title: The impact of the chromium supplementation on insulin signalling pathway in different tissues and milk yield in dairy cows.
abstract: Thirty days before expected time of parturition, 20 Holstein cows were divided into -Cr and +Cr groups. From day 25 before parturition (BP) up to day 30 after parturition (AP), +Cr cows received 10 mg of Cr (chromium-enriched yeast) daily. Muscle and adipose tissue samples were taken at days -30, -10, +7 and +10 related to parturition, when body condition score (BCS) was also determined. Hepatic tissue samples were taken at days -10 and +7. Tissue samples were used for determination of the insulin signalling pathway protein expressions. Intravenous glucose tolerance test (IVGTT) was performed at days -28, -7, +10 and +30. Milk yield was recorded during first 14 weeks AP. Milk composition was obtained at days 7 and 28 AP. At day 10 BP, protein content of β-subunit of insulin receptor (IRβ) was significantly higher (p ˂ 0.05) in muscle, and phosphorylation of insulin receptor substrate 1 at serine 307 (pIRS-1 Ser307) was significantly lower (p ˂ 0.05) in hepatic tissue of +Cr group. After parturition, pIRS-1 Ser307was significantly lower in muscle tissue at days 7 and 28 (p ˂ 0.05 and p ˂ 0.001, respectively), while phosphorylation of Akt at serine 473 (pAkt Ser473) was significantly higher (p ˂ 0.01) in hepatic tissue at day 7 AP in +Cr group. Chromium had opposite effect on insulin kinetics during IVGTTs obtained BP and AP. Insulin secretion was significantly reduced at day 7 BP and significantly enhanced at day 10 AP, when NEFA concentration was also significantly increased. Milk yield and ECM value were depressed in +Cr group. DMI and BCS were significantly enhanced in +Cr group at day 7 BP. In conclusion, chromium modulates insulin signalling pathway in dairy cows, but targeted signalling molecules are different in antepartal then post-partal period, probably due to duration of exposure to chromium and different energy status between those periods.
authors.affiliation: Laboratory for Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia.
authors.forename: M
authors.initials: M
authors.lastname: Pantelić
authors.affiliation: Department for Physiology and Biochemistry, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: L J
authors.initials: LJ
authors.lastname: Jovanović
authors.affiliation: Department for Ruminants and Swine Diseases, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: R
authors.initials: R
authors.lastname: Prodanović
authors.affiliation: Department for Ruminants and Swine Diseases, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: I
authors.initials: I
authors.lastname: Vujanac
authors.affiliation: Department for Reproduction, Fertility and Artificial Insemination, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: M
authors.initials: M
authors.lastname: Đurić
authors.affiliation: Laboratory for Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia.
authors.forename: T
authors.initials: T
authors.lastname: Ćulafić
authors.affiliation: Laboratory for Radioisotopes, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia.
authors.forename: S
authors.initials: S
authors.lastname: Vranješ-Đurić
authors.affiliation: Laboratory for Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia.
authors.forename: G
authors.initials: G
authors.lastname: Korićanac
authors.affiliation: Department for Physiology and Biochemistry, Faculty of Veterinary Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: D
authors.initials: D
authors.lastname: Kirovski
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001786:Blood Glucose; D001823:Body Composition; D002417:Cattle / Q000502:physiology*; D002857:Chromium / Q000494:pharmacology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D005260:Female; D005947:Glucose / Q000378:metabolism; D005951:Glucose Tolerance Test; D007328:Insulin / Q000378:metabolism*; D007774:Lactation / Q000502:physiology; D008892:Milk; D049590:Postpartum Period; D011247:Pregnancy; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D001786:Blood Glucose; D007328:Insulin; D002857:Chromium; D005947:Glucose
keywords: bovine; chromium; insulin signalling pathway