Plant protein diet-induced hypoimmunity by affecting the spiral valve intestinal microbiota and bile acid enterohepatic circulation in Amur sturgeon (Acipenser schrenckii)

• Published in: Fish & shellfish immunology 2020-11, Vol.106, p.421-430
• Main Authors: Wei, H.C., Xing, S.J., Chen, P., Wu, X.F., Gu, X., Luo, L., Liang, X.F., Xue, M.
• Format: Article
• Language: English
• Subjects: Amur sturgeon; Animal Feed - analysis; Animals; Bile acid enterohepatic circulation; Bile Acids and Salts - metabolism; Diet - veterinary; Dietary Supplements - analysis; Dose-Response Relationship, Drug; Enterohepatic Circulation; Fishes - immunology; Gastrointestinal Microbiome - drug effects; Hepatic lesion; Hypoimmunity; Intestines - microbiology; Plant protein; Plant Proteins, Dietary - administration & dosage; Plant Proteins, Dietary - metabolism; Random Allocation; Spiral valve intestine
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2020.08.025

An 8-week growth trial was conducted to study enterohepatic recirculation of bile acid metabolism and the intestinal microbiota of Amur sturgeon (Acipenser schrenckii) fed with three diets, including 540 g/kg, 270 g/kg or 0 g/kg fishmeal, which was correspondingly replaced by a plant protein blend (named P0, P50 and P100, respectively). The diets were designed to be isonitrogenous, isoenergetic and essential nutrients balanced. With rising levels of dietary plant protein, disruption of the spiral valve intestinal microbiota and more morbidity with liver disease were observed in the P100 group, although there were no haematological abnormalities observed. An obvious bile acids enterohepatic circulation disorder was found with phenotypes of increased liver bile acids compensatory synthesis, and reduced expression of bile acid receptors (FXR and TGR5), which induced BA accumulative toxicity. Accompanied by increased oxidative stress, it further induced hepatic lesions and hypoimmunity, which were non-negligible reasons for the high mortality and low utilization ability of plant protein by Amur sturgeon. •Hepatic damage was observed fed with full PP diet in Amur sturgeon.•Full PP diets induced spiral valve intestinal (SVI) microbial disturbance.•SVI mucosa lesions induced bile acids (BAs) reabsorption disorder.•The accumulation of hepatic BAs was regulated by inhibition of bile acid receptors.•The hypoimmunity induced by failed response of apoptosis to the increased ROS.