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Öğe Early step-down weaning of dairy calves from a high milk volume with glutamine supplementation(Elsevier Science INC., 2022) Wickramasinghe, H. K. J. P.; Kaya, C. A.; Baumgard, L. H.; Appuhamy, J. A. D. R. N.Weaning dairy calves from a high milk volume (>8.0 kg/d) can negatively affect the growth and welfare even if it is performed in a step-down manner. Supplementa-tion of Gln improved gut development of preweaning calves and mitigated weaning stresses of piglets to ex-tents achieved with antibiotics. The study objective was to examine the effect of initiating a step-down weaning scheme with a Gln supplement at an early age on calf starter intake (CSI), average daily gain (ADG), and paracellular permeability of the intestinal epithelium of calves fed a high volume of milk (9.0 kg/d). Thirty-six Holstein heifer calves were assigned to 3 treatments (n = 12) as follows: (1) initiating weaning at 49 d of age (LW), (2) initiating weaning at 35 d of age (EW), and (3) initiating weaning at 35 d with a Gln supplement (2.0% of dry matter intake) from 28 to 42 d of age (EWG). Calves were fed 9.0 kg/d of whole milk until weaning was initiated by abruptly decreasing the milk volume to 3.0 kg/d. Weaning was completed once calves achieved >1.0 kg/d of CSI. The paracellular permeability of the intestinal epithelium was assessed with lactulose-to-mannitol ratio (LMR) in the blood on 1 d before, and 3 and 7 d after the initiation of weaning. The blood was analyzed for haptoglobin, lipopolysaccharide-binding protein (LBP), and metabolites including AA. The CSI increased once milk volume was restricted in all treat-ments. The CSI of LW was greater than that of EW and EWG during the first week of weaning. The LW, EW, and EWG took 11, 19, and 16 d to achieve >1.0 kg/d of CSI and were weaned at 60, 54, and 51 d of age, respectively. The body weight (BW) of LW, EW, and EWG at the initiation of weaning were 68.2, 58.7, and 59.5 kg, respectively. Both LW and EWG achieved similar ADG, but ADG of EW was lower than LW during the first week of weaning. All calves had similar ADG during the second week of weaning. The BW of LW, EW, and EWG at weaning were 74.8, 66.5, and 66.4 kg, representing a 2.0, 1.8, and 1.8-fold increase in birth weight, respectively. All calves had similar BW of 88.6 and 164.3 kg at 10 and 20 wk of age, respectively. Regardless of the age, serum haptoglobin and plasma LBP concentrations increased on d 3 and returned to baseline concentrations on d 7 during weaning. The EW had a lower plasma LBP concentration than LW and EWG on d 3 during weaning. The LMR was similar be-tween treatments on d 3 but increased by 44% for EW and LW on d 7, whereas the LMR of EWG remained unchanged during weaning. The postprandial serum concentration of Gln, Met, Trp, and beta-hydroxybutyrate were greater for EWG than EW during weaning. Begin-ning step-down weaning at 35 d with a Gln supplement can help maintain the gut barrier function and wean dairy calves with a satisfactory CSI at 7 wk of age without affecting postweaning growth.Öğe The effect of a sanguinarine supplementation on feed intake, weight gain, hematology, and serum chemistry of calves.(Elsevier Science Inc, 2020) Wickramasinghe, H. K. J. P.; Stepanchenko, N.; Kaya, C. A.; Silva, J. V. V.; Bas, S.; Ribeiro, F. R. B.; Appuhamy, J. A. D. R. N.