Ding Qianwen, Lu Chenyao, Hao Qiang, Zhang Qingshuang, Yang Yalin, Olsen Rolf Erik, Ringo Einar, Ran Chao, Zhang Zhen, Zhou Zhigang
China-Norway Joint Lab on Fish Gastrointestinal Microbiota, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China.
Norway-China Joint Lab on Fish Gastrointestinal Microbiota, Institute of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
Front Nutr. 2022 May 23;9:894278. doi: 10.3389/fnut.2022.894278. eCollection 2022.
Succinate is widely used in the food and feed industry as an acidulant, flavoring additive, and antimicrobial agent. This study investigated the effects of dietary succinate on growth, energy budget, nutritional metabolism, protein succinylation, and gut microbiota composition of zebrafish. Zebrafish were fed a control-check (0% succinate) or four succinate-supplemented diets (0.05, 0.10, 0.15, and 0.2%) for 4 weeks. The results showed that dietary succinate at the 0.15% additive amount (S0.15) can optimally promote weight gain and feed intake. Whole body protein, fat, and energy deposition increased in the S0.15 group. Fasting plasma glucose level decreased in fish fed the S0.15 diet, along with improved glucose tolerance. Lipid synthesis in the intestine, liver, and muscle increased with S0.15 feeding. Diet with 0.15% succinate inhibited intestinal gluconeogenesis but promoted hepatic gluconeogenesis. Glycogen synthesis increased in the liver and muscle of S0.15-fed fish. Glycolysis was increased in the muscle of S0.15-fed fish. In addition, 0.15% succinate-supplemented diet inhibited protein degradation in the intestine, liver, and muscle. Interestingly, different protein succinylation patterns in the intestine and liver were observed in fish fed the S0.15 diet. Intestinal proteins with increased succinylation levels were enriched in the tricarboxylic acid cycle while proteins with decreased succinylation levels were enriched in pathways related to fatty acid and amino acid degradation. Hepatic proteins with increased succinylation levels were enriched in oxidative phosphorylation while proteins with decreased succinylation levels were enriched in the processes of protein processing and transport in the endoplasmic reticulum. Finally, fish fed the S0.15 diet had a higher abundance of Proteobacteria but a lower abundance of Fusobacteria and . In conclusion, dietary succinate could promote growth and feed intake, promote lipid anabolism, improve glucose homeostasis, and spare protein. The effects of succinate on nutritional metabolism are associated with alterations in the levels of metabolic intermediates, transcriptional regulation, and protein succinylation levels. However, hepatic fat accumulation and gut microbiota dysbiosis induced by dietary succinate suggest potential risks of succinate application as a feed additive for fish. This study would be beneficial in understanding the application of succinate as an aquatic feed additive.
琥珀酸作为酸化剂、调味剂和抗菌剂在食品和饲料工业中被广泛使用。本研究调查了饲料中添加琥珀酸对斑马鱼生长、能量收支、营养代谢、蛋白质琥珀酰化和肠道微生物群组成的影响。将斑马鱼分为对照组（0%琥珀酸）和四组添加琥珀酸的饲料组（0.05%、0.10%、0.15%和0.2%），喂养4周。结果表明，添加量为0.15%（S0.15）的饲料中的琥珀酸能最佳地促进体重增加和采食量。S0.15组鱼的全身蛋白质、脂肪和能量沉积增加。饲喂S0.15饲料的鱼空腹血糖水平降低，葡萄糖耐量提高。S0.15饲料喂养可增加肠道、肝脏和肌肉中的脂质合成。含0.15%琥珀酸的饲料抑制肠道糖异生，但促进肝脏糖异生。S0.15饲料喂养的鱼肝脏和肌肉中的糖原合成增加。S0.15饲料喂养的鱼肌肉中的糖酵解增加。此外，添加0.15%琥珀酸的饲料抑制肠道、肝脏和肌肉中的蛋白质降解。有趣的是，在饲喂S0.15饲料的鱼中观察到肠道和肝脏中不同的蛋白质琥珀酰化模式。琥珀酰化水平升高的肠道蛋白质在三羧酸循环中富集，而琥珀酰化水平降低的蛋白质在与脂肪酸和氨基酸降解相关的途径中富集。琥珀酰化水平升高的肝脏蛋白质在氧化磷酸化中富集，而琥珀酰化水平降低的蛋白质在内质网中的蛋白质加工和转运过程中富集。最后，饲喂S0.15饲料的鱼中变形菌门丰度较高，但梭杆菌门和……丰度较低。总之，饲料中的琥珀酸可促进生长和采食量，促进脂质合成代谢，改善葡萄糖稳态，并节省蛋白质。琥珀酸对营养代谢的影响与代谢中间体水平、转录调控和蛋白质琥珀酰化水平的改变有关。然而，饲料中的琥珀酸诱导的肝脏脂肪积累和肠道微生物群失调表明琥珀酸作为鱼类饲料添加剂应用存在潜在风险。本研究将有助于理解琥珀酸作为水产饲料添加剂的应用。
