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

Shibata

et al. 2014

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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.

Section: Experimental Dietssupporting

confidence: 83%

“…The importance of intracellular lysine (Lys) metabolism in the regulation of free Glu content in muscle has been demonstrated by Kobayashi et al (2011). The saccharopine pathway is the major Lys degradation pathway in mammals and birds (Higashino et al 1967;Hutzler & Dancis 1968;Grove & Roghair 1971;Wang & Nesheim 1972).…”

Section: Introductionmentioning

confidence: 99%

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

Watanabe

Shibata

et al. 2014

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“…Therefore, the current study determined the crude fat content of breast muscle. Recently, Kobayashi et al (2011) reported that 10 days of a high CP diet could increase the free Glu content of the breast muscle of broiler chickens. Thus, the difference in the SFV could not be explained by differences in the crude fat content.…”

Section: Discussionmentioning

confidence: 99%

“…Glu is a major active taste component in meat (Kato & Nishimura 1987;Fujimura et al 1996). Recently, we successfully modified the free Glu content of muscle using a nutritional approach, where high dietary CP increased the free Glu content in the muscles of chickens (Kobayashi et al 2011). The addition of Glu to the solution enhanced the sweetness, saltiness and umami taste compared with the reference solution.…”

Section: Introductionmentioning

confidence: 99%

Effects of low protein diet and low protein diet supplemented with synthetic essential amino acids on meat quality of broiler chickens

Nakashima

Ishida

et al. 2012

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We investigated the effects of a low crude protein (CP) diet and a low CP diet supplemented with synthetic essential amino acids (EAA) on the meat quality of broiler chickens. Twenty-one-day-old chickens were assigned to one of three diets: control, low CP (LCP), or low CP supplemented with EAA (ELCP). The chickens received these diets for 10 days. The shear force value (SFV) and free glutamate content of the Pectoralis major muscle were measured as indicators of the meat toughness and taste. The collagen and crude fat content of the muscle and the cross-sectional area of myofibers were measured to evaluate the effects of the LCP and ELCP diets on meat toughness. The SFV of the ELCP group was 47% lower than that of the control group (P<0.01). However, the LCP diet did not affect the SFV. The collagen and crude fat content were not affected by the dietary treatment. The cross-sectional area was lower in the LCP and ELCP groups (P<0.05) than the control group. The free glutamate content of muscle was not affected by the dietary treatment. Thus, a low CP diet supplemented with EAA is an effective means of producing tender meat.

“…; Kobayashi et al . ). In addition, our recent study showed that short‐term feeding of a high Lys diet also increased the concentrations of free Glu in muscle (Watanabe et al .…”

Section: Introductionmentioning

confidence: 97%

Reduction of dietary lysine increases free glutamate content in chicken meat and improves its taste

Watanabe

Shibata

et al. 2016

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Taste is a crucial factor of meat quality, and amino acids are important taste-active components in meat. Here, the effects of dietary lysine (Lys) content on taste-active components in meat, especially free glutamate (Glu), were investigated. Twenty-eight-day-old broilers (Gallus gallus) were fed diets with graded Lys content of 90% or 100% of the recommended Lys requirement, (according to the National Research Council, ) for 10 days. Free amino acid content in meat and sensory scores of meat soup were estimated. Free Glu content, the main taste-active component of meat, was significantly increased by a reduction of dietary Lys. Compared with the Lys 100% group (control), free Glu concentrations of meat were increased by 35.7% in the Lys 90% group (P < 0.05). In addition, free glycine, valine, isoleucine, leucine, histidine and threonine concentrations of meat were significantly increased in the Lys 90% group (P < 0.05). Sensory evaluation of meat soup made from the Lys 100% and 90% groups indicated different meat tastes. Sensory scores of taste intensity, umami and kokumi tastes were significantly higher in the Lys 90% group. These results suggest that a reduction of dietary lysine increased free glutamate content in meat and improved its taste.