Examination of the fecal microbiota in dairy cows infected with bovine leukemia virus

Microbiota and Metabolite Profiles in the Feces of Juvenile Sika Deer (Cervus nippon) from Birth to Weaning

The gut microbiota establishment in young ruminants has a profound impact on their adult production performance. However, the critical phase for the succession of the gut microbial composition and metabolic profiles of juvenile sika deer still needs to be further investigated. Here, we analyzed the fecal microbiota and metabolites of juvenile sika deer during the birth (D1), transition (D42), and rumination (D70) periods based on 16S rRNA sequencing and gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS). The results showed that the fecal bacteria and metabolites composition were significantly different in D1 compared to D42 and D70, and the number of OTUs and the Shannon index were significantly higher in D70 than in D1 (p < 0.05). The relative abundances of Lactobacillus, Lactococcus, and Lachnoclostridium showed a significant increase in D1 compared to D42 and D70, whereas the relative abundances of Ruminococcaceae UCG-005, Ruminococcaceae UCG-010, Ruminococcaceae UCG-014, Christensenellaceae R-7, and Eubacterium coprostanoligenes group were significantly decreased in D1 compared to D42 and D70 (p < 0.05). The amounts of serine, phenylalanine, aspartic acid, ornithine, citrulline, creatine, isoleucine, galactose, and ribose in the feces were significantly higher in D1 compared to D42 and D70. In contrast, the concentrations of cortexolone, resveratrol, piceatannol, fumaric acid, alpha-ketoglutarate, glycerol, uracil-5-carboxylic acid, and maleic acid were significantly decreased in D1. The enrichment analysis showed that amino acid metabolism and carbohydrate metabolism were significantly changed in D1 compared to D42 and D70. The glycine, serine and threonine metabolism; alanine, aspartate and glutamate metabolism; arginine biosynthesis; glyoxylate and dicarboxylate metabolism; citrate cycle; and pyruvate metabolism were significantly enriched across the three periods (p < 0.05). In conclusion, our results suggested that the birth-transition period is a critical phase for the gut bacterial community and metabolic function shift in juvenile sika deer.

The Global Epidemiology of Bovine Leukemia Virus: Current Trends and Future Implications

Bovine leukemia virus (BLV) is a retrovirus that causes enzootic bovine leucosis (EBL), which is the most significant neoplastic disease in cattle. Although EBL has been successfully eradicated in most European countries, infections continue to rise in Argentina, Brazil, Canada, Japan, and the United States. BLV imposes a substantial economic burden on the cattle industry, particularly in dairy farming, as it leads to a decline in animal production performance and increases the risk of disease. Moreover, trade restrictions on diseased animals and products between countries and regions further exacerbate the problem. Recent studies have also identified fragments of BLV nucleic acid in human breast cancer tissues, raising concerns for public health. Due to the absence of an effective vaccine, controlling the disease is challenging. Therefore, it is crucial to accurately detect and diagnose BLV at an early stage to control its spread and minimize economic losses. This review provides a comprehensive examination of BLV, encompassing its genomic structure, epidemiology, modes of transmission, clinical symptoms, detection methods, hazards, and control strategies. The aim is to provide strategic information for future BLV research.

Pilot evaluation of a single oral fecal microbiota transplantation for canine atopic dermatitis

The gut microbiota has been suggested to be involved in the pathogenesis of canine atopic dermatitis (cAD). However, the gut microbiota has not been well characterized in dogs with atopic dermatitis (AD). In addition, the efficacy of fecal microbiota transplantation (FMT) in dogs with AD remains unclear. This research, therefore, aimed to characterize the gut microbiota of dogs with AD and conduct pilot evaluation of the efficacy of a single oral FMT on clinical signs and the gut microbiota of dogs with AD. For these purposes, we used 12 dogs with AD and 20 healthy dogs. The 16S rRNA analysis of the fecal microbiota revealed significant differences between 12 dogs with AD and 20 healthy dogs. Next, a single oral FMT was performed in 12 dogs with AD as a single-arm, open-label clinical trial for 56 days. A single oral FMT significantly decreased Canine Atopic Dermatitis Extent and Severity Index (CADESI)-04 scores from day 0 (median score, 16.5) to day 56 (8) and Pruritus Visual Analog Scale (PVAS) scores from days 0 (median score, 3) to day 56 (1). Furthermore, a single oral FMT changed the composition of the fecal microbiota of dogs with AD at the phylum and genus levels. The number of common amplicon sequence variants in the fecal microbiota between donor dogs and dogs with AD was positively correlated with CADESI-04 and PVAS reduction ratios 56 days after FMT. Our findings suggest that the gut microbiota plays a pivotal role in the pathogenesis of cAD, and that oral FMT could be a new therapeutic approach targeting the gut microbiota in cAD.

