High-zinc diets accelerate molting and recovery by remodeling the cecal microbiome in laying hens.

INTRODUCTION

Conventional fasting molting can restore laying performance but imposes substantial physiological stress and welfare concerns. High-zinc diets (2% ZnO) have been proposed as a less stressful alternative, but their mechanisms remain unclear.

METHODS

This study compared fasting-induced molting with zinc oxide supplementation in 384 Lohmann Pink hens (65 wk). Serum, cecal contents, and ovaries were sampled across six stages from pre-molt to post-molt recovery.

RESULTS

ZnO accelerated cessation of lay (5.75 vs. 8.87 d) and earlier recovery to 50% production (15.25 vs. 16.62 d) with lower weight loss (25% vs. 30%). Multi-omics revealed that high-zinc feeding enriched beneficial microbes (e.g., Coprenecus pullicola, Fournierella spp.) involved in amino acid and cofactor biosynthesis, consistent with activated glycine/serine/lysine metabolism. ZnO also reduced inflammatory and barrier-injury signals (IL-1β, LPS, DAO) and promoted earlier recovery of reproductive hormones (higher IGF-1, earlier increases in E2 and LH). Both treatments improved post-molt egg quality; zinc better preserved albumen height and Haugh unit, while fasting increased shell thickness and yolk color.

DISCUSSION/

CONCLUSION

These findings support that a high-zinc-associated microbial-metabolic profile mitigates stress, accelerates ovarian reset, and shortens the time to restore production.