Influence of the rearing system on yolk corticosterone concentration in captive Greater Rheas (Rhea americana).

DELLA COSTA N; MARIN RH ; BUSSO JM ; HANSEN C; NAVARRO JL; MARTELLA MÓNICA BEATRIZ

ZOO BIOLOGY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 2016

0733-3188

Manyenvironmental conditions elevate plasma corticosterone in laying birds, leadingto elevated hormone accumulation in the egg. We investigated whether maternalyolk corticosterone levels in Greater Rheas differ between fresh eggs collectedfrom an intensive (IRS) and a semi-extensive (SRS) rearing system. After HPLCvalidation, yolk corticosterone was measured using a corticosterone 125Iradio-immunoassay kit. Results (mean ± SE) showed that eggs collected from theIRS exhibited a significantly higher corticosterone concentration than eggsfrom SRS (89.88 ± 8.93 vs. 45.41 ± 5.48 ng/g yolk, respectively). Our findingssuggest that rearing conditions under an intensive scheme (e.g. small pens withbare ground, no direct foraging and handling) might be perceived as morestressful for Greater Rhea females than semi-extensive rearing conditions (e.g.low animal density distributed in extensive areas and direct foraging), whichwould result in the transfer of higher yolk corticosterone levels. A betterunderstanding of environmental conditions and female traits that affect yolkcorticosterone deposition provides a background for futures studies concerningthe roles of maternal corticosterone on offspring development.