Maternal rumen and milk microbiota shape the establishment of early-life rumen microbiota in grazing yak calves

Early-life gut microbial colonization and development exert a profound impact on the health and metabolism of the host throughout the life span. The transmission of microbes from the mother to the offspring affects the succession and establishment of the early-life rumen microbiome in newborns, but the contributions of different maternal sites to the rumen microbial establishment remain unclear. In the present study, samples from different dam sites (namely, oral, rumen fluid, milk, and teat skin) and rumen fluid of yak calves were collected at 6 time points between d 7 and 180 postpartum to determine the contributions of the different maternal sites to the establishment of the bacterial and archaeal communities in the rumen during early life. Our analysis demonstrated that the dam's microbial communities clustered according to the sites, and the calves' rumen microbiota resembled that of the dam consistently regardless of fluctuations at d 7 and 14. The dam's rumen microbiota was the major source of the calves' rumen bacteria (7.9%) and archaea (49.7%) compared with the other sites, whereas the potential sources of the calf rumen microbiota from other sites varied according to the age. The contribution of dam's rumen bacteria increased with age from 0.36% at d 7 to 14.8% at d 180, whereas the contribution of the milk microbiota showed the opposite trend, with its contribution reduced from 2.7% at d 7 to 0.2% at d 180. Maternal oral archaea were the main sources of the calves' rumen archaea at d 14 (50.4%), but maternal rumen archaea became the main source gradually and reached 66.2% at d 180. These findings demonstrated the potential microbial transfer from the dam to the offspring that could influence the rumen microbiota colonization and establishment in yak calves raised under grazing regimens, providing the basis for future microbiota manipulation strategies during their early life.

Comparison of Fecal Microbiota Communities between Primiparous and Multiparous Cows during Non-Pregnancy and Pregnancy

Imbalances in the gut microbiota composition may lead to several reproductive disorders and diseases during pregnancy. This study investigates the fecal microbiome composition between primiparous and multiparous cows during non-pregnancy and pregnancy to analyze the host-microbial balance at different stages. The fecal samples obtained from six cows before their first pregnancy (BG), six cows during their first pregnancy (FT), six open cows with more than three lactations (DCNP), and six pregnant cows with more than three lactations (DCP) were subjected to 16S rRNA sequencing, and a differential analysis of the fecal microbiota composition was performed. The three most abundant phyla in fecal microbiota were Firmicutes (48.68%), Bacteroidetes (34.45%), and Euryarchaeota (15.42%). There are 11 genera with more than 1.0% abundance at the genus level. Both alpha diversity and beta diversity showed significant differences among the four groups (p < 0.05). Further, primiparous women were associated with a profound alteration of the fecal microbiota. The most representative taxa included Rikenellaceae_RC9_gut_group, Prevotellaceae_UCG_003, Christensenellaceae_R_7_group, Ruminococcaceae UCG-005, Ruminococcaceae UCG-013, Ruminococcaceae UCG-014, Methanobrevibacter, and [Eubacterium] coprostanoligenes group, which were associated with energy metabolism and inflammation. The findings indicate that host-microbial interactions promote adaptation to pregnancy and will benefit the development of probiotics or fecal transplantation for treating dysbiosis and preventing disease development during pregnancy.

Exploring variation in the fecal microbial communities of Kasaragod Dwarf and Holstein crossbred cattle

The gut microbiota and its impact on health and nutrition in animals, including cattle has been of intense interest in recent times. Cattle, in particular indigenous varieties like Kasaragod Dwarf cow, have not received the due consideration given to other non-native cattle breeds, and the composition of their fecal microbiome is yet to be established. This study applied 16S rRNA high-throughput sequencing of fecal samples and compared the Kasaragod Dwarf with the highly prevalent Holstein crossbred cattle. Variation in their microbial composition was confirmed by marker gene-based taxonomic analysis. Principle Coordinate Analysis (PCoA) showed the distinct microbial architecture of the two cattle types. While the two cattle types possess unique signature taxa, in Kasaragod Dwarf cattle, many of the identified genera, including Anaerovibrio, Succinivibrio, Roseburia, Coprococcus, Paludibacter, Sutterella, Coprobacillus, and Ruminobacter, have previously been shown to be present in higher abundance in animals with higher feed efficiency. This is the first report of Kasaragod Dwarf cattle fecal microbiome profiling. Our findings highlight the predominance of specific taxa potentially associated with different fermentation products and feed efficiency phenotypes in Kasaragod Dwarf cattle compared to Holstein crossbred cattle.

