No abstract

Avian metapneumovirus (aMPV) causes upper respiratory tract infections in chickens and turkeys. Although the swollen head syndrome (SHS) associated with aMPV in chickens has been reported in Korea since 1992, this is the study isolating aMPV from chickens in this country. We examined 780 oropharyngeal swab or nasal turbinate samples collected from 130 chicken flocks to investigate the prevalence of aMPV and to isolate aMPV from chickens from 2004-2008. Twelve aMPV subtype A and 13 subtype B strains were detected from clinical samples by the aMPV subtype A and B multiplex real-time reverse transcription polymerase chain reaction (RRT-PCR). Partial sequence analysis of the G glycoprotein gene confirmed that the detected aMPVs belonged to subtypes A and B. Two aMPVs subtype A out of the 25 detected aMPVs were isolated by Vero cell passage. In animal experiments with an aMPV isolate, viral RNA was detected in nasal discharge, although no clinical signs of SHS were observed in chickens. In contrast to chickens, turkeys showed severe nasal discharge and a relatively higher titer of viral excretion than chickens. Here, we reveal the co-circulation of aMPV subtypes A and B, and isolate aMPVs from chicken flocks in Korea.

Newcastle disease (ND) is one of the most devastating poultry infections because of its worldwide distribution and accompanying economical threat. In the present study, we characterized the ND virus (NDV) K148/08 strain from wild mallard duck, with regard to safety, thermostability, immunogenicity, and protective efficacy against velogenic ND viral infection. The NDV K148/08 strain offered enhanced immunogenicity and safety relative to commercially available vaccine strains. The NDV K148/08 strain was safe in 1-day-old SPF chicks after vaccination using a coarse or cabinet-type fine sprayer. We demonstrated that the NDV K148/08 strain elicited high levels of antibody responses and provided protective efficacy against lethal NDV challenge. In addition, the thermostability of the NDV K148/08 strain was as high as that of the thermostable V4 strain. Therefore, the NDV K148/08 strain may be useful to ensure NDV vaccine performance and effectiveness in developing countries, especially in remote areas without cold chains.

The objective of this study was to develop a method to simultaneously quantify vitamins A and E in infant formula. To determine the vitamin A and E content, vitamin A and four different vitamin E isomers (α-, β-, γ-, and δ-tocopherol) were separated by high performance liquid chromatography with a photodiode array detector using a Develosil RPAQUEOUS RP-C 3 0 column (4.6×250 mm, 5 µm). The vitamin A and E contents in the certified reference material determined using this method were within the certified range of standard values. The limits of detection (LODs) and limits of quantitation (LOQs) for vitamin A were 0.02 and 0.06 µg/L, respectively. LODs and LOQs for the vitamin E isomers ranged from 0.20 to 0.55 and from 0.67 to 1.81 µg/L, respectively. Linear analyses indicated that the square of the correlation coefficient for the vitamin A and E isomers was 0.9997-0.9999. The recovery of vitamins ranged from 96.69 to 97.79%. The results demonstrate that this novel method could be used to reliably analyze vitamin A and E content in infant formula.

The contamination level of aflatoxin M 1 (AFM 1 ) in raw milk samples produced in South Korea during the winter season was investigated using immunoaffinity column chromatography and high performance liquid chromatography equipped with a fluorescence detector. Among the test samples collected from 100 cattle ranches in 2008 and 2009, none were contaminated with AFM 1 over the maximum level (0.5 mg/L) set by South Korea and U.S. regulatory agencies. Seven percent of the tested samples obtained in 2008 were not contaminated with AFM 1 ; however, this increased to 34% for samples obtained in 2009. The percent of samples with an AFM 1 concentration in the range of 0.05-0.10 mg/L decreased from 21% in 2008 to 4% in 2009. In this study, the level of AFM 1 in raw milk was determined to be very low and safe for market milk process. PRACTICAL APPLICATIONSThis study, the first time in South Korea, contamination of aflatoxin M 1 (AFM 1 ) in raw milk, during 2 years seasons was investigated using immunoaffinity column and high performance liquid chromatography. This was a large survey for AFM 1 level in the raw milk samples from 100 dairy ranches. The result can be used as reference data to understand the current occurrence of AFM 1 and estimate the contamination levels of AFM 1 in various dairy products in South Korea.