The Role of an Early Salmonella Typhimurium Infection as a Predisposing Factor for Necrotic Enteritis in a Laboratory Challenge Model
Bibliographic record
Abstract
Necrotic enteritis (NE) caused by Clostridium perfringens (CP) in poultry is an important bacterial disease in terms of economic implications. The disease is multifactorial and is invariably associated with predisposing factors. In the present experiments, we investigated the potential predisposing role of neonatal Salmonella Typhimurium (ST) infection for NE-associated mortality in a laboratory challenge model. In two experiments, day-of-hatch chicks were randomly assigned to four groups: Group 1, nonchallenged control; Group 2, chickens received Eimeria maxima (EM) and CP; Group 3, chickens received EM and CP and were also challenged with ST at day 1 of age; Group 4, chickens received EM and CP and were also challenged with ST at day 17 of age. Challenged groups received an oral dose of EM at 18 days of age and CP (10(8) colony-forming units/chick) at 22-23 days of age. When compared to EM and CP, chicks challenged with ST (day 1) had increased NE-associated mortality and CP-associated lesion scores (P < 0.05) in both experiments. Furthermore, body weight and body weight gain were lower (P < 0.05) in chicks infected with ST (day 1) in the first experiment, even though no differences (P > 0.05) were observed in weight gain in the second experiment. Chicks challenged with ST (day 17) were similar to the EM and CP group in all of the above-mentioned parameters, indicating that a paratyphoid infection in younger chicks remarkably alters the susceptibility to secondary bacterial infections. Based on this work, the authors suggest that an ST infection early in the age of a chick may be important for altering susceptibility to NE, an observation that may be useful from the perspective of experimental reproduction of this disease and, perhaps, as an economically important reason to address the problem of paratyphoid Salmonella infections in young chicks.
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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) | 0.001 | 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 | 0.001 | 0.001 |
| 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".