Functional insights of digestion, absorption, and immunity in different segments of the intestine in Hemibarbus labeo from transcriptomic analysis

• Published in: Comparative biochemistry and physiology. Part D, Genomics & proteomics Genomics & proteomics, 2024-12, Vol.52, p.101278, Article 101278
• Main Authors: Lv, Yaoping, Gao, Xinming, Dai, Qingmin, Zhu, Ling, Liu, Siqi, Hu, Zehui, Lu, Junkai, Zhou, Haidong, Jin, Jing, Mei, Zufei
• Format: Article
• Language: English
• Subjects: Animals; Cyprinidae - genetics; Cyprinidae - immunology; Different segments of the intestine; Digestion; Digestion and absorption; Fish Proteins - genetics; Fish Proteins - metabolism; Gene Expression Profiling; Hemibarbus labeo; Immunity; Intestinal Absorption; Intestinal Mucosa - metabolism; Intestines - immunology; RNA-seq; Transcriptome
• ISSN: 1744-117X; 1878-0407; 1878-0407
• DOI: 10.1016/j.cbd.2024.101278

The intestine is an important organ for food digestion and absorption and body immunity in fish. In this study, we investigated the abundance of transcripts from different segments of the intestinal tract using transcriptome sequencing technology in Hemibarbus labeo, to provide functional insights into digestion, absorption, and immunity in the anterior intestine (AI), middle intestine (MI), and posterior intestine (PI). We found 5646 differentially expressed genes (DEGs), which were significantly enriched to GO terms of carbohydrate metabolic process, transmembrane transport, iron ion binding, lipid metabolic process, and KEGG pathway of fat digestion and absorption, mineral absorption, protein digestion and absorption, vitamin digestion and absorption, indicating that the digestion and absorption function of food is different in AI, MI, and PI. In practice, most genes, enriched in the KEGG pathway for digestion and absorption of nutrients, are upregulated in AI and MI, indicating stronger roles for food digestion and absorption in these segments. Furthermore, we found that genes involved in the KEGG pathway of lysosome and endocytosis pathway are upregulated in PI, suggesting stronger antigen-presenting capabilities in PI. However, some cytokine receptor genes, including ccr4, cxcr2, tnfrsf9, il6r, csf3r, and cxcr4, are highly expressed in AI, reflecting the regional immune specialization in different segments. This study provides functional insights into digestion, absorption, and immunity in different segments of the intestine and supports the regional functional specialization within different segments of the intestine in H. labeo. [Display omitted] •Transcriptome analysis was performed in the anterior, middle, and posterior intestine.•The anterior and middle intestine are the main sites of food digestion and absorption.•The posterior intestine may have stronger antigen-presenting capabilities.•The study provides understanding of the digestive physiology and immunity of H. labeo.•The results provide evidences for the functional specialization within fish intestine.