Response of milk performance, rumen and hindgut microbiome to dietary supplementation with Aspergillus oryzae fermentation extracts in dairy cows.

Fungal additives had beneficial effects on milk performance in dairy cows. Previous studies investigating the effects of fungal additives mainly focused on the rumen, such influences on the hindgut remain limited. This study aimed to investigate the effects of Aspergillus oryzae fermentation extracts (AOE) on the milk performance and microbiome in the rumen and hindgut using 16S rRNA gene sequencing. Twenty lactating multiparous Holstein cows were randomly assigned to control and treatment (5 g AOE per cow per day). The results showed that AOE increased the milk yield, milk protein and lactose concentration, but did not affect the milk fat concentration. Feeding AOE did not affect the ruminal VFA pattern, pH, NH₃-N, and microbial cell protein production, but decreased lipopolysaccharide concentration and tended to decrease lactate concentration. The addition of AOE increased the fecal pH and the proportions of propionate, isovalerate and valerate, and decreased the acetate to...