Relationships between ovarian cysts and morphological and hormonal state of ovarian cortex in sows

The aim of this study was to evaluate the relationship between ovarian cysts and concentrations of ovarian steroid hormones: 17β-estradiol (E2), progesterone (P4), testosterone (T), and androstendione (A4) both in blood plasma and in cysts and morphological state of the ovarian cortex in sows. Females were divided into three groups: PCO (sows with polycystical ovaries), OO (sows with oligocystic ovaries) and control (sows without ovarian cysts). The ovaries for evaluations were collected after slaughtering of 18 multiparous sows. Between the PCO and OO animals, statistically significant differences in numbers of the follicular cysts (FC) (8.6 vs. 1.5), follicular theca-lutein cysts (FTLC) (8.0 vs. 2.0), follicular lutein cysts (FLC) (4.5 vs. 2.0) and corpus luteum cysts (CLC) (1.7 vs. 0.4) (P ≤ 0.01) were noted. In the PCO sows the most common kinds of cysts were FC and FTLC (8.6 and 8.0) whilst in OO sows the cysts occurred on their ovaries on a similar level (FC – 1.6, FTLC – 2.0, FLC – 2.0). Existence of more than 10 ovarian cysts in the sows significantly decreases the frequency of physiological ovarian follicles (primary, growing and maturing) and significantly increases the pathological process of atresia on all stages of ovarian follicles development (P ≤ 0.01). The study did not reveal any effect of growing or decreasing number of ovarian cyst on concentrations of E2 and P4 in blood plasma of sows. Polycystical ovaries significantly decreased concentrations of A4 but increased the concentration of T in blood plasma (P ≤ 0.01). The general presence of ovarian cysts considerably positively correlated with concentrations of E2, T and A4 from cysts’ fluid, of all kinds of ovarian cysts and atresia of primary follicles (a correlation coefficient r from 0.72 up to 0.97, P ≤ 0.05). The phenomenon of ovarian cysts significantly negatively correlated with all generations of ovarian follicles (P ≤ 0.05).