Rumen-protected glucose supplementation alters fecal microbiota and its metabolic profiles in early lactation dairy cows

INTRODUCTION

Negative energy balance (NEB) is the pathological basis of metabolic disorders in early lactation dairy cows. Rumen-protected glucose (RPG) is a feed additive to relieve NEB of cows in early lactation. The aims of the current study were to evaluate the impact of different doses of RPG supply on fecal microbiota and metabolome in early lactation dairy cows, and their correlation with each other.

METHODS

A total of 24 multiparous Holstein dairy cows in early lactation were randomly assigned to one of four treatments for the first 35 days of the early lactation period, as follows: control group, a basal diet without RPG (CON); low RPG, a basal diet plus 200 g/d RPG (LRPG); medium RPG, a basal diet plus 350 g/d RPG (MRPG); or HRPG, high RPG, a basal diet plus 500 g/d RPG (HRPG). After 35 days, fecal samples were obtained from cows in all groups individually and using 16S rRNA gene sequencing to evaluate their microbiotas, while their metabolites were evaluated through metabolomics.

RESULTS

As expected, Firmicutes and Bacteroidetes were the core bacteria phyla. After RPG supplementation, there were an increase in Firmicutes and a decrease in Bacteroidetes. MRPG increased the relative abundance of cellulolytic bacteria, including Ruminococcaceae_UCG-005, Lachnospiraceae_UCG-008, Lachnospiraceae_FCS020_group, and Ruminiclostridium_9, while it decreased the relative abundance of Alistipes, Prevotellaceae_UCG-003, and Dorea. RPG supplementation could regulate the carbohydrate metabolism and amino acid metabolism pathway significantly and relieve lipolysis in dairy cows. Correlation analysis of fecal microbiome and metabolome showed that some major differential bacteria were the crucial contributors to differential metabolites.

CONCLUSION

In conclusion, RPG supplementation can affect the fecal microbial components and microbial metabolism, and 350 g RPG might be the ideal dose as a daily supplement.

Characterization of the oral and fecal microbiota associated with atopic dermatitis in dogs selected from a purebred Shiba Inu colony

Atopic dermatitis (AD) is a chronic and relapsing multifactorial inflammatory skin disease that also affects dogs. The oral and gut microbiota are associated with many disorders, including allergy. Few studies have addressed the oral and gut microbiota in dogs, although the skin microbiota has been studied relatively well in these animals. Here, we studied the AD-associated oral and gut microbiota in 16 healthy and nine AD dogs from a purebred Shiba Inu colony. We found that the diversity of the oral microbiota was significantly different among the dogs, whereas no significant difference was observed in the gut microbiota. Moreover, a differential abundance analysis detected the Family_XIII_AD3011_group (Anaerovoracaceae) in the gut microbiota of AD dogs; however, no bacterial taxa were detected in the oral microbiota. Third, the comparison of the microbial co-occurrence patterns between AD and healthy dogs identified differential networks in which the bacteria in the oral microbiota that were most strongly associated with AD were related with human periodontitis, whereas those in the gut microbiota were related with dysbiosis and gut inflammation. These results suggest that AD can alter the oral and gut microbiota in dogs.

Dietary supplementation with calcium propionate could beneficially alter rectal microbial composition of early lactation dairy cows

