Noroviruses (NoVs) and sapoviruses (SaVs) of the family Caliciviridae are emerging enteric pathogens in humans and animals. Recent detection of genogroup II norovirus (GII NoV) RNA from swine raises public health concerns about zoonotic transmission of porcine NoVs to humans. However, few papers reported genotype distributions and epidemiological features in swine farms and their genetic relationship to human strains, which was the objective of our study. This study investigated the epidemiological features and genotypes of caliciviruses in swine farms using 533 pig faecal samples from six farms in central and southern Taiwan, tested for viral RNA using RT-PCR targeting the conserved polymerase gene. NoVs and SaVs were detected with a positive rate of 7.1% and 0.6%, respectively. To confirm the positive rate of NoVs, 255 pig faecal samples from two farms in central Taiwan were tested with primer pairs targeting the partial capsid gene of GII, and 32.3% of the positive rate was found. Furthermore, the results from the capsid region suggested a higher positive rate of 41.7% in winter than 26.4% in summer with statistical significance (P < 0.05). Sequence analysis showed 29 strains belonging to GII.4 (human) and nine strains belonging to GII.11 (swine) identified based on the partial polymerase gene. Additional genotypes clustered with GII.2 (human) and GII.18 (swine) were also characterized based on the partial capsid gene. SaVs detected in porcine faecal samples belonged to genogroup III (GIII), which clustered with the PEC-Cowden strain. Our study demonstrated the presence of multiple genotypes of both human and porcine NoVs infecting swine of various ages asymptomatically. Although the zoonotic potential of detected human NoVs in swine was not conclusive owing to the lack of local human faecal samples, our study revealed the importance of monitoring emerging strains in swine to mitigate the potential impact of recombinant NoVs infecting the human population.

Taiwan commercial native chickens have played a vital role in the domestic market due to Taiwanese traditional cooking style and culture. This study investigated the genetic characterization and population structure of 10 Taiwan commercial native chicken populations, together with two exotic breeds and one population of red jungle fowl, using 22 microsatellites. The results showed that Taiwan commercial native chickens generally harbored high genetic diversity but lower than that of red jungle fowl population in terms of number of alleles and gene diversity. The neighbor-joining tree revealed a poor resolution with only two branches showing bootstrap values above 70%. Based on Bayesian clustering approach, thirteen populations were inferred into eight distinct clusters namely Game bird, B strain, L2 strain, White Broiler and White Leghorn with an average proportion of membership higher than 0.90 and the values higher than 0.85 for red jungle fowl, Hakka chicken and Hakka strain while four remaining breeds were closely related together. The population structure showed Taiwan commercial native chickens are more admixed, in contrast to occidental highly productive breeds. The high genetic variation within breed as shown in the results of the analysis of molecular variance, facilitated by gene exchanges, did not allow discriminating in an efficient way. This suggests that the genetic pool of Taiwan commercial native chickens is well distributed among breeds and therefore there is a good potential for adaptation to new environmental conditions or markets. Some populations, namely L2 strain and B strain showed very high inbreeding coefficient and thus could be considered at risks. Therefore, management needs to be taken into account for the populations, to prevent inbreeding depression and maintain genetic diversity.Key words: Bayesian clustering approach, genetic diversity, microsatellite, population structure, Taiwan J. Poult. Sci., 50: 290-299, 2013 Introduction Chicken meat and egg play an important role in Chinese traditional cuisine in Taiwan. There was 40 to 50% chicken meat from imported exotic White broiler (USDA, 2006) while the remaining meat production comes from Taiwan commercial native chickens (TCOM). For instance, Red feathered and Black feathered chickens produce about 80% of TCOM and the remaining 20% comes from commercial slow-growing local breeds such as Silkies, Naked Neck, Game bird, Hakka chicken, Golden chicken and Classical chicken (Lee, 2006). Taiwan native chickens were frequently crossed with imported exotic breeds (broiler-type rooster) to produce TCOM and selected by local farmers for high body weight, feed efficiency and their ability to adapt to local conditions since 1960s (Lee, 2006).Genetic diversity of chicken genetic resources provides the basis for genetic improvement in order to increase productivity but also to adapt domestic populations to changes in production environments as well as in markets, management practices, and disease challenges Boettcher et al., 2010). Moreove...