Dietary Leucine Supplementation Alters Muscle and Liver Protein Synthesis during Immune System Stimulation in Pigs
Notice bibliographique
Résumé
Introduction Immune system stimulation (ISS) adversely affects protein and amino acid (AA) metabolism, leading to a decrease in skeletal muscle protein synthesis and increases in muscle protein degradation and visceral protein synthesis. While such short‐term changes in protein metabolism are beneficial for supporting an immune response, prolonged alterations are undesirable as it negatively affects whole‐body protein deposition (PD) and body weight gain. Among essential AA, Leu has a regulatory role in protein turnover in skeletal muscle and other tissues through its effect on the mechanistic target of rapamycin complex 1 signalling pathway. However, ISS may produce a short‐term resistance to Leu in skeletal muscle that impairs the anabolic effects of this AA. Objective The objective of this study was to evaluate the effects of ISS and dietary Leu supplementation on plasma AA and urea concentrations, and protein synthesis of various tissues during ISS. Methods Yorkshire pigs (initial body weight [BW] = 10.6 ± 1.1 kg) were surgically fitted with indwelling jugular vein catheters and assigned to one of three diets: 1. CON, 1.36% standardized ileal digestible (SID) Leu; 2. LEU‐M, 2.04% SID Leu; and 3. LEU‐H, 2.72% SID Leu. Immune system stimulation was induced in all LEU‐M and LEU‐H pigs and half of CON pigs with lipopolysaccharide (ISS+; n = 7, 8, and 7 for CON, LEU‐M, and LEU‐H, respectively); the remaining CON pigs were administered saline (ISS‐; n = 6). During ISS, feed allowance of ISS− and ISS+ pigs was equivalent. Blood was collected every 12 h at 0, 12, 24, and 36‐h after ISS was induced for determining plasma AA and urea concentrations. At 36 h, FSR of liver, plasma, gastrocnemius, and longissimus dorsi (LD) proteins were determined with a flooding dose of L‐[ring‐ 2 H 5 ]‐Phe. Results Whole‐body PD was decreased in ISS+ pigs ( P < 0.01). Plasma AA and urea concentrations in ISS− pigs were constant over time, whereas they were increased in ISS+ pigs 12 h after ISS despite similar AA intake between ISS− and ISS+ pigs ( P < 0.05). Plasma AA and urea concentrations at 36 h were similar between ISS− and ISS+ pigs except Phe ( P = 0.053) and Thr ( P = 0.054), which tended to decrease in ISS− pigs, and Gln ( P = 0.072), which tended to increase in ISS+ pigs. Although dietary Leu supplementation increased plasma Leu concentration prior to ISS (Linear; P < 0.01), there was no linear effect at 36 h in ISS+ pigs. Dietary Leu supplementation decreased plasma Gln, Ile, and Val and urea concentrations at 36 h in ISS+ pigs (Linear; P < 0.05). Liver protein FSR was increased in ISS+ pigs ( P < 0.05), whereas plasma and skeletal muscle protein FSR was not affected by ISS. Dietary Leu supplementation tended to decrease liver protein FSR (Linear; P = 0.052) and increase gastrocnemius protein FSR (Linear; P = 0.085) in ISS+ pigs, but there was no linear effect on LD protein FSR. Conclusions In this study, ISS resulted in acute increases in plasma AA and urea concentrations that reflect changes in tissue AA and protein metabolism. Skeletal muscle anabolic resistance to Leu was likely transient since protein synthesis rates were not reduced in gastrocnemius and LD muscles after ISS. However, the reduction in liver protein synthesis and increase in gastrocnemius protein synthesis in response to dietary Leu supplementation may facilitate AA partitioning for muscle PD during ISS. Support or Funding Information NSERC 400994, OMAFRA 030087
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».