Semi-synthetic reference diets containing crystalline amino acids at 120% of recommendations for adult dogs are not appropriate for estimating the protein quality of ingredients used in extruded diets
Bibliographic record
Abstract
Metabolic availability (MA) of amino acids (AA) in feedstuffs has been assessed in pigs and humans using the indicator amino acid oxidation (IAAO) method. Our lab previously reported higher methionine (Met) content but lower MA in chicken meal (ChM) as compared to peas. However, the MA of met in peas or ChM was not quantified due to the absence of a crystalline AA reference diet, assumed to have 100% MA. This study aimed to quantify the MA of Met in peas and ChM compared to a semi-synthetic crystalline AA reference diet. A partially replicated 7 × 7 Latin square design was conducted in nine mixed-breed dogs [2.5 yrs old; 26.7 ± 2.7 kg body weight (BW)] fed to maintain ideal BW. Dogs received all seven dietary treatments: corn starch and barley-based reference diet supplying AA primarily as crystalline AA with Met at 19%, 40%, or 63% of requirement (BAS19, BAS40, BAS63, respectively), pea- (PEA63) and ChM- (ChM63) based diets with Met at 63%, and blends of BAS19 with peas (PEA40) or ChM (ChM40), both with Met at 40% of requirement. This created three graded levels of Met for ChM, peas, and BAS reference diets, permitting a slope ratio approach to quantify MA with the BAS diet as the common first point. Diets were isoenergetic, isonitrogenous, and met ≥ 120% of Association of American Feed Control Officials (AAFCO) AA recommendations for adult dogs (excluding Met). After 2 (D2) and 6 (D6) d of diet adaptation, IAAO was performed using L-[1-13C]-phenylalanine (Phe, 99%). Enrichment of 13CO2 in collected breath samples was measured using isotope-ratio mass spectrometry to calculate oxidation (F13CO2/kg BW/h). Data were analyzed using proc GLIMMIX with dog and period as random effects, and diet, % Met provided, IAAO day, and their interactions as fixed effects. There was no effect of day on MA, indicating the standard 2-d diet adaptation appears sufficient for determining the MA of AA using IAAO. Overall, ChM had the lowest oxidation level, and the MA of peas was 66% and 51% of ChM on D2 and D6, respectively. Additionally, the BAS diet had no response, suggesting another limiting AA in the BAS diet.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".