title: Cobalt deficiency effects on trace elements, hormones and enzymes involved in energy metabolism of cattle.
abstract: This study was conducted to investigate the physiological consequences of long-term moderate cobalt deficiency in beef cattle, which have not hitherto been studied in detail. Cobalt deficiency was induced in cattle by feeding two groups of animals either a basal corn silage-based diet that was moderately low in cobalt (83 micrograms Co/kg), or the same diet supplemented with cobalt to a total of 200 micrograms per kg, for 43 weeks. Cobalt deficiency was induced, as judged by inappetance, diminished growth gain and a markedly reduced vitamin B12 status in serum and liver. The long-term cobalt deprivation which was primarily a combination of reduced feed intake and a tissue vitamin B12 deficiency did not show evidence of a significant dysfunction of energy metabolism. The activities of glucose-6-phosphate dehydrogenase and cytochrome oxidase in liver remained unaffected by cobalt deficiency, nor was there a significant change in serum glucose level of cattle on the cobalt-deprived diet. However, analysis of thyroid hormone status indicated a slight reduction of type I thyroxine monodeiodinase activity in liver accompanied by a significant reduction of the triiodothyronine level in serum. The diminished liver vitamin B12 level resulted in significantly reduced folate level in this tissue, reduced concentrations of heme-depending blood parameters. Moreover cobalt deficiency or rather vitamin B12 deficiency was accompanied by a dramatic accumulation of the trace elements iron and nickel in liver. These results indicate that long-term moderate cobalt deficiency may induce a number of physiological changes in cattle, but a follow-up study, which excluded different feed levels by including a pair-fed control group, will be necessary to actually obtain the single effect of cobalt deficiency in cattle.
authors.affiliation: Institut für Ernährungsphysiologie, Technische Universität München, Freising-Weihenstephan, Germany.
authors.forename: G I
authors.initials: GI
authors.lastname: Stangl
authors.forename: F J
authors.initials: FJ
authors.lastname: Schwarz
authors.forename: M
authors.initials: M
authors.lastname: Kirchgessner
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle / Q000502:physiology*; D003035:Cobalt / Q000172:deficiency*; D003576:Electron Transport Complex IV / Q000378:metabolism; D004734:Energy Metabolism; D005492:Folic Acid / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006418:Heme / Q000378:metabolism; D007501:Iron / Q000097:blood; D008099:Liver / Q000378:metabolism; D008297:Male; D009532:Nickel / Q000097:blood; D013963:Thyroid Hormones / Q000502:physiology*; D014131:Trace Elements / Q000378:metabolism*; D014284:Triiodothyronine / Q000097:blood; D015032:Zinc / Q000097:blood
chemical_list: D001786:Blood Glucose; D013963:Thyroid Hormones; D014131:Trace Elements; D014284:Triiodothyronine; D003035:Cobalt; D006418:Heme; D009532:Nickel; D005492:Folic Acid; D007501:Iron; D005954:Glucosephosphate Dehydrogenase; D003576:Electron Transport Complex IV; D015032:Zinc