Effect of fed dietary yeast (Rhodotorula paludigena CM33) on shrimp growth, gene expression, intestinal microbial, disease resistance, and meat composition of Litopenaeus vannamei.

Yeast is a health-promoting and bio-therapeutic probiotic that is commonly used in aquaculture. Rhodotorula paludigena CM33 can accumulate amounts of intracellular carotenoids and lipid, which are regarded as nutritionally beneficial compounds in various aspects. The aim of this study was to evaluate the impact of different levels of R. paludigena CM33 (RD) incorporated in a dietary composition at 0% (control), 1% (1% RD), 2% (2% RD), and 5% (5% RD) on the growth of shrimp (Litopenaeus vannamei), their immune-related gene expression, intestinal health, resistance to Vibrio parahaemolyticus (VPAHPND) infection, and meat composition. The results showed significant improvements in the specific growth rate, weight gain, and survival of shrimp fed with 1% RD, 2% RD, and 5% RD, which were higher than the control group after 4 weeks of administration. The administration of 5% RD group resulted in a decrease in cumulative mortality upon VPAHPND challenge when compared to the control group. Furthermore, the expression levels of immune-responsive genes, including proPO system (prophenoloxidase-2: PO2), antioxidant enzyme (superoxide dismutase: SOD, glutathione peroxidase: GPX, and catalase: CAT), JAK/STAT pathway (signal transducer and activator of transcription: STAT, gamma interferon inducible lysosomal thiol reductase: GILT), IMD pathway (inhibitor of nuclear factor kappa-B kinase subunit beta and epsilon: IKKb and IKKe), and Toll pathway (Lysozyme) genes, were up-regulated in the 5% RD group. In the context of microbiota, microbiome analysis revealed that the main phyla in shrimp intestines were Proteobacteria, Firmicutes, Bacteroidota, Campilobacterota, Actinobacteriota, and Verrucomicrobiota. At the genus level, Vibrio was found to be reduced in the 5% RD group, whereas the abundance of potentially beneficial bacteria Bifidobacterium was increased. The 5% RD group showed a significant increase in the levels of crude protein and crude lipid, both of which are essential nutritious components. Our results show the capability of R. paludigena CM33 as a probiotic supplement in shrimp feed in improving growth, antimicrobial responses against VPAHPND, and meat quality by increasing protein and lipid content in shrimp.

A New Potential Source of Anti-pathogenic Bacterial Substances from Zamioculcas zamiifolia (Lodd.) Engl. Extracts.

BACKGROUND AND OBJECTIVE: The increase of antibiotic-resistant bacteria is a problem for global health that needs to find new antibiotic drugs. The plant is the potential source of antibiotic substances that important to solve the antibiotic-resistant bacteria. This study was aimed to evaluate the antibacterial activity of Zamioculcas zamiifolia stem extracts against nine human pathogenic bacteria. MATERIALS AND METHODS: Z. zamiifolia stems were extracted with five extraction solvents. The screening of antibacterial activity of stem extract was measured using agar disc diffusion assay. The Minimal Inhibition Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values of extracts were determined using the broth microdilution assay and colorimetric assay. RESULTS: The results indicated that the lowest MIC value of 0.09 mg mL-1 against Staphylococcus aureus TISTR 1466 was obtained from hexane extraction. The lowest MBCs value of 1.56 mg mL-1 against Bacillus cereus TISTR 2373, Listeria spp. and Escherichia coli TISTR 527 were obtained from ethanol and methanol extractions. CONCLUSION: The ethanolic and methanolic stem extracts of Z. zamiifolia demonstrated the highest anti-human pathogenic bacterial activity. This is the first report to demonstrate the high potential of antibacterial substance from Z. zamiifolia stem extracts, which can be developed further as a natural drug for treating bacterial infectious diseases.

Evaluation of the Antibacterial Activity of Spathiphyllum wallisii Extracts Against Human Pathogenic Bacteria.

BACKGROUND AND OBJECTIVE: The urgent of finding new antibiotics due to the rising of antibiotic-resistant bacteria. The plant is the main source of new antibiotic substances. The purpose of this research was to evaluate the antibacterial activity of Spathiphyllum wallisii extracts against nine human pathogenic bacteria. MATERIALS AND METHODS: The stalks, leaf, rhizome and root of S. wallisii were extracted by using hexane, dichloromethane, ethyl acetate, ethanol and methanol. The disc diffusion assay was used to screen the antibacterial activity of S. wallisii extracts. Broth dilution and colorimetric assay were used to determine the Minimal inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values of extracts. RESULTS: The lowest MIC values at 0.048 mg mL-1 were presented in the stalks extract with dichloromethane, ethyl acetate, methanol and ethanol against B. subtilis TISTR 008, the leaf extracted with hexane, dichloromethane, ethyl acetate, methanol and ethanol against B. subtilis TISTR 008; the leaf extracted with ethyl acetate, methanol and ethanol against S. aureus TISTR 1466, the leaf extracted with dichloromethane, ethyl acetate, methanol and ethanol against S. aureus PK; the rhizome extracted with methanol against S. aureus PK. The lowest of MBC value of 0.048 mg mL-1 was obtained from methanolic rhizome extract against B. subtilis TISTR 008. CONCLUSION: The methanolic rhizome extract of S. wallisii demonstrated the highest of pathogenic bacterial growth inhibition. This is the first report about the antibacterial activity of S. wallisii extracts that will add new information in natural drug discovery and development in industrial pharmacology.