Effect of Dietary Supplementation of Giloy (Tinospora cordifolia) on Innate Immunity, Haematology and Disease Resistance against Aeromonas hydrophila Infection in Striped Catfish (Pangasianodon hypophthalmus)

Abstract

The Striped catfish (Pangasianodon hypophthalmus) is a prominent inland fish species in the far Eastern Asia region, accounting for approximately 66.7% of total world catfish production in the year 2022-23. There is a growing interest in utilising herbal nutraceuticals as functional dietary additives in aquaculture to boost the immune system of fish and prevent disease occurrence. Giloy (Tinospora cordifolia) has been observed to improve non-specific humoral immune response and disease resistance to fish pathogens in fish. Hence, the current study was undertaken to evaluate the impact of dietary supplementation of Giloy on the haematology, immune response and disease resistance of Striped against Aeromonas hydrophila infection. A basal feed containing 30% protein was used for all the treatments, with Giloy incorporated at the concentrations of 1% (T1), 1.5% (T2) and 2% (T3), along with a control group (T0) without any Giloy supplementation. Significantly higher values for various haematological parameters of RBC, WBC, platelets, Hb, Hct, MCV, MCH and MCHC were observed in treatment T3 when compared to the other treatments T2, T1 and the control in pre-challenge as well as post-challenge studies (p<0.05). Studies on post-challenge immunological parameters revealed significantly higher (p<0.05) Respiratory Burst Activity (2.03±0.029 U/ml) and Lysozyme Activity (3.72±0.018×103 U/ml) in the treatment group T3 when compared to other treatments and the control (Respiratory burst activity: 0.53±0.026 U/ml and Lysozyme activity: 1.08±0.043×103 U/ml). In the challenge study against A. hydrophila, significantly higher Relative Percentage Survival (RPS) of 92.86±5.83% was observed in T3 and other treatments, while the control group exhibited significantly lower RPS of 0% (p<0.05). The T3 diet (2% Giloy) yielded a remarkably elevated survival rate when exposed to A. hydrophila infection, highlighting its potential as an effective dietary supplement for enhancing fish immunity and conferring disease resistance.