Abstract

RIOSECO H, Macarena; NORO, Mirela; RICARDO CHIHUAILAF, V  and  WITTWER M, Fernando. Selenium metabolic status and response to supplementation in grazing Chilean-Criollo horses. Rev.MVZ Cordoba [online]. 2013, vol.18, n.3, pp.3822-3828. ISSN 0122-0268.

Objective. Two experiments were conducted to determine the selenium status in grazing Chilean-Criollo horses and evaluate their response to a Na₂SeO₃ supplement. Material and methods. ^Exp.1The blood activity of glutathione peroxidase (GPx, EC.1.11.1.9) (AcGPx) was determined in horses kept grazing in 10 breeding farms from the south of Chile: PO, n= 40 horses were kept grazing during autumn (PO), 47 horses were kept grazing during autumn and supplemented with oat grain (PO+A), and 23 horses were kept grazing during spring (PP). ^Exp.223 horses kept on pasture were allotted into three groups: G1, n=7, supplemented with a dose of Na₂SeO₃ (Se= 0.05mg/kg bw, im) on day 0; G2, n=8, supplemented with similar doses of Na₂SeO₃, on days 0 and 15; and GC, n=8, control. AcGPx was determined on days 0, 30 and 120. Results. Median (Me) of the AcGPx on all the farms were below the adequate limit (>130 U/g Hb), being higher in PO+A (M_e= 92, P_25%= 47, P_75%= 129 U/g Hb) and PP (M_e = 85, P_25%= 45, P_75%=114 U/g Hb) than PO (M_e= 35, P_25%= 20, P_75%= 85 U/g Hb) (p<0.05). Initial AcGPx was similar and below adequate in the three groups and increased after Na₂SeO₃ administration (p<0.05) in G1 (121 ± 52 U/g Hb) and G2 (124 ± 69 U/g Hb). Conclusions. A deficiency is observed in Chilean-Criollo horses grazing during autumn and spring in southern Chile, parenteral administration of Na₂SeO₃ (0.05mg/kg bw) in single or double doses improves the Se status without achieving adequate values.

Keywords : Equine; GPx; sodium selenite; seasonal variations.

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