Seasonal and age-related variations of plasma concentrations of androgens and prolactin in crossbred (3/4 wild, 1/4 domestic) boars
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Department of Dietetics, Warsaw Agricultural University, Nowoursynowska 166, 02-787 Warsaw, Poland
The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 05-110 Jabłonna, Poland
Warsaw Zoological Garden, Ratuszowa 1/3, 03-461 Warsaw, Poland
Publication date: 1999-10-07
J. Anim. Feed Sci. 1999;8(4):569–577
Plasma androgen and prolactin levels were determined by radioimmunoassay in 9 male crossbred (3/4 wild, 1/4 domestic) boars between 4 and 26 months of age. The boars were kept in outdoor enclosures. Androgen concentrations showed a clear seasonal pattern with the highest level in November; 6.48±1.31 ng/ml and 13.44±1.39 ng/ml during the first and second year of life, respectively. Data for the two years studied well demonstrated age-related androgen level variations with an elevation between 5 and 7 month of life (1.74±0.18 ng/ml) and maximum in 13 month-old boars (6.48±1.31 ng/ml). The prolactin level was low at 4 months of age (0.57±0.22 ng/ml), increased until 9-10 months (24.45±2.04 ng/ml) and decreased thereafter. Higher values were observed during the summer months (24.33±2.07 ng/ml) as compared with the rest of the year. It seems that there is a seasonal and age interaction in androgen concentrations with a predominance of season-related changes.