Abstract #318
Section: Physiology and Endocrinology (orals)
Session: Physiology & Endocrinology 2
Format: Oral
Day/Time: Tuesday 11:15 AM–11:30 AM
Location: Room 262
Session: Physiology & Endocrinology 2
Format: Oral
Day/Time: Tuesday 11:15 AM–11:30 AM
Location: Room 262
# 318
Plasma branched-chain amino acids (BCAA) and mRNA abundance of 3 different BCAA transporters in adipose tissue, muscle and liver of dairy cows with high or normal body condition score.
L. A. Webb*1, H. Sadri2, K. Schuh1,3, S. Egert4,5, P. Stehle5, C. Koch6, G. Dusel3, H. Sauerwein1, 1Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany, 2Department of Clinical Science, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran, 3Department of Life Sciences and Engineering, Animal Nutrition and Hygiene Unit, University of Applied Sciences Bingen, Bingen, Germany, 4Institute of Nutritional Medicine, University of Hohenheim, Stuttgart, Germany, 5Department of Nutrition and Food Sciences, Nutritional Physiology, University of Bonn, Bonn, Germany, 6Educational and Research Center for Animal Husbandry, Hofgut Neumühle, Münchweiler a.d. Alsenz, Germany.
Key Words: branched-chain AA (BCAA) transporters, tissue abundance, body condition
Plasma branched-chain amino acids (BCAA) and mRNA abundance of 3 different BCAA transporters in adipose tissue, muscle and liver of dairy cows with high or normal body condition score.
L. A. Webb*1, H. Sadri2, K. Schuh1,3, S. Egert4,5, P. Stehle5, C. Koch6, G. Dusel3, H. Sauerwein1, 1Institute of Animal Science, Physiology and Hygiene Unit, University of Bonn, Bonn, Germany, 2Department of Clinical Science, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran, 3Department of Life Sciences and Engineering, Animal Nutrition and Hygiene Unit, University of Applied Sciences Bingen, Bingen, Germany, 4Institute of Nutritional Medicine, University of Hohenheim, Stuttgart, Germany, 5Department of Nutrition and Food Sciences, Nutritional Physiology, University of Bonn, Bonn, Germany, 6Educational and Research Center for Animal Husbandry, Hofgut Neumühle, Münchweiler a.d. Alsenz, Germany.
Branched-chain amino acid transporters (BCAAT) are crucial to sensing AA availability and regulating BCAA homeostasis, e.g., via interaction with the mechanistic target of rapamycin. Except for mammary gland and placenta, their abundance in metabolically active tissues in dairy cows is mostly unknown. Thus, we aimed to 1) compare the mRNA abundance of the most relevant BCAAT, i.e., solute carrier family 1 member 5 (SLC1A5), SLC7A5, and SLC38A2 in muscle, liver and subcutaneous adipose tissue (AT) as well as the plasma BCAA profiles and 2) test whether high and normal BCS cows may differ in these variables. Thirty-eight multiparous Holstein cows, 15 wk ante partum (a.p.) were allocated to high (HBCS; BCS > 3.75) or normal BCS groups (NBCS; BCS < 3.5) receiving 7.2 or 6.8 MJ/kg DM, respectively, until dry-off to promote the difference. During the dry period and early lactation, cows were fed the same diets; differences in BCS (P < 0.001) were maintained. Blood and biopsies from M. semitendinosus, liver and AT (tail head) were sampled at d 49 a.p., 3, 21 and 84 postpartum (p.p.). Free BCAA were quantified by HPLC; mRNA abundance was assessed via qPCR. Data were analyzed as repeated measures with a Linear Mixed Model (SPSS). Concentrations of all BCAA changed with time (P ≤ 0.01), most markedly in HBCS cows, with a nadir around calving. Neither individual nor total BCAA differed between groups. For Ile, a group × time interaction was found (P = 0.03): At d 3 p.p. HBCS cows tended to have lower Ile concentrations than NBCS cows (P = 0.08), vice versa at d 21 (P = 0.02). Abundance of BCAAT varied only with tissue and time (P < 0.01). The SLC1A5 and SLC7A5 mRNA were most abundant in AT; liver had 3 and 24% and muscle 11 and 37% of the AT values, respectively. In muscle, SLC1A5 and SLC7A5 mRNA peaked at d 21 p.p. Both AT and muscle had 4-fold greater SLC38A2 abundance than liver, with irregular time courses. Our results indicate that AT could be a major site of BCAA uptake that is rather independent of BCS and time relative to calving in dairy cows.
Key Words: branched-chain AA (BCAA) transporters, tissue abundance, body condition
