Stimulation of non-specific immunity, gene expression, and disease resistance in Nile Tilapia, Oreochromis niloticus (Linnaeus, 1758), by the methanolic extract of the marine macroalga, Caulerpa scalpelliformis

Abstract

Aim: The objective of the present study was to test the immunostimulating potential of marine macroalga, Caulerpa scalpelliformis, in terms of non-specific immune responses, gene expression, and disease resistance of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758). Materials and Methods: O. niloticus was injected intraperitoneally with three different doses of methanol extract of C. scalpelliformis (CSME) (2 mg/kg, 20 mg/kg, or 200 mg/kg body weight), or MacroGardTM (commercial immunostimulant, positive control, and 20 mg/kg body weight), or distilled water (untreated control). In one set of fish, 5 days post-injection, serum lysozyme, myeloperoxidase, and antiprotease activities were assayed. 24 h after injection, gene expression was analyzed in a separate set of fish. To another set of fish, 1 week post-administration of the products, fish were challenged with lethal dose 50 (LD50) dose of a live virulent pathogen, Aeromonas hydrophila and subsequent resistance to it was noted in terms of cumulative percent mortality. Results: CSME increased serum lysozyme, myeloperoxidase, and antiprotease activities. There was an increase in the expression of lysozyme gene in the spleen of treated fish. Mid dose of CSME caused the minimum mortality of 10% (consequent relative percentage survival = 73) which is comparable to that of the positive control. Conclusion: CSME is considered to have the potential to be developed into an immunostimulant for finfish aquaculture.

Immune response evaluation in Balb/c mice after crude extract of Anisakis typica sensitization

“…Food safety and food security due to food-borne infections are gaining interest in the past decade [1,2]. Anisakiasis, the zoonotic disease caused by nematode larvae of the genus Anisakis is considered as one of the most important biohazards in the fish products [3].…”

Assessing the susceptibility of the selected gourami (Osphronemus goramy) to Aeromonas hydrophila

“…This difference is probably due to differences in serotype and biotype of bacteria, fish species, and temperature (Olga 2014). Besides that, the difference in test results and LD50 calculations is thought to be due to the very different sources of origin of bacteria and host fish used (Makrinos and Bowden 2016;Li et al 2017;Yengkhom et al 2019). Changes in the physical and chemical characteristics of the environment can increase the abundance and virulence of pathogenic organisms as can genetic mutation, factors which must have an important influence on the outcome of a situation in which pathogens challenge fish in the water (Tripathi et al 2018).…”

Antimicrobials from Seaweeds for Food Applications

“…Additionally, Vatsos and Rebours [ 43 ] reported that in aquaculture studies, the macroalgal compounds were either incorporated directly in the feeds (dry or live) or added directly into the water in which the fish and shrimp were grown. The efficacy of microalgae such as Chlorella vulgaris or Arthrospira platensis [ 44 , 45 ] and the polysaccharide fraction of the Caulerpa scalpelliformis or Padina gymnospora [ 46 , 47 ] was reported in Nile tilapia ( Oreochromis niloticus ) and common carp ( Cyprinus carpio ). In addition, microencapsulated macroalgal extracts were tested against Aeromonas salmonicida in Oreochromis mossambicus [ 48 ].…”