Zhang Yue, Wei Zehong, Yang Mengxi, Liu Danni, Pan Mingzhu, Wu Chenglong, Zhang Wenbing, Mai Kangsen
The Key Laboratory of Aquaculture Nutrition and Feeds, Ministry of Agriculture and Rural Affairs, The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, PR China.
State Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, 410081, China.
Fish Shellfish Immunol. 2021 Feb;109:1-11. doi: 10.1016/j.fsi.2020.11.029. Epub 2020 Dec 5.
This study was conducted to explore the beneficial role of taurine against chronic high carbohydrate diet-induced oxidative stress, endoplasmic reticulum (ER) stress and inflammation, and to understand the underlying molecular mechanisms in turbot. Two 10-week feeding trials were simultaneously conducted. For the one, six experimental diets with graded levels of taurine supplementation (0, 0.4%, 0.8%, 1.2%, 1.6% and, 2.0%, respectively) and 15% of carbohydrate were used. For the other one, three graded levels of dietary taurine supplementation (0.4%, 1.2% and 2.0%, respectively) with 21% of carbohydrate were used. The results showed that higher expression level of inflammation cytokines and ER stress related genes were detected in higher dietary carbohydrate group. In both feeding trials, 1.2% of dietary taurine supplementation improved anti-oxidative status by decreasing the content of malondialdehyde, increasing the catalase activity and total anti-oxidative capacities. In feeding trial 1, appropriate taurine supplementation lowered contents of tumour necrosis factor-a, interleukin-6, aspartate aminotransferase and alkaline phosphatase in plasma, and decreased the expressions of pro-inflammatory cytokines, such as interleukin-8 (il-8) and interferon-γ (ifn-γ). Furthermore, dietary taurine reduced ER stress by decreasing the mRNA levels of activating transcription factor 6, protein kinase R-like endoplasmic reticulum kinase and G protein-coupled receptor 78. The optimal dietary taurine content was estimated as 1.40% based on the analysis of specific growth rate. In feeding trial 2, dietary taurine supplementation attenuated liver inflammation partly referring to significantly down-regulated mRNA levels of nuclear transcription factor-κB p65, ifn-γ, interleukin1β and up-regulate the transcript of ribosomal protein S6 kinase 1. Dietary taurine supplementation in feeding trial 2 significantly increased the Nrf2-related factor 2 protein level and decreased the NFκB p65 protein level only at 21% of dietary carbohydrate level. Taurine can alleviate the oxidative damage and inflammation caused by 21% of dietary carbohydrate to a certain degree. Overall, the present study confirmed that dietary taurine supplementation improved growth performance and anti-oxidative response, and reduced liver inflammatory and ER stress processes induced by high dietary carbohydrate in turbot.
本研究旨在探讨牛磺酸对慢性高碳水化合物饮食诱导的氧化应激、内质网（ER）应激和炎症的有益作用，并了解其在大菱鲆中的潜在分子机制。同时进行了两项为期10周的饲养试验。其中一项试验，使用了六种添加不同水平牛磺酸（分别为0、0.4%、0.8%、1.2%、1.6%和2.0%）且碳水化合物含量为15%的实验饲料。另一项试验，使用了三种添加不同水平牛磺酸（分别为0.4%、1.2%和2.0%）且碳水化合物含量为21%的饲料。结果表明，在高碳水化合物饲料组中检测到炎症细胞因子和内质网应激相关基因的表达水平更高。在两项饲养试验中，添加1.2%的牛磺酸可通过降低丙二醛含量、提高过氧化氢酶活性和总抗氧化能力来改善抗氧化状态。在饲养试验1中，适当补充牛磺酸可降低血浆中肿瘤坏死因子-α、白细胞介素-6、天冬氨酸转氨酶和碱性磷酸酶的含量，并降低促炎细胞因子如白细胞介素-8（il-8）和干扰素-γ（ifn-γ）的表达。此外，饲料中的牛磺酸通过降低激活转录因子6、蛋白激酶R样内质网激酶和G蛋白偶联受体78的mRNA水平来减轻内质网应激。基于特定生长率的分析，估计最佳饲料牛磺酸含量为1.40%。在饲养试验2中，补充饲料牛磺酸部分减轻了肝脏炎症，这主要表现为核转录因子-κB p65、ifn-γ、白细胞介素1β的mRNA水平显著下调，以及核糖体蛋白S6激酶1的转录上调。在饲养试验2中，仅在饲料碳水化合物含量为21%时，补充饲料牛磺酸显著提高了Nrf2相关因子2蛋白水平并降低了NFκB p65蛋白水平。牛磺酸可在一定程度上减轻21%饲料碳水化合物引起的氧化损伤和炎症。总体而言，本研究证实，补充饲料牛磺酸可改善大菱鲆的生长性能和抗氧化反应，并减轻高碳水化合物饲料诱导的肝脏炎症和内质网应激过程。
