 전파수단, 품종, 나이, 사양형태에 따른 감수성의 차이, 발병 전후의 백신접종이 피해를 줄이는데 미치는 영향 등을 조사하였다. 6개 대상농장 중 5개 농장에서는 ILT발생 직전 또는 직후 백신접종을 실시하였으며 겨울철에 발생한 2개 농장에서는 발생직후 철저한 전파수단의 차단에 의해서 농장별로 1-2계군의 발생에 그치고 나머지 5-7계군은 발생이 없었다. 계군간의 전파속도는 평사계군이 평균 6일로서 케이지계군(11.5일)보다 빨랐으나 유의적인 차이는 인정할 수 없었다. 한편 케이지계군 중 산란을 하지 않는 미성숙계군간의 전파기간이 17일인데 반하여 산란중인 계군에서는 8일로서 유의적인 차이가 인정되어 난좌나 집란과정에 의한 전파촉진 가능성을 엿볼 수 있었다. 발병계군 내에서의 폐사기간은 평균 18일로서 사육형태. 품종 및 나이에 따른 차이를 인정할 수 없었다. 또한 폐사율은 평균 6.5%로서 미성숙육계종계군(2.9%)이 미성숙산란계군(11.8%)이나 산란중인 육계종계군(6.9%)에 비하여 월등히 낮았을 뿐 다른 어떤 기준에서도 궤사율의 차이를 인정할 수 없었다. 조사대상 농장 중 여름철에 발생한 한 육계종계 농장에서는 계군의 나이에 따라 37주령 이상된 7개 계군에서는 모두 수탉이 암탉에 비하여 두배 이상의 높은 폐사율을 보여 주었다.

• 한국가금학회지
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• 제40권4호
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• pp.379-388
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• 2013

Avian paramyxovirus (APMV) type 4 and 6 were isolated during an avian influenza (AI) surveillance program of wild birds. This study also conducted experimental infection of wild-bird-origin APMV type 4 and 6 in specific pathogen free (SPF) chickens to study pathogenicity and transmission within domestic flocks. In addition, serological prevalence data of APMV type 4 and 6 in domestic fowls was conducted with chicken sera collected from 2007 to 2009 in order to understand infection status. The results of the animal experiment showed that APMV type 4 and 6 had the ability to infect chickens with sero-conversion and to transmit the virus from infected birds to contacted birds, but showed low pathogenicity. Serological tests revealed that APMV type 4 was widespread in the poultry industry, especially in layer flocks, but the positive rate for APMV type 6 was very low. This study concluded that wild bird-origin APMV type 4 and 6 could infect the chickens by inter-species transmission and the seroprevalence of APMV type 4 was quite high in Korean poultry. However, since almost all the chicken flocks had a high level of antibody titer against APMV type 1, there was possibility of cross reaction between APMV type 1 and 4, which made the interpretations more complicated. In order to understand infection status in the natural environment, additional study is necessary regarding the seroprevalence of APMV type 4 and 6 in the wild bird population.

• 대한수의학회지
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• 제45권3호
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• pp.405-410
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• 2005

To analyze and identify selected risk factors for infectious bronchitis virus (IBV) infection in the growing and laying period of laying-hen flocks, a longitudinal field study was conducted with 27 commercial flocks reared in three provinces of Korea during the period from May 2003 to April 2004. Using monitored data for IBV infection status among study flocks we computed the multivariate odds ratios (ORs) and their corresponding confidence intervals (CIs), and population attributable risks (PARs). Multivariate logistic regression showed significant risk increments for: continuous entry of chick (OR=1.9, 95% CI, 0.7-69.1) and operation years of the layer house greater than or equal to 5 years (OR=3.2, 95%CI, 1.6-389.9). No significant interaction was found between variables. The PAR suggested that continuous entry of chick (PAR=32%) and ${\geq}5years$ of house operation (PAR=84%) had the highest impacts on IB presence in laying-hen flocks under study. Of the two significant factors, however, operation year of the layer house lacks an easy applicability in preventing IB control strategies, and the possibility of confounder cannot be ruled out.

