Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias
Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias
Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias
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16 t h International Congress on Animal <strong>Reproduction</strong><br />
Poster Abstracts 107<br />
P238<br />
Immunocytochemical localization of lept<strong>in</strong> (Ob) and lept<strong>in</strong><br />
receptor (Ob-R) <strong>in</strong> preovulatory and <strong>in</strong> vitro matured<br />
horse oocytes related to prepuberty and different weight<br />
breeds<br />
Lange Consiglio, A 1 *, Arrighi, S 2 , Bosi, GP 2 , Aralla, M 2 , Cremonesi, F 2<br />
1Veter<strong>in</strong>ary Cl<strong>in</strong>ical Sciences, <strong>Reproduction</strong> Unit, University of Milano, Faculty<br />
of Veter<strong>in</strong>ary Medic<strong>in</strong>e, Italy; 2 Department of Veter<strong>in</strong>ary Science and<br />
Technologies, University of Milano, Faculty of Veter<strong>in</strong>ary Med, Italy<br />
The onset of puberty <strong>in</strong> humans and animals is associated with an<br />
<strong>in</strong>crease <strong>in</strong> fat and consequent <strong>in</strong>crease <strong>in</strong> circulat<strong>in</strong>g lept<strong>in</strong>,<br />
suggest<strong>in</strong>g that lept<strong>in</strong> may be required for normal growth and<br />
<strong>de</strong>velopment of reproductive organs. Moreover, lept<strong>in</strong> amount <strong>in</strong> the<br />
blood is proportional to body energy stores and/or body mass, so,<br />
<strong>in</strong>a<strong>de</strong>quate nutrition might impair reproductive function lead<strong>in</strong>g, for<br />
example, to the <strong>de</strong>layed onset of puberty. A similar relationship<br />
between nutrition and reproductive efficiency is not un<strong>de</strong>rstood <strong>in</strong> the<br />
mare where, besi<strong>de</strong>s many reports quantify<strong>in</strong>g the correlation of<br />
circulat<strong>in</strong>g concentration of lept<strong>in</strong> with body condition scores, only<br />
few <strong>in</strong>formations exist about the presence of lept<strong>in</strong> (Ob) and lept<strong>in</strong><br />
receptor (Ob-R) <strong>in</strong> the ovary or <strong>in</strong> the oocyte. Tak<strong>in</strong>g this <strong>in</strong>to<br />
account, we carried out an immunocytochemical study to <strong>in</strong>vestigate<br />
the presence of Ob and Ob-R <strong>in</strong> compact cumulus oocytes recovered<br />
from fillies and from mares of light or heavy body weight breeds after<br />
slaughter<strong>in</strong>g dur<strong>in</strong>g the autumnal transition. The occurrence of<br />
immunofluorescence was <strong>de</strong>term<strong>in</strong>ed by scann<strong>in</strong>g laser confocal<br />
microscopy <strong>in</strong> oocytes immediately upon collection and after <strong>in</strong> vitro<br />
maturation (IVM) us<strong>in</strong>g monoclonal antibody conjugated to a<br />
fluorescent label. IVM was accomplished <strong>in</strong> TCM199 supplemented<br />
with 1 mM pyruvate, 0.1 IU LH, 0.1 IU FSH, 100 ng IGF, 50 ng EGF,<br />
1 µl ITS and 1 µl estrogen per ml. Oocytes were <strong>in</strong>cubated for 40 h at<br />
38°C at 5% CO2. Both Ob and Ob-R, <strong>de</strong>tected <strong>in</strong> immature oocytes of<br />
all k<strong>in</strong>ds of animals analyzed, were uniformly distributed throughout<br />
the ooplasm, but the <strong>in</strong>tensity of reaction was lower either <strong>in</strong> light<br />
weight mares or <strong>in</strong> fillies oocytes, than <strong>in</strong> oocytes of heavy weight<br />
mares. After IVM, heavy breed mares had a higher proportion of<br />
oocytes that reached metaphase II than light mares and fillies<br />
(35.53±2.71%, 19,84±1.48% and 15,82±1,52 respectively; P