Relationship of protein molecular structure to metabolisable proteins in different types of dried distillers grains with solubles: a novel approach
Bibliographic record
Abstract
To date, there has been no study of protein molecular structures affected by bioethanol processing in relation to protein nutritive values of the new co-products of bioethanol production. The objective of the present study was to investigate the relationship between protein molecular structures (in terms of protein α-helix and β-sheet spectral intensity and their ratio and amide I to amide II spectral intensity and their ratio) and protein rumen degradation kinetics (rate and extent), estimated protein intestinal digestibility and total truly absorbed protein in small intestine (metabolisable protein) in different types of dried distillers grains with solubles (DDGS), such as wheat DDGS, maize DDGS and blend DDGS (wheat:maize = 70:30). The protein molecular structures of the different types of DDGS affected by processing were identified using diffuse reflectance IR Fourier transform spectroscopy. The results showed that the protein structure α-helix to β-sheet ratio in the DDGS had a strongly negative correlation with estimated intestinal digestibility of ruminally undegraded protein (%dRUP, R - 0.95, P = 0.04), tended to have a significant correlation with the protein PC subfraction (which was undegradable and contained proteins associated with lignin and tannins and heat-damaged proteins) (R 0.91, P = 0.09) and had no correlation (P>0.10) with rumen degradation kinetics (rate and extent), total intestinally absorbed protein supply and degraded protein balance. However, the protein amide I to amide II ratio in the DDGS had a strongly positive correlation with soluble crude protein (CP) (R 0.99, P < 0.01), protein PA subfraction (which was instantaneously solubilised at time zero) (R 0.99, P < 0.01), protein PB2 subfraction (which was intermediately degradable) (R - 0.95, P = 0.04) and total digestible CP (R 0.95, P = 0.04). The amide I to amide II ratio also had strongly negative correlations with ruminally undegraded protein (%RUP: R - 0.96, P = 0.03) and the degraded protein balance (OEB: R - 0.97, P = 0.02), but had no correlation (P>0.10) with the total intestinally absorbed protein supply. Multiple regression results show that the protein structure α-helix to β-sheet ratio was a better predictor of %dRUP with R² 0.92. The amide I to II ratio was a better predictor of the degraded protein balance with R² 0.93 in the DDGS. In conclusion, the changes in the protein molecular structure α-helix to β-sheet ratio and the amide I to amide II ratio during bioethanol processing (either due to fermentation processing or due to heat drying) were highly associated with estimated protein intestinal digestibility and degraded protein balance, but were not associated with total intestinally absorbed protein supply from the DDGS to dairy cattle. The present study indicates that a potential novel method could be developed based on the protein molecular structure parameters to improve the estimation of protein value after a validation in a large-scale in vivo study is done.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".