Dietary supplementation with calcium propionate can effectively alleviate negative energy balance and hypocalcemia of dairy cows in early lactation. The objective of this study was to investigate the effects of calcium propionate feeding levels on the immune function, liver function, and fecal microbial composition of dairy cows in early lactation. Thirty-two multiparous Holstein cows were randomly assigned to four treatments after calving. Treatments were a basal diet plus 0, 200, 350, and 500 g calcium propionate per cow per day throughout a 5-week trial period. Cows were milked three times a day, and blood was sampled to measure immune function and liver function on d 7, 21, and 35. The rectal contents were sampled and collected on d 35 to analyze the microbial composition using 16S rRNA gene sequencing. The results indicated that increasing amounts of calcium propionate did not affected the serum concentrations of total protein, IgG, IgM, and calcium, but the concentrations of albumin and IgA changed quadratically. With the increase of calcium propionate, the activity of serum alanine transaminase and aspartate aminotransferase increased linearly, in contrast, the activity of alkaline phosphatase decreased linearly. Moreover, dietary supplementation with increasing levels of calcium propionate tended to quadratically decrease the relative abundance of Firmicutes while quadratically increased the abundance of Bacteroidetes, and consequently linearly decreased the Firmicutes/Bacteroidetes ratio in the rectal microbiota. Additionally, the supplementation of calcium propionate increased the relative abundances of Ruminococcaceae_UCG-005 and Prevotellaceae_UCG-004 linearly, and Ruminococcaceae_UCG-014 quadratically, but decreased the relative abundances of Lachnospiraceae_NK3A20_group and Family_XIII_AD3011_group quadratically. Compared with the CON group, the calcium propionate supplementation significantly decreased the relative abundance of Acetitomaculum but increased the abundances of Rikenellaceae_RC9_gut_group and Alistipes. In summary, these results suggested that the supplementation of calcium propionate to dairy cows in early lactation could beneficially alter the rectal microbiota.

Gut Microbiota of Obese Children Influences Inflammatory Mucosal Immune Pathways in the Respiratory Tract to Influenza Virus Infection: Optimization of an Ideal Duration of Microbial Colonization in a Gnotobiotic Pig Model

The impact of obesity on the human microbiota, immune maturation, and influenza virus infection has not been yet established in natural host animal models of influenza. In this study, gnotobiotic (Gn) pigs were colonized with human fecal microbiota (HFM) of obese (oHFM) or healthy lean (hHFM) children and infected at different periods (2-, 3-, and 5-weeks post-transplantation) using a zoonotic influenza virus strain. The infected oHFM pigs were characterized by lower levels of Firmicutes (Lactococcus, Lactobacillus, Turicibacter, and Streptococcus) and Actinobacteria (Bifidobacterium), which was associated with higher levels of Proteobacteria (Klebsiella), Bacteroidetes, and Verrucomicrobia (Akkermansia) compared with the infected hHFM group (P < 0.01). Furthermore, these genera significantly correlated with the expression of immune effectors, immune regulators, and inflammatory mediators, and displayed opposite trends between oHFM and hHFM groups (P < 0.01). The lymphoid and myeloid immune cell frequencies were differently modulated by the oHFM and hHFM colonization, especially apparent in the 5-weeks HFM colonized piglets. In addition, oHFM group had higher pro-inflammatory cytokines (IL-6, IL-12, TNF-α, and IFNγ) gene expression in the respiratory tract compared with the hHFM colonized pigs was detected. In conclusion, pigs colonized for longer duration, established oHFM increased the immune maturation favoring the activation of inflammatory mediators, however, the influenza virus load remained comparable with the hHFM group. Further, a longer duration of microbial colonization (5 weeks) may be required to reveal the impact of microbiome on the host immune maturation and susceptibility to influenza virus infection in the humanized Gn pig model. IMPORTANCE The diversity of gut microbiome of obese people differs markedly from that of lean healthy individuals which, in turn, influences the severity of inflammatory diseases because of differential maturation of immune system. The mouse model provides crucial insights into the mechanism(s) regulating the immune systems mediated by the gut microbiota but its applicability to humans is questionable because immune cells in mice are poorly activated in microbiota humanized mice. Several important strains of Bifidobacterium, Lactobacillus, and Clostridium fails to colonize the murine gut. Thus, understanding the role of certain important commensal gut bacterial species influences upon health and disease, a suitable large animal model like pig that supports the growth and colonization of most of the important human gut bacteria and possess comparable immunology and physiology to humans is beneficial to improve health.

Screening of bacterial DNA in bile sampled from healthy dogs and dogs suffering from liver- or gallbladder-associated disease

Although the biliary system is generally aseptic, gallbladder microbiota has been reported in humans and some animals apart from dogs. We screened and analyzed the bacterial deoxyribonucleic acid in canine gallbladders using bile sampled from 7 healthy dogs and 52 dogs with liver- or gallbladder-associated disease. PCR screening detected bacteria in 17.3% of diseased dogs (9/52) and none in healthy dogs. Microbiota analysis of PCR-positive samples showed that the microbial diversity differed between liver- and gallbladder-associated disease groups. Thus, a specific bacterial community appears to occur at a certain frequency in the bile of diseased dogs.

