Probiotic yeast <i>Saccharomyces cerevisiae</i> drenching modulates ruminal solubility and systemic bioavailability of macro-minerals and heavy metals in fattening sheep fed a total mixed ration

This study examined the effect of live yeast (Saccharomyces cerevisiae; LYS) supplementation on rumen solubility and systemic bioavailability of Mg, P, Ca, Cd, and Pb in the serum and tissues of fattening lambs fed a total mixed ration. The 60-day feeding trial involved 24 fattening lambs randomly assigned to three treatments receiving 0.0, 1.5, or 3.0 g of LYS per animal daily. Results indicated that yeast supplementation, at either level, did not significantly (p > 0.05) affect ruminal mineral solubility. However, 3 g yeast significantly (p < 0.05) increased meat Ca and Pb concentrations while decreasing meat P and meat Cd and serum Pb levels, indicating improved systemic meat Ca utilization and heavy metal clearance through reducing meat Cd and serum Pb accumulations by 34.4% and 95%, respectively. Serum Ca, P, and Mg levels increased compared with baseline, whereas Pb decreased and Cd remained unchanged. Correlation analysis revealed significant interactions among minerals and heavy metals, suggesting that LYS modulates their absorption and metabolism through shared pathways or competitive interactions. However, elevated lead in meat warrants further investigation. In conclusion, live yeast supplementation can serve as an effective probiotic additive to enhance mineral metabolism and reduce heavy metal risk in fattening lambs.HighlightsLive yeast (Saccharomyces cerevisiae) supplementation boosted Ca bioavailability in blood and meat, leading to improved mineral utilization in fattening sheep.Phosphorus levels exhibited a dynamic response, with serum levels rising and meat levels falling at higher yeast doses, indicating potential changes in systemic retention.Cadmium accumulation in meat decreased linearly (up to 34.4%) with yeast supplementation, suggesting partial clearance benefits.Yeast dramatically reduced lead (Pb) concentrations in serum (up to 60.24%; from 249 to 99 ug/L), indicating a robust protective clearance effect.Serum Ca, P, and Mg concentrations increased, and Pb levels decreased post 60 days’ intervention of supplementation, whereas Cd remained unchanged.The mineral solubility in the ruminal remained largely unchanged, which confirms that the influence of yeast primarily has a postruminal or systemic effect.Live yeast plays a crucial role in regulating macromineral-heavy metal dynamics, either positively through a shared absorption pathway or negatively through mineral interactions (correlations highlighted).