Assessment of apparent effectiveness of chemical egg disinfectants for improved artificial hatching in Oreochromis karongae (Pisces: Cichlidae)
Bibliographic record
Abstract
Oreochromis karongae is one of the three key Tilapia species locally known as 'Chambo' which is endemic to Lake Malawi.The species is favored by consumers and due to high demand its catches have significantly declined over time.Aquaculture holds the potential to supplement catches as well as produce seed for restocking purposes.However, seed production of O.karongae in artificial hatcheries has registered little success due to high egg and fry mortalities.Therefore, a study was conducted to compare the apparent effectiveness of three chemical egg disinfectants in an attempt to improve hatching success and reduce fry mortality in O. karongae in an artificial re-circulating incubation system at the National Aquaculture Center, Domasi, Malawi.Batches of 200 stage II eggs were immersed for 5 minutes in 50ml solutions of (1) 50mg/l Potassium Permanganate, (2) 500mg/l Formalin, (3) 1000mg/l Sodium Chloride, (4) 5000mg/l Sodium Chloride, while treatment (5) was a control without any chemical treatment.Each treatment was replicated three times in 1.2 L plastic incubation jars with continuous water flow rate of 0.17 l/s operated at 10% daily water replacement.There was significantly low total mortality and high hatchability in treatments (1), ( 2) and ( 3) than ( 4) and (5) (p<0.05).The results provided evidence that pre-incubation egg treatment using chemicals has potential to significantly reduce mortalities and increase fry production in an artificial re-circulating incubation system.It is recommended, based on the findings that lower concentrations of sodium chloride, being a safer and less toxic chemical can be used for disinfecting O.karongae eggs.Future studies should focus on undertaking a toxicity test with various levels of the chemical disinfectants to identify optimum doses.This should be coupled with microbiological assays to validate the apparent effectiveness found in this study and identify the key microbial species that are responsible for mortalities during incubation of O.karongae eggs in a re-circulating system.
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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".