5.6.1. Estradiol

Estradiol concentrations in the blood plasma of gilts were analyzed at the Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences in Olsztyn, Poland, as described previously [37]. Plasma E<sup>2</sup> levels were determined by the radioimmunoassay (RIA) method with a commercial kit (ESTR-US-CT, CIS BIO ASSAYS) as described previously [58]. Estradiol concentrations were determined in accordance with the method described previously [37].

### 5.6.2. Progesterone

Progesterone was quantified at the Analytical Laboratory of the Municipal Hospital with Polyclinic in Olsztyn, Poland, by the ECLIA electrochemiluminescence assay with the use of Elecsys Progesterone II and Cobas c 6000 analyzers (Hitachi, Tokyo, Japan). Progesterone concentrations were determined in accordance with the method described previously [37].

#### 5.6.3. Statistical Analysis

Data were processed statistically at the Department of Discrete Mathematics and Theoretical Computer Science, of the Faculty of Mathematics and Computer Science of the University of Warmia and Mazury in Olsztyn, Poland, as described previously [37].

**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/toxins14110790/s1, Figure S1. Tree map of ZEN, α-ZEL, and β-ZEL concentrations in reproductive system, hypothalamic, and pituitary gland tissues in Group ZEN5 gilts (5 µg ZEN/kg BW). Key: D1—exposure day 7; D2—exposure day 21; D3—exposure day 42.; Figure S2. Tree map of ZEN, α-ZEL, and β-ZEL concentrations in reproductive system, hypothalamic, and pituitary gland tissues in Group ZEN10 gilts (10 µg ZEN/kg BW). Key: D1 exposure day 7; D2—exposure day 21; D3 – exposure day 42; Figure S3. Tree map of ZEN, α-ZEL, and β-ZEL concentrations in reproductive system, hypothalamic, and pituitary gland tissues in Group ZEN15 gilts (15 µg ZEN/kg BW). Key: D1—exposure day 7; D2—exposure day 21; D3—exposure day 42.

**Author Contributions:** The experiments were conceived and designed by M.G. and M.T.G. The experiments were performed by M.G., Ł.Z. and A.B. Data were analyzed and interpreted by M.G., Ł.Z. and A.B. The manuscript was drafted by M.G., and critically edited by Ł.Z. and M.T.G. All authors have read and agreed to the published version of the manuscript.

**Funding:** The study was supported by the Polish Ministry of Science and Higher Education as part of Project No. 12-0080-10/2010. Project financially supported by the Minister of Education and Science under the program entitled "Regional Initiative of Excellence" for the years 2019–2023, Project No. 010/RID/2018/19, amount of funding 12.000.000 PLN.

**Institutional Review Board Statement:** All experimental procedures involving animals were carried out in compliance with Polish regulations setting forth the terms and conditions of animal experimentation (Opinions No. 12/2016 and 45/2016/DLZ of the Local Ethics Committee for Animal Experimentation of 27 April 2016 and 30 November 2016). All investigators are authorized to perform experiments on animals.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
