478 Impact of crude protein and phosphorus deficiencies on liver mitochondrial content and transcriptome in growing Merino wethers
Notice bibliographique
Résumé
Abstract In grazing systems in Northern Australia, crude protein (CP) and phosphorus (P) availability varies, affecting ruminant production due to voluntary reduced intake and therefore body weight (BW) gain. We were interested in understanding metabolic regulation in this model system, both in terms of a) identifying key tissues, and b) detecting any modifications in mitochondrial physiology, given the central role of this organelle in bioenergetic homeostasis. Merino wethers (n = 24) were subjected to three dietary regimens: High CP, High P, (Control), Low CP, Low P (Deficient), and High CP, High P, with restricted feed intake (Restricted). Mitochondrial DNA (mtDNA) copy numbers, indicative of mitochondrial content, were measured via qPCR. Transcriptomic analyses through RNA sequencing targeted mitochondria-associated gene expression changes and pathways, using the MitoCarta 3.0 database. There was a significant decrease of mtDNA copy numbers in the liver of sheep under either Deficient and Restricted diets (P < 0.01), with as much as a 2-fold difference between the Control and Deficient diets. This may suggest reduced mitochondrial biogenesis as an adaptation to decreased energy intake. When compared with the Control group, both the Deficient and Restricted groups upregulated pathways related to vitamin metabolism (Log2FC: 0.231 and 0.449) and folate and 1-C metabolism (Log2FC: 0.409 and 0.706). However, impacted pathways shared between these two comparisons (Control v Deficient, Control v Restricted) also include choline and betaine metabolism, amino acid metabolism, and glycine metabolism, which suggests similar mechanisms being impacted by decreased energy intake, regardless of whether it is due to satiety from nutrient deficiency or restricted feed intake. Notably, the creatine metabolism pathway was uniquely upregulated in the Restricted group compared with the Deficient group (Log2FC: 0.114), although the CKMT2 gene was upregulated in the Restricted group compared with both the Control and Deficient group (Log2FC: 1.30 and 0.879). Additionally, the SLC25A family pathway, responsible for mitochondrial metabolite transport, was found to be upregulated in the Restricted group when compared with both Control and Deficient groups (Log2FC: 0.33 and 0.865). Overall, this study demonstrated a pronounced decrease in mitochondrial content in the liver of growing Merino wethers subjected to nutritional deficiencies and feed restriction. Multiple metabolic pathways were shared between the comparisons of the Control diet group to both Deficient and Restricted nutritional treatments. However, the SLC25A transporter family pathway was uniquely upregulated in the Restricted group compared with either an optimal or deficient diet. The regulation of these metabolic pathways is a subject of further study that may represent a systemic response to maintain homeostasis while undergoing significantly lower energy intake, with implications for animal growth, tissue deposition, and energetic maintenance. Understanding distinctions in the response to feed restriction and nutrient deficiency induced reduction in intake may help improve production strategies for ruminants grazing in these conditions.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| 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) | 0,001 | 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 source (Gemma direct ou Codex distillé), 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 ».