CUT&tag-seq analysis of heat stress response in broiler liver provides novel insights into the improved thermotolerance by dietary phloretin

Abstract

This work aimed to study the effect of phloretin on antioxidant profiles through nuclear factor erythroid 2–related 2 (Nrf2)-DNA interactions in the liver of heat-stressed broilers by Cleavage Under Targets and Tagmentation combined with high-throughput sequencing (CUT&Tag-seq). One hundred and sixty 22-day-old Arbor Acres broilers were divided into four groups: a normal temperature group (NT: 22.8–23.4 °C and 46–55.8 % humidity) was fed a basal diet and three high temperature groups (China Summer condition: 29.7–31.7 °C and 77.9–94.8 % humidity) were fed the basal diet supplemented with 0 (HT group), 100 mg/kg (LT group) and 200 mg/kg (PT group) phloretin. Liver samples were taken from 42-day-old broilers. High temperature condition increased (P ≤ 0.05) the malondialdehyde (MDA) level, but decreased (P ≤ 0.05) the activities and mRNA expression levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), and Nrf2. Dietary 200 mg/kg phloretin decreased (P ≤ 0.05) the MDA level, but increased (P ≤ 0.05) the activities and mRNA expression levels of GSH-Px, SOD, CAT and Nrf2 in the liver of heat-stressed broilers. CUT&Tag-seq showed that 4042 DEPs were up-regulated, while 2322 DEPs were down-regulated in the PT group compared with the HT group. The Nrf2-binding gene of DEPs contained SOD3, CAT, SOD2, and p38 mitogen-activated protein kinase. Most TOP20 significant KEGG pathways were associated with “Environmental Information Processing”. Summary, phloretin could improve oxidative damage by Nrf2 and its downstream DNA-sites including genes and Nrf2-bingding non-coding RNAs in the liver of heat-stressed broilers.