胆汁酸和胆固醇对白对虾生长性能、免疫反应及肠道微生物群的协同效应

胆固醇(CHO)是甲壳动物一种昂贵的必需营养素。胆汁酸(BAs)作为乳化剂可促进脊椎动物对脂质的吸收，在生长和固醇代谢中起着关键作用。本研究通过为期2个月的投喂实验，旨在探究饲料中添加胆固醇和发酵胆汁酸(FBAs；一种新型发酵胆汁酸)对淡水环境下凡纳滨对虾生长性能、免疫反应及肠道健康的独立及联合效应。实验共设计了12种等氮等脂饲料，在基础饲料中分别添加0.04% FBAs(A3)，0.05%(C1)、0.10%(C2)、0.20%(C3)、0.30%(C4)和0.40%(C5)的CHO，以及A3C1、A3C2、A3C3、A3C4和A3C5的FBAs与CHO复合物，并设置不添加FBAs与CHO的对照组(N)。鉴于基础饲料本身含有0.08%的CHO(来源于鱼粉等原料)且未检测到FBAs，实际CHO水平调整为0.08%(N)、0.13%(C1)、0.18%(C2)、0.28%(C3)、0.38%(C4)和0.48%(C5)。60天后，终末体重、增重率和特定生长率表明，FBAs、CHO及其复合物均能改善对虾生长性能，其中A3C2和A3C3组效果最佳。双因素方差分析显示FBAs与CHO之间存在显著协同效应。结果表明，CHO促进生长的效率高于FBAs，但与FBAs联用时其效率可显著提升。血淋巴生化参数(包括天冬氨酸氨基转移酶、丙氨酸氨基转移酶、α-淀粉酶、甘油三酯和酸性磷酸酶)均受不同处理的显著影响。肝胰腺基因表达水平显示，各处理组的抗脂多糖因子(ALF)、酚氧化酶原(proPO)和α2-巨球蛋白(α2M)表达显著降低，而碱性磷酸酶(AKP)表达显著高于对照组。饲料中添加FBAs、CHO及其复合物提高了凡纳滨对虾肠道菌群多样性。在门水平上，与对照组相比，变形菌门丰度显著降低，厚壁菌门、软壁菌门和蓝藻菌门丰度显著增加。在属水平上，FBAs与CHO处理组的假交替单胞菌属弧菌、弧菌科弧菌、希瓦氏菌属和聚球藻属丰度高于对照组。综上所述，在淡水养殖条件下，饲料中添加0.18%–0.28%胆固醇与0.04%发酵胆汁酸可通过协同效应显著提升凡纳滨对虾的生长性能、肝胰腺和肠道健康及肠道菌群状况。本研究通过优化FBAs与CHO配比，为提高淡水环境下凡纳滨对虾养殖效率提供了新方案，同时为降低饲料胆固醇含量、节约养殖成本提供了潜在策略。Abstract

Cholesterol (CHO) is an expensive essential nutrient for crustaceans. Bile acids (BAs), which function as emulsifiers facilitating lipid absorption in vertebrates, play a crucial role in the growth and sterol metabolism. This study conducted a 2-month feedingexperiment and aimed to investigate both the individual and interactive effects of dietary CHO and fermented BAs (FBAs; a novel type of FBAs) on growth performance, immune response, and intestinal health in Litopenaeus vannamei in freshwater environ- ment. A total of 12 isonitrogenous and isolipidic diets were formulated. These diets were formulated based on a basal diet by separately adding FBAs at a level of 0.04% (A3), CHO at levels of 0.05% (C1), 0.10% (C2), 0.20% (C3), 0.30% (C4), and 0.40% (C5) as well as combinations of FBAs and CHO at levels of A3C1, A3C2, A3C3, A3C4, and A3C5. A control group (N) without the addition of either FBAs or CHO was also included. Considering that the basic diet contained 0.08% CHO (from fish meal and other ingredients) and no detectable FBAs, the actual levels of CHO were adjusted to 0.08% (N), 0.13% (C1), 0.18% (C2), 0.28% (C3), 0.38% (C4), and 0.48% (C5). After 60 days, both FBAs, CHO, and their combination could improve the growth performance of shrimp, as indicated by final weight (FW), weight gain (WG), and specific growth rate (SGR). The best promoting effect was found in A3C2 and A3C3 groups. Two-way analysis of variance (ANOVA) analysis revealed significant synergistic effects between FBAs and CHO (p <0:05). These results suggest that CHO is more efficient than FBAs in promoting growth, but its efficiency can be significantly enhanced when combined with FBAs. Hemolymph biochemical parameters, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), α-amylase (α-AMS), triglycerides (TGs), and acid phosphatase, were significant affected by different treatments (p <0:05). Gene expression levels in the hepatopancreas showed significantly lower levels of anti- lipopolysaccharride factor (ALF), prophenoloxidase (proPO), and alpha-2-macroglobulin (α2M) and significantly higher levels of alkaline phosphatase (AKP) in different treated groups compared to the control groups (p <0:05). The addition of FBAs, CHO, and their combination to the diet increased gut microbiota diversity in L. vannamei. At the phylum level, there was a significant decrease in Proteobacteria abundance and a significant increase in Firmicutes, Tenericutes, and Cyanobacteria compared to the control group. At the genus level, Pseudoalteromonadaceae Vibrio, Vibrionaceae vibrio, Shewanella, and Synechococcus were found to be more abundant in the FBAs and CHO treatment group compared to the control group. In conclusion, a combination of 0.18%–0.28% CHO and 0.04% FBAs into feed formulations demonstrated synergistic effects on L. vannamei under freshwater conditions, significantly enhancing their growth performance, hepatopancreatic and intestinal health, and gut microbiota. This study provides a novel approach for improving the efficiency of L. vannamei breeding in freshwater environments by optimizing the ratio of FBAs and CHO. Furthermore, it provides a potential strategy to reduce dietary CHO content, thereby lowering feeding costs.翻译：宋紫菱(黄海水产研究所营养饲料团队)转载自：胖鲀先生；胖鲀文献速览：9月第四周(英文文献-B篇)原文：Guo Q, Pei S, Zhao L, et al. Synergistic Effects of Fermented Bile Acids and Cholesterol on Growth Performance, Immune Response, and Intestinal Microbiota of Litopenaeus vannamei in Freshwater Environment[J]. Aquaculture Research, 2025, 2025(1): 5959199.备注：转载只为分享，以学习交流为目的，如有侵权，联系删除。