Effect of feeding a high-protein diet following an 18-hour period of feed withholding on mammalian target of rapamycin-dependent signaling in skeletal muscle of mature horses.
Abstract: To determine the effect of refeeding following an 18-hour period of feed withholding on the phosphorylation of translation initiation factors in the skeletal muscle of mature horses. Methods: 8 adult horses. Methods: Following an 18-hour period of feed withholding, horses either continued to have feed withheld (postabsorptive state) or were fed 2 g/kg of a high-protein feed (33% crude protein) at time 0 and 30 minutes (postprandial state). Blood samples were taken throughout the experimental period. At 90 minutes, a biopsy specimen was taken from the middle gluteal muscle to measure the phosphorylation of translation initiation factors and tissue amino acid concentrations. Plasma glucose, insulin, and amino acid concentrations were also measured. Results: Horses in the postprandial state had significantly higher plasma insulin, glucose, and amino acid concentrations than did those in the postabsorptive state at the time of biopsy. Refeeding significantly increased the phosphorylation state of riboprotein S6 and eukaryotic initiation factor 4E binding protein 1. Conclusions: In mature horses, feeding resulted in increased mammalian target of rapamycin signaling and the mechanism appeared to be independent of an increase in Akt phosphorylation at Ser⁴⁷³. Results indicate that adult horses may be able to increase rates of muscle protein synthesis in response to feeding and that dietary amino acids appear to be the main mediators of this effect.
Publication Date: 2011-02-02 PubMed ID: 21281201DOI: 10.2460/ajvr.72.2.248Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research conducted is about the effect of high-protein diet refeeding on adult horses in their postprandial state, after an 18-hour period of feed withholding. The findings show increased rates of muscle protein synthesis due to the diet, with the amino acids in the feed serving as the primary drivers for this outcome.
Research Methods
- The study involved 8 adult horses.
- The horses were subjected to an 18-hour period of feed withholding.
- Post feed withholding, the horses were either continued on the fasting or were re-fed a high-protein feed consisting of 33% crude protein at time intervals of time 0 and 30 minutes, designating them as being in a postprandial state.
- Blood samples were collected throughout the experimental phase.
- After 90 minutes, a muscle biopsy was taken from the middle gluteal muscle to assess the phosphorylation of translation initiation factors and tissue amino acid concentrations.
- Various measures, including plasma glucose, insulin, and amino acid concentrations, were also recorded.
Results
- It was observed that horses in their postprandial state had higher levels of plasma insulin, glucose, and amino acid concentrations than those that remained in their postabsorptive state during the biopsy.
- Refeeding proved to significantly increase the phosphorylation state of the riboprotein S6 and the eukaryotic initiation factor 4E binding protein 1.
Conclusion
- The study concludes that in adult horses, feeding causes a surge in the mammalian target of rapamycin (mTOR) signaling.
- This mechanism to increase signalling appeared to be separate from any increase in Akt phosphorylation at Ser⁴⁷³.
- Consequentially, it indicates that adult horses might increase rates of muscle protein synthesis in a feeding response. Moreover, the dietary amino acids in the horse feed seem to be the principal contributors to this impact.
Cite This Article
APA
Urschel KL, Escobar J, McCutcheon LJ, Geor RJ.
(2011).
Effect of feeding a high-protein diet following an 18-hour period of feed withholding on mammalian target of rapamycin-dependent signaling in skeletal muscle of mature horses.
Am J Vet Res, 72(2), 248-255.
https://doi.org/10.2460/ajvr.72.2.248 Publication
Researcher Affiliations
- Middleburg Agricultural Research and Extension Center, Virginia Tech, Middleburg, VA 20117, USA. klur222@uky.edu
MeSH Terms
- Amino Acids / blood
- Animal Feed / analysis
- Animal Nutritional Physiological Phenomena
- Animals
- Blood Glucose
- Diet / veterinary
- Dietary Proteins / administration & dosage
- Dietary Proteins / pharmacology
- Female
- Food Deprivation
- Gene Expression Regulation / drug effects
- Horses
- Insulin / blood
- Muscle Proteins / genetics
- Muscle Proteins / metabolism
- Muscle, Skeletal / metabolism
- Postprandial Period
- Signal Transduction / physiology
- TOR Serine-Threonine Kinases / genetics
- TOR Serine-Threonine Kinases / metabolism
Citations
This article has been cited 7 times.- Hong J, Clizer D, Cline P, Samuel R. Effects of branched-chain amino acids to lysine ratios in corn distillers dried grains with solubles containing diets on growth performance, plasma nitrogen profile, carcass traits, and economic analysis in growing-finishing pigs. Transl Anim Sci 2023 Jan;7(1):txad066.
- Loos CMM, McLeod KR, Vanzant ES, Stratton SA, Bohannan AD, Coleman RJ, van Doorn DA, Urschel KL. Differential effect of two dietary protein sources on time course response of muscle anabolic signaling pathways in normal and insulin dysregulated horses. Front Vet Sci 2022;9:896220.
- Loos CMM, McLeod KR, Stratton SC, van Doorn DA, Kalmar ID, Vanzant ES, Urschel KL. Pathways regulating equine skeletal muscle protein synthesis respond in a dose-dependent manner to graded levels of protein intake. J Anim Sci 2020 Sep 1;98(9).
- DeBoer ML, Martinson KM, Pampusch MS, Hansen AM, Wells SM, Ward C, Hathaway M. Cultured equine satellite cells as a model system to assess leucine stimulated protein synthesis in horse muscle. J Anim Sci 2018 Feb 15;96(1):143-153.
- Valberg SJ, Nicholson AM, Lewis SS, Reardon RA, Finno CJ. Clinical and histopathological features of myofibrillar myopathy in Warmblood horses. Equine Vet J 2017 Nov;49(6):739-745.
- Wagner AL, Urschel KL, Lefta M, Esser KA. Effect of gluteus medius muscle sample collection depth on postprandial mammalian target of rapamycin signaling in mature Thoroughbred mares. Am J Vet Res 2013 Jun;74(6):910-7.
- Perez-Palencia JY, Ramirez-Camba CD, Haydon K, Urschel KL, Levesque CL. Effects of increasing dietary arginine supply during the three first weeks after weaning on pig growth performance, plasma amino acid concentrations, and health status. Transl Anim Sci 2024;8:txae047.
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