In-vitro evaluation of the probiotic potential and the fermentation profile of Pediococcus and Enterococcus strains isolated from Moroccan camel milk

Insights into the microbiota of raw milk from seven breeds animals distributing in Xinjiang China

Owing to its high nutritional content, raw milk contains a rich microbiota. Thus, to study microorganisms present in raw milk available in Xinjiang China, 142 raw milk samples from seven animal breeds (cow, sheep, goat, donkey, horse, camel, and yak) and four regions (Hami, Tarbagatay, Kashgar, and Ili) were analyzed by high-throughput DNA sequencing. These microorganisms were characterized by 10 dominant phyla. Proteobacteria (68.33%) was the major phylum, followed by Firmicutes (18.80%) and Thermi (3.16%). Horse milk contained more Bacteroidetes, sheep milk contained more Gammaproteobacteria, and donkey milk contained more unclassified sequences. Camel and donkey milk contained the highest and lowest bacterial diversity compared with that contained by the remaining milk samples, respectively. Additionally, spoilage microorganisms, including Chryseobacterium, Propionibacterium, and Flavobacterium, and pathogenic bacteria, including Ochrobactrum anthropi and Sphingomonas, were more prevalent in horse and yak milk, whereas probiotic lactic acid bacteria (LAB), such as Leuconostoc, Lactococcus, or Lactobacillus, were more prevalent in goat, donkey, and camel milk. Furthermore, Moraxella was abundantly present in goat, camel, and yak milk, Acinetobacter was more abundant in camel milk, and Pseudomonas was relatively abundant in sheep and donkey milk. Overall, specific harmful microorganisms and probiotic lactic acid bacteria were found in the raw milk samples obtained from different animals, which provided a basis for preventing and controlling the growth of harmful bacteria, as well as investigating probiotic resources in raw milk.

Dellaglioa Algida Cell-Free Supernatant Inhibits Pseudomonas Fluorescence and Pseudomonas Fragi by Destroying Cell Membranes

The aim of this study was to examine the components of the cell-free supernatant (CFS) derived from a novel strain of psychrophilic Lactobacillus, Dellaglioa algida, and to further elucidate the impact of this CFS on various cellular processes. Specifically, we sought to understand its effects on the cell membrane, protein and DNA release, protease activity, and metabolites of Pseudomonas fluorescens and Pseudomonas fragi, thereby clarifying the antibacterial mechanism involved. The CFS components were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS), the Coomassie Brilliant Blue method, and the phenol-sulfuric acid method. The inhibitory effect of the CFS on Pseudomonas fluorescens and Pseudomonas fragi was assessed using the ethidium bromide (EB) assay, Oxford cup assay, and ultramicroassay. Additionally, we analyzed the metabolites produced by Pseudomonas fluorescens and Pseudomonas fragi when treated with the CFS. The findings reveal that the CFS of Dellaglioa algida contains 94 volatile components, with protein and sugar concentrations of 32.857 ± 0.9705 mg/mL and 98.250 ± 4.210 mg/L, respectively. The CFS induces varying degrees of damage to the cell membranes of both Pseudomonas fluorescens and Pseudomonas fragi, leading to the release of intracellular proteins and DNA. Furthermore, the CFS reduced the protease activity and metabolic capacity of Pseudomonas fluorescens and Pseudomonas fragi. These results enhance our understanding of the mechanism by which psychrophilic Dellaglioa algida inhibits Pseudomonas fluorescens and Pseudomonas fragi, confirming that its inhibitory effect predominantly occurs through damage to the biological cell membranes of Pseudomonas. Dellaglioa algida is a newly identified cold-adapted inhibitor of Pseudomonas, indicating that its CFS is an effective microbial inhibitor in cold environments. This discovery suggests potential applications in inhibiting the growth and reproduction of Pseudomonas fluorescens and Pseudomonas fragi in food, pharmaceuticals, perfumes, and other chemicals, providing a valuable new reference for industrial preservation.

Microbial diversity in camel milk from Xinjiang, China as revealed by metataxonomic analysis

The quality of raw camel milk is affected by its bacterial composition and diversity. However, few studies have investigated the bacterial composition and diversity of raw camel milk. In this study, we obtained 20 samples of camel milk during spring and summer in Urumqi and Hami, Xinjiang, China. Single-molecule real-time sequencing technology was used to analyze the bacterial community composition. The results revealed that there were significant seasonal differences in the bacterial composition and diversity of camel milk. Overall, Epilithonimonas was the most abundant bacterial genus in our samples. Through the annotated genes inferred by PICRUSt2 were mapped against KEGG database. Non-parametric analysis of the bacterial community prediction function revealed a strong bacterial interdependence with metabolic pathways (81.83%). There were clear regional and seasonal differences in level 3 metabolic pathways such as fat, vitamins, and amino acids in camel milk. In addition, we identified lactic acid bacteria in camel milk with antibacterial and anti-tumor activities. Our findings revealed that camel milk from Xinjiang had serious risk of contamination by psychrophilic and pathogenic bacteria. Our research established a crucial theoretical foundation for ensuring the quality and safety of camel milk, thereby contributing significantly to the robust growth of China's camel milk industry.

Bacillus subtilis PM5 from Camel Milk Boosts Chicken Immunity and Abrogates Salmonella entertitidis Infections

With the practice of a successful livestock industry using antibiotics, which has continued for more than five decades, researchers have long been interested in finding alternatives to antibiotics for poultry production. Probiotics can potentially reduce enteric diseases in livestock and enhance their productivity. The aim of this study was to isolate putative probiotics from camel milk and test them against Salmonella infection as well as host immune development. Thirteen different isolates were obtained from six different camel milk samples from dairy farms in Saudi Arabia. Three of the six isolates (PM1, PM2, PM3, PM4, PM5, and PM6) that showed Gram-positive characters reacted negatively to catalase and hemolytic assays. PM1, PM5, and PM6 showed significant nonpolar surface properties (>51% hydrophobic) and potent antimicrobial activities against avian pathogens, namely S. enterica, S. typhi, S. aureus, and E. coli. PM5 exhibited substantial probiotic traits; therefore, further focus was given to it. PM5 was identified as Bacillus subtilis OQ913924 by the 16S rRNA sequencing method and showed similarity matrix > 99%. An in vivo chicken model was used to access the health benefits of probiotics. After salmonella infection, the mucosal immune response was significantly increased (p < 0.01), and none of the challenge protocols caused mortality or clinical symptoms after infection in intestinal contents. S. enterica organ infiltration in the spleen, thymus, and small intestine was significantly reduced in the B. subtilis PM5-fed chickens. The S. enterica load in chicken feces was reduced from CFU 7.2 to 5.2 in oral-fed B. subtilis PM5-fed chickens. Probiotic-fed chickens showed buffered intestinal content and positively regulated the level of butyric acid (p < 0.05), and intestinal interleukin 1 beta (IL1-β), C-reactive protein (CRP), and interferon gamma (IFN-γ) levels were reduced (p < 0.05). In addition, B. subtilis PM5 showed significant binding to peritoneal macrophages cells and inhibited S. enterica surface adhesion, indicating co-aggregation of B. subtilis PM5 in macrophage cells. It could be concluded that supplementation with probiotics can improve the growth performance of broilers and the quality of broiler chickens against enteric pathogens. The introduction of this probiotic into the commercial poultry feed market in the near future may assist in narrowing the gap that now exists between chicken breeding and consumer demand.