RESUMO
Liver abscesses in feedlot cattle are detrimental to animal performance and economic return. Tylosin, a macrolide antibiotic, is used to reduce prevalence of liver abscesses, though there is variable efficacy among different groups of cattle. There is an increased importance in better understanding the etiology and pathogenesis of this condition because of growing concern over antibiotic resistance and increased scrutiny regarding use of antibiotics in food animal production. The objective of this study was to compare the microbiomes and antimicrobial resistance genes (resistomes) of feces of feedlot cattle administered or not administered tylosin and in their pen soil in 3 geographical regions with differing liver abscess prevalences. Cattle (total of 2,256) from 3 geographical regions were selected for inclusion based on dietary supplementation with tylosin (yes/no). Feces and pen soil samples were collected before harvest, and liver abscesses were identified at harvest. Shotgun and 16S rRNA amplicon sequencing were used to evaluate the soil and feces. Microbiome and resistome composition of feces (as compared by UniFrac distances and Euclidian distances, respectively) did not differ (P > 0.05) among tylosin or no tylosin-administered cattle. However, feedlot location was associated with differences (P ≤ 0.05) of resistomes and microbiomes. Using LASSO, a statistical model identified both fecal and soil microbial communities as predictive of liver abscess prevalence in pens. This model explained 75% of the variation in liver abscess prevalence, though a larger sample size would be needed to increase robustness of the model. These data suggest that tylosin exposure does not have a large impact on cattle resistomes or microbiomes, but instead, location of cattle production may be a stronger driver of both the resistome and microbiome composition of feces.
Assuntos
Antibacterianos/administração & dosagem , Doenças dos Bovinos/prevenção & controle , Suplementos Nutricionais/análise , Abscesso Hepático/veterinária , Microbiota/efeitos dos fármacos , Tilosina/administração & dosagem , Ração Animal/análise , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/microbiologia , Farmacorresistência Bacteriana , Fezes/microbiologia , Feminino , Geografia , Abscesso Hepático/epidemiologia , Abscesso Hepático/microbiologia , Abscesso Hepático/prevenção & controle , Masculino , Metagenômica , Microbiota/genética , Modelos Estatísticos , Prevalência , Microbiologia do SoloRESUMO
The gastrointestinal microbiota (GIM) plays an essential role in maintaining intestinal homeostasis with disruptions having profound effects on the wellbeing of the host animal. Parasitic infection is a long-standing issue for the equine industry, and the use of anthelmintic drugs for parasite control has long been standard practice. The impact of anthelmintic treatment on the GIM in healthy horses is not well known. This study evaluated the hypothesis that anthelmintic administration will alter the equine fecal microbiota in horses without an observed helminth infection. Ten horses were treated with a single dose of QUEST PLUS (active ingredients: Moxidectin and Praziquantel) (Zoetis), and fecal samples were collected before and after treatment. Amplicon sequencing data were quality filtered, processed, and analyzed using QIIME2. Anthelmintic treatment corresponded with a small but significant decrease in alpha diversity (P-value < .05). Analysis of taxonomic abundances before and after treatment with DESeq2 identified 21 features that were significantly different after treatment (Padj-value < .05). Differences in beta diversity associated with treatment were not significant and potentially suggest factors unique to the individual may play an essential role in the specific responses observed. Overall, the present study does not indicate a broad, large-scale impact on the GIM after anthelmintic treatment. The results do, however, suggest the potential of individualized responses that are based instead on host factors. Identification of these factors and investigation of their impact on the host/microbiota relationship will contribute significantly to our understanding of the role of the microbiome in horse health.
Assuntos
Anti-Helmínticos/uso terapêutico , Microbioma Gastrointestinal , Doenças dos Cavalos/tratamento farmacológico , Microbiota , Animais , Fezes , CavalosRESUMO
The causes of Late Pleistocene megafaunal extinctions (60,000 to 11,650 years ago, hereafter 60 to 11.65 ka) remain contentious, with major phases coinciding with both human arrival and climate change around the world. The Americas provide a unique opportunity to disentangle these factors as human colonization took place over a narrow time frame (~15 to 14.6 ka) but during contrasting temperature trends across each continent. Unfortunately, limited data sets in South America have so far precluded detailed comparison. We analyze genetic and radiocarbon data from 89 and 71 Patagonian megafaunal bones, respectively, more than doubling the high-quality Pleistocene megafaunal radiocarbon data sets from the region. We identify a narrow megafaunal extinction phase 12,280 ± 110 years ago, some 1 to 3 thousand years after initial human presence in the area. Although humans arrived immediately prior to a cold phase, the Antarctic Cold Reversal stadial, megafaunal extinctions did not occur until the stadial finished and the subsequent warming phase commenced some 1 to 3 thousand years later. The increased resolution provided by the Patagonian material reveals that the sequence of climate and extinction events in North and South America were temporally inverted, but in both cases, megafaunal extinctions did not occur until human presence and climate warming coincided. Overall, metapopulation processes involving subpopulation connectivity on a continental scale appear to have been critical for megafaunal species survival of both climate change and human impacts.