Cross-sectional studyindependent cross-checkabstract checked★ key study I-FSH-112 in-depth review
Chicken manure in Egyptian fish ponds: no benefit, more resistance genes
Poultry manure fertilization of Egyptian aquaculture ponds brings more cons than pros
Overview
Nyberg O et al.. Aquaculture 2024 · DOI 10.1016/j.aquaculture.2024.741040
In 501 Egyptian tilapia farms, chicken manure did not raise yields or profit, and ponds using it had more antibiotic-resistance genes in the sediment.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Weigh pros and cons of chicken manure use.
- How was the study done?
Farm data and sediment genetics.
- How many people, animals or samples were studied?
501 farms, 28 ponds.
- What was actually found?
No yield gain; more tetracycline resistance genes.
- How large was the observed effect?
Not in abstract.
- What do the results mean in everyday life?
The practice is real and should stop, mainly for resistance and pollution reasons.
- What are the study's limitations?
Fish meat not tested.
- What does it say about Elawady's specific claim?
Supports the premise, not the conclusion that the fish is harmful to eat.
- Do the results apply to Germany and Europe?
Low.
- What can explicitly not be concluded from this study?
Health effects in consumers.
Scientific in-depth review
1. Full reference
- Authors
- Nyberg O et al.
- Journal
- Aquaculture
- Year
- 2024
- Identifier
- DOI 10.1016/j.aquaculture.2024.741040
- Verification
- verified – No PMID; Crossref record fetched 2026-10-26 (no update-to or relation); abstract read via Europe PMC (AGR IND609024471); OpenAlex is_retracted false; publisher full text not accessible (HTTP 403)
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
Does chicken-manure fertilisation benefit Egyptian tilapia farms, and does it increase antibiotic resistance genes?
3. Study design and population
- Study design
- Cross-sectional study – Farm production survey plus sediment qPCR
- Population
Egyptian tilapia farms (earthen ponds around the Northern Delta Lakes)
- Country
Egypt
- Period
not stated in abstract
- Sample size
501 farms; sediment from 28 ponds
4. Methods and endpoints
- Exposure / intervention
Chicken-manure fertilisation
- Comparator
Farms not using chicken manure
- Endpoints
Yield, profitability, nutrient load, tetracycline resistance genes
- Statistical methods
Comparison of production data; qPCR abundance
5. Actual results
- Results
Chicken-manure fertilisation is 'a common practice among farms'. 'The analysis showed no significant benefits to fish yields or profitability in farms where CM was applied, but a risk of significantly increased nutrient loads.' 'We detected increased abundances of tetA and tetW resistance genes in fish pond sediment where CM was applied.'
- Absolute risks
not reported
- Authors' conclusion
Egyptian tilapia farmers should refrain from using chicken manure.
6. Strengths
- Large farm sample
- Egypt-specific
7. Weaknesses
- Abstract only
- Fish flesh contamination and consumer health not measured
- Observational
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Abstract only.
9. Assessment of the statistical interpretation
10. Relevance to the specific claim
C-FSH-12: confirms that poultry manure is commonly used in Egyptian tilapia ponds and is undesirable (resistance genes, nutrient load), without showing harm to people who eat the fish.
11. Independent contrary findings
12. Transferability to Germany and Europe
Low (EU practice differs).
13. Overall methodological judgement
Strongest support for the factual premise of C-FSH-12.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
15. Linked fact checks
- Farmed fish (e.g. tilapia, mullet) are forbidden because their food is not clean: they are fed poultry manure and poultry offal, and the waste of fish farms is in turn fed to cattle. – Studies supporting the claim
- Current agricultural practices - feeding animals unnatural feed and using hormones - produce contaminated food (archive quote attributed to the episode 'The New Food Pyramid', January 2026). – Studies supporting the claim