title: Alterations in lipid metabolism induced by recombinant bovine tumor necrosis factor-alpha administration to dairy heifers.
abstract: Endotoxin induces marked changes in lipid metabolism via its effects on cytokines. To evaluate the role of tumor necrosis factor-alpha (TNF) in mediating changes of lipid metabolism in ruminants, we performed a crossover saline-controlled study in Holstein heifers (n = 8; 394.0 kg average BW), investigating the metabolic effects of a single intravenous administration of recombinant bovine TNF (rbTNF, 5.0 microg/kg). Blood samples were taken from a jugular vein at 0 (1100, just before injection), 0.5, 6, 12, and 24 h after each treatment. Dry matter intake in the heifers was not affected by single administration of the rbTNF. The rbTNF produced early as well as later hypertriglyceridemia (P < 0.05) in dairy heifers. The rbTNF also induced an early and sustained rise (P < 0.05) in the plasma NEFA concentration. Plasma retinol concentration was decreased (P < 0.05) at 24 h after rbTNF injection, whereas the a-tocopherol concentration was not significantly affected by rbTNF treatment. At 0.5 and 24 h, there was an increase (P < 0.05) in the plasma concentration of the very-low-density lipoprotein (VLDL) fraction in rbTNF-treated heifers. Between 6 and 24 h after rbTNF treatment, concentration of the low-density lipoprotein fraction declined (P < 0.05) but the high-density lipoprotein fraction was not altered in the rbTNF-treated heifers. These results indicate that TNF produces a hypertriglyceridemic response associated with an increase of the VLDL fraction and a disturbance of retinol metabolism in dairy heifers.
authors.affiliation: Department of Animal Production, National Agricultural Research Center for Tohoku Region, Iwate, Japan. mendoza@affrc.go.jp
authors.forename: S
authors.initials: S
authors.lastname: Kushibiki
authors.forename: K
authors.initials: K
authors.lastname: Hodatet
authors.forename: H
authors.initials: H
authors.lastname: Shingu
authors.forename: T
authors.initials: T
authors.lastname: Hayashi
authors.forename: E
authors.initials: E
authors.lastname: Touno
authors.forename: M
authors.initials: M
authors.lastname: Shinoda
authors.forename: Y
authors.initials: Y
authors.lastname: Yokomizo
mesh_terms: D000818:Animals; D002417:Cattle / Q000097:blood / Q000378:metabolism*; D018592:Cross-Over Studies; D005230:Fatty Acids, Nonesterified; D005260:Female; D015228:Hypertriglyceridemia / Q000139:chemically induced / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000097:blood* / Q000378:metabolism; D011897:Random Allocation; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014801:Vitamin A / Q000097:blood / Q000378:metabolism*
chemical_list: D005230:Fatty Acids, Nonesterified; D008055:Lipids; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D014801:Vitamin A