Effects of paraprobiotics on bile acid metabolism and liver health in largemouth bass (Micropterus salmoides) fed a cottonseed protein concentrate-based diet

Xiaoze Xie; Xiaofang Liang; Hao Wang; Qiang Zhu; Junjun Wang; Ying Chang; Eric Leclercq; Min Xue; Jie Wang

doi:10.1016/j.aninu.2023.02.011

Effects of paraprobiotics on bile acid metabolism and liver health in largemouth bass (Micropterus salmoides) fed a cottonseed protein concentrate-based diet

Anim Nutr. 2023 Mar 7:13:302-312. doi: 10.1016/j.aninu.2023.02.011. eCollection 2023 Jun.

Authors

Xiaoze Xie^{1

2}, Xiaofang Liang¹, Hao Wang¹, Qiang Zhu³, Junjun Wang², Ying Chang⁴, Eric Leclercq⁴, Min Xue¹, Jie Wang^{1

3}

Affiliations

¹ National Aquafeed Safety Assessment Center, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
² State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
³ Xinjiang Jinlan Plant Protein Co., Ltd, Shihezi 833200, China.
⁴ Lallemand SAS, Blagnac 31702, France.

Abstract

Cottonseed protein concentrate is a sustainable fishmeal alternative in aquafeed. A 10-week experiment was conducted to investigate the effects of a cottonseed protein concentrate-based diet with and without multi-strain yeast fractions (MsYF) on growth, bile acid metabolism, and health in largemouth bass. Four hundred fish (54.0 ± 0.0 g) were casually distributed into 16 tanks (4 replicates/diet). Fish were fed with 4 iso-nitrogen and iso-energetic diets 3 times daily, including a fishmeal diet (FM), a soy protein concentrate-based diet (SPC; replacing 81% fishmeal protein), a cottonseed protein concentrate-based diet (CPC; replacing 81% fishmeal protein), and a CPC diet supplemented with 800 mg/kg MsYF (CPCY). Results showed that the survival of SPC was the lowest, i.e., 48%, with no apparent diet effect among other treatments; we omitted the SPC in additional analyses. Fish fed cottonseed protein concentrate-based diets showed lower growth than FM (P < 0.05). Fish fed CPC showed the highest nuclear dense hepatic phenotypes ratio (50%), followed by CPCY (33%) and FM (17%). Further, dietary CPC increased hepatic total cholesterol and triglyceride levels with concurrently increased cholesterol synthesis but decreased triglyceride synthesis-associated transcription levels (P < 0.05). Furthermore, dietary CPC increased bile acid synthesis but decreased bile acid transport-associated transcription levels (P < 0.05), and then induced an increment of plasma cholic acid and hepatic chenodeoxycholic acid content and the decrement of genus Romboustia (P < 0.05). Regarding the effect of MsYF, fish fed CPCY reduced hepatic lipid accumulation and total plasma bile acid content (P < 0.05) compared to CPC, suggesting an improvement in liver health. Also, dietary MsYF could reverse the microbiota community structure showing a similar gut microbial composition to FM. In conclusion, 81% of fishmeal protein replaced by cottonseed protein concentrate suppressed growth and liver health, while dietary MsYF might mitigate the negative impact of a high cottonseed protein concentrate level diet on liver functions via gut microbiota regulation.

Keywords: Bile acid metabolism; Cottonseed protein concentrate; Gut microbiota; Liver health; Micropterus salmoides; Multi-yeast strain fractions.