Bovine Leukaemia Virus: Current Epidemiological Circumstance and Future Prospective

Bovine leukaemia virus (BLV) is a deltaretrovirus that is closely related to human T-cell leukaemia virus types 1 and 2 (HTLV-1 and -2). It causes enzootic bovine leukosis (EBL), which is the most important neoplastic disease in cattle. Most BLV-infected cattle are asymptomatic, which potentiates extremely high shedding rates of the virus in many cattle populations. Approximately 30% of them show persistent lymphocytosis that has various clinical outcomes; only a small proportion of animals (less than 5%) exhibit signs of EBL. BLV causes major economic losses in the cattle industry, especially in dairy farms. Direct costs are due to a decrease in animal productivity and in cow longevity; indirect costs are caused by restrictions that are placed on the import of animals and animal products from infected areas. Most European regions have implemented an efficient eradication programme, yet BLV prevalence remains high worldwide. Control of the disease is not feasible because there is no effective vaccine against it. Therefore, detection and early diagnosis of the disease are essential in order to diminish its spreading and the economic losses it causes. This review comprises an overview of bovine leukosis, which highlights the epidemiology of the disease, diagnostic tests that are used and effective control strategies.

Grazing and Supplementation of Dietary Yeast Probiotics Shape the Gut Microbiota and Improve the Immunity of Black Fattening Goats (Capra hircus)

This study aimed to investigate the effects of different feeding modes on the growth performance, gut microbiota, and immunity of Black Fattening Goat (Capra hircus). A total of 30 goats were grouped in three groups by their feeding modes (pasture grazing group, PG; barn feeding group, BF; barn feeding + probiotics, BF + P; n = 10) and the study was performed for 114 days. After a 2-week adaptation period, the first growth performance test was conducted, and the blood and fecal samplings (day 0) were collected on January 17, 2020, while the second and third test and samplings were conducted on days 53 and 100 of feeding. The species-composition of fecal microbiota was analyzed by 16S ribosomal RNA gene-sequencing using PacBio single molecule real time (SMRT) sequencing technology. Both the BF and BF + P groups had the highest (P < 0.05) body’s weight and length, and chest circumference at days 53 and 100, especially at day 100, the body’s weight of both the BF groups were more than 18 kg. The levels of immunoglobulin A (IgA) and immunoglobulin G (IgG) were found to be significantly higher (P < 0.05) in the PG and BF + P groups at day 100. The PG group exhibited the highest number of operational taxonomic unit (OTUs) and alpha diversity. Firmicutes, Bacteroidetes, and Verrucomicrobia were the predominant phyla in all the fecal samples. The relative abundance of Akkermansia muciniphila and Ruminococcus flavefaciens were found to be significantly higher (P < 0.05) in PG group and BF + P group at day 100, respectively, which might partially explain the significantly higher (P < 0.05) levels of IgA and IgG in these two groups. These findings suggested that BF supplemented with 5 g probiotics (Saccharomyces cerevisiae and mannan oligosaccharides) per day has the potential to enhance the growth and immunity of Black Fattening Goats.

Use of Recombinant Endolysin to Improve Accuracy of Group B Streptococcus Tests

Group B Streptococcus (GBS) causes serious neonatal infection via vertical transmission. The prenatal GBS screening test is performed at the late stage of pregnancy to avoid risks of infection. In this test, enrichment culture is performed, followed by GBS identification. Selective medium is used for the enrichment; however, Enterococcus faecalis, which is a potential contaminant in swab samples, can interfere with the growth of GBS. Such bacterial contamination can lead to false-negative results. Endolysin, a bacteriophage-derived enzyme, degrades peptidoglycan in the bacterial cell wall; it is a promising antimicrobial agent for selectively eliminating specific bacterial genera/species. In this study, we used the recombinant endolysin EG-LYS, which is specific to E. faecalis; the endolysin potentially enriched GBS in the selective culture. First, in the false-negative model (coculture of GBS and E. faecalis, which disabled GBS detection in the subsequent GBS identification test), EG-LYS treatment at 0.1 mg/ml improved GBS detection. Next, we used 548 vaginal swabs to test the efficacy of EG-LYS treatment in improving GBS detection. EG-LYS treatment (0.1 mg/ml) increased the GBS-positive ratio to 17.9%, compared to 15.7% in the control (phosphate-buffered saline [PBS] treatment). In addition, there were an increased number of GBS colonies under EG-LYS treatment in some samples. The results were supported by the microbiota analysis of the enriched cultures. In conclusion, EG-LYS treatment of the enrichment culture potentially improves the accuracy of the prenatal GBS screening test. IMPORTANCE Endolysin is a bacteriophage-derived enzyme that degrades the peptidoglycan in the cell wall of host bacteria; it could be used as an antimicrobial agent for selectively eliminating specific bacterial genera/species. Group B Streptococcus (GBS) causes neonatal infection via vertical transmission; prenatal GBS screening test, in which enrichment culture is followed by bacterial identification, is used to detect the presence of GBS in pregnant women. However, the presence of commensal bacteria such as Enterococcus faecalis in clinical specimens can inhibit GBS growth in the selective enrichment culture, resulting in false-negative result. Here, we demonstrated that the application of originally isolated endolysin in the enrichment culture improved the test accuracy by inhibiting unwanted E. faecalis growth and therefore avoiding false-negative results, not only in experimental settings, but also in tests using vaginal swabs.

