Background: The gut microbiome is a large and complex organic assemblage with subtle and close relationships with the host. This symbiotic mechanism is important for the health and adaptability of the host to the environment. Compared with other ruminants, there are few studies on yak intestinal microbes. The study of the gut microbiota of the yak will help us better understand the correlation between the microbiota and the environmental adaptability of the host. In this study, we adapted 16S rDNA sequencing technology to investigate the diversity and composition of the intestinal microbial community in free-range yaks and captive yaks living on the Qinghai–Tibet Plateau (QTP). Results: Sequencing results showed that the intestinal microbial community diversity was significantly different between free-range yaks and captive yaks. Firmicutes and Bacteroidetes were the dominant bacteria in both free-range and captive yaks. However, there were differences between the microbes of the two analyzed feeding styles in different classification levels. Compared with the captive type, free-range yaks had a higher abundance of Ruminococcaceae, Eubacteriaceae, Desulfovibrionaceae, Elusimicrobium, and Oscillibacter, while the abundance of Succinivibrionaceae, Clostridiales, Lachnospiraceae, Prevotellaceae, Roseburia, and Barnesiella was relatively low. The feeding method may be the key factor for the formation of intestinal flora differences in yaks, while altitude did not significantly affect Qinghai yak. Conclusions: In this study, we used 16S rDNA sequencing technology to investigate the composition of intestinal flora in free-range and captive yaks living on the QTP. The exploration of dietary factors can provide a theoretical basis for scientifically and rationally breeding yaks and provides a new direction for the development of prebiotics and microecological agents.

Contagious ecthyma dermatitis, caused by Orf virus (ORFV), is an important zoonotic disease of small ruminants, particularly goats and sheep, and can occasionally infect humans. The morbidity of the disease is high in newborn kids or lambs as compared with adult animals, even leading to death in severe cases due to emaciation or secondary infections. Despite its significance, the precise route of ORFV transmission to newborn kids or lambs has remained unclear. In this study, we hypothesized that ORFV may be transmitted transplacentally from dam to fetus and investigated the presence of the virus in maternal–fetal interface tissues. Molecular detection targeting the ORFV B2L gene provided evidence supporting vertical transmission. The average viral loads in placental cotyledons and umbilical cords were 10 ^4.25 copies/mg and 10 ^3.50 copies/mg, respectively. Furthermore, vaccination of pregnant goats significantly reduced the vertical transmission rate of ORFV, with the ORFV-positive rate decreasing from 90.0% in non-vaccinated dams to 56.14% in vaccinated dams, from 71.43% to 14.29% in umbilical cord blood, and from 36.67% to 0% in kids born to vaccinated dams. Collectively, these findings identify vertical transmission as an important, previously under-recognized route of ORFV infection and highlight the importance of maternal vaccination in mitigating infection risk among newborn kids or lambs.

Duck Hepatitis A Virus type 3 (DHAV-3) causes high mortality in Pekin ducks, and the role of post-transcriptional regulation in disease resistance remains unclear. Here, we performed Oxford Nanopore full-length transcriptome sequencing on liver samples from resistant and susceptible ducks at 0 h and 24 h after DHAV-3 infection. Only one differentially expressed gene (DEG) and four differentially expressed transcripts (DETs) were identified pre-infection (0 h), whereas post-infection (24 h) we detected 2,539 DEGs and 2,909 DETs, indicating strong group-specific expression divergence. Functional enrichment revealed immune-related and metabolic pathway dysregulation in susceptible ducks, while resistant ducks maintained homeostasis. BulkSignalR identified an ECM-Integrin-JAK/Src module unique to the resistant group. Alternative splicing (AS) events increased from 16 pre-infection to 310 post-infection, enriched in immune and signaling pathways. Key immune genes showed isoform switching; in susceptible ducks, SELENOP transcripts lacked multiple selenocysteine sites, and a truncated PRPF8 isoform was highly expressed, while high DHX58 expression may suppress RIG-I activation. These findings highlight the critical role of post-transcriptional regulation in antiviral immunity and provide potential targets for improvement of disease resistance.