Interactions among the branched-chain amino acids and their effects on methionine utilization in growing pigs effects on plasma amino- and keto-acid concentrations and branched-chain keto-acid dehydrogenase activity

S Langer, P W D Scislowski, David Stanley Brown, P Dewey, M F Fuller

    Research output: Contribution to journalArticle

    38 Citations (Scopus)

    Abstract

    The present experiment was designed to elucidate the mechanism of the methionine-sparing effect of excess branched-chain amino acids (BCAA) reported in the previous paper (Langer & Fuller, 2000). Twelve growing gilts (30-35 kg) were prepared with arterial catheters. After recovery, they received for 7d a semipurified diet with a balanced amino acid pattern. On the 7th day blood samples were taken before (16h postabsorptive) and after the morning meal (4h postprandial). The animals were then divided into three groups and received for a further 7d a methionine-limiting diet (80 % of requirement) (1) without any amino acid excess; (2) with excess leucine (50 % over requirement); or (3) with excesses of all three BCAA (leucine, isoleucine, valine, each 50 % over the requirement). On the 7th day blood samples were taken as in the first period, after which the animals were killed and liver and muscle samples taken. Plasma amino acid and branched-chain keto acid (BCKA) concentrations in the blood and branched-chain keto-acid dehydrogenase (BCKDH; EC 1.2.4.4) activity in liver and muscle homogenates were determined. Compared with those on the balanced diet, pigs fed on methionine-limiting diets had significantly lower (P < 0.05) plasma methionine concentrations in the postprandial but not in the postabsorptive state. There was no effect of either leucine or a mixture of all three BCAA fed in excess on plasma methionine concentrations. Excess dietary leucine reduced (P < 0.05) the plasma concentrations of isoleucine and valine in both the postprandial and postabsorptive states. Plasma concentrations of the BCKA reflected the changes in the corresponding amino acids. Basal BCKDH activity in the liver and total BCKDH activity in the biceps femoris muscle were significantly (P < 0.05) increased by excesses of leucine or all BCAA.

    Original languageEnglish
    Pages (from-to)49-58
    Number of pages10
    JournalBritish Journal of Nutrition
    Volume83
    Issue number1
    DOIs
    Publication statusPublished - Jan 2000

    Keywords

    • branched-chain amino acids
    • methionine
    • amino acid utilization
    • food-intake
    • skeletal-muscle
    • protein turnover
    • dietary amino
    • leucine
    • rat
    • metabolism
    • brain
    • antagonism
    • isoleucine

    Cite this

    Interactions among the branched-chain amino acids and their effects on methionine utilization in growing pigs effects on plasma amino- and keto-acid concentrations and branched-chain keto-acid dehydrogenase activity. / Langer, S ; Scislowski, P W D ; Brown, David Stanley; Dewey, P ; Fuller, M F .

    In: British Journal of Nutrition, Vol. 83, No. 1, 01.2000, p. 49-58.

    Research output: Contribution to journalArticle

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    abstract = "The present experiment was designed to elucidate the mechanism of the methionine-sparing effect of excess branched-chain amino acids (BCAA) reported in the previous paper (Langer & Fuller, 2000). Twelve growing gilts (30-35 kg) were prepared with arterial catheters. After recovery, they received for 7d a semipurified diet with a balanced amino acid pattern. On the 7th day blood samples were taken before (16h postabsorptive) and after the morning meal (4h postprandial). The animals were then divided into three groups and received for a further 7d a methionine-limiting diet (80 {\%} of requirement) (1) without any amino acid excess; (2) with excess leucine (50 {\%} over requirement); or (3) with excesses of all three BCAA (leucine, isoleucine, valine, each 50 {\%} over the requirement). On the 7th day blood samples were taken as in the first period, after which the animals were killed and liver and muscle samples taken. Plasma amino acid and branched-chain keto acid (BCKA) concentrations in the blood and branched-chain keto-acid dehydrogenase (BCKDH; EC 1.2.4.4) activity in liver and muscle homogenates were determined. Compared with those on the balanced diet, pigs fed on methionine-limiting diets had significantly lower (P < 0.05) plasma methionine concentrations in the postprandial but not in the postabsorptive state. There was no effect of either leucine or a mixture of all three BCAA fed in excess on plasma methionine concentrations. Excess dietary leucine reduced (P < 0.05) the plasma concentrations of isoleucine and valine in both the postprandial and postabsorptive states. Plasma concentrations of the BCKA reflected the changes in the corresponding amino acids. Basal BCKDH activity in the liver and total BCKDH activity in the biceps femoris muscle were significantly (P < 0.05) increased by excesses of leucine or all BCAA.",
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    AU - Scislowski, P W D

