Xin Zhao

McGill University | McGill · Department of Animal Science

There is an urgent need for accurate measurement for emissions of ammonia (NH3) and hydrogen sulfide (H2S) in dairy barns in order to obtain reliable emission inventories and to develop and evaluate abatement strategies. This experiment was performed on three dairy farms in central China during 14 consecutive days in the winter 2020. Concentrations...

Chicken is a valuable model for understanding fundamental biology, vertebrate evolution and diseases, as well as a major source of nutrient-dense and lean-protein-enriched food globally. Although it is the first non-mammalian amniote genome to be sequenced, the chicken genome still lacks a systematic characterization of functional impacts of geneti...

The major histocompatibility complex (MHC) is a highly polymorphic cluster of genes which contribute to immune response. Located on chromosome 16, the chicken MHC has great influence over disease resistance and susceptibility. Through the use of a high-density SNP panel which encompasses the MHC-B region, haplotypes can be easily identified. This s...

Unlike PIWI-interacting RNA (piRNA) in other species that mostly target transposable elements (TEs), >80% of piRNAs in adult mammalian testes lack obvious targets. However, mammalian piRNA sequences and piRNA-producing loci evolve more rapidly than the rest of the genome for unknown reasons. Here, through comparative studies of chickens, ducks, mic...

Salmonella enterica serovar Enteritidis is a globally significant zoonotic foodborne pathogen. Chicken liver is a vital organ that has been recently implicated in several reported human salmonellosis outbreaks in the U.S. One promising strategy for reducing Salmonella in chickens could be through supplementation with natural antimicrobial additives...

Objectives A defining feature of MRSA is the SCCmec element. The excision and integration of SCCmec elements are catalysed by Ccr recombinases. Currently, seven ccrA, eight ccrB and two ccrC allotypes have been described. However, there have been no recent reports of a novel Ccr recombinase and thus this area should be explored. Methods According...

The intensively intermittent use of antibiotics promotes the rapid evolution of tolerance, which may lead to resistance acquisition in the following evolutionary trajectory. In addition to directly exporting antibiotics as an instant resistance strategy, efflux pumps are overexpressed in tolerant strains. To investigate how efflux pumps participate...

Abstract Background Mastitis caused by different pathogens including Streptococcus uberis (S. uberis) is responsible for huge economic losses to the dairy industry. In order to investigate the potential genetic and epigenetic regulatory mechanisms of subclinical mastitis due to S. uberis, the DNA methylome (whole genome DNA methylation sequencing)...

Staphylococcus aureus is one of the most important bacterial pathogens causing bovine mastitis, which leads to huge economic losses worldwide. Here, we report draft genome sequences and antimicrobial resistance gene profiles of five Staphylococcus aureus strains that were isolated from bovine milk in Pakistan.

To meet the increasing demand for meat and milk, the livestock industry has to increase its production. Without improving its efficiency, increased livestock, especially ruminant animals, will worsen the environmental damage, mainly from enteric CH4 emission. Enteric CH4 emission from ruminants not only exacerbates the global greenhouse effect but...

Background Post-weaning diarrhea in piglets reduces growth performance and increases mortality, thereby causing serious economic losses. The intestinal epithelial cells and microbiota reciprocally regulate each other in order to maintain intestinal homeostasis and control inflammation. However, a relative paucity of research has been focused on the...

This study examined changes in soil bacterial community composition and diversity in response to fertilization with litter from chickens fed diet with no antibiotics, bambermycin, penicillin, bacitracin, salinomycin, and mix of salinomycin and bacitracin. Litter was applied to 24 agricultural-plots. Non-fertilized plots were used as a negative cont...

Climate change, especially weather extremes like extreme cold or extreme hot, is a major challenge for global livestock. One of the animal breeding goals for sustainable livestock production should be to breed animals with excellent climate adaptability. Indigenous livestock and poultry are well adapted to the local climate, and they are good resou...

A balanced diet with many dietary components maintains immune homeostasis directly by interacting with innate and adaptive immune components or indirectly through gut microbiota and their metabolites. Dietary components may inhibit pro-inflammatory mediators and promote anti-inflammatory functions or vice versa. Western diets with imbalanced dietar...

