Probiotic Potential of Yeast, Mold, and Intermediate Morphotypes of Geotrichum candidum in Modulating Gut Microbiota and Body Physiology in Mice.

Geotrichum candidum, a polymorphic fungus, exists in yeast, mold, and intermediate morphotypes, each with varying genome sizes and phenotypic traits. While G. candidum has been studied as a probiotic in dairy cattle and aquaculture, the differential probiotic potential of its morphotypes has not been fully investigated; therefore, the current study was designed to investigate their impact on the modulation of physiological and gut microbial diversity in BALB/c male mice. In this study, four strains of G. candidum were used, comprising two yeast morphotypes (QAUGC01 and UCMA3730), one mold morphotype (UCMA103), and one intermediate morphotype (UCMA91). BALB/c male mice were administered G. candidum yeast, intermediate, and mold morphotypes via drinking water for 4 weeks. After 4 weeks of experimentation, the yeast morphotype (QAUGC01) notably facilitated healthy weight gain compared to other groups. This was accompanied by significant increases in red blood cell count (p = 0.01). Importantly, QAUGC01 showed no detrimental effects on kidney function, as evidenced by significantly reduced CPK levels (77.25 ± 4.87 U/L) and low cholesterol levels (64.75 ± 0.83 mg/dL). Metagenomic analysis revealed that Firmicutes, Bacteroidetes, and Proteobacteria were predominant bacterial phyla, while Ascomycota and Basidiomycota dominated the fungal populations. Lactobacillus and Bifidobacterium were prominent in the gastrointestinal tract of QAUGC01-treated mice, while Lactococcus correlated with intermediate and mold morphotypes. Predictive functional annotation (PICRUSt2) has revealed the maximum relative abundance of metabolic pathways in mold and intermediate-supplemented mice gut. In contrast, the yeast morphotype (UCMA3730) exhibited a higher metabolic pathway activity in the large intestine. Conclusively, yeast morphotypes increase beneficial bacterial diversity, including Brevibacillus and Bacillus, particularly lactic acid bacteria throughout the gastrointestinal tract. These findings suggest that different G. candidum morphotypes have distinct probiotic potentials, with implications for enhancing gut health in food and feed applications.