Prebiotic characteristics of arabinogalactans during in vitro fermentation through multi-omics analysis

BACKGROUND AND OBJECTIVES

Dietary fibers have beneficial effects on human health through the interaction with gut microbiota. Larch wood arabinogalactan (LA-AG) is one kind of complex soluble dietary fibers that may be utilized by human gut microbiota.

METHODS AND RESULTS

In this study, the LA-AG degradation by gut microbiota were characterized by investigating the change of LA-AG, microbiota composition, and the production of short-chain fatty acids (SCFAs), lactic acid, succinic acid, as well as volatile organic metabolites. During the fermentation, pH decreased continuously, along with the organic acids (especially acetic acid and lactic acid) accumulating. LA-AG was degraded by gut microbiota then some beneficial metabolites were produced. In addition, LA-AG inhibited the proliferation of some gut microbiota (Unclassified_Enterobacteriaceae and Citrobacter) and the accumulation of some metabolites (Sulfide and indole) released by gut microbiota.

CONCLUSION

LA-AG was partly fermentable fibers with prebiotic potential for human gut health.

Characterizing the Cattle Gut Microbiome in Farms with a High and Low Prevalence of Shiga Toxin Producing Escherichia coli

Cattle are the main reservoirs of Shiga toxin producing Escherichia coli (STEC), a major foodborne pathogen associated with acute enteric disease and hemolytic-uremic syndrome in humans. A total of 397 beef and dairy cattle from 5 farms were included in this study, of which 660 samples were collected for 16S rRNA gene sequencing. The microbiota of farms with a high-STEC prevalence (HSP) had greater richness compared to those of farms with a low-STEC prevalence (LSP). Longitudinal analyses showed STEC-shedders from LSP farms had higher microbiome diversity; meanwhile, changes in the microbiome composition in HSP farms were independent of the STEC shedding status. Most of the bacterial genera associated with STEC shedding in dairy farms were also correlated with differences in the percentage of forage in diet and risk factors of STEC carriage such as days in milk, number of lactations, and warm temperatures. Identifying factors that alter the gut microbiota and enable STEC colonization in livestock could lead to novel strategies to prevent fecal shedding and the subsequent transmission to humans.

Describing the intestinal microbiota of Holstein Fasciola-positive and -negative cattle from a hyperendemic area of fascioliasis in central Colombia

The ability to identify compositional changes in the intestinal microbiota of parasitized hosts is important for understanding the physiological processes that may affect animal productivity. Within the field of host–parasite interactions, many studies have suggested that helminths can influence the microbial composition of their hosts via their immunomodulatory effects. Bovine fascioliasis is a helminthiasis widely studied by immunologists, but with little information available regarding gut microbial communities. Thus, we aimed to describe the composition of the intestinal microbiota of Holstein Fasciola-positive and -negative cattle using parasitological methods and ELISA (enzyme-linked immunosorbent assay). Bovine fecal samples (n = 65) were obtained from livestock slaughter plants in the Cundi-Boyacense Colombian highlands (a hyperendemic region for bovine fascioliasis) and studied by amplicon-based next-generation 16S-rRNA and 18S-rRNA gene sequencing. From these samples, 35 were Fasciola hepatica-negative and, 30 were F. hepatica-positive in our detection analysis. Our results showed a reduction in the relative abundance of Bacteroidetes and Ascomycota in the Fasciola-positive samples, along with decreased relative abundances of the commensal taxa previously associated with fermentation and digestion processes. However, metabolomic approaches and functional analyzes of the intestinal microbiota are necessary to support these hypothesis. These findings are a small first step in the development of research aimed at understanding how microbial populations in bovines are modulated in liver helminth infections.

