Impact of Probiotic Geotrichum candidum QAUGC01 on Health, Productivity, and Gut Microbial Diversity of Dairy Cattle.

Gut microbial diversity is a determinant of animal productivity and health. Probiotic supplementation in feed has been known to modulate the gut microbial diversity resulting in better feed utilization and resistance against diseases. The current study was designed to determine the probiotic potential of Geotrichum candidum QAUGC01 (VHDP00000000) in Sahiwal-Friesian crossbred dairy cows and its impact on gut microbial diversity, health, and productivity. To evaluate health and productivity, growth performance, determination of blood parameters, serum biochemistry, feed efficiency, milk yield & composition, and nutrients digestibility was determined and compared between control and experimental groups. Moreover, at the end of the experiment, the gut microbial diversity was evaluated through MiSeq (Illumina) sequencing of bacterial and fungal/yeast DNA in dung samples of both control and experimental cows. Inspite of a significant reduction in dry matter intake the increase in feed efficiency and milk yield was observed in experimental cows with normal hematological and serum biochemical profile. The increase in anaerobic bacterial count and decrease in the shredding of pathogenic flora was observed in experimental cows. Metagenomic analysis revealed Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes to be the four dominating phyla among bacteria and, Ascomycota followed by Basidiomycota and Neocallimastigomycota among the fungal population in both groups. The diversity of the core microbiome revealed high bacterial and Fungal Alpha diversity in the experimental group than in control via the Shannon index. This study provided insights into the safe use of G. candidum as a probiotic, to improve growth performance, health, productivity and gut microbial diversity of dairy cattle.