In Vitro Assessment of Marine Bacillus for Use as Livestock Probiotics

Abstract

Six antimicrobial-producing seaweed-derived Bacillus strains were evaluated in vitro as animal probiotics, in comparison to two Bacillus from an EU-authorized animal probiotic product. Antimicrobial activity was demonstrated on solid media against porcine Salmonella and E. coli. The marine isolates were most active against the latter, had better activity than the commercial probiotics and Bacillus pumilus WIT 588 also reduced E. coli counts in broth. All of the marine Bacillus tolerated physiological concentrations of bile, with some as tolerant as one of the probiotics. Spore counts for all isolates remained almost constant during incubation in simulated gastric and ileum juices. All of the marine Bacillus grew anaerobically and the spores of all except one isolate germinated under anaerobic conditions. All were sensitive to a panel of antibiotics and none harbored Bacillus enterotoxin genes but all, except B. pumilus WIT 588, showed some degree of β-hemolysis. However, trypan blue dye exclusion and xCELLigence assays demonstrated a lack of toxicity in comparison to two pathogens; in fact, the commercial probiotics appeared more cytotoxic than the majority of the marine Bacillus. Overall, some of the marine-derived Bacillus, in particular B. pumilus WIT 588, demonstrate potential for use as livestock probiotics.

<i>In vitro</i> evaluation of candidate <i>Bacillus</i> spp. for animal feed

“…The isolates CM2, CM4, CM11, CM35 and CF2 showed a 100% decrease in cell viability when exposed to simulated gastric conditions at 37∞C for 30 min, while CM40 and PF7 showed 25.84% and 22.33% survival, respectively (Table 2). This result was in agreement with that of a previous study, which showed that the vegetative cells of almost all marine-derived Bacillus, except for B. pumilus WIT 584 and B. licheniformis WIT 586, were undetectable after only 30 min of exposure to simulated gastric juice (pH 2.2) (Prieto et al, 2014). However, our findings were not consistent with those observed for the vegetative cells of B. polyfermenticus CJ6, which exhibited a very high survival rate (60-96%) after acid treatment for up to 2 h (Jung et al, 2012).…”

“…Our isolates showed an adherence ability to HT-29 which was higher than those reported (0.001-0.06%) for marine-derived Bacillus (Prieto et al, 2014). The spores of CM35 and PF7 displayed the strongest adherence to HT-29 and Caco-2 cells at 1.73% and 3.18%, respectively.…”

“…After exposure for 3 h, vegetative cells of CM2, CM4, CM35, CM40, PF7 and CF2 showed more than 70% survival, while CM11 showed an almost 50% decrease in cell viability. Bile salts tolerance of Bacillus vegetative cells were reported (Cenci et al, 2006;Prieto et al, 2014). In contrast, the spores from all selected isolates displayed more than 90% survival after exposure for 90 min in simulated gastric conditions and for 3 h in 0.3% bile salt (Table 2).…”

Selection of Bacillus species for targeted in situ release of prebiotic galacto-rhamnogalacturonan from potato pulp in piglets

“…It has previously been suggested that biofilm formation of Bacilli is a prerequisite for prolonged persistence in the intestine (Tam et al 2006;Prieto et al 2014) and we therefore tested for the ability to produce biofilm specifically testing for pellicle formation in order to include the biofilm formation ability in our assessment of the suitability of the strains. Using this approach, all selected strains with the exception of B. subtilis strain 5036 were able to produce robust biofilms ( Supplementary Fig.…”

Food ingredients from the marine environment. Marine biotechnology meets food science and technology

“…They participate in fermentation of marine foods (Dewapriya and Kim, 2014;Tanasupawat and Visessanguan, 2014), can produce various compounds to be used as natural food additives and/or functional ingredients and can also be exploited as probiotics for use in human or productive animals diet Dewapriya and Kim, 2014;Prieto et al, 2014).…”