ALBERT

Description: 〈p〉Publication date: Available online 13 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology〈/p〉 〈p〉Author(s): A. Panigrahi, R.R. Das, M.R. Sivakumar, A. Saravanan, C. Saranya, N.S. Sudheer, K.P. Kumaraguru Vasagam, P. Mahalakshmi, S. Kannappan, G. Gopikrishna〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Effect of bio-augmentation of 〈em〉Bacillus spp〈/em〉 in biofloc on growth, survival and immunity in Indian white shrimp 〈em〉Penaeus indicus〈/em〉 was evaluated. Nine 〈em〉Bacillus〈/em〉 strains were isolated and screened individually as well as in the form of a consortia. To maintain a C:N ratio of 12:1 a blend of carbohydrate sources was used. Bio-augmentation with bacterial consortium and 〈em〉Virgibacillus sp.〈/em〉 produced improved growth and immunity. Shrimp survival ranged from 80 to 95% among treatments. Production was higher (35%) in the biofloc tanks with an average body weight (ABW) of 10.89 ± 1.2 g. On evaluating the immune responses, it was found that trypsin significantly (P 〈 0.05) enhanced Prophenoloxidase (PO) activity in 〈em〉Lysinibacillus〈/em〉, 〈em〉Bacillus cereus〈/em〉, 〈em〉Bacillus licheniformis〈/em〉 and 〈em〉Bacillus subtilis〈/em〉 bio-augmented groups. Laminarin induced PO activity was observed in groups supplemented with 〈em〉Oceanobacillus sp.〈/em〉, 〈em〉Bacillus sp.〈/em〉and 〈em〉Bacillus megaterium〈/em〉. The lysozyme (LZ) activity was significantly (P 〈 0.05) higher in 〈em〉B. cereus〈/em〉 and Microbial Consortia (MC), while other treatments were less effective. Total hemocyte count (THC) significantly (P 〈 0.05) increased in all treatment groups compared to the control. Hyaline hemocyte (HH) count was significantly (P 〈 0.05) higher in the control group (14.43%). Semi granular hemocytes (SGH) was higher in groups treated with 〈em〉Lysinibacillus, Bacillus sp., B. licheniformis〈/em〉 and 〈em〉B. subtilis.〈/em〉 The granular hemocyte (GH) count was significantly (P 〈 0.05) higher in 〈em〉Virgibacillus sp.〈/em〉, 〈em〉B. cereus〈/em〉, 〈em〉B.megaterium〈/em〉 and 〈em〉Oceanobacillus sp.〈/em〉 The biofloc alone (BF), treated and augmented with 〈em〉B. megaterium〈/em〉 significantly (P 〈 0.05) increased phagocytic activity. Highly significant phagocytic index (PI) was observed in bio-augmented groups, BF and MC. The relative expression levels of immune genes were found to be significantly up-regulated in shrimps grown in bio-augmented groups. Enhanced immunological parameters implies that bio-augmentation of biofloc with 〈em〉Bacillus spp.〈/em〉 improved immunity in shrimps. Hence, bio-augmentation of probiotics in biofloc may be useful in improving culture conditions to produce 〈em〉P. indicus.〈/em〉〈/p〉〈/div〉 〈/div〉