title: Chronic stress effects of high doses of vitamin D3 on Megalobrama amblycephala.
abstract: Dietary vitamin D3 plays an important role in the growth of aquatic animals, but long-term excessive feeding has potential hazards. In this study, Megalobrama amblycephala specimens were fed different experimental diets with 2000 IU/kg or 200,000 IU/kg of vitamin D3 for 90 days, in order to evaluate chronic stress effects of high doses of vitamin D3 on growth, immunity, and structural damage to enterohepatic tissues. The results showed that high doses of vitamin D3 did not have a significant influence on the growth performance of M. amblycephala (P > 0.05), but it significantly reduced the survival rate after infection by Aeromonas hydrophila (P < 0.05). Serum albumin, alkaline phosphatase, and insulin levels, as well as hepatic total antioxidant capacity, were also significantly reduced (P < 0.05). Serum cortisol levels and hepatic heat stress protein 70 expression in M. amblycephala showed that high doses of vitamin D3 significantly inhibit the anti-stress ability of M. amblycephala (P < 0.05). Paraffin tissue sections and electron microscopy showed that high doses of vitamin D3 could cause different degrees of structural damage to enterohepatic tissues of M. amblycephala. Our results indicate that, although M. amblycephala can tolerate high doses of dietary vitamin D3 over a long period, its glycolipid metabolism, immune function, anti-stress function, and resistance to pathogenic infections are adversely affected.
authors.affiliation: Fishery College, Nanjing Agriculture University, Wuxi 214081, China; Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Jiangsu, Wuxi 214081, China.
authors.forename: Ling-Hong
authors.initials: LH
authors.lastname: Miao
authors.affiliation: Fishery College, Nanjing Agriculture University, Wuxi 214081, China; Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Jiangsu, Wuxi 214081, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xie
authors.affiliation: Fishery College, Nanjing Agriculture University, Wuxi 214081, China; Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Jiangsu, Wuxi 214081, China. Electronic address: gexp@ffrc.cn.
authors.forename: Xian-Ping
authors.initials: XP
authors.lastname: Ge
authors.affiliation: Fishery College, Nanjing Agriculture University, Wuxi 214081, China.
authors.forename: Ke-Bao
authors.initials: KB
authors.lastname: Wang
authors.affiliation: Fishery College, Nanjing Agriculture University, Wuxi 214081, China; Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Jiangsu, Wuxi 214081, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Fishery College, Nanjing Agriculture University, Wuxi 214081, China; Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Jiangsu, Wuxi 214081, China. Electronic address: liub@ffrc.cn.
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.affiliation: Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Jiangsu, Wuxi 214081, China.
authors.forename: Ming-Chun
authors.initials: MC
authors.lastname: Ren
authors.affiliation: Fishery College, Nanjing Agriculture University, Wuxi 214081, China; Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Jiangsu, Wuxi 214081, China.
authors.forename: Qun-Lan
authors.initials: QL
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Genetic Breeding and Aquaculture Biology of Freshwater Fishes, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Jiangsu, Wuxi 214081, China.
authors.forename: Liang-Kun
authors.initials: LK
authors.lastname: Pan
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002762:Cholecalciferol / Q000009:adverse effects*; D003530:Cyprinidae / Q000033:anatomy & histology / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D005393:Fish Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism; D016905:Gram-Negative Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013312:Stress, Physiological
chemical_list: D029941:Fish Proteins; D018840:HSP70 Heat-Shock Proteins; D002762:Cholecalciferol
keywords: Chronic stress; Immunity; Megalobrama amblycephala; Tissue structure; Vitamin D(3)