Dose-dependent co-infection of Argulus sp. and Aeromonas hydrophila in goldfish (Carassius auratus) modulates innate immune response and antioxidative stress enzymes. Issue 114 (July 2021)

• Record Type: Journal Article
• Authors: Shameena, S.S.; Kumar, Kundan; Kumar, Saurav; Kumari, Pushpa; Krishnan, Rahul; Karmakar, Sutanu; Sanath Kumar, H.; Rajendran, K.V.; Raman, R.P.
• Is Part Of: Fish & shellfish immunology. Issue 114(2021)
• Page Start: 199
• Page End: 206
• Publication Date: 2021-07
• Subjects: Co-infection -- Dose -- Carassius auaratus -- Argulus -- Aeromonas hydrophila; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2021.04.026
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: Co-infection with parasites and bacteria is of frequent occurrence in aquaculture, leads to growth impedance otherwise mortality in fish depending on the varying degree of a load of primary pathogen either parasite or bacteria. The mechanistic regulation of immune response during co-infection in fish has merely documented. The aim of this study was to determine the impact of co-infection with Aeromonas hydrophila at three exposure doses of Argulus sp. on the innate immune responses and antioxidative stress enzymes of goldfish ( Carassius auratus ). The experimental fish were randomly distributed into eight treatment groups viz. T1 (control group without Argulus and A. hydrophila infection), T2 (fish exposed to a sub-lethal dose of A. hydrophila ), T3 (low Argulus- infested fish), T4 (T3 + sub-lethal dose of A. hydrophila ), T5 (moderate Argulus- infested fish), T6 (T5 + sub-lethal dose of A. hydrophila ), T7 (high Argulus- infested fish) and T8 (T7+ sub-lethal dose of A. hydrophila ) in duplicates. After distributing experimental fish into their respective treatment group, A. hydrophila was injected to T2, T4, T6 and T8. After the bacterial challenge, four fish from each experimental group were randomly sampled on 24, 72, and 168 h and subjected to the hematological, innate immune parameters and enzymatic analysis. In the co-infection group T8, a high degree of enhanced pathogenicity of A. hydrophila was noticed with increased mortalities (84.2%) in comparison to other groups. The current study shows a declining pattern in RBC, PCV and Hb values with the degree of parasite infestation without co-infection groups. Moreover, in the T8 group, exposure of a sub-lethal dose of bacteria resulted in a drastic reduction of the recorded parameters. Furthermore, a decreased value for WBC, monocyte and neutrophil was found in higher parasite group co-infected with a sub-lethal dose of bacteria relative to other co-infected groups during the experimental period. Also, a decrease in innate immune parameters and antioxidative stress enzymes were observed in the T8 group compared to T7 and T2 groups throughout the trial period. These findings indicate that a rise in the dose of Argulus infection improves A. hydrophila colonization in goldfish and contributes to suppression of the innate immune system and increased mortality. Highlights: Rate of mortality is more in co-infected group when compared to single pathogen group. Dose dependent reduction in hematological parameters is observed among co-infected groups. Co-infection with heavy dose of parasite impacts the innate immune parameters and antioxidant stress enzymes. Dosage of pathogens during co-infection have role in regulating the innate immune system.