Page 99 - 《水产学报》2025年第10期

孙克龙，等 水产学报, 2025, 49(10): 109607

Analysis of bile acid composition in Megalobrama amblycephala tissues and
effects of high-carbohydrate diet feeding

SUN Kelong , CHEN Weiliang , LIU Wenbin , LI Xiangfei *
Key Laboratory of Aquatic Animal Nutrition and Feed Science of Jiangsu Province, College of Animal Science and Technology,
Nanjing Agricultural University, Nanjing 210095, China

Abstract: Carbohydrate is an important non-protein energy source in aquaculture. Adding an appropriate amount of carbo-
hydrate to feed not only spares dietary protein and improves its utilization, but also reduces ammonia-nitrogen excretion and
water pollution. However, excessive carbohydrate inhibits growth, induces hepatobiliary disorders and lowers stress
tolerance, ultimately impairing production efficiency. Previous studies indicated that dietary bile acid supplementation can
modulate glycolipid metabolism and alleviate high-carbohydrate-induced disturbances, yet the long-term effects of high-carbo-
hydrate feeding on the bile acid profile of fish have not yet been examined. This study determined the bile-acid spectrum of
Megalobrama amblycephala and evaluated its response to long-term high-carbohydrate feeding, thereby clarifying mechan-
isms underlying carbohydrate-associated hepatobiliary syndromes and informing nutritional interventions. A total of two exper-
imental diets were prepared, including a control diet (29% nitrogen-free extract) and a high-carbohydrate diet (HC, 41% nitro-
gen-free extract). Each diet was fed to four replicates of juvenile M. amblycephala [(35.20 ± 0.15) g] for 12 weeks. Then, the
bile acid spectrum of M. amblycephala was analyzed in the liver, gallbladder, hindgut and plasma using the high-throughput
target quantitative detection technology. The results showed that both taurochenodeoxycholic acid (TCDCA) and taurocholic
acid (TCA) are the main bile acids in M. amblycephala, and there was a significant positive correlation between them. Com-
pared with the control group, the contents of taurolithocholic acid-3-sulfate (TLCA-3S) increased significantly in the liver of
the HC group. The contents of chenodeoxycholic acid (CDCA), taurolithocholic acid-3-sulfate (LCA-3S), glycocholic acid
(GCA), TCDCA, TCA, chenodeoxycholic acid (ACA) and taurodeoxycholic acid (TDCA) all decreased significantly in the
liver of the HC group. The contents of TCDCA and TCA both increased significantly in the gallbladder of the HC group, while
that of LCA-3S and lithocholic acid (LCA) both decreased significantly. The levels of LCA increased significantly in the
hindgut of the HC group, while that of cholic acid (CA), LCA-3S, GCA, TCDCA, TCA and glycodeoxycholic acid (GDCA) all
decreased significantly. Furthermore, the contents of cholic acid (CA), LCA and TLCA-3S all increased significantly, while
that of chenodeoxycholic acid 24-acyl-β-D-glucuronide (CDCA-24Gln) decreased significantly. In addiiton, glycine-conjug-
ated bile acids were found in the tissues of M. amblycephala, including GCA, glycochenodeoxycholic acid (GCDCA) and gly-
coursodeoxycholic acid (GUDCA). Furthermore, tauro-α-muricholic acid (T-α-MCA) was first found in fish. In conclusion,
both TCDCA and TCA are the main bile acids in M. amblycephala, and there was a significant positive correlation between
them. A long-term feeding of the HC diet significantly decreased the total bile acid content, and altered the component of bile
acids.
Key words: Megalobrama amblycephala; bile acid profile; correlation analysis; high-carbohydrate feed

Corresponding author: LI Xiangfei. E-mail: xfli@njau.edu.cn
Funding projects: Jiangsu Agricultural Science And Technology Innovation Fund [CX(22)3080]

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
13