Effects of dietary supplementation of nitrate on enteric methane production, performance, and rumen microbiome of Hanwoo steers
Bibliographic record
Abstract
An in vivo experiment was performed to evaluate the effects of calcium ammonium nitrate (CAN; 5Ca (NO3)2·NH4NO3·10H2O, 75% DM NO₃⁻) supplementation on enteric CH4 emissions, ruminal fermentation and microbial community and productivity in Hanwoo (Korean native cattle) steers. Twenty Hanwoo steers (average body weight 348 ± 18 kg) were randomly allocated to 5 pens (4 head/pen) balanced for body weight, and then randomly assigned to 1 of 2 dietary treatments (2 head/treatment/pen): (1) the control (CON), 500 g/kg long stem timothy hay and 500 g/kg commercial concentrates; (2) NIT, control diet top-dressed with 2.5% CAN (1.578% NO3- in the dietary DM) for 115 d in a completely randomized design. Methane measurement was performed for 3 d starting from days 21, 51, 80, and 112 using whole-body respiratory chambers (RC). Rumen fluid and blood samples were collected on days 25 and 26, respectively. A decrease (P = 0.05) in dry matter intake (DMI) was observed in steers fed NIT both in the pen and RC. However, average daily gain and gain:feed were not adversely affected. Additionally, methemoglobin concentration was not influenced by the treatment, suggesting no potential toxicity of NO₃⁻ in steers fed NIT. A decrease (P < 0.05) in CH4 production (g/d) was noted in NIT throughout the feeding trial, but CH4 yield (g/kg DMI) was not different (P > 0.05) between treatments. Ruminal pH, ammonia concentration, and total volatile fatty acid production were not affected by the treatment, but NIT increased and decreased (P < 0.01) acetate and butyrate proportions, respectively, compared with CON. Steers in NIT group had increased (P < 0.05) ruminal abundance of Ruminococcus sp. and a tendency for increased Succiniclasticum (P = 0.07), and Selenomonas ruminantium (P = 0.07). However, NIT decreased (P < 0.05) the abundance of Olsenella, Atopobium and tended to decrease (P = 0.07) Methanobrevibacter ruminantium in the rumen. Overall, dietary supplementation of NO₃⁻ demonstrated a potential to reduce enteric CH4 production (g/d) by an average of 25.4% in Hanwoo beef cattle over time without causing NO₃⁻ intoxication in the early stage or negatively affecting growth performance throughout the trial. However, the lack of a sustained mitigation effect on CH₄ yield (g/kg DMI) suggests that further evaluation of NO₃⁻ supplementation under different dietary conditions is necessary.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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 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".