The compromised egg quality and leg abnormality during the end of the laying cycle (after 40 weeks) have been leading to poor animal welfare and substantial economic losses. Therefore, the effects of fermented calcium (Ca) butyrate, produced by fermentation by , on production, eggshell quality, and tibial property of hens were explored. A total of 192 Hy-line brown laying hens at 50-week-old were assigned to a basal diet or the basal diet with 300 mg/kg of the fermented Ca butyrate from 50 to 58 weeks of age. Each treatment had 6 replicates with 16 hens each. The diet supplemented with 300 mg/kg fermented Ca butyrate notably increased egg weight, ovarian follicle number, and eggshell strength ( = 0.072) as compared to the basal diet, which were associated with cytokine secretion, toll-like receptor signaling pathways, and intestinal immunity based on the RNA-seq data from the granulosa. Dietary Ca butyrate inclusion decreased the expression of ileal tumor necrosis factor-alpha and serum pro-inflammatory cytokine concentration, as well as increased the content of serum immunoglobulin A when compared to the basal diet (both < 0.05). The birds that received fermented Ca butyrate diets exhibited higher villus height ( < 0.05) and upregulated expression of tight junction proteins, whereas it did not alter the composition of cecal microbiota ( > 0.05). In addition, the diet with fermented Ca butyrate reduced the number of osteoclasts in the proximal tibia and the level of C-terminal cross-linked telopeptide of type I collagen, a bone resorption marker ( < 0.05), whereas it tended to increase the concentration of the procollagen type I N-terminal propeptide that reflects bone formation marker in serum. Moreover, the layers fed fermented Ca butyrate diets possessed higher ( < 0.05) bone area and trabecular number of the proximal tibia, yield load, and ultimate load than those that consumed basal diets. Collectively, dietary fermented Ca butyrate supplementation in post-peak layer diets improved the ovarian function and tibia quality, which might be related to enhancing intestinal integrity and consequently decreasing inflammation mediated bone resorption.

中文翻译：

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产蛋高峰后补充发酵丁酸钙可通过“肠骨”轴改善​​卵巢功能和胫骨质量

产蛋周期结束时（40 周后）鸡蛋质量下降和腿部异常导致动物福利不佳和巨大的经济损失。因此，探讨了发酵产生的发酵丁酸钙(Ca)对母鸡产量、蛋壳质量和胫骨特性的影响。总共192只50周龄的海兰褐蛋鸡在50至58周龄期间被分配给基础日粮或添加300 mg/kg发酵丁酸钙的基础日粮。每个处理有 6 个重复，每个重复 16 只母鸡。与基础饮食相比，添加 300 mg/kg 发酵丁酸钙的饮食显着增加了蛋重、卵泡数量和蛋壳强度 (= 0.072)，这些与细胞因子分泌、Toll 样受体信号通路和肠道菌群相关。基于颗粒 RNA-seq 数据的免疫。与基础饮食相比，膳食中添加丁酸钙可降低回肠肿瘤坏死因子-α 的表达和血清促炎细胞因子浓度，并增加血清免疫球蛋白 A 的含量（均 < 0.05）。接受发酵丁酸钙日粮的鸡表现出较高的绒毛高度（<0.05）和紧密连接蛋白的表达上调，但它没有改变盲肠微生物群的组成（>0.05）。此外，含有发酵丁酸钙的饮食减少了胫骨近端破骨细胞的数量和骨吸收标志物I型胶原C末端交联端肽的水平（<0.05），但倾向于增加浓度反映血清中骨形成标志物的 I 型前胶原 N 末端前肽。此外，饲喂发酵丁酸钙日粮的蛋鸡比饲喂基础日粮的蛋鸡具有更高的（<0.05）骨面积和近端胫骨小梁数量、产负荷和极限负荷。总的来说，在高峰蛋鸡日粮中添加发酵丁酸钙可以改善卵巢功能和胫骨质量，这可能与增强肠道完整性并从而减少炎症介导的骨吸收有关。