# Dietary Supplementation with Chenodeoxycholic Acid or Ursodeoxycholic Acid Modulates Growth, Thyroid Status, and Hepatopancreatic–Intestinal Health in Juvenile Little Yellow Croaker Larimichthys polyactis

## TL;DR

Adding chenodeoxycholic or ursodeoxycholic acid to the diet of juvenile little yellow croaker improves growth and reduces liver-intestinal damage caused by poor nutrition.

## Contribution

The study identifies optimal bile acid supplementation levels to improve health and growth in L. polyactis.

## Key findings

- Both CDCA and UDCA improved growth and altered thyroid hormone metabolism in L. polyactis.
- 300 mg/kg CDCA and 600 mg/kg UDCA reduced liver vacuolation and lipid accumulation.
- Dietary BAs enhanced intestinal antioxidant capacity but also induced inflammation.

## Abstract

Commercial feeds formulated for Larimichthys crocea are commonly used in intensive farming of Larimichthys polyactis; however, their nutritional composition is suboptimal for the latter. The study evaluated the effects of dietary chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA) supplementation on mitigating nutritional mismatch-induced growth retardation and hepatopancreatic–intestinal metabolic disorders in L. polyactis. Fish were fed seven feeds: a commercial feed (control) and feeds supplemented with 300, 600, and 1200 mg/kg of CDCA or UDCA. Results showed that both bile acids (BAs) supplementation improved growth, altered thyroid hormone metabolism, with significant changes in hepatopancreatic–intestinal types of deiodination. Both BAs increased hepatopancreatic energy metabolism and cholic acid synthesis, while inducing hepatopancreatic oxidative damage. Notably, 300 mg/kg CDCA and 600 mg/kg UDCA significantly reduced hepatopancreatic vacuolation and lipid accumulation, which was associated with enhanced protease and lipase activities (p < 0.05). Dietary both BAs supplementation enhanced intestinal antioxidant capacity, but contributed to the inflammation, with 300 mg/kg UDCA improving intestinal mucosal morphology (p < 0.05). These findings suggest that supplementation with dietary 300 mg/kg CDCA, 300 and 600 mg/kg UDCA could alleviate growth restriction and liver–intestinal structural damage caused by nutritional mismatch, reduce hepatic fat accumulation, and enhance intestinal antioxidant capacity of L. polyactis.