Location: Aquatic Animal Health ResearchTitle: Grass carp which survive Dactylogyrus ctenopharyngodonid infection also gain partial immunity against Ichthyophthirius multifiliis Author
|Li, Jian-pei - Jinan University|
|Fu, Yaowu - Jinan University|
|Zhang, Qi-zhong - Jinan University|
|Liu, Yan-meng - Jinan University|
|Zhou, Sheng-yu - Jinan University|
|Lin, De-jie - Jinan University|
Submitted to: Diseases of Aquatic Organisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2018
Publication Date: 5/28/2018
Citation: Li, J., Fu, Y., Zhang, Q., Xu, D., Liu, Y., Zhou, S., Lin, D. 2018. Grass carp which survive Dactylogyrus ctenopharyngodonid infection also gain partial immunity against Ichthyophthirius multifiliis. Diseases of Aquatic Organisms. 129:63-70.
Interpretive Summary: The monogenean parasite Dactylogyrus ctenopharyngodonid and the protozoan parasite Ichthyophthirius multifiliis are capable of infecting the gills, skin, or fins of fish, leading to significant injury and high mortality. Independently, both parasites can induce an immune response in the fish which allows them to develop resistance against re-infection from either parasite. However, it is not known whether fish surviving D. ctenopharyngodonid infection could resist an I. multifiliis infection. The objective of study was to evaluate the protective immunity of grass carp that survived a D. ctenopharyngodonid infection against D. ctenopharyngodonid and I. multifiliis co-infection. The results demonstrated that when grass carp were infected by D. ctenopharyngodonid, the number of red blood cells and the percentages of thrombocytes, monocytes, and neutrophils significantly increased at the early stages of infection. The increasing numbers of monocytes and neutrophils could promote innate immunity and alleviate the damage caused by the parasites. The surviving grass carp resisted D. ctenopharyngodonid re-infection and were partially protected from an I. multifiliis infection. The study results will improve an understanding of parasite immunity and assist in the development of effective fish health management strategies.
Technical Abstract: Dactylogyrus ctenopharyngodonid and Ichthyophthirius multifiliis are two important ectoparasites of fish. Both parasites could induce fish immune response by decreasing the parasites infection intensity and developing resistance against parasites re-infection. The present study aimed to study the protective immunity of grass carp survived from D. ctenopharyngodonid infection against D. ctenopharyngodonid and I. multifiliis co-infection. The results demonstrated that when grass carp infected by D. ctenopharyngodonid, the red blood cell (RBC) and the percentages of thrombocytes, monocytes, and neutrophils significantly increased at the early stage of infection. The percentage of lymphocytes increased with the prolonging of infection period. The mean intensity of D. ctenopharyngodonid decreased to 0 on day 28. The activities of serum acid phosphatase (ACP), alkaline phosphatase (AKP), lysozyme (LZM), and superoxide dismutase (SOD) significantly increased after D. ctenopharyngodonid infection. In addition, the survived grass carp could resist D. ctenopharyngodonid re-challenge and partially protect fish from I. multifiliis infection.