Ceccotti Chiara, Al-Sulaivany Basim S A, Al-Habbib Omar A M, Saroglia Marco, Rimoldi Simona, Terova Genciana
Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy.
Department of Biology, Faculty of Science, University of Zakho, Zakho, 420011 Kurdistan Region, Iraq.
Animals (Basel). 2019 Aug 26;9(9):607. doi: 10.3390/ani9090607.
Taurine (Tau) is an amino sulfonic acid, which is widely distributed in animal tissues, whereas it is almost lacking in plants with the exception of certain algae, seaweeds, and few others. In the aquafeed industry, Tau is mainly used as a feed additive to promote growth in marine fish species with limited cysteine sulfinate decarboxylase activity. In particular, Tau supplementation is required in feeds in which fishmeal (FM) is substituted with high percentages of plant-derived protein sources such as soybean meals (SBM) that have much lower levels of Tau than FM. In addition to being a growth promoter, Tau exert powerful antioxidant properties being a scavenger of the reactive oxygen species (ROS). Under sustained swimming conditions, an intracellular increase in ROS production can occur in fish red muscle where the abundance of mitochondria (the main site of ROS formation) is high. Accordingly, this study aimed at investigating the effects of dietary Tau on European seabass () growth and oxidative stress response induced by swimming exercise. Individually tagged fish of 92.57 ± 20.33 g mean initial weight were fed two experimental diets containing the same low percentage of FM and high percentage of SBM. One diet was supplemented with 1.5% of Tau. Tau supplemented in the diet had a positive effect on fish growth, and enhanced swimming performance and antioxidant status. Two swim endurance tests were performed during the feeding trial. Metabolic oxygen consumption (MO) was measured during exercise at incremental swimming speeds (0.7, 1.4, 2.1, 2.8, 3.5, and then 4.2 BL (body length) s, until fatigue). Fish maximal sustainable swimming speed (Ucrit) was determined too. To investigate the antioxidant effect of dietary Tau, we also measured ROS production in fish blood by RBA (respiratory burst activity) assay and quantified the expression of genes coding for antioxidant enzymes by qPCR (quantitative polymerase chain reaction) , such as SOD (superoxide dismutase), GPX (glutathione peroxidase), and CAT (catalase) in red muscle and liver. There was a significant effect of Tau upon Ucrit during exercise. Additionally, ROS production was significantly lower in fish fed with Tau supplemented diet, supporting the role of Tau as ROS scavenger. The protective effect of Tau against oxidative stress induced by forced swimming was denoted also by a significant decrease in antioxidant enzymes gene expression in fish liver and muscle. Taken together these results demonstrate that Tau is beneficial in low FM-based diets for seabass.
牛磺酸（Tau）是一种氨基磺酸，广泛分布于动物组织中，而在植物中几乎不存在，某些藻类、海藻及其他少数植物除外。在水产饲料行业，牛磺酸主要用作饲料添加剂，以促进半胱氨酸亚磺酸脱羧酶活性有限的海水鱼类生长。特别是，在用高比例植物源蛋白质（如豆粕，其牛磺酸含量远低于鱼粉）替代鱼粉的饲料中，需要添加牛磺酸。除了作为生长促进剂外，牛磺酸还具有强大的抗氧化特性，是活性氧（ROS）的清除剂。在持续游泳条件下，鱼类红色肌肉中ROS的产生可能会增加，因为红色肌肉中线粒体（ROS形成的主要部位）含量很高。因此，本研究旨在探讨日粮中添加牛磺酸对欧洲鲈鱼生长及游泳运动诱导的氧化应激反应的影响。将平均初始体重为92.57±20.33克、单独标记的鱼投喂两种实验饲料，这两种饲料含有相同低比例的鱼粉和高比例的豆粕。其中一种饲料添加了1.5%的牛磺酸。日粮中添加牛磺酸对鱼类生长有积极影响，并提高了游泳性能和抗氧化状态。在投喂试验期间进行了两次游泳耐力测试。在以递增游泳速度（0.7、1.4、2.1、2.8、3.5，然后是4.2倍体长/秒，直至疲劳）运动时测量代谢氧消耗（MO）。还测定了鱼类的最大可持续游泳速度（Ucrit）。为了研究日粮中牛磺酸的抗氧化作用，我们还通过呼吸爆发活性（RBA）测定法测量了鱼血液中ROS的产生，并通过定量聚合酶链反应（qPCR）定量了红色肌肉和肝脏中编码抗氧化酶的基因表达，如超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GPX）和过氧化氢酶（CAT）。牛磺酸对运动期间的Ucrit有显著影响。此外，投喂添加牛磺酸日粮的鱼体内ROS产生显著降低，这支持了牛磺酸作为ROS清除剂的作用。牛磺酸对强迫游泳诱导的氧化应激的保护作用还表现为鱼肝和肌肉中抗氧化酶基因表达显著降低。综上所述，这些结果表明牛磺酸对以低鱼粉为基础的鲈鱼日粮有益。
