Animal Nutrition Institute, Sichuan Agricultural University, Sichuan, Chengdu 611130, China.
Animal Nutrition Institute, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Sichuan, Chengdu 611130, China; Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Sichuan, Chengdu 611130, China.
Fish Shellfish Immunol. 2017 Jul;66:497-523. doi: 10.1016/j.fsi.2017.05.048. Epub 2017 May 23.
Our study investigated the effects of dietary zinc (Zn) deficiency on growth performance, intestinal immune and physical barrier functions of young grass carp (Ctenopharyngodon idella). A total of 630 grass carp (244.14 ± 0.40 g) were fed graded levels of zinc lactate (10.71, 30.21, 49.84, 72.31, 92.56, 110.78 mg Zn/kg diet) and one zinc sulfate group (56.9 mg Zn/kg diet) for 60 days. At the end of the feeding trial, fish were challenged with Aeromonas hydrophila for 14 days. These results indicated that compared with optimal dietary Zn level, dietary Zn deficiency (10.71 mg/kg diet) decreased the production of antibacterial compounds, up-regulated pro-inflammatory cytokines related to nuclear factor kappa B (NF-κB) and down-regulated anti-inflammatory cytokines related to target of rapamycin (TOR) in three intestinal segments of young grass carp (P < 0.05), suggesting that dietary Zn deficiency could impair intestinal immune barrier of fish; decreased the activities and mRNA levels of antioxidant enzymes related to NF-E2-related factor 2 (Nrf2), up-regulated the mRNA levels of caspase-3, -7, -8, -9 related to p38 mitogen activated protein (p38 MAPK) and c-Jun N-terminal protein kinase (JNK), down-regulated the mRNA levels of tight junction complexes (TJs) related to myosin light chain kinase (MLCK) in three intestinal segments of young grass carp (P < 0.05), demonstrating that dietary Zn deficiency could injury intestinal physical barrier of fish. Besides, the Zn requirements (zinc lactate as Zn source) based on percent weight gain (PWG), against enteritis morbidity, acid phosphatase (ACP) activity in the proximal intestine (PI) and malondialdehyde (MDA) content in the PI of young grass carp was estimated to be 61.2, 61.4, 69.2 and 69.5 mg/kg diet, respectively. Finally, based on specific growth rate (SGR), feed efficiency (FE) and against enteritis morbidity of young grass carp, the efficacy of zinc lactate relative to zinc sulfate were 132.59%, 135.27% and 154.04%, respectively.
本研究探讨了饲粮锌缺乏对草鱼幼鱼（Ctenopharyngodon idella）生长性能、肠道免疫和物理屏障功能的影响。将 630 尾草鱼（244.14±0.40g）分别投喂梯度锌水平的乳酸锌（10.71、30.21、49.84、72.31、92.56、110.78mg Zn/kg 饲料）和硫酸锌组（56.9mg Zn/kg 饲料）60 天。在饲养试验结束时，用嗜水气单胞菌攻毒 14 天。结果表明，与最佳饲粮锌水平相比，饲粮锌缺乏（10.71mg/kg 饲料）降低了草鱼三个肠段抗菌化合物的产生，上调了与核因子κB（NF-κB）相关的促炎细胞因子，下调了与雷帕霉素靶蛋白（TOR）相关的抗炎细胞因子（P<0.05），表明饲粮锌缺乏可损害鱼类肠道免疫屏障；降低与核因子 E2 相关因子 2（Nrf2）相关的抗氧化酶的活性和 mRNA 水平，上调与 p38 丝裂原活化蛋白激酶（p38 MAPK）和 c-Jun N 末端蛋白激酶（JNK）相关的半胱天冬酶-3、-7、-8、-9 的 mRNA 水平，下调与肌球蛋白轻链激酶（MLCK）相关的紧密连接复合物（TJs）的 mRNA 水平草鱼三个肠段（P<0.05），表明饲粮锌缺乏可损伤鱼类肠道物理屏障。此外，基于增重率（PWG）、肠炎发病率、近端肠（PI）酸性磷酸酶（ACP）活性和 PI 丙二醛（MDA）含量，估计草鱼幼鱼对饲粮锌的需要量（以乳酸锌计）分别为 61.2、61.4、69.2 和 69.5mg/kg 饲料。最后，基于草鱼幼鱼特定生长率（SGR）、饲料效率（FE）和肠炎发病率，乳酸锌相对于硫酸锌的功效分别为 132.59%、135.27%和 154.04%。
