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==What are Branched-Chain Amino Acids?==

==What are Branched-Chain Amino Acids?==

The branched-chain amino acids (i.e., leucine, isoleucine and valine) are '''essential dietary amino acids for dogs and cats'''. Leucine is ketogenic; valine is gluconeogenic; and isoleucine is both ketogenic and gluconeogenic. Dietary branched-chain amino acids are absorbed by a neutral amino acid transporter in the [[Small Intestine Overview - Anatomy & Physiology|small intestine]] (particularly the [[Jejunum - Anatomy & Physiology|jejunum]]) and plasma branched-chain amino acids are actively reabsorbed in the [[Nephron Microscopic Anatomy#Proximal Tubule|proximal tubule]] of the kidney.

The branched-chain [[Amino Acids Overview - Nutrition|amino acids]] (i.e. leucine, isoleucine and valine) are '''essential dietary amino acids for dogs and cats'''. Leucine is [[Amino Acids Overview - Nutrition|ketogenic]]; valine is [[Amino Acids Overview - Nutrition|gluconeogenic]]; and isoleucine is both ketogenic and gluconeogenic. Dietary branched-chain amino acids are absorbed by a neutral amino acid transporter in the [[Small Intestine Overview - Anatomy & Physiology|small intestine]] (particularly the [[Jejunum - Anatomy & Physiology|jejunum]]) and plasma branched-chain amino acids are actively reabsorbed in the [[Nephron Microscopic Anatomy#Proximal Tubule|proximal tubule]] of the kidney.

==Why are they Important?==

==Why are they Important?==

Branched-chain amino acids are '''structural components of protein'''. The hydrophobic side chains of branched-chain amino acids induce inward folding of protein structures.

Branched-chain amino acids are '''structural components of [[Protein Overview - Nutrition|protein]]'''. The hydrophobic side chains of branched-chain amino acids induce inward folding of protein structures.

Severe liver disease may result in decreased plasma branched-chain amino acid concentrations relative to aromatic amino acids, and this is thought to play a role in the clinical signs of [[Hepatic Encephalopathy|hepatic encephalopathy]]<ref>Strombeck DR and Rogers Q. Plasma amino acid concentrations in dogs with hepatic disease. JAVMA 1978; 178;93-96.</ref><ref>Meyer HP, et al. Effects of a branched-chain amino acid-enriched diet on chronic hepatic encephalopathy in dogs. Metab Br Dis 1999;14:103-110.</ref>. However, the clinical impact of attempting to alter amino acid balance favouring branched-chain amino acids in animals with hepatic encephalopathy is unknown.  

Severe liver disease may result in decreased plasma branched-chain amino acid concentrations relative to [[Nutrition Glossary#Aromatic Amino Acids|aromatic amino acids]], and this is thought to play a role in the clinical signs of [[Hepatic Encephalopathy|hepatic encephalopathy]]<ref>Strombeck DR and Rogers Q. Plasma amino acid concentrations in dogs with hepatic disease. JAVMA 1978; 178;93-96.</ref><ref>Meyer HP, et al. Effects of a branched-chain amino acid-enriched diet on chronic hepatic encephalopathy in dogs. Metab Br Dis 1999;14:103-110.</ref>. However, the clinical impact of attempting to alter amino acid balance favouring branched-chain amino acids in animals with hepatic encephalopathy is unknown.

==Roles in the Body==

==Roles in the Body==

Isoleucine, leucine and valine are constituents of [[Protein Overview - Nutrition|protein]]. Leucine is also a key catabolic regulator of l branched-chain amino acids<ref name="Harris">Harris RA, et al. Regulation of branched-chain α-keto acid dehydrogenase kinase expression in rat liver. J Nutr 2001;131:841S-845S.</ref>. Leucine also influences protein synthesis and muscle deposition by increasing plasma insulin secretion<ref>Yang J, et al. Leucine metabolism in regulation of insulin secretion from pancreatic beta cells. Nutr Rev 2010;68:270-279.</ref>, sensitivity of insulin binding to muscle cells<ref>Prod’homme M, et al. Insulin and amino acids both strongly participate to the regulation of protein metabolism. Curr Opin Clin Nutr Met Car 2004;7:71-7.</ref><ref>Anthony JC, et al. Contribution of insulin to the translational control of protein synthesis in skeletal muscle by leucine. Am J Physiol Endo Metab 2002;282:E1092-E1101.</ref><ref>Liu H, et al. Leucine facilitates the insulin-stimulated glucose uptake and insulin signalling in skeletal muscle cells: involving mTORC1 and mTORC2. Amino Acids 2014;46:1971-1979.</ref>, and inhibiting muscle catabolism<ref>Nagasawa T, et al. Rapid suppression of protein degradation in skeletal muscle after oral feeding of leucine in rats. J Nutr Biochem 2002;13:121-127.</ref><ref>Kadowaki M and Kanazawa T. Amino Acids as Regulators of Proteolysis. J Nutr 2003;133:2052S-2056S.</ref>.

Isoleucine, leucine and valine are constituents of [[Protein Overview - Nutrition|protein]]. Leucine is also a key catabolic regulator of l branched-chain amino acids<ref name="Harris">Harris RA, et al. Regulation of branched-chain α-keto acid dehydrogenase kinase expression in rat liver. J Nutr 2001;131:841S-845S.</ref>. Leucine also influences protein synthesis and muscle deposition by increasing plasma [[insulin]] secretion<ref>Yang J, et al. Leucine metabolism in regulation of insulin secretion from pancreatic beta cells. Nutr Rev 2010;68:270-279.</ref>, sensitivity of insulin binding to muscle cells<ref>Prod’homme M, et al. Insulin and amino acids both strongly participate to the regulation of protein metabolism. Curr Opin Clin Nutr Met Car 2004;7:71-7.</ref><ref>Anthony JC, et al. Contribution of insulin to the translational control of protein synthesis in skeletal muscle by leucine. Am J Physiol Endo Metab 2002;282:E1092-E1101.</ref><ref>Liu H, et al. Leucine facilitates the insulin-stimulated glucose uptake and insulin signalling in skeletal muscle cells: involving mTORC1 and mTORC2. Amino Acids 2014;46:1971-1979.</ref>, and inhibiting muscle catabolism<ref>Nagasawa T, et al. Rapid suppression of protein degradation in skeletal muscle after oral feeding of leucine in rats. J Nutr Biochem 2002;13:121-127.</ref><ref>Kadowaki M and Kanazawa T. Amino Acids as Regulators of Proteolysis. J Nutr 2003;133:2052S-2056S.</ref>.

==Consequences of Branched-Chain Amino Acid Deficiency==

==Consequences of Branched-Chain Amino Acid Deficiency==

==Dietary Sources==

==Dietary Sources==

Sufficient leucine, isoleucine, and valine are found in plant and animal protein sources, such as muscle meat, eggs, dairy protein (i.e., casein), cereal grains, and pulses (i.e., legumes).

Sufficient leucine, isoleucine, and valine are found in plant and animal protein sources, such as muscle meat, eggs, dairy protein (i.e. casein), cereal grains, and pulses (i.e. legumes).

==Diagnosing Branched-Chain Amino Acid Deficiency==

==Diagnosing Branched-Chain Amino Acid Deficiency==

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[[Category:To Do - Nutrition]]

[[Category:To Do - Nutrition preMars]]

{{Reviewed Nutrition 1

 

[[Category:Amino Acids]]