• 한국가금학회지
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• 제50권4호
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• pp.203-212
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• 2023

본 연구는 산란능력이 우수한 토종 실용산란계를 개발하기 위하여 토종 종계 4계통(YC, YD, CK, CF)을 이용하여 이면 교배조합 검정시험(diallel crossbreeding test)을 실시하였다. 능력검정은 6개 조합의 312수를 대상으로 발생 후부터 60주령까지 생존율, 체중, 초산일령, 난중, 산란율 및 난질을 조사하고, 이들의 생산능력 및 결합능력을 분석하였다. 분석 결과, 전체 조합의 평균 생존율은 77.1±18.8%이고, 조합 중 YDYC조합의 생존율이 가장 높았고, YCCF조합의생존율이 가장 낮았다. YDYC조합의 경우, YD와 YC계통 간의 특정결합능력이 특히 우수하였다. 체중은 모든 측정 주령에서 조합 간의 유의한 차이가 있었는데, 전 기간 YDYC 조합의 자손이 다른 조합의 자손들보다 무거운 것으로 나타났다(P<0.01). 평균 초산일령은 121.3±2.5일로 조합 간의 차이는 없는 것으로 나타났다. 20주령부터 60주령까지 전체조합의 평균 일계산란율은 74.0±6.4%이었고, 산란지수는181.4±33.8개로 일계산란율은 조합 간에 유의한 차이를 보였다(P<0.05). 조합 중 YDCF 및 YCCK조합의 산란 성적이 가장 높았고, YDYC 및 CKCF조합이 가장 낮았으며, 이들의 성적은 일반결합능력보다 특정결합능력에 의해 더욱 큰 영향을 받는 것으로 나타났다. 난중은 측정 시점 모두에서 조합 간 유의한 차이를 보였고(P<0.05), YDYC조합의난중이 전체적으로 낮게 나타났다. 난각색, 난각 두께, 난각 무게 모두 조합 간에 유의한 차이를 보이며(P<0.01), 난각색은 YDYC조합의 달걀이 가장 짙었고, 난각 두께는 YDCF조합이 가장 두꺼웠다. 내부 난질은 조합 간 차이가 없었으며, 난황색은 YDCF조합이 가장 짙은 것으로 나타났다. 결론적으로 산란 능력을 바탕으로 최적의 토종 실용산란계를 선정시 산란율이 우수하면서 생존율이 높은 YCCK조합과 산란율이 우수하면서 상대적으로 난질이 양호한 YDCF조합이 가장 바람직한 조합으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권5호
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• pp.776-782
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• 1999

Two Bangladeshi varieties of yellow corn-'Barnali' and 'Khaibhutta' were chemically analysed and used in the diet of laying chicken to determine their replacement value for wheat. Both the new varieties of yellow corn were found to be good sources of energy and the CP contents were comparable to wheat. Forty two, 29-week old randomly selected Starcross Brown commercial pullets were assigned to 7 dietary treatments with 6 replicates, each being an experimental unit. Diets were formulated replacing wheat quantitatively by two varieties of yellow corn either 0, 50, 75 or 100 per cent from a wheat based control diet. The production performance of laying hens fed diets formulated with Barnali or Khaibhutta at different dietary levels during an experimental period of 16 weeks was satisfactory and comparable to wheat based diet. Except egg yolk colour, the other internal arid external egg quality characteristics at 8th and 16th weeks of the experiment did not differ significantly. The egg yolk colour improved significantly (p<0.01) by feeding both the new varieties of corn and the degree of pigmentation of yolk increased as the dietary levels of corn increased at the expense of wheat. Considering laying performance, the new varieties of yellow corn, Barnali or Khaibhutta can be used in layer diet as replacement of wheat. Such a replacement would better that wheat-based diet in terms of egg yolk pigmentation.

• 농업과학연구
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• 제46권4호
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• pp.991-997
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• 2019

This study was conducted to investigate the laying period performance of two crossbred Korean native chicken (KNC) grand parent stock (GPS) layer during 20 to 40 weeks. A total of 351 20-week-old KNC GPS were allocated in a completely randomized design to give 4 birds per each cage. The chickens were fed commercial diets [i.e., week 20 - 32, crude protein (CP) 18.0% and metabolizable energy (ME) 2,850 kcal/kg; week 32 - 40, CP 17.0% and ME 2,800 kcal/kg)] and fresh water during the whole experiment period ad libitum basis. Body weight, age of sexual maturity, egg weight, hen-day egg production (HDP) and feed conversion ratio (FCR) were measured during the experiment period (week 20 - 40). The results show no significant difference in the Body weight, age of sexual maturity, egg weight, and hen-day egg production (HDP) except for egg weight. 1B had a higher egg weight on week 36 only. We expect that the reason why most factors showed no significant difference is the lack of nutrients caused by limited feeding which follows the standard feeding system for the grand-parent stock. These results provide basic information for laying data in 2-way crossbred Korean native chickens.