Influence of Symbiotic Probiont Strains on the Growth of Amphora and Chlorella and Its Potential Protections Against Vibrio spp. in Artemia

Temporal variability of microbiome in the different plankton hosts revealed distinct environmental persistence of Vibrio parahaemolyticus in shrimp farms

Plankton-bacteria interactions may play essential roles in maintaining the persistence of pathogenic Vibrio spp. However, the actual plankton host of the toxigenic Vibrio parahaemolyticus that harbors thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH) remains unclear. To answer this question, we measured the abundance of toxigenic and nontoxigenic Vibrio parahaemolyticus in different types of plankton by most probable number (MPN)-PCR. We next investigated the dynamics of the microbiomes of rearing water, copepods, Chlorella, four predominant diatom genera (Nitzschia, Melosira, Skeletonema and Chaetoceros) and the gut of the shrimp in two recirculated shrimp farming systems from April to September using high-throughput 16 S rRNA amplicon sequencing. The survival of trh-positive and trh-negative V. parahaemolyticus in seawater and different plankton hosts was examined under low temperature and starvation conditions. The results showed that copepods harbored the highest proportion of trh-positive V. parahaemolyticus, followed by diatoms. Chitinous diatoms (CD) harbored a high proportion of Vibrionaceae, of which a high abundance of V. parahaemolyticus was found in summer. In contrast, Vibrio spp. is rarely found in Chlorella and nonchitinous diatoms. Taxon-specific associations were also observed, including a relatively high abundance of Vibrio and Halodesulfovibrio on copepods and covariation of Aeromonas and Bacillus inside the Chlorella. The survival assays showed that, in comparison to trh-negative V. parahaemolyticus, trh-positive V. parahaemolyticus showed better survival in copepods and CD under starvation conditions and maintained high persistence in the above hosts at low temperature. In conclusion, the results herein suggested that chitinous plankton might provide protection for V. parahaemolyticus, especially trh-positive V. parahaemolyticus, and improve their persistence under harsh conditions. Our study provided in-depth insights into the persistence of V. parahaemolyticus in the environment, which would promote targeted disease prevention measures.

Fortified milk-beverage with amphora algae and its functionality for aflatoxin inactivation in rats

Aflatoxins are considered a severe hazard, contaminate dietary products, and cause malignant alterations in liver tissues. Fermented milk (FM) is prepared using probiotic lactic acid strains. This investigation aimed to produce an integrated milk beverage, inactivating aflatoxins toxicity and biotransformation. The proximate analysis of the investigated materials and biochemical parameter changes of the in-vivo experiment were determined. Results reflected the extract’s valuable content of polysaccharides and antioxidants. Nine phenolics were identified predominantly with catechin (39.67 ± 1.5 µg/g). FM-fortification is reflected by enhancement in protein (49.5 ± 2.97 g/Kg) and fiber content (1.78 ± 0.54 g/Kg) compared to the FM content. Relative rats’ weight gain improved to 34.29% for the fortified-FM group close to the control; it was recorded at 16.47% for the AFM1 group. Alkaline phosphatase in AFM1 rats was 99.2 ± 1.86 U/L and decreased to 44.2 ± 0.71 U/L in the fortified-FM group (44.2 ± 0.71 U/L) to be close to the control group. Aflatoxin M1 rats exposure reflects tissue alterations and cell damage, which recorded lesser in rats treated by extract and beverage administrations. The beverage’s corrective action relied on two integrated mechanisms, aflatoxin-binding to bacterial and bioactivity interaction of extract substances. This beverage stopped tissue alterations that occurred due to aflatoxins. The result supports the future production of fortified-milk beverages as a bio-shield against aflatoxin toxicity, besides their nutritional and functional properties.

Efficacy of Single and Multi-Strain Probiotics on In Vitro Strain Compatibility, Pathogen Inhibition, Biofilm Formation Capability, and Stress Tolerance

Compatibility of each strain in a multi-strain probiotic (MSP), along with its properties, becomes a strong base for its formulation. In this study, single-strain probiotics (SSPs) and multi-strain probiotics (MSPs) were evaluated in vitro for strain compatibility, microbial antagonism, biofilm formation capacity, and stress tolerance. Bacillus amyloliquefaciens L11, Enterococcus hirae LAB3, and Lysinibacillus fusiformis SPS11 were chosen as MSP1 candidates because they showed much stronger antagonism to Aeromonas hydrophila and Streptococcus agalactiae than a single probiotic. MSP 2 candidates were Lysinibacillus fusiformis strains SPS11, A1, and Lysinibacillus sphaericus strain NAS32 because the inhibition zone produced by MSP 2 against Vibrio harveyi and Vibrio parahaemolyticus was much higher than that produced by its constituent SSPs. MSP1 in the co-culture assay reduced (p < 0.05) A. hydrophila count from 9.89 ± 0.1 CFU mL−1 to 2.14 ± 0.2 CFU mL−1. The biofilm formation of both MSPs were significantly higher (p < 0.05) than its constituent SSPs and the pathogens. The SSPs in both MSPs generally showed resistance to high temperatures (80, 90, and 100 °C) and a wide range of pH (2 to 9). This in vitro assessment study demonstrates that MSP1 and 2 have the potential to be further explored as multi-strain probiotics on selected aquatic species.