Sonic Hedgehog promotes in vitro oocyte maturation and term development of embryos in Taiwan native goats.

The aim of this study was to investigate the effects of Shh (Sonic Hedgehog) protein on caprine oocyte maturation, early embryo development, and developmental competence after embryo transfer of vitrified-thawed in vitro-produced embryos. Cumulus-oocyte complexes (COCs) derived from abattoir were randomly allocated to the in vitro maturation (IVM) medium supplemented with 0 (Control), 0.125, 0.25, 0.5, or 1.0 µg mL-1 recombinant mouse Shh protein. After IVM, COCs were fertilized with frozen-thawed semen and the presumptive zygotes were cultured on goat oviduct epithelial monolayers in M199 medium for 9 days. Our results showed that supplementation of Shh (0.25 or 0.5 µg mL-1) enhanced oocyte maturation as compared with the control group (92.4% and 95.0% vs. 86.2%, P < 0.05), yet the effect could be reversed by the simultaneous addition of cyclopamine (an inhibitor of Shh signaling by direct binding to the essential signal transducer Smo). Subsequently, an improved blastocyst rate (66.3 ± 10.9, P < 0.05) was observed for the embryos derived from the oocytes matured in the presence of 0.5 µg mL-1 Shh compared with the control group (41.4 ± 12.9). Expressions of Shh, SMO and Gli1 were observed in the ovaries, granulosa cells, COCs, cumulus cells, oocytes and oviduct epithelia. Notably, Ptch1 was expressed in nearly all of the aforementioned tissues and cells except cumulus cells. The embryos exhibited a higher survival rates in the Shh-supplemented group (37.5%) compared to those without Shh supplementation (14.8%; P < 0.05) after embryo transfer. This study demonstrated the beneficial effects of Shh supplementation on oocyte maturation and subsequent embryo development both in vitro and in vivo, suggesting a functional existence of Shh signaling during the final stage of folliculogenesis and early embryogenesis in caprine.

Development of a recombinase polymerase amplification lateral flow dipstick (RPA-LFD) for the field diagnosis of caprine arthritis-encephalitis virus (CAEV) infection.

Caprine arthritis-encephalitis (CAE) in goats is a complex disease syndrome caused by a lentivirus. This persistent viral infection results in arthritis in adult goats and encephalitis in lambs. The prognosis for the encephalitic form is normally poor, and this form of the disease has caused substantial economic losses for goat farmers. Hence, a more efficient detection platform based on recombinase polymerase amplification (RPA) and a lateral flow dipstick (LFD) was developed in the present study for detecting the proviral DNA of caprine arthritis-encephalitis virus (CAEV). Under the optimal incubation conditions, specifically, 30min at 37°C for RPA followed by 5min at room temperature for LFD, the assay was found to be sensitive to a lower limit of 80pg of total DNA and 10 copies of plasmid DNA. Furthermore, there was no cross-reaction with other tested viruses, including goat pox virus and bovine leukemia virus. Given its simplicity and portability, this RPA-LFD protocol can serve as an alternative tool to ELISA for the primary screening of CAEV, one that is suitable for both laboratory and field application. When the RPA-LFD was applied in parallel with serological ELISA for the detection of CAEV in field samples, the RPA-LFD assay exhibited a higher sensitivity than the traditional method, and 82% of the 200 samples collected in Taiwan were found to be positive. To our knowledge, this is the first report providing evidence to support the use of an RPA-LFD assay as a specific and sensitive platform for detecting CAEV proviral DNA in goats in a faster manner, one that is also applicable for on-site utilization at farms and that should be useful in both eradication programs and epidemiological studies.

Characterization of the genetic diversity and population structure for the yellow cattle in Taiwan based on microsatellite markers.

In recent years, the population size of Taiwan yellow cattle has drastically declined, even become endangered. A preservation project, Taiwan Yellow Cattle Genetic Preservation Project (TYCGPP), was carried out at the Livestock Research Institute (LRI) Hengchun branch (1988-present). An analysis of intra- and inter- population variability was performed to be the first step to preserve this precious genetic resource. In this work, a total number of 140 individuals selected from the five Taiwan yellow cattle populations were analyzed using 12 microsatellite markers (loci). These markers determined the level of genetic variation within and among populations as well as the phylogenetic structure. The total number of alleles detected (122, 10.28 per locus) and the expected heterozygosity (0.712) indicated that these five populations had a high level of genetic variability. Bayesian cluster analysis showed that the most likely number of groups was 2 (K = 2). Genetic differentiation among clusters was moderate (F ST = 0.095). The result of AMOVA showed that yellow cattle in Taiwan had maintained a high level of within-population genetic differentiation (91%), the remainder being accounted for by differentiation among subpopulations (4%), and by differentiation among regions (5%). The results of STRUCTURE and principal component analysis (PCA) revealed two divergent clusters. The individual unrooted phylogenetic tree showed that some Kinmen yellow cattle in the Hengchun facility (KMHC individuals) were overlapped with Taiwan yellow cattle (TW) and Taiwan yellow cattle Hengchun (HC) populations. Also, they were overlapped with Kinmen × Taiwan (KT) and Kinmen yellow cattle (KM) populations. It is possible that KMHC kept similar phenotypic characteristics and analogous genotypes between TW and KM. A significant inbreeding coefficient (F IS = 0.185; P < 0.01) was detected, suggesting a medium level of inbreeding for yellow cattle in Taiwan. The hypothesis that yellow cattle in Taiwan were derived from two different clusters was also supported by the phylogenetic tree constructed by the UPGMA, indicating that the yellow cattle in Taiwan and in Kinmen should be treated as two different management units. This result will be applied to maintain a good level of genetic variability and rusticity (stress-resistance) and to avoid further inbreeding for yellow cattle population in Taiwan.