PMID- 31255267 OWN - NLM STAT- MEDLINE DCOM- 20191125 LR - 20211204 IS - 1525-3198 (Electronic) IS - 0022-0302 (Linking) VI - 102 IP - 9 DP - 2019 Sep TI - Effects of rumen-protected methionine and other essential amino acid supplementation on milk and milk component yields in lactating Holstein cows. PG - 7936-7947 LID - S0022-0302(19)30547-8 [pii] LID - 10.3168/jds.2018-15703 [doi] AB - Objectives of this study were to investigate the effects of supplementing rumen-protected methionine (RP-Met), threonine (RP-Thr), isoleucine (RP-Ile), and leucine (RP-Leu) individually or jointly to a low-protein diet, on the performance of lactating dairy cows, as well as to determine the effects of these amino acids (AA) on the mammalian target of rapamycin (mTOR) in vivo. Ten lactating Holstein cows were randomly allocated to a repeated 5 x 5 Latin square experiment with five 19-d periods. Treatments were high-protein diet (16% crude protein, positive control; HP), low-protein diet (12% crude protein, negative control; LP), LP plus RP-Met (LPM), LP plus RP-Met and RP-Thr (LPMT), and LP plus RP-Met, RP-Thr, RP-Ile, and RP-Leu (LPMTIL). The dry matter intakes (DMI) of the LP, LPM, and LPMT diets were lower than that of the HP diet, whereas the DMI of the LPMTIL diet was intermediate between the HP diet and the other LP diets. Supplementing RP-Met to the LP diet increased the yields of milk and milk protein, increased the content of milk urea N, and tended to increase milk N efficiency. Co-supplementation of RP-Thr with RP-Met resulted in no further milk production increase. Co-supplementation of all 4 rumen-protected amino acids (RP-AA) increased milk and lactose yields to the level of the HP diet and tended to increase milk protein yield compared with the LPMT diet. We found no significant differences in the contents and yields of milk components between the LPMTIL and HP diets except for a lower milk urea N content in the LPMTIL diet. Venous concentrations of the measured AA were similar across the LP and LP diets supplemented with RP-AA. Relative to levels of the HP diet, LP diets had higher venous concentrations of Met and Gly and tended to have higher Phe concentration and lower concentrations of Val and BCAA. The LPMTIL diet had higher venous concentrations of Arg, Lys, Met, Phe, and Glu, and a lower Val concentration. Phosphorylation status of the measured mTOR components in LPM and LPMT treatments were similar to those in the LP treatment but phosphorylation status of mTOR and eIF4E-binding protein 1 (4eBP1) in LPMTIL treatment were higher. The phosphorylation rates of eukaryotic elongation factor 2 (eEF2) in the 4 LP and LP plus RP-AA diets were higher than that of the HP diet. Overall, results of the present study supported the concept that under the relatively short time of this experiment, supplementing RP-AA, which are believed to stimulate the mTOR signal pathway, can lead to increased milk protein yield. This increase appears to be due to increased DMI, greater mTOR signaling, and greater eEF2 activity. CI - Copyright (c) 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved. FAU - Zhao, K AU - Zhao K AD - Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China. FAU - Liu, W AU - Liu W AD - Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China. FAU - Lin, X Y AU - Lin XY AD - Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China. FAU - Hu, Z Y AU - Hu ZY AD - Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China. FAU - Yan, Z G AU - Yan ZG AD - Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China. FAU - Wang, Y AU - Wang Y AD - Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China. FAU - Shi, K R AU - Shi KR AD - Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China. FAU - Liu, G M AU - Liu GM AD - Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China. FAU - Wang, Z H AU - Wang ZH AD - Ruminant Nutrition and Physiology Laboratory, College of Animal Science and Technology, Shandong Agricultural University, Taian 271018, P. R. China. Electronic address: zhwang@sdau.edu.cn. LA - eng PT - Journal Article DEP - 20190627 PL - United States TA - J Dairy Sci JT - Journal of dairy science JID - 2985126R RN - 0 (Amino Acids, Essential) RN - 0 (Milk Proteins) RN - 8W8T17847W (Urea) RN - AE28F7PNPL (Methionine) RN - EC 2.7.11.1 (TOR Serine-Threonine Kinases) RN - J2B2A4N98G (Lactose) RN - N762921K75 (Nitrogen) SB - IM MH - Amino Acids, Essential/*administration & dosage/analysis MH - Animals MH - Cattle/*physiology MH - Dairying MH - Diet/veterinary MH - Diet, Protein-Restricted/veterinary MH - Dietary Supplements/*analysis MH - Female MH - Lactation/drug effects MH - Lactose/metabolism MH - Methionine/administration & dosage MH - Milk/chemistry/*metabolism MH - Milk Proteins/*analysis MH - Nitrogen/analysis/*metabolism MH - Rumen/metabolism MH - Signal Transduction/drug effects MH - TOR Serine-Threonine Kinases/metabolism MH - Urea/analysis OTO - NOTNLM OT - dairy cow OT - milk protein OT - nitrogen efficiency OT - rumen-protected amino acid EDAT- 2019/07/01 06:00 MHDA- 2019/11/26 06:00 CRDT- 2019/07/01 06:00 PHST- 2018/09/17 00:00 [received] PHST- 2019/05/02 00:00 [accepted] PHST- 2019/07/01 06:00 [pubmed] PHST- 2019/11/26 06:00 [medline] PHST- 2019/07/01 06:00 [entrez] AID - S0022-0302(19)30547-8 [pii] AID - 10.3168/jds.2018-15703 [doi] PST - ppublish SO - J Dairy Sci. 2019 Sep;102(9):7936-7947. doi: 10.3168/jds.2018-15703. Epub 2019 Jun 27.