The current study focused on assessing the outcome of methanol extract of Chaetomorpha antennina (MECA) on the growth performance and immune modulation in both specific and non-specific immune responses through the assessment of neutrophil, serum lysozyme, serum myeloperoxidase, antiprotease, ceruloplasmin, reactive oxygen species (ROS), and reactive nitrogen species (RNS) activity in Labeo rohita (rohu) at 28 days post treatment along with assessment of the disease resistance capacity against Edwardsiella tarda at 30days post immunization. Fishes (n = 144; average weight 50.0 ± 0.23 g) were evenly divided into four treatments, with 12 fishes per tank in triplicates. The MECA was injected intraperitoneally in the fishes at different doses as 0, 25, 75, and 150 mg/kg of the body weight. The results demonstrated that fish treated with MECA have an increased body weight, specific growth rate, and feed conversion ratio (p < 0.05) with respect to the control group. Results suggested that the MECA inclusion can significantly enhance (p < 0.05) the levels of serum lysozyme, neutrophil function, serum antiprotease activity, cellular RNS, and ROS production. Exposure to MECA of 75 mg/kg showed a significantly higher survival percentage against E. tarda disease infection. These results indicate MECA as a stimulant of immunity in L. rohita against E. tarda. The results suggested that MECA is a potent immunostimulant in finfish aquaculture and can offer higher economic welfare.
Keywords: MECA; challenge test; growth performance; immunostimulant; rohu.