Dietary effects of chelated zinc supplementation and lysine levels in ISA Brown laying hens on early and late performance, and egg quality
Bibliographic record
Abstract
It has been hypothesized that zinc (Zn) levels beyond those that are nutritionally required may favor the utilization of dietary lysine, and consequently reduce the level of its inclusion into the diet. Therefore, the possible effects of interaction between chelated Zn and the level of lysine (Lys) on egg production and egg quality of laying hens were evaluated. In total, 720 ISA Brown layer hens aged 24 to 36 wk (early phase) and 48 to 60 wk (late phase) were allotted in a completely randomized factorial design that used 3 Zn and 5 Lys levels (6 replications, 8 birds/replication). All birds aged 37 to 47 wk (between early and late phases) were fed a standard diet and maintained under the same experimental design. The Zn levels used were 137, 309, and 655 mg/kg; and the Lys levels were 0.560, 0.612, 0.677, 0.749, and 0.851%. The optimal levels of Lys digestibility were based on laboratory analyses with regard to the weighted average relationship between 83.5% digestibility and the total Lys from principal ingredients. There was no effect of interaction found between the dietary levels of Zn and Lys for most of the variables studied; however, each had an independent effect on the variables. An increase in Zn from 137 to 655 mg/kg had no significant effect (P > 0.05) on the performance of hens in both phases; however, it showed a significant effect on egg quality (P < 0.01), principally on mineral composition. Increased Zn resulted in decreased shell weight, percentage of ash, yolk ash deposition, and total ash deposition. On the other hand, an increase in Lys from 0.560 to 0.851% significantly affected (P < 0.002) several performance parameters and the chemical composition of the eggs, including feed intake, feed conversion efficiency, BW gain, egg weight, and production. In conclusion, there was no interaction found between Zn and Lys, but higher dietary levels of chelated Zn reduced bird performance and egg quality parameters, whereas higher Lys levels could be beneficial to bird performance and egg quality.
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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 | 0.001 |
| 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 | 0.001 |
| 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".