Effect Of Selenium-enriched Yeast On Intestinal Mucosal Immune And Oxidative Damage Induced By Ochratoxin A In Broilers

Ochratoxin A(OTA)is a mycotoxin produced by filamentous fungi that seriously affects human and animal health by contaminating food and feed.However,the mechanism of action of OTA on intestinal toxicity in broilers is not clear.Selenium(Se)is an essential micronutrient for humans and animals and plays a key role in the inflammatory signaling pathway and antioxidant defense.Selenium Rich Yeast(SeY)is a probiotic that is rich in Se and is beneficial to the absorption of small intestines.The effect of SeY on OTA-induced intestinal toxicity in chickens has not been studied.The purpose of this study was to determine whether SeY can alleviate the immune and oxidative damage of the duodenum,jejunum,and ileum induced by OTA in broilers.In this experiment,80 broilers of 1 day old age with similar body weight were selected and randomly divided into four groups,20 in each group.Control group(0.5mL normal saline + 0.5 mL sunflower oil),OTA group(50 ?g/kg.bw OTA + 0.5 mL sunflower oil),SeY group(0.4 mg/kg SeY),OTA+SeY group(50 ?g/kg).bw OTA+0.4 mg/kg SeY)Continuous gavage for 21 days,during which time drinking water is free.Record the weight of broilers during the trialThe weight of broiler chickens was recorded during the test.After the test,the duodenum,jejunum and ileum were collected.The length of the small intestine villi and the depth of the crypt were detected by HE staining.The number of goblet cells in the small intestine of the intestine was detected by PAS staining.The changes of antioxidant levels in intestinal tissues were detected.The expression levels of mRNA and marker proteins of NF-?B and Nrf2 signaling pathways were detected by qPCR and Western Blot.The results showed that:(1)OTA caused a significant decrease in body weight of broilers,a significant decrease in the length of villi in the small intestine,a significant decrease in the V/C ratio,and a significant decrease in the number of goblet cells.(2)SeY can inhibit the weight loss,the reduction of the villus length and the decrease of the V/C ratio of broilers caused by OTA exposure.(3)SeY can significantly increase the number of goblet cells and promote the secretion of intestinal mucosa in broilers.(3)SeY inhibited OTA exposure to reduce the antioxidant status of duodenum,jejunum and ileum by reducing SOD activity,T-AOC content,T-GSH content and increasing MDA content.(4)SeY up-regulates the mRNA levels of Il-1? and TNF-? by activating NF-?B and Nrf2 signaling pathways,andup-regulates the mRNA levels of Nrf2 and HO-1,and enhances the anti-inflammatory and anti-oxidative stress of broilers..The expression of NF-?B protein is decreased and the expression of Nrf2 protein is increased,which further enhances the body's anti-inflammatory response and its anti-oxidative stress,and enhances the injury of broiler small intestine caused by OTA exposure.The above results indicate that SeY can protect the small intestine function of broilers induced by OTA through the regulation of NF-? B and Nrf2 signaling pathways,thereby alleviating the body's anti-inflammatory response and anti-oxidative stress.