Taurine-conjugated bile acids are the predominant form in hens and have potential impact on lipid metabolism in the liver

Abstract

In mammals, bile acids composition varies with species, age, physiological conditions. However, the role of bile acids in the laying cycle of hens and their impact on lipid metabolism in chicken liver is not well understood. This study aimed to elucidate the role of bile acids in hen laying cycles, investigating their distribution across ages and assessing the impact of taurine-conjugated lithocholic acid (TLCA) on oleic acid-induced fatty liver cells in chickens. Results revealed an age-related increase in total bile acid concentration in hens blood, with taurine-conjugated bile acids prevailing. Among specific bile acids analysed, taurodeoxycholic acid (TDCA) decreased with age, while taurochenodeoxycholic acid (TCDCA) increased (n = 8). TLCA concentration also decreased gradually, while lycocholic acid (GCA) was elevated in 16-week-old hens (n = 8). Primary bile acids, cholic acid (CA), and chenodeoxycholic acid (CDCA) were higher at 16 weeks compared to egg production commencement (22 weeks) and 34 weeks (n = 8). Moreover, 5ß-Cholenic acid-7a-ol-3-one concentration was elevated in 74-week-old hens post-laying (n = 8). Investigating TLCA's impact on chicken liver lipid metabolism, TLCA significantly reduced lipid droplet accumulation, especially at 20 μM, while upregulating TLCA concentrations correlated with decreased SREBP1 protein expression responsible for triglyceride synthesis. In conclusion, taurine-conjugated bile acids potentially regulate lipid metabolism in hens, offering avenues for enhancing hens health and production through further mechanistic exploration and their potential integration into hens feed.

HIGHLIGHTS

Age-related changes in bile acid composition in hens were observed, with taurine-conjugated bile acids being predominant. Taurine-conjugated lithocholic acid showed promising effects in reducing lipid droplet accumulation and suppressing SREBP1 protein expression in fatty liver cells.

Keywords:

• Bile acids
• taurine-conjugated lithocholic acid
• laying hens

Ethical approval

The experimental protocol and sample collection were carried out in accordance with the regulations by the National Taiwan University. And the animal experimental protocol was approved by the Institutional Animal Care and Use Committee of National Taiwan University (NTU110-EL-00024).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data presented in this study are available on request from the corresponding author.

Additional information

Funding

Funds supporting this study were provided by the Council of Agriculture, Executive Yuan, Taiwan (grant number 112AS-5.1.6-AD-U1), National Science and Technology Council, Taiwan (grant number 111-2313-B-002-059), and National Taiwan University, Taiwan (grant number 112L7240).