85400 20201117095023.0 doi 10.1016/j.anireprosci.2018.11.007 sideral 109744 ART-2019-109744 eng Carvajal-Serna, M. Changes in melatonin concentrations in seminal plasma are not correlated with testosterone or antioxidant enzyme activity when rams are located in areas with an equatorial photoperiod 2019 Access copy available to the general public Unrestricted In temperate climates, photoperiod and melatonin regulate ram reproduction, modulating hormonal secretions, sperm quality, and seminal plasma composition. Information on the effect of an equatorial photoperiod (12L:12D) on ram reproduction, however, is scarce, and no data on hormonal concentrations and antioxidant enzyme activity in seminal plasma have been reported. Thus, the variation was investigated of melatonin and its relationship with testosterone and antioxidant enzyme activity in the seminal plasma of three sheep breeds in Colombia, when there was a consistent photoperiod during two dry and two rainy seasons per year. Semen was collected once a week from 12 mature rams (four of each breed: Colombian Creole, Hampshire, and Romney Marsh). Seminal plasma was obtained by centrifugation. The concentration of melatonin and testosterone were quantified along with the enzymatic activity of glutathione peroxidase (GPx), glutathione reductase (GRD), and catalase (CAT). Correlation analyses between melatonin and testosterone concentrations or enzymatic activity were also performed. Melatonin concentration was affected by season (P < 0.05) but not breed, with lesser concentrations in the first rainy season. Testosterone concentration, however, was affected by breed and season, with greater concentrations (P < 0.01) in the Hampshire and Romney Marsh rams during the second dry season. Regarding antioxidant enzyme activity, there was only seasonal variation in GPx activity (P < 0.05). When correlation analyses were used for data assessments, there was a negative correlation between melatonin and testosterone concentrations in Hampshire rams. In conclusion, melatonin concentrations in seminal plasma of rams that were located in an area with an equatorial photoperiod was affected by the climatological season but there was no positive correlation with testosterone concentration or antioxidant enzyme activity. info:eu-repo/grantAgreement/ES/MINECO-FEDER/AGL2014-57863-R info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 1.66 2019 AGRICULTURE, DAIRY & ANIMAL SCIENCE 22 / 63 = 0.349 2019 Q2 T2 REPRODUCTIVE BIOLOGY 26 / 29 = 0.897 2019 Q4 T3 0.66 2019 Animal Science and Zoology 2019 Q1 Medicine (miscellaneous) 2019 Q2 Food Animals 2019 Q2 Endocrinology 2019 Q3 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Torres-Ruda, F. Cardozo, J.A. Grajales-Lombana, H. (orcid)0000-0001-9842-6197 Cebrián-Pérez, J.Á. Universidad de Zaragoza (orcid)0000-0003-1306-8517 Muiño-Blanco, T. Universidad de Zaragoza (orcid)0000-0002-2312-6402 Pérez-Pé, R. Universidad de Zaragoza (orcid)0000-0003-1997-4262 Casao, A. Universidad de Zaragoza 1002 819 Universidad de Zaragoza Dpto. Bioq.Biolog.Mol. Celular Área Zoología 1002 060 Universidad de Zaragoza Dpto. Bioq.Biolog.Mol. Celular Área Bioquímica y Biolog.Mole. 200 (2019), 22-30 Anim. reprod. sci. Animal Reproduction Science 0378-4320 533820 http://zaguan.unizar.es/record/85400/files/texto_completo.pdf Postprint 224971 http://zaguan.unizar.es/record/85400/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:85400 articulos driver 2020-11-17-09:44:09 ARTICLE