High-temperature stored soybean meal alters intestinal chyme composition and disrupts intestinal redox balance by increasing jejunal MAPK14 protein expression in broilers

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.