Ivermectin (IVM) is a versatile drug used against many microorganisms. Staphylococcus aureus is one of the most devastating microorganisms. IVM sensitive and resistant S. aureus strains were recently reported. However, the underlying molecular mechanisms of resistance are unknown. Clinical isolates of S. aureus were used for determination of the se...

Background Multi-omics data can provide a stereoscopic view to explore potential causal variations and genes, as well as underlying genetic mechanisms of complex traits. However, for many non-mammalian species, including chickens, these resources are poorly integrated and reused, greatly limiting genetic research and breeding processes of the speci...

Background Mastitis caused by different pathogens including Streptococcus uberis (S. uberis) is responsible for huge economic losses to the dairy industry. In order to investigate the potential genetic and epigenetic regulatory mechanisms of subclinical mastitis due to S. uberis, the DNA methylome (whole genome DNA methylation sequencing) and trans...

The gene numbers and evolutionary rates of birds were assumed to be much lower than those of mammals, which is in sharp contrast to the huge species number and morphological diversity of birds. It is therefore necessary to construct a complete avian genome and analyze its evolution. We constructed a chicken pan-genome from 20 de novo assembled geno...

Salmonella is a common pathogen which can secrete outer membrane vesicles (OMVs). However, the effect of OMVs from Salmonella enterica Serovar Typhimurium (S. Typhimurium) of poultry origin on cells of the chicken innate immune system is not well known. In this study, S. Typhimurium OMVs were first isolated from three different poultry strains of S...

COVID-19 is deemed as the most critical world health calamity of the 21st century, leading to dramatic life loss. There is a pressing need to understand the multi-stage dynamics, including transmission routes of the virus and environmental conditions due to the possibility of multiple waves of COVID-19 in the future. In this paper, a systematic exa...

Early weaning stress (EWS) in piglets is associated with intestinal dysfunction. Here, utilizing a pig EWS model to mimic early-life stress (ELS) in humans, we investigated the mechanism of ELS-induced intestinal diseases through integrated multi-omics analyses of proteome, glycome, and microbiome. Our results demonstrated that EWS resulted in disr...

Johne’s Disease (JD), caused by Mycobacterium avium subsp paratuberculosis (MAP), is an incurable disease of ruminants and other animal species and is characterized by an imbalance of gut immunity. The role of MAP infection on the epigenetic modeling of gut immunity during the progression of JD is still unknown. This study investigated the DNA meth...

The Chantecler chicken, a unique Canadian indigenous breed, is well adapted to extremely cold environments. However, its genetic characteristics have not been well studied. Here, we analyzed the whole genomes of 10 Chantecler chickens and 121 worldwide chickens, which indicated that Chantecler chickens were derived from commercial chickens and exhi...

The gene numbers and evolutionary rates of birds were assumed to be much lower than that of mammals, which in sharp contrast to the huge species number and morphological diversity of birds. It is very necessary to construct a complete avian genome and analyze its evolution.We constructed a chicken pan-genome from 20 de novo genome assemblies with h...

Milk fat and protein content are among key elements of milk quality, and they are attracting more attention in response to consumers′ demand for high-quality dairy products. To investigate the potential regulatory roles of DNA methylation underlying milk component yield, whole genome bisulfite sequencing was employed to profile the global DNA methy...

Bovine mastitis, commonly caused by bacteria, is one of the most devastating diseases for the dairy industry worldwide, with high economic, social, and public health impacts. Among the pathogenic bacteria, Staphylococcus aureus is one of the leading pathogens in most countries. Success rate of antibiotic treatment is low such that effective control...

Milk protein content is attracting considerable attention due to increasing demand for high-quality products. Epigenetic marks including DNA methylation have demonstrated considerable potential to contribute to the achievement of increased gain in bovine milk traits. To investigate potential roles of DNA methylation in regulating milk protein produ...

Phenotypic heterogeneity within a bacterial population may confer new functionality and allow microorganisms to adapt to fluctuating environments. Previous work has suggested that Staphylococcus aureus could form small colony variants to avoid elimination by therapeutic antibiotics and host immunity systems. Here we show that a reversible non-pigme...

Most isolated strains of Staphylococcus sciuri contain mecA1, the evolutionary origin of mecA, but are sensitive to β-lactams (OS-MRSS, oxacillin-susceptible mecA1-positive S. sciuri). In order to improve the efficacy of antibiotic treatment, it is important to clarify whether the resistance of OS-MRSS to β-lactams is an inducible phenotype. In thi...

