l-Leucine acts as a potential agent in reducing body temperature at hatching and affords thermotolerance in broiler chicks

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• 作者：Guofeng Han^a ; Hui Yang^a ; Mohammad A. Bahry^a ; Phuong V. Tran^a ; Phong H. Do^a ; Hiromi Ikeda^a ; Mitsuhiro Furuse^a ; Vishwajit S. Chowdhury^b ; ^{vc-sur@artsci.kyushu-u.ac.jp}
• 关键词：l-Leucine ; Thermal manipulation ; In ovo injection ; Body temperature ; Thermotolerance ; Chicks
• 刊名：Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：204
• 期：Complete
• 页码：48-56
• 全文大小：566 K
• 卷排序：204

文摘

Thermal manipulation (TM) of incubation temperature causes metabolic alterations and contributes to improving thermotolerance in chicks post hatching. However, there has been no report on amino acid metabolism during TM and the part it plays in thermotolerance. In this study, we therefore first analyzed free amino acid concentrations in the embryonic brain and liver during TM (38.6 °C, 6 h/d during embryonic day (ED) 10 to ED 18). It was found that leucine (Leu), phenylalanine and lysine were significantly decreased in the embryonic brain and liver. We then chose l-Leu and other branched-chain amino acids (l-isoleucine (L-Ile) and l-valine (l-Val)) for in ovo injection on ED 7 to reveal their roles in thermoregulation, growth, food intake and thermotolerance in chicks. It was found that in ovo injection of l-Leu, but not of l-Ileu or l-Val, caused a significant decline in body temperature at hatching and increased food intake and body weight gain in broiler chicks. Interestingly, in ovo injection of l-Leu resulted in the acquisition of thermotolerance under high ambient temperature (35 ± 1 °C for 180 min) in comparison with the control thermoneutral temperature (28 ± 1 °C for 180 min). These results indicate that the free amino acid concentrations during embryogenesis were altered by TM. l-Leu administration in eggs caused a reduction in body temperature at hatching, and afforded thermotolerance in heat-exposed young chicks, further suggesting that l-Leu may be one of the key metabolic factors involved in controlling body temperature in embryos, as well as in producing thermotolerance after hatching.