Sukhovskaya Irina V, Lysenko Liudmila A, Fokina Natalia N, Kantserova Nadezhda P, Borvinskaya Ekaterina V
Laboratory of Environmental Biochemistry, Institute of Biology, Karelian Research Centre of the Russian Academy of Sciences, 185910 Petrozavodsk, Russia.
Institute of Biology, Irkutsk State University, 664025 Irkutsk, Russia.
Animals (Basel). 2023 Apr 14;13(8):1345. doi: 10.3390/ani13081345.
Natural feed supplements have been shown to improve fish viability, health, and growth, and the ability to withstand multiple stressors related to intensive cultivation. We assumed that a dietary mix of plant-origin substances, such as dihydroquercetin, a flavonoid with antioxidative, anti-inflammatory, and antimicrobial properties, and arabinogalactan, a polysaccharide with immunomodulating activity, would promote fish stress resistance and expected it to have a protective effect against infectious diseases. Farmed rainbow trout fish, , received either a standard diet or a diet supplemented with 25 mg/kg of dihydroquercetin and 50 mg/kg of arabinogalactan during a feeding season, from June to November. The fish in the control and experimental groups were sampled twice a month (eight samplings in total) for growth variable estimations and tissue sampling. The hepatic antioxidant status was assessed via the quantification of molecular antioxidants, such as reduced glutathione and alpha-tocopherol rates, as well as the enzyme activity rates of peroxidase, catalase, and glutathione-S-transferase. The lipid and fatty acid compositions of the feed and fish liver were analyzed using thin-layer and high-performance liquid chromatography. The viability, size, and biochemical indices of the fish responded to the growth physiology, environmental variables such as the dissolved oxygen content and water temperature, and sporadic factors. Due to an outbreak of a natural bacterial infection in the fish stock followed by antibiotic treatment, a higher mortality rate was observed in the fish that received a standard diet compared to those fed supplemented feed. In the postinfection period, reduced dietary 18:2n-6 and 18:3n-3 fatty acid assimilation contents were detected in the fish that received the standard diet in contrast to the supplemented diet. By the end of the feeding season, an impaired antioxidant response, including reduced glutathione S-transferase activity and glutathione content, and a shift in the composition of membrane lipids, such as sterols, 18:1n-7 fatty acid, and phospholipids, were also revealed in fish fed the standard diet. Dietary supplementation with plant-origin substances, such as dihydroquercetin and arabinogalactan, decreases lethality in fish stocks, presumably though the stimulation of natural resistance in farmed fish, thereby increasing the economic efficacy during fish production. From the sustainable aquaculture perspective, natural additives also diminish the anthropogenic transformation of aquaculture-bearing water bodies and their ecosystems.
天然饲料添加剂已被证明可提高鱼类的生存能力、健康状况和生长速度，并增强其抵御与集约化养殖相关的多种应激源的能力。我们假设，一种由植物源物质组成的日粮混合物，如具有抗氧化、抗炎和抗菌特性的类黄酮二氢槲皮素，以及具有免疫调节活性的多糖阿拉伯半乳聚糖，将促进鱼类的抗应激能力，并预期其对传染病具有保护作用。养殖的虹鳟鱼在6月至11月的投喂季节中，分别接受标准日粮或添加了25毫克/千克二氢槲皮素和50毫克/千克阿拉伯半乳聚糖的日粮。对照组和实验组的鱼每月采样两次（共八次采样），用于生长变量评估和组织采样。通过定量分子抗氧化剂（如还原型谷胱甘肽和α-生育酚比率）以及过氧化物酶、过氧化氢酶和谷胱甘肽-S-转移酶的酶活性比率来评估肝脏的抗氧化状态。使用薄层和高效液相色谱法分析饲料和鱼肝的脂质和脂肪酸组成。鱼类的生存能力、大小和生化指标对生长生理、环境变量（如溶解氧含量和水温）以及偶发因素有反应。由于鱼群中爆发了自然细菌感染并随后进行了抗生素治疗，与喂食补充饲料的鱼相比，接受标准日粮的鱼的死亡率更高。在感染后时期，与补充日粮相比，接受标准日粮的鱼体内检测到膳食中18:2n-6和18:3n-3脂肪酸同化含量降低。到投喂季节结束时，喂食标准日粮的鱼还出现了抗氧化反应受损，包括谷胱甘肽S-转移酶活性和谷胱甘肽含量降低，以及膜脂组成发生变化，如固醇、18:1n-7脂肪酸和磷脂。日粮中添加植物源物质，如二氢槲皮素和阿拉伯半乳聚糖，可降低鱼群的死亡率，推测这是通过刺激养殖鱼类的天然抵抗力实现的，从而提高了鱼类生产期间的经济效益。从可持续水产养殖的角度来看，天然添加剂还减少了水产养殖水体及其生态系统的人为改造。
