Zearalenone exposure differentially affects the ovarian proteome in pre-pubertal gilts during thermal neutral and heat stress conditions.

ABSTRACT

Zearalenone (ZEN), a nonsteroidal estrogenic mycotoxin, causes endocrine disruption and porcine reproductive dysfunction. Heat stress (HS) occurs when exogenous and metabolic heat accumulation exceeds heat dissipation. Independently, HS and ZEN both compromise swine reproduction; thus, the hypothesis investigated was two-pronged that ZEN exposure would alter the ovarian proteome and that these effects would differ in thermal neutral (TN) and HS pigs. Pre-pubertal gilts (n = 38) were fed ad libitum and assigned to either (TN 21.0 ±â€…0.1 °C) or HS (12 h cyclic temperatures of 35.0 ±â€…0.2 °C and 32.2 ±â€…0.1 °C). Within the TN group, a subset of pigs were pair-fed (PF) to the amount of feed that the HS gilts consumed to eliminate the confounding effects of dissimilar nutrient intake. All gilts orally received a vehicle control (CT) or ZEN (40 µg/kg/BW) resulting in six treatment groups thermoneutral (TN) vehicle control (TC; n = 6); TN ZEN (TZ; n = 6); PF vehicle control (PC; n = 6); PF ZEN (PZ; n = 6); HS vehicle control (HC; n = 7); or HS ZEN (HZ; n = 7) for 7 d. When compared to the TC pigs, TZ pigs had 45 increased and 39 decreased proteins (P ≤ 0.05). In the HZ pigs, 47 proteins were increased and 61 were decreased (P ≤ 0.05). Exposure to ZEN during TN conditions altered sec61 translocon complex (40%), rough endoplasmic reticulum membrane (8.2%), and proteasome complex (5.4%), asparagine metabolic process (0.60%), aspartate family amino acid metabolic process (0.14%), and cellular amide metabolic process (0.02%) pathways. During HS, ZEN affected cellular pathways associated with proteasome core complex alpha subunit complex (0.23%), fibrillar collagen trimer (0.14%), proteasome complex (0.05%), and spliceosomal complex (0.03%). Thus, these data identify ovarian pathways altered by ZEN exposure and suggest that the molecular targets of ZEN differ in TN and HS pigs.

Zearalenone (ZEN) is an estrogenic mycotoxin that impairs fertility in swine. This study was designed to identify the ovarian molecular impacts of ZEN exposure in thermal neutral (TN) pre-pubertal pigs. Additionally, whether heat stress (HS) would affect the ovarian ZEN response was also queried. Using a mass spectrometry approach, proteins that are altered in the ovaries of TN and HS pigs were noted to include those involved with chemical detoxification, metabolism, and inflammation. These findings may be of use in developing mitigation strategies to improve fertility in swine exposed to ZEN via contaminated feeds.