# The Effects of Dual-Yeast Compound Preparation on the Intestinal Health and Metabolism of Lambs

## TL;DR

Adding a mix of two yeast strains to lamb feed improves their growth, gut health, and metabolism, offering a new way to enhance lamb productivity and animal husbandry.

## Contribution

This study demonstrates that a composite yeast culture improves lamb productivity and gut microbiota, offering novel insights into ruminant microecological preparations.

## Key findings

- Lambs fed with composite yeast culture showed higher daily weight gain and feed intake.
- Yeast-fed lambs had increased Bacteroidetes abundance and enriched mTOR signaling pathways.
- Levels of ketones and benzoic acid substances were elevated in yeast-fed lambs.

## Abstract

With the aim of clarifying the effects and mechanisms of yeast microbiota preparations on the health of young ruminants, the influence of yeast culture on the growth, gut microbiota, and metabolism of weaned lambs was studied and analyzed. In this study, we divided twenty weaned lambs into four groups and fed each group separately with basic feed and different yeast cultures. The study continued for 40 days, and relevant indicators were detected. The results showed that the lambs added with composite yeast culture had significantly higher daily weight gain and feed intake, improved feed utilization efficiency, increased abundance of Bacteroidetes in the intestine, enrichment of specific signaling pathways, and increased levels of ketones and benzoic acid substances. Research has indicated that adding yeast culture to feed can have a positive effect on lamb productivity performance and intestinal health, providing a basis for the development of microecological preparations for ruminants, helping to improve lamb breeding efficiency and animal product quality, and having value for the development of animal husbandry.

Microecological preparations exert beneficial effects on the health of young ruminant animals; however, the mechanism is unclear. As a result, the present study analyzed the effects of yeast cultures on the growth properties, microbiome, and metabolism of weaned lambs. In this study, a total of 20 weaned lambs were randomly, stochastically divided into four teams: the control group (Group A) were fed a basic diet; Group B were fed with Saccharomyces cerevisiae BC strain culture (30 g/head/d); Group C were fed with Kluyveromyces marquez XR4 strain culture (30 g/head/d); Group D were fed with a composite culture of the two yeast strains (30 g/head/d). The study lasted for 40 days, with daily records of lamb feed intake and weight. Lamb feces were collected regularly for metagenomic sequencing and metabolomics analysis. The average daily weight gain and average daily yield of Group D lambs were significantly higher than those of Group A lambs (p < 0.01). The feed utilization rate in the yeast-fed groups was considerably higher than in the control group (p < 0.05), indicating that the addition of yeast crops to lamb feed might improve lamb feed performance. Bacteroides and the mTOR signaling pathway were dramatically enriched in the intestines of weaned lambs in the yeast-culture-fed groups, and their expression levels of ketones and benzoic acid compounds were significantly upregulated. These results indicated that yeast culture had excellent effects on weaned lambs in regulating immunological functioning and the intestinal environment, protecting the enteric mucosal barrier, improving digestion and nutritional absorption, and enhancing antioxidant function. In summary, adding yeast culture to weaned lamb feed can generate a positive effect on its productivity performance and gut health. These findings provide novel insights into promoting the health of young ruminants.