Oral administration of terpenoids and phenol fraction of Padina gymnospora stimulates the nonspecific immune response and expression of immune genes, and protects the common carp (Cyprinus carpio) from experimental Aeromonas hydrophila infection

• Published in: Fish & shellfish immunology 2023-11, Vol.142, p.109141-109141, Article 109141
• Main Authors: Priyadarshini, Sekaran Kalaivani, Murugesan, Monica, Michael, R. Dinakaran, Aiya Subramani, Parasuraman, Rajendran, Priyatharsini
• Format: Article
• Language: English
• Subjects: Aeromonas hydrophila; Aquaculture; Common carp; Immune gene expression; Immunostimulation; Nonspecific immune response; Padina gymnospora; Terpenoids and phenol fraction (TPF)
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2023.109141

Common carp (Cyprinus carpio), a valuable aquaculture species susceptible to various infections, requires effective immune enhancement strategies. This study investigates the immunomodulatory effects of orally administered terpenoids and phenol fraction (TPF) from Padina gymnospora in C. carpio, focusing on stimulation of nonspecific immune response, immune gene expression, and protection against experimental infection. P. gymnospora is a brown seaweed species known for its bioactive compounds and medicinal properties. TPF was extracted using the Harborne fractionation method, and the presence of terpenoids and phenol compounds was confirmed by qualitative analysis and high-performance thin layer chromatography (HPTLC). TPF was administered orally in different doses to carp. Nonspecific immune responses were evaluated by measuring cellular ROS, RNI, and peroxidase production. The expression of immune genes (lysozyme and interleukin-1β) was assessed by reverse transcriptase PCR. Furthermore, the protective efficacy of TPF was determined by infecting carp with a virulent pathogen, Aeromonas hydrophila, and monitoring mortality rates and disease symptoms. The results demonstrate that oral TPF administration significantly enhances nonspecific immune responses, with increased ROS, RNI, and peroxidase production, indicating improved immune function. Expression levels of lysozyme and interleukin-1β were upregulated, suggesting immune system activation. Moreover, TPF exhibited significant protection against experimental infection, with lower mortality rates compared to the control group. These findings highlight TPF's potential as an effective immunostimulatory agent, enhancing immune responses and providing infection protection in carp. In conclusion, oral TPF administration stimulates nonspecific immune responses, modulates immune gene expression, and confers protection against experimental infection in carp, displaying its potential for enhancing immune responses and disease resistance in aquaculture species, and contributing to sustainable fish health management. •Terpenoids & phenol fraction boost carp's immune response - oral administration study.•Padina gymnospora extract protects carp from Aeromonas hydrophila infection.•Immune gene expression upregulated by terpenoids & phenol fraction in carp.•Potential immunomodulatory agent for aquaculture: Padina gymnospora extract.