Metformin is a widely used antidiabetic drug for the treatment of type 2 diabetes and has been recently demonstrated to possess anti-inflammatory properties via AMPK-mediated modulation of M2 macrophage activation. However, the anti-inflammatory mechanisms of metformin on inflammatory macrophages are still not fully elucidated. In this study, we fo...

Mature and stable intestinal microbiota in chickens is essential for health and production. Slow development of microbiota in young chickens prolongs the precarious period before reaching mature configuration. Whether probiotics can play a role in the early maturation of intestinal microbiota is unknown. To address this, day-old chicks were assigne...

Plants pigments, such as chlorophyll and carotenoids, absorb light within specific wavelength ranges, impacting their response to environmental light changes. Although the color-specific response of plants to natural levels of light is well described, extreme high-light stress is still being discussed as a general response, without considering the...

Background Antibiotic tolerance allows bacteria to overcome antibiotic treatment transiently and potentially accelerates the emergence of resistance. However, our understanding of antibiotic tolerance at the genetic level during adaptive evolution of Staphylococcus aureus remains incomplete. We sought to identify the mutated genes and verify the ro...

Lactiplantibacillus plantarum are probiotic bacteria, maintaining the integrity of the gastrointestinal epithelial barrier, and preventing the infection of pathogenic bacteria. Exopolysaccharides (EPSs) are often involved in the probiotic property of L. plantarum . Here, we identified a new EPS-synthetic gene cluster, cpsWc , carrying 13 genes, lai...

MicroRNAs (miRNAs) are small endogenous RNAs that regulate gene expression post-transcriptionally by targeting either the 3′ untranslated or coding regions of genes. They have been reported to play key roles in a wide range of biological processes. The recent remarkable developments of transcriptomics technologies, especially next-generation sequen...

Objective Our goals were to evaluate the antitumour efficacy of Lactobacillus rhamnosus GG (LGG) in combination with immune checkpoint blockade (ICB) immunotherapies on tumour growth and to investigate the underlying mechanisms. Design We used murine models of colorectal cancer and melanoma to evaluate whether oral administration of LGG improves t...

Cranberry and blueberry pomaces are rich in antimicrobial and antioxidant compounds. They have been identified as potential antibiotic-alternatives in animal feed, but their ability of anti-oxidative capacity for maintaining or improving the meat quality in broilers is not well documented. This study was to determine whether cranberry and wild blue...

Genomic selection methodologies and genome-wide association studies use powerful statistical procedures that correlate large amounts of high-density SNP genotypes and phenotypic data. Actual 305-d milk (MY), fat (FY), and protein (PY) yield data on 695 cows and 76,355 genotyping-by-sequencing-generated SNP marker genotypes from Canadian Holstein da...

Several investigations on disease progression of Mycobacterium avium subsp. paratuberculosis (MAP) infection in dairy cows have revealed molecular mechanisms including genes and pathways implicated in MAP pathogenesis. Epigenetic processes including DNA methylation are known to regulate the expression of genes and many biological processes. However...

Johne’s Disease (JD), caused by Mycobacterium avim spp paratuberculosis (MAP), is a chronic and incurable disease of ruminants with devastating consequences to the dairy industry. MAP can alter the expression of genes and biological processes during the progression of JD. While some studies have examined the role of gene expression regulators like...

Extracellular vesicles (EVs) provide a novel intercellular communication mechanism to transfer biologically important molecules to target cells. Although several pieces of evidence have shown that EVs have potential to respond to bacterial infections, our knowledge about the role of circular RNA (circRNA), an important cargo of EV, behind this proc...

Heat stress (HS) in dairy cows can be classified into short-term heat stress (STHS) and long-term heat stress (LTHS) according to the number of consecutive days in HS. The comparative study of these 2 types of HS is limited in terms of their effects on the production and energy metabolism of cows. In this study, 4 lactating Holstein cows (102.5 ± 1...

Probiotics are being developed as alternatives to antibiotic growth promoters. The aim of the study was to investigate the effects of two novel strains of Bacillus pumilus and Bacillus subtilis on production, intestinal microbiota, gut health and immunity of broilers raised under sub-optimal conditions. Day old chicks (Cobb-500, n=2073) were random...

