Liang Xiaofang, Wang Jia, Gong Guan, Xue Min, Dong Yingchao, Wu Xiufeng, Wang Xin, Chen Chunshan, Liang Xufang, Qin Yuchang
National Aquafeed Safety Assessment Station, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Key Laboratory of Feed Biotechnology of Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Anim Nutr. 2017 Sep;3(3):284-294. doi: 10.1016/j.aninu.2017.06.001. Epub 2017 Jun 15.
Gluconeogenesis responses was assessed during a short starvation period and subsequent refeeding in Siberian sturgeon () previously fed different dietary carbohydrates levels and experienced to a glucose stimuli during early life. The sturgeon larvae were previously fed either a high glucose diet (G) or a low glucose diet (F) from the first feeding to yolk absorption (8 to 12 d post-hatching [dph]). Each group of fish was sub-divided into 2 treatments at 13 dph and was fed either a high-carbohydrate diet (H) or a low carbohydrate diet (L) until 20 wk. In the current study, the fish in 4 groups (GL, FL, GH and FH) were experienced to starvation for 21 d following by re-feeding of their corresponding diets for 21 d. Fish were sampled at postprandial 6 and 24 h before starvation (P6h and P24h), starvation 7, 14 and 21 d (S7, S14 and S21) and 1, 7, 14 and 21 d during refeeding (R1, R7, R14 and R21). Plasma samples during refeeding were taken at P6h at each time point. Glycaemia levels, liver and muscle glycogen contents, activities and mRNA levels of hepatic gluconeogenic enzymes were examined. We found that both dietary carbohydrate levels and early glucose stimuli significantly affected the metabolic responses to starvation and refeeding in Siberian sturgeon ( < 0.05). During prolonged starvation, Siberian sturgeon firstly mobilized the liver glycogen and then improved gluconeogenesis when the dietary carbohydrates were abundant, whereas preserved the liver glycogen stores at a stable level and more effectively promoted gluconeogenesis when the dietary carbohydrates are absent to maintain glucose homoeostasis. During refeeding, as most teleostean, Siberian sturgeon failed controlling the activities and mRNA levels of phosphoenolpyruvate carboxykinase cytosolic forms (), fructose-1,6-bisphosphatase (), but particularly controlled phosphoenolpyruvate carboxykinase mitochondrial forms () activities and mRNA expression of glucose-6-phosphatase (, except in GL group). Siberian sturgeon has a full compensatory ability on growth, but this ability would be obstructed by early glucose stimuli when refeeding the low carbohydrate diet after S21.
在短期饥饿期及随后的重新投喂过程中，对之前投喂不同碳水化合物水平日粮并在幼鱼期经历过葡萄糖刺激的西伯利亚鲟（）的糖异生反应进行了评估。西伯利亚鲟幼鱼从首次摄食至卵黄吸收（孵化后8至12天[dph]）期间，分别投喂高糖日粮（G）或低糖日粮（F）。在13 dph时，每组鱼再分为2个处理组，分别投喂高碳水化合物日粮（H）或低碳水化合物日粮（L），直至20周龄。在本研究中，4组鱼（GL、FL、GH和FH）先饥饿21天，然后重新投喂相应日粮21天。在饥饿前的餐后6小时和24小时（P6h和P24h）、饥饿7天、14天和21天（S7、S14和S21）以及重新投喂期间的1天、7天、14天和21天（R1、R7、R14和R21）对鱼进行采样。重新投喂期间的血浆样本在每个时间点的P6h采集。检测血糖水平、肝脏和肌肉糖原含量、肝脏糖异生酶的活性和mRNA水平。我们发现日粮碳水化合物水平和早期葡萄糖刺激均显著影响西伯利亚鲟对饥饿和重新投喂的代谢反应（<0.05）。在长期饥饿期间，当日粮碳水化合物丰富时，西伯利亚鲟首先动用肝脏糖原，然后增强糖异生；而当日粮中缺乏碳水化合物时，它会将肝脏糖原储备维持在稳定水平，并更有效地促进糖异生以维持葡萄糖稳态。在重新投喂期间，与大多数硬骨鱼类一样，西伯利亚鲟无法控制胞质型磷酸烯醇式丙酮酸羧激酶（）、果糖-1,6-二磷酸酶（）的活性和mRNA水平，但能特别控制线粒体型磷酸烯醇式丙酮酸羧激酶（）的活性以及葡萄糖-6-磷酸酶（，GL组除外）的mRNA表达。西伯利亚鲟具有完全的生长补偿能力，但在S21后重新投喂低碳水化合物日粮时，这种能力会受到早期葡萄糖刺激的阻碍。
