High-temperature stored soybean meal alters intestinal chyme composition and disrupts intestinal redox balance by...

This study aimed to investigate the effects of feeding broilers basal diets with high-temperature (35°C) stored soybean meal (SBM). A total of 192 one-day-old Arbor Acres Plus broilers (male) were divided into three groups with eight replicates for a 42-d experimental period. The three groups were fed a basal diet with fresh SBM, SBM stored at 35°C for 2 and 4 wks, respectively. The results showed that the protein carbonyl content of high-temperature stored SBM increased linearly (P = 0.083) and the protein free thiols content decreased (P = 0.021). Compared with the control group, SBM stored at high temperatures for 4 wks decreased the average daily gain (P = 0.002) and body weight (P = 0.002) of broilers, and increased the feed conversion ratio of 1-21 d (P = 0.008). The high-temperature stored SBM for 4 wks increased the 21-d ileal trypsin activity (P = 0.047), duodenal carbonyl content (P = 0.012), jejunal reactive oxygen species levels (P = 0.047) and 42-d duodenal and jejunal ROS levels of broilers (P = 0.029). The high-temperature stored SBM for 4 wks decreased the 21-d duodenal total superoxide dismutase activity (P = 0.003) and catalase activity (P = 0.006). Moreover, The high-temperature stored SBM altered intestinal chyme composition, increased 42-d jejunal methionine sulfoxide and cystine levels, and decreased L-leucine and lysine levels. These changes have caused 114 DEPs in the jejunum of broilers, there were 53 up-regulated and 61 down-regulated. Furthermore, the upregulated MAPK14 significantly affected the downstream transcription factors c-JUN and FoxO1. Our findings revealed the effects and mechanisms by which intestinal function was affected after broiler chickens ingested protein-oxidized SBM and identified the composition changes in intestinal chyme, DEPs and signaling pathways in the intestinal tissue.