Effects of Saccharomyces cerevisiae fermentation products on growth performance, fecal short chain fatty acids, and microbiota of pre-weaning calves

Objective: This research aims to explore the effects of incorporating <i>Saccharomyces cerevisiae</i> fermentation products (SCFP) on growth performance, nutrient digestibility, antioxidant capacity, fecal short-chain fatty acids, and microbial composition of pre-weaning calves.Methods: Twenty Holstein calves, 10 days old and weighing an average of 48.63±0.91 kg, were randomly assigned to either the control group (CON) or the SCFP group, with 10 calves in each group. The CON group received only a basal diet, while the SCFP group received the starter diet supplemented with 5 g/head/d of SCFP products. The pre-trial period lasted for 5 days, followed by a main experimental period of 45 days.Results: The SCFP group had significantly higher final weight, average daily gain, and feed efficiency compared to the CON group (p<0.05). Moreover, the SCFP group exhibited increased apparent digestibility of dry matter, crude protein, ether extract, acid detergent fiber, Ca, and P (p<0.05). Additionally, supplementation with SCFP led to elevated content of growth hormone, insulin-like growth factor-1, and glucagon-like peptide-1 in serum. The inclusion of SCFP also raised serum catalase content and reduced serum malondialdehyde content in pre-weaning calves. Furthermore, SCFP supplementation influenced the composition of intestinal microflora by decreasing <i>Actinobacteriota</i> abundance and increasing the abundance of <i>Ruminococcus</i>, <i>Lachnospiraceae_AC2044_group</i>, <i>Parabacteroides</i>, and <i>Butyricimonas</i>.Conclusion: The addition of SCFP has a positive impact on the growth performance, nutrient digestibility, antioxidant capacity, and intestinal microflora composition of pre-weaning calves.