Immunology

Biography

Biography: V. Kalarani

Abstract

Indiscriminate use of antibiotics to prevent and control diseases affecting the health of fish has led to the development and propagation of antibiotic resistant bacteria in the aquatic ecosystems. Amongst the various alternatives proposed, the most widely accepted approach is the use of probiotics to enhance immunity in fish. In this experiment, we have used Bacillus subtilis as probiotic bacteria and studied the effect of dietary administration of B. subtilis (107 cfu /g-1) on the immune and humoral responses of L. rohita fed for 30(B1) and 60(B2) days. The results show that serum phagocytic activity significantly increased by 36%(B1) and 39%(B2); respiratory burst activity increased by 60%(B1) and 90%(B2); Myeloperoxidase activity increased by 26%(B1) and 71%(B2); serum IgM levels increased by 46%(B1) but decreased by 6%(B2) and serum lectins have increased by 20%(B1) and 46%(B2) in fish fed on diet supplemented with B. subtilis compared to those fed on normal diets. Similarly haemagglutination (70% and 90% respectively in B1 and B2 groups) and haemolytic activity (77% and 98% respectively in B1 and B2 groups) also increased significantly in fish fed on B. subtilis supplemented diets in B1 and B2 groups compared to those fed on control diets. Similar experiment was done using Terribacillus saccharophillus, isolated for the first time from laboratory reared L. rohita. It was found that T. saccharophillus (107 cfu /g-1) supplemented diet also significantly increased the immune responses, though to a lesser extent, in L. rohita. The results suggest that T. saccharophillus could also be used as a potent probiont similar to B. subtilis and will have potential applications in fish feed formulations and disease prevention.