Coronaviruses (CoVs) are enveloped, positive sense, single-stranded RNA viruses. The viruses have adapted to infect a large number of animal species, ranging from bats to camels. At present, seven CoVs infect humans, of which Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is responsible for causing the Coronavirus Disease 2019 (COVID-...

Neuroinflammation, characterized by the activation of microglia and astrocytes, is important in the pathogenesis of many neurological disorders, such as Alzheimer’s disease. Nonsteroidal anti-inflammatory drugs (NSAIDs), a group of chemically heterogenous medications, are used widely in the treatment of inflammation. However, the safety of these dr...

In late December 2019, a disease known as Coronavirus Disease (COVID-19), later known to be caused by a novel coronavirus, SARS-CoV-2, was first reported from Wuhan, China. This highly contagious disease has become a pandemic. The hospitalized patients are being treated mainly for a typical viral pneumonia with supplemental oxygen therapy and mecha...

Staphylococcus aureus is a major opportunistic pathogen, infecting animals, and human beings. The bacterial cell wall plays a crucial role in antimicrobial resistance and its infection to host cells. Peptidoglycans (PGs) are a major component of the cell wall in S. aureus, which is heavily decorated with wall teichoic acids (WTAs) and capsular poly...

An autosomal recessive defect caused by a loss of function mutation in the bovine apolipoprotein B (APOB) gene causes cholesterol deficiency with strong effects on calf survival and development. This study examined the distribution of cholesterol deficiency haplotype (CDH) in the APOB gene in Canadian Holstein cows and their impact on milk producti...

Laccases are multi-copper oxidases with important industrial value. In the study, a novel laccase gene (mco) in a Staphylococcus haemolyticus isolate is identified and heterologously expressed in Escherichia coli. Mco shares less than 40% of amino acid sequence identities with the other characterized laccases, exhibiting the maximal activity at pH...

High blood cholesterol concentration, mainly caused by high dietary cholesterol, is a potential risk factor for human health. Dairy products are important sources of human dietary cholesterol intake. Therefore, monitoring bovine milk cholesterol concentration is important for human health benefit. Genetic selection for improvement of cow milk chole...

Context Replacing starch with sugar could maintain dietary energy density with reduced risks of rumen acidosis and milk fat depression, but the underlying mechanism is not well understood, and the effects of sugar feeding might vary among sugars. Aims Objectives of the present study were to evaluate the effects of replacing corn starch in a diet co...

Background: MicroRNAs (miRNAs) in milk-derived exosomes may reflect pathophysiological changes caused by mastitis. This study profiled miRNAs in exosomes from both normal milk and mastitic milk infected by Staphylococcus aureus (S. aureus). The potential targets for differentially expressed (DE) miRNAs were predicted and the target genes for bta-m...

Eleven mid-lactation Holstein cows were milked twice daily during the first 2 experimental weeks. During wk 3 to 10, the cows were differentially milked: right quarters were milked thrice daily (3×) and left quarters were milked once daily (1×). During wk 11 to 14, all quarters were milked twice daily. After 4 wk of differential milking, the cows r...

Background Mastitis-specialized lineages of Staphylococcus aureus are important pathogens in the dairy industry. The molecular mechanisms underlying host- and organ-specialization in these lineages are still not fully understood. Recent findings suggested that differential expression of genes may have contributed to the evolution of strains with en...

Background: MicroRNAs (miRNA) in milk-derived exosomes may reflect pathophysiological changes caused by mastitis. This study profiled miRNAs in exosomes from both normal milk and mastitic milk infected by Staphylococcus aureus (S. aureus). The potential targets for differentially expressed (DE) miRNAs were predicted and the target genes for bta-miR...

Chickens reared in high altitude regions suffer from a high mortality, possibly due to poor immune responses induced by hypoxia. This experiment was conducted to evaluate whether increasing the oxygen level or administration of a probiotic could improve mortality and immune response of chickens at high altitude (2,986 m above the sea level). One-d-...

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translate...

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translate...

MicroRNAs (miRNA) in milk-derived exosomes may reflect pathophysiological changes caused by mastitis. This study profiled miRNAs in milk exosomes and potential markers for quality control of milk infected by Staphylococcus aureus (S. aureus). Total RNA from milk exosomes was collected from healthy cows (n=3) and S. aureus infected cows (n=6). Two h...