INTRODUCTION

This study investigated the effects of feed fermented with LN33 on growth performance, antioxidant capacity, immune response, intestinal barrier function, and gut microbiota in Cherry Valley ducks.

METHODS

A total of 480 healthy 7-day-old Cherry Valley ducks (197.33 ± 5.90 g) were randomly divided into four groups. One group received a basal diet (control), while the other three received the basal diet supplemented with 1%, 3%, or 5% fermented feed for 28 days.

RESULTS

Ducks fed 3% fermented feed showed significantly higher final body weight (3,020.00 ± 52.20 g) and average daily gain (100.79 ± 1.73 g) than the control group (2,896.00 ± 120.93 g and 96.39 ± 4.23 g, respectively; < 0.05). The feed-to-gain ratio decreased significantly (1.79 ± 0.03 vs. 1.87 ± 0.08; < 0.05), with similar feed intake across groups. Antioxidant enzyme activity increased, while pro-inflammatory cytokine levels decreased. Expression of intestinal tight junction proteins and immune markers improved. The relative abundances of , and increased significantly and were positively correlated with intestinal and immune function.

DISCUSSION

These results suggest that -fermented feed enhances growth performance and overall health in Cherry Valley ducks by boosting antioxidant defenses, modulating immune responses, and reshaping the gut microbiota.