10 Development of an Essential Oil-Based Intranasal Spray Against Bovine Respiratory Pathogens: <i>in vitro</i> Selection Based on Antimicrobial, Antiviral, Immunomodulatory, and Antibiofilm Activities
Bibliographic record
Abstract
Abstract The objective of this study was to screen and select candidate essential oils (EOs) for the development of an intranasal EO spray against bacterial and viral pathogens associated with bovine respiratory disease (BRD) as an alternative to antibiotics. The effects of previously selected EOs (N = 6; ajowan, cinnamon leaf, citronella, grapefruit, fennel, and thyme) on bovine nasopharyngeal microbiota culture was evaluated using 16S rRNA gene sequencing. The microbiota culture was prepared by growing nasopharyngeal swabs obtained from finishing beef heifers in brain heart infusion broth with and without the presence of EOs (0.025%, vol/vol). The sequencing was performed on genomic DNA extracted from the microbiota culture harvested after 24 h incubation. These EOs were then evaluated for their immunomodulation effect on bovine turbinate (BT) cells by analyzing the concentrations of 15 cytokines and chemokines in cell culture after 24 h incubation. The EOs were further characterized by assessing their antibiofilm activity against E. coli UMN026 using a crystal violet assay. Finally, 15 EOs were screened for their antiviral activity against the bovine viral diarrhea virus 1 (BVDV1) using BT cells and a fluorescence-based method. Ajowan, fennel, and thyme resulted in a moderate reduction of overall nasopharyngeal microbiota growth, and significant alterations of both α- and β-diversity, and relative abundance of predominant bacterial families (e.g., boosting Enterobacteriaceae while suppressing Moraxellaceae) compared with control (P < 0.05). Only IL-6 and IL-8 cytokine concentrations were affected by EOs (P < 0.05). Ajowan, thyme, fennel, and cinnamon leaf exhibited antibiofilm activity at the concentration of 0.05%. Reduction of BVDV1 viral replication on BT cells was observed with thyme (strong), ajowan, and citronella (moderate; 0.0125%). Accordingly, ajowan, thyme, fennel, cinnamon leaf, and citronella EOs were selected for development as an intranasal EO spray to prevent and control BRD pathogens in feedlot cattle.
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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) | 0.000 | 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".