Studies on the use of probiotics in the Larval rearing of the shrimp Penaeus monodon (Fabricius, 1798)

The study regarding 'Studies on the use of probiotics in the larval rearing of the shrimp Penaeus monodon . was carried out by studying the effect of three probiOlic organisms. Saccharomyces boulardii. Lactobacillus plal1farulll and Bacillus sublilis. The parameters monitored were. level of enrichment in larvae and post larvae, survival. weight gain, effect on other bacterial flora and resistance to a pathogenic Vibrio harveyii infection. Attempts were made to find out the optimum enrichment duration and maximum enrichment levels of the above probiotic organisms in Arlemia nauplii and also the difference in enrichment level between two brands of Arlemia nauplii . The study \\as carried out in larval as well as in post larval stages. Direct additions of probiOlics were carried out in larval stages while Saccharomyces boulardii and Bacillus sublilis enriched Arlemia metanauplii \\ere fed to the larvae in post larval section. Anemia enrichment experiments revealed the maximum enrichment levels as 3410 for Saccharomyces boulardii. 2093 for Bacillus sublilis and 105 CFUllarva for Laclobacillus plantarum. Enrichment levels also varied between the t\\O brands. 3410 CFU/nauplii for OSI and 1120 CFU/nauplii for Red Dragon brand in the case of Saccharomyces boulardii. Significant increase in weight gain and survival rate were noticed in larvae as well as post larvae in the experiments conducted. Highest enrichment levels were noticed for mysis Ill. Maximum enrichment levels noticed were 1535 CFUllarva for Saccharomyces boulardii and 2133 CFUllarva for Bacillus subtilis in the larval stages from zoea to PL I. while in post larvae it was I CFUllarva for Saccharomyces boulardii and 66 CFUllarva for Bacillus sub/ilis. Laclobacills planlarum could not be detected during the enrichment study. Addition of Saccharomyces bOl/lardii as \\ell as Bacillus sub/ilis significantly reduced Vibrio counts during mysis stage as well as during post larval stages. Effect on sea water agar counts were not significant during larval stages while in post larvae sea water agar counts were decreased with the application of Saccharomyces boulardii and Bacillus subtilis. Enrichment of Lactobacillus plan/anlln did not produce any significant effect on other bacterial flora. Addition of Saccharomyces boulardii and Bacillus sublilis increased the resistance of larvae to pathogenic Vibrio hmwyii infection in larvae as \I ell as post larvae. About 103 CFU/ml Saccharomyces boulardii broth and 104 to 105 CFU/ml of Bacillus sublilis cells were necessary to surmount Vibrio han'eyii infection in PL. I. Post colonization studies after discontinuing the feeding resulted in 98% reduction in Saccharomyces boulardii counts and 13% reduction in Bacillus sublilis counts after five days from PL I. In post larvae Bac/lus sub/ilis showed only 7% reduction in five days from PL 21. Post larvae fed with live enriched nauplii performed better than those fed with dead enriched nauplii. for the parameters studied. From the above study it is evident that Saccharomyces boulardii and Bacilllls sub/lis can be used as effective probiotic species for shrimp larviculture while Laclobacillusplantarum is not a suitable species