169 Effects of Intranasal Prebiotics, Probiotics and Synbiotics on the Nasopharyngeal Microbiota of Feedlot Cattle
Bibliographic record
Abstract
Abstract The emergence of antibiotic-resistant pathogens associated with bovine respiratory disease (BRD) presents a significant challenge to the beef industry, as antibiotic administration is commonly used to prevent and control BRD in feedlot cattle. Alternatives to antibiotics are therefore needed as part of new management strategies to reduce antibiotic use and BRD. We recently developed probiotics comprised of six Lactobacillus strains that inhibited the BRD pathogen Mannheimia haemolytica, and conferred longitudinal modulation of the nasopharyngeal microbiota in calves when a single dose was administered intranasally. In the present study, we evaluated the effects of a prebiotic (lactulose) alone and in combination with probiotic bacteria on the nasopharyngeal microbiota of feedlot calves. The probiotic bacteria consisted of 6 strains of Lactobacillus originated from the nasopharyngeal microbiota of healthy feedlot cattle. The calves were assigned to one of five treatments (n = 8 calves per treatment) and house individually: 1) Syringe-Probiotic group received intra-nasal probiotic cocktail via syringe that was attached to a 25-cm long catheter; 2) MAD-Probiotic group received an intra-nasal probiotic cocktail with a mucosal atomization device; 3) MAD-Synbiotic group received an intra-nasal probiotic cocktail containing prebiotic lactulose (0.5%, suspended in PBS) with a mucosal atomization device; 4) MAD-Prebiotic group received intra-nasal prebiotic lactulose (0.5%, suspended in PBS) with a mucosal atomization device; and 5) MAD-PBS (Control) group received only PBS with a mucosal atomization device. Utilization of a syringe versus mucosal atomization device was tested to determine if mode of probiotic bacteria delivery had an impact on the respiratory microbiota. Deep nasopharyngeal swab samples were collected on day 0 (24 h prior to treatment administration), 2 (24h post intranasal treatment), 3, 6, 9 and 14 days. Genomic DNA was extracted from the swabs and processed for nasopharyngeal microbiota characterization by sequencing 16S rRNA gene amplicon sequencing. When administered to calves intranasally, lactulose had no effect on the diversity or community structure of bacteria (PERMANOVA, P > 0.05) and had limited prolonged effect on specific genera. In addition, when administered as a synbiotic with a multi-strain cocktail of Lactobacillus probiotic bacteria, colonization was not enhanced. However, probiotic bacteria did affect the bacterial structure of NP bacteria (P < 0.05) and increased microbial network interactions. The strongest effect was observed when probiotic bacteria were administered alone, using an atomization device. Overall, this study showed that the bovine respiratory microbiota can be altered by administration of probiotics and may therefore provide new opportunities to enhance microbiome-mediated respiratory resistance against BRD pathogens. While colonization and growth of probiotic bacteria in the respiratory tract are unlikely to be modified by prebiotics delivered in PBS solution, the delivery method and time of application are important factors that need to be evaluated to have optimal efficacy of biologicals.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".