[Abstract Not Available]Öğe Effects of branched-chain amino acids on glucose uptake and lactose synthesis rates in bovine mammary epithelial cells and lactating mammary tissue slices(Elsevier Science INC., 2022) Silva, J. V. V.; Ganesan, S.; Wickramasinghe, H. K. J. P.; Stepanchenko, N.; Kaya, C. A.; Beitz, D. C.; Appuhamy, J. A. D. R. N.Even though supplementations of essential AA (EAA) are often related to increased lactose yields in dairy cows, underlying mechanisms connecting EAA availability to the mammary glands and lactose synthesis are poorly understood. The objective of this study was to examine the effects of branched-chain AA (BCAA) including Leu, Ile, and Val on (1) glucose transporter (GLUT1) abundance and glucose uptake, (2) the abundance of proteins regulating lactose synthesis pathway, and (3) fractional synthesis rates of lactose (FSR) using bovine mammary epithelial cells (BMEC) and mammary tissues slices (MTS). The BMEC (n = 4) were allocated randomly to regular Dulbecco's Modified Eagle Medium with Ham's F12 (DMEM/F12) medium (+EAA) or +EAA deficient (by 90%) in all EAA (- EAA), all BCAA (-BCAA), only Leu (-Leu), only Ile (-Ile) or only Val (-Val). Western immunoblotting analyses, depletion of glucose in media, and a proteomic analysis were performed to determine the abundance of GLUT1 in the cell membrane, net glucose uptake, and the abundance of enzymes involved in lactose synthesis pathway in BMEC, respectively. The MTS (n = 6) were allocated randomly to DMEM/F12 medium having all EAA and C-13-glucose at concentrations similar to plasma concentrations of cows (+EAA(p)), and +EAA(p) deprived of all BCAA (-BCAA(p)) or only Leu (-Leup) for 3 h. The C-13 enrichments of free glucose pool in MTS (EGlu-free) and the enrichments of glucose incorporated into lactose in MTS and media [ELactose-bound ((T&M))] were determined and used in calculating FSR. In BMEC, -BCAA increased the fraction of total GLUT1 translocated to the cell membrane and the fraction that was potentially glycosylated compared with +EAA. Among individual BCAA, only-Leu was associated with a 63% increase in GLUT1 translocated to the cell membrane and a 40% increase in glucose uptake of BMEC. The-BCAA tended to be related to a 75% increase in the abundance of hexokinase in BMEC. Deprivation of Leu tended to increase glucose uptake of MTS but did not affect EGlu-free, ELactose-bound ((T&M)), or FSR relative to +EAA(p). On the other hand, -BCAA(p) did not affect glucose uptake of MTS but was related to lower ELactose-bound (T&M), or FSR relative to +EAA(p). Considering together, decreasing Leu supply to mammary tissues enhances GLUT1 and thus glucose uptake, which, however, does not affect lactose synthesis rates. Moreover, the deficiency of other BCAA, Ile, and Val alone or together with the deficiency of Leu seemed to decrease lactose synthesis rates without affecting glucose uptake. The data also emphasize the importance of addressing the effect of the supply of other nutrients to the mammary glands than the precursor supply in describing the synthesis of a milk component.Öğe Effects of extracellular branched-chain amino acid availability on the abundance of glucose transporter 1 (GLUT1) in bovine mammary epithelial cells(Elsevier Science Inc, 2019) Silva, J. V. V.; Ganesan, S.; Kaya, C. A.; Wickramasinghe, H. K. J. P.; Appuhamy, J. A. D. R. N.[Abstract Not Available]Öğe Effects of extracellular branched-chain amino acid availability on the abundance of proteins regulating fat synthesis in bovine mammary cells: A proteomics analysis(Elsevier Science Inc, 2019) Ganesan, S.; Silva, J. V. V.; Kaya, C. A.; Wickramasinghe, H. K. J. P.; Appuhamy, J. A. D. R. N.[Abstract Not Available]Öğe L-Glutamine improves weight gain and starter intake in Holstein heifer calves weaned early from a high volume of milk.(Elsevier Science Inc, 2019) Wickramasinghe, H. K. J. P.; Kaya, C. A.; Appuhamy, J. A. D. R. N.[Abstract Not Available]
