Department of Fisheries, Faculty of Marine Natural Resources, Khoramshahr Marine Science and Technology University, Khoramshahr, Khouzestan, Iran.
Fish Physiol Biochem. 2012 Apr;38(2):431-40. doi: 10.1007/s10695-011-9524-x. Epub 2011 Jun 14.
This experiment was conducted to examine the effect of dietary nucleotides (NT) on fish performance and acute stress response on fingerling rainbow trout (23 g ± 0.01, mean weight ± SEM). Five experimental diets according to different levels of supplemented nucleotides (0, 0.05, 0.1, 0.15, and 0.2%) were assayed on experimental fish for 8 weeks. Growth, hematological parameters (hematocrit, hemoglobin, erythrocyte, lymphocyte, and neutrophil count), serum proteins (globulin, albumin), and plasma enzymatic activity (alkaline phosphatase, ALP; aspartate transaminase, AST; lactate dehydrogenase, LDH; alanine transaminase, ALT) were assayed. At the end of feeding trial, fish fed the control and 0.2% diets were subjected to handling and crowding stress. Modulatory effects of nucleotides on acute stress response (cortisol and glucose) and plasma electrolytes (Na(+), Cl(-), K(+), and Ca(2+)) were studied. The percentage of body weight gain (WG) and feed efficiency (FE) of fish were better when the fish were fed 0.15-0.2% diets. Fish fed the nucleotide-supplemented diets tended to have lower levels of serum enzymes including ALP, AST, LDH, and ALT. Plasma cortisol levels of fish fed on 0.2% diet under handling and crowding stress were significantly lower than fish fed the control diet at all post-stress time intervals. In our study, fish fed nucleotide-supplemented diet had significantly lower concentrations of glucose compared to those fed the basal diet. The concentrations of sodium, chloride, calcium, and potassium of fish fed the control diet were significantly lower than in fish fed nucleotide-supplemented diet. Dietary nucleotides administration seems to promote growth and to enhance resistance against handling and crowding stress in fingerling rainbow trout.
本实验旨在研究日粮核苷酸（NT）对鱼类生长性能和急性应激反应的影响。选用 23g±0.01（平均值±SEM）的幼虹鳟作为实验鱼，用 5 种不同核苷酸添加水平（0、0.05、0.1、0.15 和 0.2%）的实验饲料进行 8 周饲养实验。检测生长性能、血液学参数（红细胞压积、血红蛋白、红细胞、淋巴细胞和嗜中性粒细胞计数）、血清蛋白（球蛋白、白蛋白）和血浆酶活性（碱性磷酸酶、AST；谷丙转氨酶、ALT；乳酸脱氢酶、LDH）。在饲养试验结束时，用对照组和 0.2%饲料组的鱼进行处理和拥挤应激实验。研究了核苷酸对急性应激反应（皮质醇和葡萄糖）和血浆电解质（Na+、Cl-、K+和 Ca2+）的调节作用。当鱼摄食 0.15%-0.2%的饲料时，其体重增重（WG）和饲料效率（FE）更好。摄食核苷酸补充饲料的鱼血清酶水平（包括 ALP、AST、LDH 和 ALT）较低。在处理和拥挤应激下，摄食 0.2%饲料的鱼血浆皮质醇水平在所有应激后时间点均显著低于摄食对照组饲料的鱼。在本研究中，摄食核苷酸补充饲料的鱼的葡萄糖浓度明显低于摄食基础饲料的鱼。摄食对照组饲料的鱼的钠、氯、钙和钾浓度明显低于摄食核苷酸补充饲料的鱼。日粮核苷酸的添加似乎能促进幼虹鳟的生长，并增强其对处理和拥挤应激的抵抗力。
