Asparagus racemosus aqueous root extract induced effects on cellular immune reaction of Labeo rohita (Hamilton)

Abstract

The present study was undertaken to evaluate the effect of Asparagus racemosus aqueous root extract on cellular immune reaction of Labeo rohita (Hamilton) fingerlings with response to bacterial infection caused by Aeromonas hydrophila at cool hilly mid altitude region of Meghalaya. Four concentrates mixtures of pelleted diet were formulated viz. without A. racemosus aqueous root extract (control); with 50 mg A. racemosus aqueous root extract/kg of diet (AR1); with 100 mg A. racemosus aqueous root extract/kg of diet (AR2); and with 150 mg A. racemosus aqueous root extract/kg of diet (AR3). Feeding trial was conducted for 60 days. Immune reactions, viz. NBT level, phagocytic activity, total immunoglobulin level, lysozyme activity, antiprotease activity and myeloperoxidase activity of fish were determined at 0, 15, 30, 45 and 60 days of feeding. Fish were infected with A. hydrophila 60 days post feeding, mortalities (%) and agglutination antibody titre were recorded over 14 days post infection. The results showed that in the treatment group AR2, AR3, there was significantly enhanced NBT level, phagocytic activity, lysozyme activity, immunoglobulin level, antiprotease activity and myeloperoxidase activity compared to control. The treatment group AR1 NBT level, phagocytic activity, lysozyme activity, myeloperoxidase activity were significantly enhanced whereas immunoglobulin level and antiprotease activity were nonsignificant compared to control. The highest survival was recorded in the AR2 (43.36±0.65) group, followed by AR3 (24.32±0.14), AR1 (17.26±0.45) and lowest were recorded in the control (3.42±0.02). The highest agglutination antibody titre was recorded in the AR2 (87.36±0.65) group followed by AR3 (49.32±0.14) and AR1 (38.26±0.45) group and lowest in control (17.42±0.02) against A. hydrophila infection. Thus, from the present study it can be deduced that feed containing A. racemosus aqueous root extracts/kg diet can influence immune reaction in L. rohita; however, AR2 group showed better result in terms of immune reaction and protection against pathogenic A. hydrophila at cool hilly mid altitude region of Meghalaya.