Immunological, ionic and biochemical responses in blood serum of the marine fish Trachinotus ovatus to poly-infection by Cryptocaryon irritans.
To investigate the response of pompano fish (Trachinotus ovatus) to white spot disease, we used the protozoan Cryptocaryon irritans to infect live 450-g specimens at concentrations of 40,000 theronts/fish. We assessed the relative infection intensity (RII), serum immobilizing titer, and immunity-related enzyme activities (ACP, AKP, LZM), and assessed feeding, serum ion concentrations (Na(+), Cl(-), Ca(2+) and K(+)) and blood biochemistry (ALT, AST, LDH) of pompano. The fish were then treated with a lethal dose of C. irritans (70,000 theronts/fish) and the number of deaths was recorded. We found that the relative infection intensities of the control group, group I, and group II were 0, 0.630 ± 0.179, and 0.014 ± 0.006. Poly-infection induced a significant increase in the serum immobilizing titer (853.33 ± 295.60) of group II. In terms of the biochemical assessment, group II had significantly higher alkaline phosphatase and acid phosphatase activities than the other groups, and the lowest lysozyme activity (P < 0.05), compared to higher activity in the control group and the highest level in group I. Only the fishes of group I had stopped feeding after treatment. The concentrations of Na(+), Cl(-), and Ca(2+) in blood serum did not differ significantly among the three groups, but K(+) concentration increased with the increasing infection frequency. Alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase activities in fish of group II were significantly higher than those of the other groups. Survival of the fish subjected to the lethal dose of C. irritans was 0, 0, and 100 in groups control, I, and II, respectively. In conclusions, based on the food intake of group II, along with the results of relative infection intensity, serum immobilizing titer, and survival, we speculate that the fish in that group acquired high protective immunity following poly-infection by C. irritans, experiencing limited harm for pompano.
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, China. Electronic address: yinf@ecsf.ac.cn.
Fei
F
Yin
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, China.
Peng
P
Sun
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, China.
Baojun
B
Tang
College of Animal Science, South China Agricultural University, Guangzhou, Guangdong Province 510642, China.
Xueming
X
Dan
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, China. Electronic address: lianxing@mail.sysu.edu.cn.
Anxing
A
Li
D000135:Acid Phosphatase / Q000097:blood; D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D002118:Calcium / Q000097:blood; D002713:Chlorine / Q000097:blood; D016770:Ciliophora Infections / Q000097:blood / Q000276:immunology / Q000378:metabolism / Q000662:veterinary*; D005393:Fish Diseases / Q000097:blood* / Q000276:immunology / Q000378:metabolism; D005398:Fisheries; D005399:Fishes; D007770:L-Lactate Dehydrogenase / Q000097:blood; D009113:Muramidase / Q000097:blood; D011188:Potassium / Q000097:blood; D011897:Random Allocation; D012623:Seawater; D012964:Sodium / Q000097:blood
D002713:Chlorine; D012964:Sodium; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D009113:Muramidase; D011188:Potassium; D002118:Calcium
Biochemical status; Cryptocaryon irritans; Poly-infection; Protective immunity; Trachinotus ovatus