Gut Fungal Microbiome Responses to Natural Cryptosporidium Infection in Horses.

It is critical to characterize changes in the structure and composition of the host fungal community in natural Cryptosporidium infection, because it gives the possible overview of gut microbiome in host homeostasis and disease progression. A total of 168 rectal fecal samples were collected and examined using nPCR. The positive samples were double-checked using 18S rDNA high-throughput sequencing. After confirmation, ITS high-throughput sequencing was utilized to investigate the fungal community's response to natural Cryptosporidium infection. Results showed that a total of three positive samples (1.79%) were identified with an increased abundance of fungi associated with health hazards, such as class Dothideomycetes, families, i.e., Cladosporiaceae, Glomerellaceae, and genera, i.e., Wickerhamomyces, Talaromyces, Cladosporium, Dactylonectria, and Colletotrichum. On the contrary, taxa associated with favorable physiological effects on the host were shown to have the reverse impact, such as families, i.e., Psathyrellaceae, Pseudeurotiaceae and genera (Beauveria, Nigrospora, and Diversispora). For the first time, we evaluated the condition of natural Cryptosporidium infection in horses in Wuhan, China, and discovered distinct variations in the fungal microbiome in response to natural infection. It might prompt a therapy or prevention strategy to apply specific fungal microorganisms that are probably responsible for decreased susceptibility or increased resistance to infection.

Effects of Milk Replacer-Based Lactobacillus on Growth and Gut Development of Yaks' Calves: a Gut Microbiome and Metabolic Study.

The gut microbiota and its metabolic activities are crucial for maintaining host homoeostasis and health, of which the role of probiotics has indeed been emphasized. The current study delves into the performance of probiotics as a beneficial managemental strategy, which further highlights their impact on growth performance, serologic investigation, gut microbiota, and metabolic profiling in yaks' calves. A field experiment was employed consisting of 2 by 3 factorial controls, including two development stages, namely, 21 and 42 days (about one and a half month), with three different feeding treatments. Results showed a positive impact of probiotic supplements on growth performance by approximately 3.16 kg (P < 0.01) compared with the blank control. Moreover, they had the potential to improve serum antioxidants and biochemical properties. We found that microorganisms that threaten health were enriched in the gut of the blank control with the depletion of beneficial bacteria, although all yaks were healthy. Additionally, the gut was colonized by a microbial succession that assembled into a more mature microbiome, driven by the probiotics strategy. The gut metabolic profiling was also changed significantly after the probiotic strategy, i.e., the concentrations of metabolites and the metabolic pattern, including enrichments in protein digestion and absorption, vitamin digestion and absorption, and biosynthesis of secondary metabolites. In summary, probiotics promoted gut microbiota/metabolites, developing precise interventions and achieving physiological benefits based on intestinal microecology. Hence, it is important to understand probiotic dietary changes to the gut microbiome, metabolome, and the host phenotype. IMPORTANCE The host microbiome is a composite of the trillion microorganisms colonizing host bodies. It can be impacted by various factors, including diet, environmental conditions, and physical activities. The yaks' calves have a pre-existing imbalance in the intestinal microbiota with an inadequate feeding strategy, resulting in poor growth performance, diarrhea, and other intestinal diseases. Hence, targeting gut microbiota might provide a new effective feeding strategy for enhancing performance and maintaining a healthy intestinal environment. Based on the current findings, milk replacer-based Lactobacillus feeding may improve growth performance and health in yaks' calves.

Integrated Bacterial and Fungal Diversity Analysis Reveals the Gut Microbial Alterations in Diarrheic Giraffes.

