López Alonso, María MartaMiranda Castañón, Marta InésHernández Bermúdez, JoaquínCastillo Rodríguez, CristinaAyala de la Peña, IgnacioBenedito Castellote, José Luis2021-01-192021-01-191997J. Anim. Feed Sci. 1997;6(3):343–3511230-1388http://hdl.handle.net/10347/24230Blood glutathione peroxidase (GSH-Px; E.C. 1.11.1.9) activity, a measure of selenium status, as well as the plasma indicators of muscle damage creatine kinase (CK; E.C. 2.7.3.2) and aspartate aminotransferase (AST; E.C. 2.6.1.1) were evaluated in sheep in a region with low selenium levels during the spring and the summer, because this time may be critical for suffering selenium deficiencies. GSH-Px activity was highest during the spring, when mean values ranged from 74.16 and 90.51 Ul/g Hb, descending drastically during the summer, below physiological levels (P < 0.001) with mean values ranging from 43.33 to 50.01 Ul/g Hb. GSH-Px activity, within the deficiency range, registered during the summer did not originate muscle damage, since the muscle enzymes CK and AST were within their normal rangeengThis is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedAtribución 4.0 Internacionalhttp://creativecommons.org/licenses/by/4.0/EnzymesSeleniumEwesjournal article10.22358/jafs/69530/1997open access