    AU - Brown, David Stanley

    AU - Dewey, P

    AU - Fuller, M F

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    N2 - The present experiment was designed to elucidate the mechanism of the methionine-sparing effect of excess branched-chain amino acids (BCAA) reported in the previous paper (Langer & Fuller, 2000). Twelve growing gilts (30-35 kg) were prepared with arterial catheters. After recovery, they received for 7d a semipurified diet with a balanced amino acid pattern. On the 7th day blood samples were taken before (16h postabsorptive) and after the morning meal (4h postprandial). The animals were then divided into three groups and received for a further 7d a methionine-limiting diet (80 % of requirement) (1) without any amino acid excess; (2) with excess leucine (50 % over requirement); or (3) with excesses of all three BCAA (leucine, isoleucine, valine, each 50 % over the requirement). On the 7th day blood samples were taken as in the first period, after which the animals were killed and liver and muscle samples taken. Plasma amino acid and branched-chain keto acid (BCKA) concentrations in the blood and branched-chain keto-acid dehydrogenase (BCKDH; EC 1.2.4.4) activity in liver and muscle homogenates were determined. Compared with those on the balanced diet, pigs fed on methionine-limiting diets had significantly lower (P < 0.05) plasma methionine concentrations in the postprandial but not in the postabsorptive state. There was no effect of either leucine or a mixture of all three BCAA fed in excess on plasma methionine concentrations. Excess dietary leucine reduced (P < 0.05) the plasma concentrations of isoleucine and valine in both the postprandial and postabsorptive states. Plasma concentrations of the BCKA reflected the changes in the corresponding amino acids. Basal BCKDH activity in the liver and total BCKDH activity in the biceps femoris muscle were significantly (P < 0.05) increased by excesses of leucine or all BCAA.

    AB - The present experiment was designed to elucidate the mechanism of the methionine-sparing effect of excess branched-chain amino acids (BCAA) reported in the previous paper (Langer & Fuller, 2000). Twelve growing gilts (30-35 kg) were prepared with arterial catheters. After recovery, they received for 7d a semipurified diet with a balanced amino acid pattern. On the 7th day blood samples were taken before (16h postabsorptive) and after the morning meal (4h postprandial). The animals were then divided into three groups and received for a further 7d a methionine-limiting diet (80 % of requirement) (1) without any amino acid excess; (2) with excess leucine (50 % over requirement); or (3) with excesses of all three BCAA (leucine, isoleucine, valine, each 50 % over the requirement). On the 7th day blood samples were taken as in the first period, after which the animals were killed and liver and muscle samples taken. Plasma amino acid and branched-chain keto acid (BCKA) concentrations in the blood and branched-chain keto-acid dehydrogenase (BCKDH; EC 1.2.4.4) activity in liver and muscle homogenates were determined. Compared with those on the balanced diet, pigs fed on methionine-limiting diets had significantly lower (P < 0.05) plasma methionine concentrations in the postprandial but not in the postabsorptive state. There was no effect of either leucine or a mixture of all three BCAA fed in excess on plasma methionine concentrations. Excess dietary leucine reduced (P < 0.05) the plasma concentrations of isoleucine and valine in both the postprandial and postabsorptive states. Plasma concentrations of the BCKA reflected the changes in the corresponding amino acids. Basal BCKDH activity in the liver and total BCKDH activity in the biceps femoris muscle were significantly (P < 0.05) increased by excesses of leucine or all BCAA.

    KW - branched-chain amino acids

    KW - methionine

    KW - amino acid utilization

    KW - food-intake

    KW - skeletal-muscle

    KW - protein turnover

    KW - dietary amino

    KW - leucine

    KW - rat

    KW - metabolism

    KW - brain

    KW - antagonism

    KW - isoleucine

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    DO - 10.1017/S0007114500000088

    M3 - Article

    VL - 83

    SP - 49

    EP - 58

    JO - British Journal of Nutrition

    JF - British Journal of Nutrition

    SN - 0007-1145

    IS - 1

    ER -