Wu Chenglong, Ye Jinyun, Gao Jun'e, Chen Lian, Lu Zhibin
Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, School of Life Science, Huzhou University, 759 Erhuan Road (E), Huzhou 313000, PR China; Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, 759 Erhuan Road (E), Huzhou 313000, PR China.
Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, School of Life Science, Huzhou University, 759 Erhuan Road (E), Huzhou 313000, PR China.
Fish Shellfish Immunol. 2016 Feb;49:132-42. doi: 10.1016/j.fsi.2015.12.030. Epub 2015 Dec 23.
The present study was focused on the growth, antioxidant capacities, innate immune responses and pathogen resistance in juvenile Black carp Mylopharyngodon piceus fed with graded levels of dietary carbohydrate (CHO) (0.6, 106.5, 194.3, 288.4, 379.1 and 473.8 g kg(-1)) for 9 weeks. Results showed that highest weight gain and special growth ratio was obtained at 288.4 g kg(-1) dietary CHO. And adequate dietary CHO content (288.4 g kg(-1)) could significantly increase the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (Gpx), promote reduced glutathione (GSH) content and then increase the total antioxidant capacities (TAOC) in the liver of M. piceus. However, the malondialdehyde (MDA) levels in the fish liver could be significantly aggravated by excessive dietary CHO. Serum cortisol (COL) levels could be significantly increased in juvenile Black carp M. piceus fed with 379.1 g kg(-1) dietary CHO compared with CHO-deficient diets. Activities of alanine transaminase (GPT) and aspartate transaminase (GOT) were both decreased in the serum of juvenile Black carp M. piceus fed with 194.3 g kg(-1) dietary CHO compared with CHO-deficient diets (0.6 and 106.5 g kg(-1)) or CHO-excess diets (379.1 and 473.8 g kg(-1)). In addition, 288.4 g kg(-1) dietary CHO could significantly up-regulate the mRNA expression levels of hepcidin (HEPC), natural resistance-associated macrophage protein (NRAMP), tumor necrosis factor-α (TNF-α) and interferon (IFN), lysozyme (LYZ) and complement component 3 (C3) in the blood and liver samples of juvenile Black carp M. piceus compared with the CHO-deficient diets (0.6 and 106.5 g kg(-1)). Moreover, 288.4 g kg(-1) dietary CHO could also enhance the contents of C3 and plasma nitrogen monoxide (NO), and increase the activities of LYZ and total nitric oxide synthase (t-NOS) in the serum compared with the CHO-deficient or CHO-excess diets. Furthermore, the survival rates were also increased by adequate dietary CHO (194.3 and 288.4 g kg(-1)) fed to juvenile Black carp M. piceus after infection with Aeromonas hydrophila. In conclusion, these results suggest that adequate dietary CHO (288.4 g kg(-1)) could increase growth, reduce oxidative stress, enhance innate immune responses, improve the health states and then promote disease resistance in juvenile Black carp M. piceus.
本研究聚焦于投喂不同梯度水平（0.6、106.5、194.3、288.4、379.1和473.8 g kg⁻¹）碳水化合物（CHO）饲料9周的草鱼幼鱼的生长、抗氧化能力、先天免疫反应和病原体抗性。结果表明，当饲料中CHO含量为288.4 g kg⁻¹时，草鱼幼鱼获得最高的体重增加和特定生长率。适宜的饲料CHO含量（288.4 g kg⁻¹）可显著提高草鱼肝脏中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（Gpx）的活性，促进还原型谷胱甘肽（GSH）含量增加，进而提高总抗氧化能力（TAOC）。然而，饲料中CHO过量会显著加重鱼肝中丙二醛（MDA）水平。与CHO缺乏饲料相比，投喂379.1 g kg⁻¹饲料的草鱼幼鱼血清皮质醇（COL）水平显著升高。与CHO缺乏饲料（0.6和106.5 g kg⁻¹）或CHO过量饲料（379.1和473.8 g kg⁻¹）相比，投喂194.3 g kg⁻¹饲料的草鱼幼鱼血清中谷丙转氨酶（GPT）和谷草转氨酶（GOT）的活性均降低。此外，与CHO缺乏饲料（0.6和106.5 g kg⁻¹）相比，288.4 g kg⁻¹饲料可显著上调草鱼幼鱼血液和肝脏样本中抗菌肽（HEPC）、天然抗性相关巨噬细胞蛋白（NRAMP）、肿瘤坏死因子-α（TNF-α）、干扰素（IFN）、溶菌酶（LYZ）和补体成分3（C3）的mRNA表达水平。此外，与CHO缺乏或过量饲料相比，288.4 g kg⁻¹饲料还可提高血清中C3和血浆一氧化氮（NO）的含量，增加LYZ和总一氧化氮合酶（t-NOS）的活性。此外，给感染嗜水气单胞菌的草鱼幼鱼投喂适宜的饲料CHO（194.3和288.4 g kg⁻¹）后，其存活率也有所提高。总之，这些结果表明，适宜的饲料CHO（288.4 g kg⁻¹）可促进草鱼幼鱼生长，减轻氧化应激，增强先天免疫反应和改善健康状况，进而提高抗病能力。