Fasciola hepatica, a liver parasite, infects a wide variety of hosts, mostly ruminants. Ruminant infections with this parasite cause economic losses worldwide, mainly in livestock. Given its importance, much research has been carried out on this parasite, a lot of which has focused on its ability to alter the immune responses of its host. However, little is known about the numerous other interactions it has with the host and how they might affect the host’s intestinal microbiota. Here, we observed a reduction in the abundance of microorganisms associated with the fermentation and digestion of vegetable fiber, two important processes in animal health and productivity. Therefore, it is possible that F. hepatica, in addition to the previously documented liver alterations, also generates changes in the intestinal microbiota that may impact its bovine host. These findings are a small first step in the research of microbial populations in cattle infected with liver helminths which open the door to further research aimed at identifying alternative treatments for parasites such as F. hepatica.

Inflammation-Associated Microbiota Composition Across Domestic Animals

Domestic animals represent important resources for understanding shared mechanisms underlying complex natural diseases that arise due to both genetic and environmental factors. Intestinal inflammation, particularly inflammatory bowel disease (IBD), is a significant health challenge in humans and domestic animals. While the etiology of IBD is multifactorial, imbalance of symbiotic gut microbiota has been hypothesized to play a central role in disease pathophysiology. Advances in genomic sequencing and analytical pipelines have enabled researchers to decipher the composition of the intestinal microbiota during health and in the context of naturally occurring diseases. This review compiles microbiome genomic data across domestic species and highlights a common occurrence of gut microbiome dysbiosis during idiopathic intestinal inflammation in multiple species, including dogs, cats, horses, cows, and pigs. Current microbiome data obtained from animals with intestinal inflammation are mostly limited to taxonomical analyses in association with broad clinical phenotype. In general, a pathogen or pathosymbiont were not detected. Rather, functional potential of the altered microbiota has been suggested to be one of the key etiologic factors. Among the domestic species studied, canine analyses are currently the most advanced with incorporation of functional profiling of microbiota. Canine IBD parallels features of the disease in humans, thus canines represent a strong natural model for human IBD. While deeper analyses of metagenomic data, coupled with host molecular analyses are needed, comparative studies across domestic species can reveal shared microbial alterations and regulatory mechanisms that will improve our understanding of intestinal inflammation in both animals and humans.

Sacran, a sulfated polysaccharide, suppresses the absorption of lipids and modulates the intestinal flora in non-alcoholic steatohepatitis model rats

AIMS

The objective of this study was to investigate the effects of administering sacran, a sulfated polysaccharide, on liver biology, gut microbiota, oxidative stress, and inflammation on stroke-prone spontaneously hypertensive (SHRSP5/Dmcr) rats that develop fibrotic steatohepatitis with histological similarities to that of non-alcoholic steatohepatitis (NASH).

MAIN METHODS

Four groups of 8-week-old SHRSP5/Dmcr rats were fed a high fat-cholesterol (HFC) diet for 4 and 8 weeks and administered either sacran (80 mg/kg/day) or a non-treatment, respectively. Liver function was evaluated by biochemical and histopathological analyses. Hepatic inflammatory markers were measured using mRNA expression. Fecal microbial profiles were determined via 16S rRNA sequencing. A triglyceride (TG) absorption test was administered to the 8-week-old Sprague-Dawley (SD) rats.

KEY FINDING

Sacran administration was observed to decrease the extent of oxidative stress and hepatic biochemical parameters in serum and hepatic injury with the levels of transforming growth factor-beta (TGF-β1) and tumor necrosis factor-alpha (TNF-α), being increased compared to those of the non-treatment group. At the genus level, sacran administration caused a significant decrease in the harmful Prevotella genus, and a significant increase in the useful Blautia genus was observed. Sacran administration also decreased the serum TG increase that was induced by administering corn oil to the SD rats.

SIGNIFICANCE

We conclude that sacran administration has the potential to reduce the absorption of lipids into blood and to improve several gut microbiotas, in the gastrointestinal tract, thereby inhibiting the subsequent development of oxidative stress and hepatic markers in the systematic circulation on NASH.

