Effects of high fat in the diet on growth, antioxidant, immunity and fat deposition of Macrobrachium rosenbergii post-larvae

Bile acid and short chain fatty acid metabolism of gut microbiota mediate high-fat diet induced intestinal barrier damage in Macrobrachium rosenbergii

The limited tolerance of crustacean tissue physiology to a high-fat diet has captured the attention of researchers. Yet, investigations into the physiological response mechanisms of the crustacean intestinal barrier system to a high-fat diet are progressing slowly. Elucidating potential physiological mechanisms and determining the precise regulatory targets would be of great physiological and nutritional significance. This study established a high-fat diet-induced intestinal barrier damage model in Macrobrachium rosenbergii, and systematically investigated the functions of gut microbiota and its functional metabolites. The study achieved this by monitoring phenotypic indicators, conducting 16S rDNA sequencing, targeted metabolomics, and in vitro anaerobic fermentation of intestinal contents. Feeding prawns with control and high-fat diets for 8 weeks, the lipid level of 7 % in the CON diet and 12 % in the HF diet. Results showed that high-fat intake impaired the intestinal epithelial cells, intestinal barrier structure, and permeability of M. rosenbergii, activated the tight junction signaling pathway inhibiting factor NF-κB transcription factor Relish/myosin light chain kinase (MLCK), and suppressed the expression of downstream tight junction proteins zona occludens protein 1 (ZO-1) and Claudin. High-fat intake resulted in a significant increase in abundance of Aeromonas, Enterobacter, and Clostridium sensu stricto 3 genera, while Lactobacillus, Lactococcus, Bacteroides, and Ruminococcaceae UCG-010 genera were significantly decreased. Targeted metabolomics results of bile acids and short-chain fatty acids in intestinal contents and in vitro anaerobic fermentation products showed a marked rise in the abundance of DCA, 12-KetoLCA, 7,12-diketoLCA, and Isovaleric acid, and a significant reduction in the abundance of HDCA, CDCA, and Acetate in the HF group. Pearson correlation analysis revealed a substantial correlation between various genera (Clostridium sensu stricto 3, Lactobacillus, Bacteroides) and secondary metabolites (DCA, HDCA, 12-KetoLCA, Acetate), and the latter was significantly correlated with intestinal barrier function related genes (Relish, ZO-1, MLCK, vitamin D receptor, and ecdysone receptor). These findings indicate that gut microorganisms and their specific bile acids and short-chain fatty acid secondary metabolites play a crucial role in the process of high-fat-induced intestinal barrier damage of M. rosenbergii. Moreover, identifying and targeting these factors could facilitate precise regulation of high-fat nutrition for crustaceans.

Transcriptome analysis reveal the effect of freshwater sediments containing 2,3,7,8-tetrachlorodibenzo-p-dioxin on the Macrobrachium rosenbergii hepatopancreas, intestine, and muscle

This research evaluated the hepatopancreas, intestine, and muscle transcriptome alternation of Macrobrachium rosenbergii, and to confirm the relative glycerophospholipid, cytochrome P450 system, and fatty acid metabolism gene expression in sediments containing 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) of 60 ng/sediment (g) and 700 ng/sediment (g) for 90 days of culture. Transcriptome analysis revealed that the TCDD sediment affected the hepatopancreatic metabolism of xenobiotics in M. rosenbergii via the cytochrome P450 system, drug metabolism-other enzymes, drug metabolism-cytochrome P450, chemical carcinogenesis, and lysosome function. Intestinal analysis also showed a similar phenomenon, but this finding was not observed in the muscle tissue. qPCR analysis indicated that the expression levels of APTG4, LPGAT1, ACHE, GPX4, ECHS1, ATP5B, FABP, and ACC in the hepatopancreatic and intestinal tissues decreased, but those in the muscle tissues did not. In summary, TCDD sediment induced tissue metabolism, especially in the hepatopancreas and intestine. TCDD sediment mainly affected the digestive enzyme gene expression with concentration. These results indicated that the presence of TCDD in the sediment played a major role in the hepatopancreatic and intestinal metabolism system of M. rosenbergii.