Saisonabhängige Veränderungen der Ovargröße sowie Konzentration von Steroidhormonen und Thyroxin in der Follikelflüssigkeit beim Schwein

Zusammenfassung

Gegenstand und Ziel: Bestimmung der Konzentration von 17-®-Östradiol (E2), Progesteron (P4), Testosteron (T) und Thyroxin (T4) in der Follikelflüssigkeit sowie Erfassung der Ovargröße beim Schwein in den einzelnen Jahreszeiten. Material und Methoden: Die Untersuchungen wurden in vier Jahreszeiten an Ovarien von Sauen im Alter von 7–9 Monaten durchgeführt. Vor Aspiration der Follikelflüssigkeit erfolgte eine Vermessung der Ovarien. In der Follikelflüssigkeit wurde mit der Immunfluoreszenzmethode die Konzentration von 17-®-Östradiol (E2), Progesteron (P4), Testosteron (T) und Thyroxin (T4) bestimmt. Ergebnisse: Masse der Ovarien sowie ihre Länge und Breite waren im Winter signifikant größer (p ≤ 0,01) als in den übrigen Jahreszeiten. Die E2-Konzentrationen und der P4-Gehalt lagen im Winter und Herbst signifikant höher (p ≤ 0,01) als im Sommer und Frühling. Die im Winter entnommene Follikelflüssigkeit wies gegenüber Herbst, Sommer und Frühling einen signifikant höheren (p ≤ 0,01) T-Gehalt auf. Im Frühling war die T4-Konzentration in der Follikelflüssigkeit signifikant höher (p ≤ 0,01) als im Sommer und Herbst. Schlussfolgerungen: Saisonale Differenzen der Ovargröße bestätigen den saisonalen Charakter der Reproduktionsaktivität beim Schwein. Unterschiede in der Konzentration von Steroidhormonen zeugen vom saisonabhängigen Verlauf der steroidogenen Follikelaktivität. Die Thyroxingehalte in der Follikelflüssigkeit bestätigen den Einfluss dieses Hormons auf die Funktion der Ovarialfollikel und die saisonabhängigen Unterschiede in seiner Konzentration verweisen auf einen Zusammenhang zwischen der Zusammensetzung der Follikelflüssigkeit und der Jahreszeit. Die Ergebnisse sollen bei In-vitro-Untersuchungen an Oozyten berücksichtigt werden, die zu verschiedenen Jahreszeiten gewonnenen wurden.

Summary

Subject: The domestic pig is not a typical seasonal breeder. However, most parameters of pigs’ reproduction are worse during summer and early autumn, whereas fertility tends to improve during winter-spring season. Objective: The aim of this study was to determine concentrations of 17-®-estradiol (E2), progesterone (P4), testosterone (T) and thyroxine (T4) in the follicular fluid of gilts (7–9 months old) and seasonal changes of ovarian morphology in relation to season. Material and methods: Follicular fluid was aspirated from porcine ovaries obtained from a local slaughterhouse in autumn, winter, spring and summer. The concentrations of hormones were measured by fluorimmunoassay. Statistical differences between the groups of follicles were examined using the Mann-Whitney U-test. Results: Mass, length and width of ovaries in winter was higher (p ≤ 0.01) than in the remaining seasons. Estradiol and progesterone concentrations were significantly higher in winter and autumn than in summer and spring. In winter a significantly higher concentration of testosterone could be measured compared to summer (p ≤ 0.01) and spring (p ≤ 0.05). The highest thyroxine concentration was recorded in spring. Conclusion: In conclusion, shown differences ovary size in the different seasons confirm the occurrence of seasonal changes in sexual activity in pigs. Moreover, our results show seasonal differences in the concentration of the ovarian steroid hormones, which suggest different steroidogenic capacity of porcine ovarian follicles in the different seasons. In addition, varying intrafollicular thyroxine concentration in the different seasons confirms the effect of this hormone on ovarian follicular development and function.

Schlüsselwörter

Schwein - Reproduktion - Jahreszeit - Ovarialfollikel - Steroidhormone - Thyroxin

Keywords

Pig - breeding season - ovarian follicle - steroid hormones - thyroxine

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