Fifteen isolates of Infectious bronchitis virus (IBV) were obtained from the kidney, trachea, and cecal tonsil of IB suspected chickens between 2001 and 2002 years in Korea. The S1 glycoprotein gene of IBV isolates were amplified by reverse transcriptase - polymerase chain reaction (RT-PCR) and analyzed by restriction fragment length polymorphism (RFLP) analysis. Fifteen Korean IBV isolates were classified into 4 groups by their RFLP patterns using restriction enzymes, HaeIII, BstYI, and XcmI. The RFLP patterns for 3, 1, and 1 of 15 isolates corresponded to the patterns of IBV Arkansas, Connecticut, and Massachusetts strains, respectively. Ten of 15 isolates generated unique KM91 RFLP pattern that was observed in the IBV KM 91 strain previously isolated in Korea. To confirm genetic diversity in the S1 genes of IBV isolates, viral RNAs of representative 9 of 15 IBV isolates were amplified, cloned, sequenced and compared with published sequences for non-Korean IBV strains. Korean IBV isolates showed amino acid sequence similarity between 61.8% (K446-01 and K161-02) and 96.1% (K281-01 and K210-02) with each other and they showed amino acid sequence similarity between 42.9% (K161-02 and GA980470) and 96.5% (K203-02 and KB8523) compared to non-Korean IBV strains. By phylogenetic tree analysis, Korean IBV field isolates were branched into five clusters in which 3 clusters were differentiated from non-Korean IBV strains. Especially, Korean IBV isolates K069-01, K507-01, K774-01 and K142-02 formed a separate cluster. It seems that IBVs continue to evolve and IBVs showing various genetic differences may cocirculate in Korea.

The akirin 2 gene, located on chromosome 9 in cattle, was previously reported to be associated with nuclear factor-kappa B (NF-κB), involved in immune reactions and marbling of meat. To determine whether a single nucleotide polymorphism (SNP) in akirin 2 is associated with economically important traits of Korean native cattle, the c.*188G>A SNP DNA marker in the 3'-UTR region of akirin 2 was analyzed for its association with carcass weight, longissimus muscle area and marbling. The c.*188G>A SNP was genotyped by polymerase chain reaction restriction fragment length polymorphism, and the frequency of the AA, AG, and GG genotypes were 6.82%, 71.29% and 21.88% respectively. This SNP was significantly associated with longissimus muscle area (Bonferroni corrected P < 0.05), and marbling score (Bonferroni corrected P < 0.01). These results suggest that the c.*188G>A SNP of akirin 2 might be useful as a DNA marker for longissimus muscle area and marbling scores in Korean native cattle.

The objectives of this study were to investigate the correlations between various blood parameters compared with cortisol and lactate levels under the standard pre-slaughter procedure and handling conditions and to assess their potential as indicators of pork quality traits. Despite there being no additional pre-slaughter stress treatment, there is considerable variation in blood parameters at exsanguination. Serum cortisol and blood lactate levels, widely used indicators of stress, were positively correlated with blood glucose and electrolytes, such as calcium, potassium and sodium. Moreover, these parameters were significantly correlated with a rapid rate of early postmortem glycolysis and reduced water-holding capacity. In particular, blood lactate and glucose levels significantly differed between porcine quality classes. However, other blood parameters including electrolytes did not significantly differ between quality classes though they significantly correlated with pork quality traits. Therefore, serum cortisol, blood lactate and glucose have potential as indicators of the rate and extent of postmortem metabolism and ultimate pork quality under the standard procedure and handling conditions of pre-slaughter.

This study was carried out to investigate the effect of feeding levels and periods of Rhus verniciflua Stokes (RVS) on the quality of M. longissimus from gilts (Landrace × Yorkshire × Duroc) at finishing stage. The gilts were fed diets containing 0 (control), 2 and 4% RVS for 5 weeks (the latter feeding periods) and 8 weeks (the first feeding periods + the latter feeding periods) before slaughtering, respectively. Samples were stored at 3 ± 0.2 for 8 days. Crude fat content was decreased by feeding diets of 4% RVS (p<0.05). Water-holding capacity (WHC) was higher in RVS treatments than in control during storage (p<0.05). L*(Lightness) value was higher in 5 weeks-RVS treatment than in control during storage (p<0.05). a*(Redness) and b*(yellowness) were not affected by the levels and periods of RVS supplementation. Thiobarbituric acid reactive substances (TBARS) value was lower in RVS treatment than in control (p<0.05), and the 5 weeks with 4% RVS treatment showed the highest antioxidative activity. Fatty acid compositions of pork were changed by RVS feeding levels and periods. The meat supplemented with RVS showed high levels of unsaturated fatty acid (UFA) composition and monounsaturated fatty acid (MUFA)/saturated fatty acid (SFA) ratio compared with control. The dietary 8 weeks-RVS treatments had lower stearic acid(18:0) and higher polyunsaturated fatty acid (PUFA) contents than in other treatments. Melting point of backfat also decreased by increasing the level and period of RVS supplementation (p<0.05). Therefore, RVS fed pork decreased fat content and melting point, increased WHC and UFA composition, and delayed lipid oxidation during storage.