title: Stress, antioxidant defence and mucosal immune responses of the large yellow croaker Pseudosciaena crocea challenged with Cryptocaryon irritans.
abstract: To clarify the effects of a Cryptocaryon irritans infection on the stress, antioxidant and mucosal immune response of the large yellow croaker Pseudosciaena crocea, this study utilized C. irritans at dose of 12,000 (group I); 24,000 (group II); and 36,000 (group III) theronts/fish to infect large yellow croaker weighing 100 ± 10 g. The food intake, survival and relative infection intensity (RII); levels of reactive oxygen species (ROS), malondialdehyde (MDA) and vitamin C (VC), activities of super oxide dismutase (SOD) and catalase (CAT) in liver; variation patterns of lysozyme (LZM), alkaline phosphatase (AKP), complement component 3 (C3) and immunoglobulin M (IgM) levels in the body surface mucus at different time points after infection were compared. These results showed that with the increase of the infection dose and the passage of time, the food intake and survival of the fish gradually decreased. The final survival of the control group (0 theronts/fish), group I, group II, and group III was 100, 100, 96.67 ± 5.77, and 48.33 ± 7.64. Group I, II, and III stopped feeding respectively on the third, third and second days after infection. RII increased significantly with increased infection dose. The RII of the control group, group I, group II, and group III was 0, 0.73 ± 0.06, 1.30 ± 0.26, and 1.84 ± 0.02. With the infection dose increased, ROS contents showed an overall upward trend; MDA contents of the group I, group II and group III did not show significant changes at any timepoint compared with the control group; Activities of SOD and CAT and the overall VC levels in the liver of P. crocea dropped; LZM activity showed an overall upward trend; AKP activity increased first then dropped at each timepoint with its highest level appearing at group II; Complement C3 and IgM levels in body surface mucus were significantly increased. In conclusion, P. crocea has a strong ability to resist oxidative stress caused by the infection of C. irritans. The body surface mucus of P. crocea contains high levels of immune factors, which presented a rapid and significant response to the infection of C. irritans.
authors.affiliation: Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, PR China. Electronic address: yinf@ecsf.ac.cn.
authors.forename: Fei
authors.initials: F
authors.lastname: Yin
authors.affiliation: Institute of Biotechnology, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian Province 350003, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Gong
authors.affiliation: Key Laboratory of Large Yellow Croaker in Fujian Province, Ningde Fufa Fisheries Co., Ltd., Ningde, Fujian Province 352000, PR China.
authors.forename: Qiaozhen
authors.initials: Q
authors.lastname: Ke
authors.affiliation: Key Laboratory for Aquatic Products Safety of Ministry of Education, State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong Province 510275, PR China. Electronic address: lianxing@mail.sysu.edu.cn.
authors.forename: Anxing
authors.initials: A
authors.lastname: Li
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D016798:Ciliophora / Q000502:physiology*; D016770:Ciliophora Infections / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D005247:Feeding Behavior; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000469:parasitology; D018928:Immunity, Mucosal; D008136:Longevity; D010473:Perciformes; D013312:Stress, Physiological
chemical_list: D000975:Antioxidants
keywords: Cryptocaryon irritans; Mucosal immune; Pseudosciaena crocea; Stress; Survival