Replacing Hydrolyzed Soybean Meal with Recombinant β-Glucosidase Enhances Resistance toin Broilers Through Immune Modulation.

Abstract

Aglycone soy isoflavones have notable immune-regulatory bioactivity, while glycosidic forms in soybean meal pose challenges for absorption. &#x3b2;-Glucosidase (EC 3.2.1.21) catalyzes the non-reducing terminal &#x3b2;-d-glucosidic bonds, releasing &#x3b2;-d-glucan and aglycones. This study evaluated the impact of enzymatically hydrolyzed soybean meal (ESM) using recombinant &#x3b2;-glucosidase fromon the growth performance and intestinal immune function of broilers underinfection. Prior to the feeding trial, soybean meal was enzymatically digested with recombinant &#x3b2;-glucosidase, ensuring almost complete conversion of glycosides to aglycones. After a week of pre-feeding, a total 180 healthy AA broilers were randomly assigned to three groups-control, semi-replacement of ESM (50% ESM), and full-replacement of ESM (100% ESM)-with 6 replicates of 10 chickens, and the trial lasted 28 days. On the 36th day, broilers were challenged with 1 mL of 1 &#xd7; 10CFU/mL() via gavage for 3 days. The results showed that the substitution of ESM had no effect on the body weight gain of broilers but significantly reduced the feed consumption and feed-to-gain ratio (< 0.01). The study revealed thatsignificantly disrupted jejunal morphology, while ESM significantly mitigated this damage (< 0.05). Real-time PCR results demonstrated that compared to thegroup, ESM restored-induced intestinal barrier impairments (e.g.,,,), normalized aberrant cellular proliferation () and apoptosis (and), and upregulated the expression of anti-inflammatory factorwhile suppressing pro-inflammatory cytokines (,, and) (< 0.05). Moreover, flow cytometry analyses demonstrated that ESM promoted Treg cell-derived Il-10, which alleviated macrophage-derived inflammation. Substituting conventional soybean meal with &#x3b2;-glucosidase, enzymatically treated, significantly reduced feed consumption and alleviated the intestinal damage and immune dysfunctions induced byinfection in broilers.