The aim of this study is to investigate the polymorphism of the Pituitary transcription factor ( PIT-1) and Prolactin ( PRL) genes in Holstein Friesian cows (HF) bred in Vietnam and their effects on...

Toxoplasma gondii and Neospora caninum are closely related protozoan parasites, they share many common hosts, and can cause neurological diseases in dogs. Dogs can have close contacts with humans and livestock and therefore they can act as reservoirs of these parasites. The aim of this study was to survey the seroprevalence of antibodies against T. gondii and N. caninum and their co-infection rate in dogs in Korea. In total, sera from 553 domestic dogs were collected from different breeds, sexes, and ages of dogs from nine provinces across the country of Korea during 2006 and 2007. The presence of antibodies against T. gondii and N. caninum was analyzed using the latex agglutination test (LAT) with a cut-off value of 1:32, and the indirect fluorescent antibody test (IFAT) using a serum titer of 1:100. In the total dog population, 71 (12.8%) dogs were positive for anti-T. gondii antibodies and only 20 (3.6%) were positive for anti-N. caninum antibodies. Relatively higher seropositive frequencies of antibodies against T. gondii (20.1%) and N. caninum (4.9%) were detected in the dog population from the Gyeonggi. A higher proportion of animals seropositive for anti-T. gondii antibodies was found in stray dog populations as compared to household dog populations: 18.5% (59/319) vs 5.1% (12/234), respectively. The Chi-square tests revealed significant differences in the seropositive frequencies of antibodies against T. gondii between stray and household dogs in the total population (p<0.0001), and in dogs from the Gyeonggi (p0.05). The first serological survey on antibodies against both T. gondii and N. caninum parasites across the entire country showed that co-infection was not common in these canine populations with a seropositive level of 0.72%. The significantly higher positive frequency of T. gondii antibodies in stray dogs in both, Gyeonggi and in the total dog populations suggests that further investigation on the seroprevalence of parasites should focus on stray dogs.

Genetic diversity of four Vietnamese indigenous chicken breeds including Lien Minh (GLM), Dong Tao (GDT), Nhan (GNH) and Chin Cua (G9C) were evaluated using mitochondrial DNA (mtDNA) D-loop sequence polymorphism. 1,050 bp of D-loop region of 66 individuals was amplified, sequenced, and analyzed. Comparative alignment results showed that the four local chickens shared 96.6% - 99.9% nucleotide identity with each other. Results of D-loop sequencing analysis revealed 53 variable sites (gaps included) in native Vietnamese chickens as compared to reference sequence (AB268540). Among them, there were six nucleotide deletions, ten nucleotide insertions (positions) and 37 nucleotide substitutions (sites). The estimated haplotype diversity (Hd) within breed was relatively high, ranged from 0.824 (GNH) to 0.913 (GLM). Phylogenetic study based on hypervariable region of 455 bp D-loop showed that all Vietnamese native chicken breeds were distributed over 16 haplotypes belonged to five haplogroups A, B, C, D and E, of which clade B was dominant. Individual of GLM, GDT, and G9C breeds clustered mainly in clade B (34/48) and GNH chicken (18 individuals) belonged to clade C and D. This study shows the relatively high genetic diversity of native Vietnamese chicken breeds and contributes to the conservation and breeding strategy of indigenous chicken in Vietnam. Key words: DNA D-loop sequence, genetic diversity, Vietnamese indigenous chickens.

Copy number variants (CNVs) are large-scale genomic alterations that contribute substantially to genetic diversity and may influence phenotypic variation in livestock. This study investigated the genome-wide CNV landscape of three Vietnamese indigenous chicken breeds. Whole-genome sequencing on the Illumina platform (3–5× coverage) was performed on 24 individuals from Dong Tao (DT), Cay Cum (CC), and Ri (RI) breeds. A total of 1743 CNVs were detected, clustering into 315 copy number variation regions (CNVRs). Most CNVRs were rare, with 31.7% present in only one animal among breeds. Across the genome, 122 unique CNVRs were distributed over 28 chromosomes, predominantly the first five. Losses were the most frequent type (45.9%), followed by gains (39.3%), and mixed events (14.8%). Within these CNVRs, 3633 genes were identified. In DT and RI, CNVR-embedded genes included several candidates, potentially related to adaptability, development, and phenotypic diversification. Notably, DT harbored genes such as EGLN1, OASL, GPX1, DUOX1/DUOXA2 (adaptation, stress/immune response) and LRP4, ZIC1, ZIC4, JARID2, KMT2C, OGN, OMD, and PLOD2 (developmental and skeletal traits), whereas in RI they included genes such as CACNA1S, CALCR, CAPN3, and MAPK13/MAPK14, which may contribute to muscle, bone, and physiological regulation. Functional enrichment analysis revealed numerous genes and Quantitative Trait Loci (QTLs) associated with metabolic, developmental, and immune-related pathways. This study provides the first comprehensive genome-wide CNV profile of Vietnamese indigenous chickens and offers a valuable genomic resource for investigating the genetic basis of breed-specific and adaptive phenotypes.