Prevalence of bovine leukemia in 1983-2019 in China: A systematic review and meta-analysis

Bovine leukemia is a chronic, progressive, contagious tumor disease characterized by malignant lymphoid cell hyperplasia and systemic lymphadenopathy, and is caused by bovine leukemia virus (BLV). The disease affects almost all countries and regions where livestock are raised, and may even be a potential zoonotic disease. Monitoring and early prevention of bovine leukemia is very important. Therefore, we conducted this meta-analysis, the first of its type in the country, to estimate the prevalence of bovine leukemia in 1983-2019 in China. We included a total of 35 publications reported in 1983-2019 from the PubMed, ScienceDirect, Chinese Web of Knowledge (CNKI), VIP Chinese, and Wan Fang databases. In those articles, a total of 34,954 cattle had been tested, of which 4701 were positive for BLV infection. The estimated pooled BLV prevalence was 10.0% (4701/34,954). Subgroup analysis showed that there were significant differences for sampling years, detection methods, and age. BLV prevalence was highest in the following subgroups: sampled before 1985 (38.5%, 437/1134), age 3-5 years (22.5%, 231/1044), and detected by PCR (17.9%, 1228/5100). Regarding geographic factors, there were significant differences in the latitude and elevation subgroups. BLV prevalence was lowest in the subgroups of 20-30° latitude (3.3%, 255/5069) 200-1000 m altitude (2.2%, 560/11,990). We also analyzed other subgroups such as region, variety, breeding method, precipitation, humidity, and temperature, however, the differences were not significant. Our research indicated that the BLV was still prevalent in some of areas in China. We recommend strengthening the testing of cattle aged >1 year and using flexible testing methods such as PCR to control the prevalence of bovine leukemia and to prevent persistent infection.

Development of multipurpose recombinant reporter bovine leukemia virus

Bovine leukemia virus (BLV) is a global problem that results in significant economic losses to the livestock industry. We developed three virus strains by inserting the HiBiT reporter tag from NanoLuc luciferase (NLuc) into limited sites within BLV molecular clones. Initial analysis for site selection of the tag insertion revealed a permissible site immediately downstream of the viral envelope gene. Therefore, NLuc activity could be used to measure virus copy numbers in the supernatant and the levels of cell infection. Productivity and growth kinetics of the reporter virus were similar to those of the wild-type strain; therefore, the reporter virus can be used to characterize the replication of chimeric viruses as well as responses to the antiviral drug, amprenavir. Collectively, our results suggest that the BLV reporter virus with a HiBiT tag insertion is a highly versatile system for various purposes such as evaluating virus replication and antiviral drugs.

Effects of surface-deacetylated chitin nanofibers on non-alcoholic steatohepatitis model rats and their gut microbiota

Nonalcoholic steatohepatitis (NASH), a more advanced form of nonalcoholic fatty liver disease (NAFLD), is associated with increased cardiovascular and liver-related mortality. Stroke-prone spontaneously hypertensive rats (SHRSP5/Dmcr) that are fed a high-fat and high-cholesterol diet develop hepatic lesions that are similar to those observed in human NASH pathology. We investigated the hepatic protective and antioxidant effects of surface-deacetylated chitin nanofibers (SDACNFs) that were administered to SHRSP5/Dmcr rats for 8 weeks. The administration of SDACNFs (80 mg/kg/day) resulted in a significant decrease in hepatic injury, oxidative stress, compared with the non-treatment. The SDACNFs also caused a reduction in the population of harmful members of the Morganella and Prevotella genus, and increased the abundance of the Blautia genus, a useful bacterium in gut microbiota. We therefore conclude that SDACNF exerts anti-hepatic and antioxidative effects not only by adsorbing lipid substances but also by reforming the community of intestinal microflora in the intestinal tract.

Microbiota in viral infection and disease in humans and farm animals

The influence of the microbiota on viral infection susceptibility and disease outcome is undisputable although varies among viruses. The purpose of understanding the interactions between microbiota, virus, and host is to identify practical, effective, and safe approaches that target microbiota for the prevention and treatment of viral diseases in humans and animals, as currently there are few effective and reliable antiviral therapies available. The initial step for achieving this goal is to gather clinical evidences, focusing on the viral pathogens-from human and animal studies-that have already been shown to interact with microbiota. The subsequent step is to identify mechanisms, through experimental evidences, to support the development of translational applications that target microbiota. In this chapter, we review evidences of virus infections altering microbiota and of microbiota enhancing or suppressing infectivity, altering host susceptibility to certain viral diseases, and influencing vaccine immunogenicity in humans and farm animals.