循环热应激对黄羽肉鸡生长性能、空肠组织形态及空肠黏膜转录组和代谢组的影响OA

This study aimed to investigate the effects of cyclic heat stress on growth performance,jejunal mor-phology and jejunal mucosal transcriptome and metabolome of yellow-feathered broilers.A total of 120 male fast-growing yellow-feathered broilers aged 35 days with similar body weight were randomly allocated into two groups:a control group and a heat-stressed group.Each group consisted of 6 replicates with 10 birds per repli-cate.Birds in both groups were fed the same basal diet.The control group was reared at 26℃,whereas the heat-stressed group was subjected to a 7-day gradual temperature increase followed by a 14-day cyclic heat stress(32 to 35℃).The results showed as follows:1)in comparison with the control group,the body weight at 56 days of age,average daily feed intake and average daily gain of broilers in the heat stress group decreased significantly(P<0.05),and the feed to gain ratio increased significantly(P<0.05).In addition,the jejunal villi in the heat-stressed group appeared sparse and fractured,and both villus height and the ratio of villus height to crypt depth were significantly reduced compared with the control group(P<0.05).2)The jejunal mucosa transcriptome analysis showed that a total of 325 differentially expressed genes(DEGs)between the two groups were identified,which were mainly enriched in pathways such as C5-branched dibasic acid metabo-lism,cytokine-cytokine receptor interaction and cell adhesion molecules.Notably,the expression of genes C-C motif chemokine ligand 19(CCL19),C-C motif chemokine ligand 21(CCL21),interleukin-1 receptor 2(IL1R2)and citrate decarboxylase 1(ACOD1)were significantly upregulated in the heat-stressed group.3)The jejunal mucosal metabolome analysis showed that a total of 16 differentially expressed metabolites(DEMs)between the two groups were identified.The levels of metabolites such as 1-palmitoyl-2-octadecenoic-sn-glycerol-3-phosphocholine,2-oilyl-1-palmitoyl-sn-glycerol-3-phosphocholine,ethyl sulfate,α-ketoglutaric acid and biliverdin were significantly upregulated in the heat-stressed group.4)The integrated transcriptomic and metabolomic analysis revealed that DEGs and DEMs in jejunal mucosa were co-significantly enriched in the C5-branched dibasic acid metabolism pathway.Correlation analysis further suggested that ACOD1 gene may mediate this pathway to regulate α-ketoglutarate production,thereby participating in the maintenance of energy and immune homeostasis.In summary,cyclic heat stress can induce metabolic and immune disorders in the je-junal mucosa of yellow feathered broilers,as evidenced by the enhancement of the C5 branched dibasic acid metabolism pathway and the activation of immune inflammatory pathways such as cytokine cytokine receptor interaction.These changes subsequently trigger intestinal immune and inflammatory responses,leading to jeju-nal villous atrophy and nutrient malabsorption,and ultimately suppressing growth performance.