Gut microbiota has been demonstrated to be associated with multiple gastrointestinal diseases, but information regarding the gut microbial alternations in diarrheic giraffe remains scarce. Here, 16S rDNA and ITS gene amplicon sequencing were conducted to investigate the gut microbial composition and variability in diarrheic giraffes. Results demonstrated that Firmicutes and Proteobacteria were the most dominant phyla in the gut bacterial community, whereas Ascomycota and Basidiomycota were observed to be predominant in the gut fungal community regardless of health status. However, the species and relative abundance of preponderant bacterial and fungal genera in healthy and diarrheic giraffes were different. In contrast to the relatively stabilized gut fungal community, gut bacterial community displayed a significant decrease in the alpha diversity, accompanied by distinct changes in taxonomic compositions. Bacterial taxonomic analysis revealed that the relative abundances of eight phyla and 12 genera obviously increased, whereas the relative abundances of two phyla and eight genera dramatically decreased during diarrhea. Moreover, the relative richness of five fungal genera significantly increased, whereas the relative richness of seven fungal genera significantly declined in diarrheic giraffes. Taken together, this study demonstrated that diarrhea could cause significant alternations in the gut microbial composition of giraffes, and the changes in the gut bacterial community were more significant than those in the gut fungal community. Additionally, investigating the gut microbial characteristics of giraffes in different health states is beneficial to provide a theoretical basis for establishing a prevention and treatment system for diarrhea from the gut microbial perspective.

Prevalence, Characterization, and Pathogenicity of Salmonella enterica Subspecies enterica Serovar Derby from Yaks in the Aba Tibetan Autonomous Prefecture, China.

Salmonella enterica subsp. enterica serovar Derby (S. Derby) is one of the numerous non-typhoidal Salmonella serovars and has been recognized as a food-borne pathogen. In 2019, outbreaks of salmonellosis were reported in 13 yak farms in the Aba Tibetan Autonomous Prefecture, China. A total of 32 salmonella strains were isolated from 162 fecal samples of yaks with diarrhea as well as from drinking water samples. The isolates were subjected to serovar identification, animal experiments, and whole-genome sequencing (WGS) analyses. The serovar of all the isolates was S. Derby, and the sequence types (STs) were ST40. The analysis of the differences of single-nucleotide polymorphisms (SNPs) showed that the salmonella strains isolated from 13 farms were clonally related. Animal experiments showed that the lethal dose (LD50) was 4.57 × 107 CFU (colony-forming units); the shedding time of S. Derby in mice was 24 days; the bacterial loads in spleen were higher than those in other organs (ileum, liver, and cecum). Pathological analyses by hematoxylin and eosin (H&E) staining revealed obvious damage in the spleen, liver, and intestine. These results indicate that the S. Derby from yaks can cause infection in mice.

Antimicrobial Resistance, Virulence Genes, and Biofilm Formation Capacity Among Enterococcus species From Yaks in Aba Tibetan Autonomous Prefecture, China.

Yaks provide necessities such as meat and milk for Tibetans living at high altitudes on and around the Qinghai-Tibetan Plateau. Enterococci are ubiquitous members of the animal gut microbiota that can cause biofilm-associated opportunistic infections. Meanwhile, multidrug-resistant Enterococcus also poses a serious threat to public health. This study aims to characterize antibiotic resistance, virulence genes, and biofilm formation of enterococci from yaks. From April 2018 to July 2019, we collected 395 fecal samples of yaks in Aba Tibetan Autonomous Prefecture, China. Enterococci isolated from the samples were identified and classified according to the 16S rDNA sequence. The antibiotic resistance of each isolate was detected according to the Kirby-Bauer disk diffusion method, and antibiotic resistance genes were detected by polymerase chain reaction (PCR) and sequencing. Enterococcal biofilms were assessed using standard procedures. Different virulence genes were detected by PCR and sequencing. In total, 381 enterococci strains were recovered, with Enterococcus faecalis (41.99%) and Enterococcus faecium (37.80%) being the predominant species. Many isolates were multidrug- resistant (60.37%) and showed a high resistance rate to rifampicin (64.30%) and tetracycline (61.54%). We also detected various antimicrobial resistance (AMR) genes in the tested strains. The E. faecalis strains had higher frequency of biofilm formation and virulence genes than other enterococcal species. This is the first report that shows yaks are repositories for drug-resistant enterococci with virulent determinants and biofilms that may spread into humans and to environment. This study also provides useful data suggesting that enterococci may pose a potential health risk to yaks. Therefore, active surveillance of AMR and pathogenesis in enterococci from yaks is urgently warranted.