Seasonal Change of Plasma Free Amino Acids with Special Reference to 3-Methylhistidine in Racehorses |
Kumiko Sawada*, Jun You Li, Yasuko Kuribayashi, Hisao Itabashi |
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Correspondence:
Kumiko Sawada, |
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Abstract |
Seasonal changes in the concentration of free amino acids were determined monthly in plasma from the jugular blood of 50 thoroughbred racehorses that compete during the night between June and September and during the day between October and January. The concentration of most free amino acids remained relatively constant between June and January. However, those of glutamic acid, alanine, isoleucine and lysine tended to decrease and that of arginine (Arg) significantly decreased between July and September. The concentration of methionine (Met) gradually increased between June and September and significantly decreased thereafter. The concentration of 3-methylhistidine (3-MH) significantly increased between July and September and decreased thereafter. There were significant correlation between 3-MH and Arg. In conclusion, this study provided evidence of significant seasonal change in plasma 3-MH, Arg and Met of racehorses, and this was considered to relate to an environmental effect. Moreover, our study is the first to show 3-MH in plasma of racehorses affected by environmental change. |
Keywords:
Heat Stress; 3-Methylhistidine; Plasma Free Amino Acid; Racehorse |
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