Regulation of taste-active components of meat by dietary leucine

The major taste active component, glutamate (Glu), improves the taste of meat. In this study, we investigated the effect of a short-term high-protein (HCP) diet on the intramuscular free Glu content to improve the taste of meat. Furthermore, we elucidated how the muscle free Glu content was controlled by the HCP diet. Chicks (14 days old) were fed the control diet or HCP diet for 10 days. Plasma and muscle free amino acid concentrations, and activity and messenger RNA (mRNA) expression of muscle enzymes related to Glu metabolism were determined. Muscle free Glu content was increased (P < 0.01) by 51%. Activity and mRNA expression of glutaminase (GA), which is one of the major Glu-related enzymes, were significantly decreased (P < 0.05) in the HCP group because of feedback inhibition. The mRNA expression of lysine α-ketoglutarate reductase (LKR), which is the enzyme involved in lysine (Lys) degradation and Glu production, was significantly increased (P < 0.001) in the HCP group. These results suggest that short-term dietary HCP feeding is an effective treatment for improving the taste of meat. Furthermore, our results suggest that the free Glu content in muscle is regulated by GA and LKR.

Section: Discussionmentioning

confidence: 99%

“…The free amino acid levels in muscle were measured as described by Imanari et al . (2007) using an amino acid analyser (JLC‐500/V; JEOL, Tokyo, Japan).…”

Section: Methodsmentioning

confidence: 99%

Regulation of muscular glutamate metabolism by high‐protein diet in broiler chicks

Kobayashi

Eguchi

Takano

et al. 2010

“…Muscle extracts were prepared as described by Imanari et al (2007). The muscles were homogenized in 10% perchloric acid with a high-speed homogenizer (Ultra-turrax T25 basic, Ikawerke, Staufen, Germany).…”

Section: Free Amino Acid and Dipeptide Contentmentioning

confidence: 99%

Effect of dietary histidine on contents of carnosine and anserine in muscles of broilers

Kai

Watanabe

Kubota

et al. 2014

Carnosine (β-alanyl-L-histidine) and anserine (β-alanyl-1-methyl-L-histidine) are dipeptides mainly found in skeletal muscle and brain of many vertebrates, and particularly high concentrations are observed in chicken pectoral muscles. It was reported that these peptides have many functions, such as antioxidant activity. In this study, we examined the effect of different levels of dietary histidine on carnosine and anserine contents in broiler muscles. The 14-days-old female Chunky strain broilers were given feeds containing three different levels of histidine; 67% (Low-His), 100% (Control) and 200% (High-His) of histidine requirement according to the NRC (1994). Chicks were fed experimental diets for 10 days. Both dipeptides in muscle were significantly decreased. In particular, carnosine was not detected at all in the Low-His group and was significantly increased in the High-His group. Both dipeptides were not detected in plasma. These results indicated the possibility to produce chicken meat with enhanced amount of these dipeptides by high histidine feeding.

“…Muscle and liver extracts were prepared as described by Imanari et al (2007). The muscles and livers were homogenized in 10% perchloric acid with a highspeed homogenizer (Ultra-turrax T25 basic; Ikawerke, Staufen, Germany).…”

Section: Preparation Of Muscle and Liver Extractsmentioning

confidence: 99%

Regulation of free glutamate content in meat by dietary lysine in broilers

Watanabe

Kobayashi

Shibata

et al. 2014

Regulation of taste is important for improving meat quality and glutamate (Glu) is one of the important taste-active components in meat. Here, the effects of dietary lysine (Lys) content on taste-active components in meat, especially free Glu, were investigated. Fourteen-day-old broiler chicks (Gallus gallus) were fed on diets containing 100% or 150% of the recommended Lys content for 10 days. Concentrations of free amino acids in plasma, muscle and liver were measured. The levels of messenger RNAs (mRNAs) for enzymes related to Glu metabolism were determined in muscle and liver. The concentration of muscle metabolites was also determined. The free Glu content in muscle of chicks fed the Lys150% diet was increased by 44.0% compared with that in chicks fed the Lys100% diet (P < 0.01). The mRNA level of lysine α-ketoglutarate reductase, which is involved in Lys degradation and Glu production, was significantly increased (P < 0.05) in the Lys150% group. Metabolome analysis showed that the Lys degradation products, muscular saccharopine, pipecolic acid and α-aminoadipic acid, were increased in the Lys150% group. Our results suggest that free Glu content in muscle is regulated by Lys degradation. These results suggest that a short-term feeding of high-Lys diet could improve the taste of meat.