Probiotic administration of Litopenaeus vannamei: Is there any negative effect on the fatty acid profile of meat?

It has been found that appropriate probiotic applications increased growth performance and disease resistance in shrimp. Bacillus subtilis has been suggested as a potent probiotic in improving growth performance and enhancing immune response in white shrimp, Litopenaeus vannamei. The aim of this work was to evaluate the possible effect of B. subtilis administration on the meat fatty acid profile of white shrimp, L. vannamei. Two groups of shrimps received B. subtilis strains L10 and G1 from the B. subtilis-supplemented feed (10^5 and 10^8 CFU g^-1) while two other groups received it from the rearing water (10^5 and 10^8 CFU ml^-1). One group received no B. subtilis and served as control. According to the results, there was no significant difference between the muscle fatty acid profiles of shrimps administrated by probiotic and control group. This study showed that B. subtilis administration, in either diets or water, did not have any negative effect on fatty acid profiles of L. vannamei meat

Heterologous expression of antigenic peptides in Bacillus subtilis biofilms

Background Numerous strategies have been developed for the display of heterologous proteins in the surface of live bacterial carriers, which can be used as vaccines, immune-modulators, cancer therapy or bioremediation. Bacterial biofilms have emerged as an interesting approach for the expression of proteins of interest. Bacillus subtilis is a well-described, endospore-forming organism that is able to form biofilms and also used as a probiotic, thus making it a suitable candidate for the display of heterologous proteins within the biofilm. Here, we describe the use of TasA, an important structural component of the biofilms formed by B. subtilis, as a genetic tool for the display of heterologous proteins. Results We first engineered the fusion protein TasA-mCherry and showed that was widely deployed within the B. subtilis biofilms. A significant enhancement of the expression of TasA-mCherry within the biofilm was obtained when depleting both tasA and sinR genes. We subsequently engineered fusion proteins of TasA to antigenic peptides of the E. granulosus parasite, paramyosin and tropomyosin. Our results show that the antigens were well expressed within the biofilm as denoted by macrostructure complementation and by the detection of the fusion protein in both immunoblot and immunohistochemistry. In addition, we show that the recombinant endospores of B. subtilis preserve their biophysical and morphological properties. Conclusions In this work we provide strong evidence pointing that TasA is a suitable candidate for the display of heterologous peptides, such as antigens, cytokines, enzymes or antibodies, in the B. subtilis biofilms. Finally, our data portray that the recombinant endospores preserve their morphological and biophysical properties and could be an excellent tool to facilitate the transport and the administration.ISSN:1475-285