Abstract
Increasing apparent nutrient digestibility is critical for improving beef cattle growth performance and increasing ranch profitability. Therefore, we investigated the effects of the dynamic assembly process of Allium mongolicum Regel powder (AMRP) on the fecal microbiome of Angus calves as well as the apparent nutrient digestibility, and growth performance. Twenty-four Angus calves were divided into four groups (n = 6) and treated with 0 (ZAMR), 10 (LAMR), 15 (MAMR), or 20 (HAMR) g/d/calf AMRP for 122 days. Growth performance parameters were recorded, and fecal samples were collected on days 1, 90, and 122. The results showed that the addition of AMRP did not affect Firmicutes or Bacteroidota, which are core microbes in the fecal microbiome. There was a decrease in the alpha diversity of the fecal microbes on day 122 compared to that on days 1 and 90, with 23 differential microbes screened. Correlation analysis revealed that a variety of differential microbes were significantly associated with apparent nutrient digestibility and growth performance. The apparent digestibility of dry matter and crude protein were significantly greater in the LAMR group (P < 0.050). In conclusion, AMRP at a dose of 10 g/d/calf was more favourable for increasing apparent nutrient digestibility, and improving growth performance.