Qin Fenju, Shi Miaomiao, Yuan Hongxia, Yuan Linxi, Lu Wenhao, Zhang Jie, Tong Jian, Song Xuehong
Department of Biological Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China.
School of Biology and Basic Medical Sciences, Soochow University, Suzhou 215123, China.
Fish Shellfish Immunol. 2016 Jul;54:481-8. doi: 10.1016/j.fsi.2016.04.131. Epub 2016 May 3.
Hypoxia is a relevant physiological challenge for crab culture, and the hemolymph plays a crucial role in response to the hypoxia. In a 60 d feeding trial, Chinese mitten crabs (Eriocheir sinensis) fed a diet containing 0.2 mg/kg nano-selenium (nanoSe) showed a significantly increased weight gain rate (WGR) and a reduced feed coefficient (FC) compared to those fed diets with 0, 0.1, 0.4, 0.8, and 1.6 mg/kg nanoSe. Another 90 d feeding trial was conducted to determine the influence of dietary nanoSe on the immune response in juvenile Chinese mitten crabs kept under the condition of hypoxia. The results showed that hypoxia stress resulted in significantly increased hemocyte counts (THC, LGC, SGC, and HC), expression levels of the hemocyanin gene and protein, lactic acid level, and antioxidant capacity (T-AOC activities, SOD activities, GSH-Px and GSH content) in hemolymph supernatant. When these crabs were infected with Aeromonas hydrophila bacteria, hypoxia exposure increased mortality, but it was alleviated by a diet supplemented with 0.2 mg/kg nanoSe. The up-regulative effects of nanoSe (0.2 mg/kg) on antioxidant capacity, hemocyte counts, and hemocyanin expression under hypoxia exposure were further strengthened throughout, whereas lactic acid levels induced by hypoxia stress were restored. Thus, the observations in this study indicate that the level of dietary nanoSe is important in regulating immunity and disease resistance in crabs kept under hypoxia stress.
低氧是河蟹养殖中一个相关的生理挑战，血淋巴在应对低氧方面起着关键作用。在一项为期60天的投喂试验中，与投喂含0、0.1、0.4、0.8和1.6mg/kg纳米硒（nanoSe）饲料的中华绒螯蟹相比，投喂含0.2mg/kg纳米硒饲料的中华绒螯蟹的增重率（WGR）显著提高，饲料系数（FC）降低。进行了另一项为期90天的投喂试验，以确定饲料中纳米硒对处于低氧条件下的中华绒螯蟹幼蟹免疫反应的影响。结果表明，低氧应激导致血淋巴上清液中的血细胞计数（THC、LGC、SGC和HC）、血蓝蛋白基因和蛋白的表达水平、乳酸水平以及抗氧化能力（总抗氧化能力（T-AOC）活性、超氧化物歧化酶（SOD）活性、谷胱甘肽过氧化物酶（GSH-Px）和谷胱甘肽（GSH）含量）显著增加。当这些螃蟹感染嗜水气单胞菌时，低氧暴露会增加死亡率，但补充0.2mg/kg纳米硒的饲料可缓解这种情况。在整个低氧暴露过程中，纳米硒（0.2mg/kg）对抗氧化能力、血细胞计数和血蓝蛋白表达的上调作用进一步增强，而低氧应激诱导的乳酸水平得以恢复。因此，本研究中的观察结果表明，饲料中纳米硒的水平对于调节处于低氧应激下的河蟹的免疫力和抗病性很重要。
