Intermittent Leucine Pulses during Continuous Feeding Alters Novel Components Involved in Skeletal Muscle Growth of Neonatal Pigs
Bibliographic record
Abstract
Extra‐uterine growth restriction in low‐birth‐weight (LBW) infants is associated with the development of chronic metabolic derangements, and emphasizes the need for improved nutritional protocols to optimize growth. Supplementation with intermittent pulses of leucine in continuously fed neonatal pigs enhanced skeletal muscle protein synthesis through the upregulation of mammalian target of rapamycin signaling. Piglets (n = 23, 7‐d‐old) were continuously fed a milk formula via orogastric tube for 21 d, with an additional parenteral infusion of either leucine (800 μmol·kg −1 ·h −1 , LEU) or alanine (CON) for 1 h every 4 h. To identify novel genes by which LEU may promote neonatal muscle growth, we performed RNA‐Seq analysis of longissimus dorsi muscle from 4 pigs per group, followed by gene ontology (GO) analysis of differentially expressed genes (DEG). In addition, protein abundance/activation of DEG products involved in both muscle protein anabolic or catabolic pathways was assessed by immunoblots. RNA‐Seq was performed on a HiSeq2000 sequencer analyzer. Reads were analyzed using CLCBio Genomics workbench software, assembled against the porcine reference genome, and normalized by a threshold of ‘reads per kilo base per million mapped reads’ (RPKM) ≥ 0.2. A total of 465 genes were differentially expressed between LEU and CON groups (RPKM P < 0.05). GO analyses showed developmental processes, cell junction assembly, regulation of cellular process and organ development as the terms most significantly enriched among the 465 genes. Applying more stringent parameters (RPKM P < 0.01 + >2 fold change), 18 differential expressed genes were identified between CON and LEU pigs, of which tumor necrosis factor receptor‐associated factor 6 (TRAF6) and mammalian Ste20‐like kinase 1 (MST1), both negative regulators of muscle growth, were decreased by > 2‐fold ( P < 0.01) in LEU compared to CON. Western blot analysis also showed a downregulation of MST1 and TRAF6 abundance in LEU animals ( P < 0.01) compared to CON. Together, these findings suggest that intermittent leucine pulses in continuously fed neonate pigs lead to downregulation in the gene and protein expression of signaling components that limit muscle growth. Support or Funding Information NIH AR444474, NIHHD072891, USDA NIFA 2013‐67015‐20438, and USDA/ARS 6250‐51000‐055
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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".