必需氨基酸通过重塑胆汁酸循环缓解草鱼肠炎并促生长

摘要  

高植物蛋白饲料可能对水产养殖品种的生长和健康存在一定限制。本研究通过基于氨基酸平衡原理在草鱼饲料中添加必需氨基酸，探究其对缓解上述问题的作用。对照组饲料以豆粕、菜籽粕和棉籽粕为主要蛋白源，实验组饲料则额外添加0.21%赖氨酸、0.32%蛋氨酸和0.23%苏氨酸。将300尾草鱼(61.3g)随机分配至6个网箱，分别投喂对照组和实验组饲料，为期8周。结果表明：饲料中补充氨基酸显著提高了增重率、特定生长率和饲料效率；同时下调了TLR/MyD88/NFκB信号通路及促炎细胞因子的mRNA表达，从而缓解肠道炎症。在肠道菌群方面，该处理提高了ACE和Chao指数，伴随厚壁菌门丰度上升而螺旋体门和短螺旋体属丰度下降。此外，饲料中补充氨基酸显著提高了肝脏sm转录水平和胆固醇含量，并刺激cyp7a1的mRNA表达，导致肝脏胆酸、牛磺胆酸、牛磺鹅去氧胆酸及糖基去氧胆酸3-硫酸二钠盐水平升高，同时增加肠道胆汁酸浓度。综上所述，补充必需氨基酸通过促进肝脏胆固醇和胆汁酸合成并影响肠道菌群组成，重塑了宿主的胆汁酸循环，缓解肠道炎症并促进草鱼生长。研究结果表明，优化饲料配方中的氨基酸平衡可提升鱼类生长性能与健康水平，同时降低生产成本，从而为水产养殖业的可持续发展提供有力支持。

亮点 

·添加必需氨基酸改善了草鱼的生长表现。

·添加必需氨基酸抑制了肠道TLR/MyD88/NFkB通路。

·添加必需氨基酸改变了肠道微生物群的组成和丰富度。

·添加必需氨基酸促进了胆固醇和胆汁酸的合成。

Abstract

High-plant protein diets can present certain limitations for the growth and health of aquaculture species. By incorporating essential amino acids into grass carp feed based on amino acid balance, this study investigated their role in alleviating the previously mentioned challenges. The control diet consisted of soybean meal, rapeseed meal, and cottonseed meal as the major protein sources. In contrast, the experimental diet was fortified with 0.21 % lysine, 0.32 % methionine, and 0.23 % threonine. A total of 300 grass carp (61.3 g) were randomly allocated into six net cages and fed with either the control or experimental diet for eight weeks. The results demonstrated that dietary amino acid supplementation improved weight gain rate, specific growth rate, and feed efficiency (P < 0.05). Moreover, it downregulated the mRNA expression of the TLR/MyD88/NFκB signaling pathway and pro-inflammatory cytokines (P < 0.05), mitigating intestinal inflammation. Regarding the intestinal microbiota, this treatment increased ACE and Chao indices, accompanied by an elevation in the abundance of Firmicutes and a concomitant reduction in Spirochaetota and Brevinema (P < 0.05). Furthermore, the diet with amino acid supplementation increased hepatic sm transcript levels and cholesterol contents (P < 0.05). It also stimulated the mRNA expression of the cyp7a1, leading to elevated levels of hepatic cholic acid, taurocholic acid, taurochenodeoxycholic acid, and glycochenodeoxycholic acid 3 sulfate disodium salt and increased intestinal bile acid concentrations (P < 0.05). In summary, the essential amino acid supplementation reshaped the bile acid cycle of the host by promoting hepatic cholesterol and bile acid synthesis and influencing the composition of the gut microbiota, alleviated intestinal inflammation, and improved the growth of grass carp. The findings revealed that optimizing the amino acid balance in feed formulations can improve fish growth performance and health while lowering production costs, thereby supporting the sustainable advancement of the aquaculture sector.

Highlights

•Dietary amino acid addition improved the growth performance of grass carp.

•Dietary amino acid addition suppressed intestinal TLR/MyD88/NFκB pathway. 

•Dietary amino acid addition reshaped gut microbiota composition and richness. 

• Dietary amino acid addition promoted cholesterol and bile acid synthesis.

翻译：任浩天（黄海水产研究所营养饲料团队）

转载自：胖鲀先生

原文：Yu, Yongning, et al. "Effects of adding essential amino acids to plant-based diets on growth performance, intestinal health and bile acid biosynthesis of grass carp (Ctenopharyngodon idella)." Aquaculture Reports 44 (2025): 103014.

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