Abstract The effects of chitooligosaccharide (COS) supplementation in laying hen diets on egg production, egg quality, blood biochemistry, antioxidant capacity and immunity during the late laying period were investigated in this 10-week trial. A total of 3000 Fengda No.1 laying hens, 52 weeks of age, were randomly allocated to three treatment groups, each of which included five replicates of 200 hens. Treatments consisted of the basal diet only or the basal diet supplemented with COS at 75 or 125 mg/kg. Hens fed with both COS supplemented diets had improved hen-day egg production, egg mass and feed conversion ratio than control birds. The higher level of COS supplementation exerted positive effects on eggshell strength and eggshell thickness, but significantly decreased yolk colour. Addition of 125 mg/kg COS was also found to significantly increase serum albumin content and significantly decrease serum cholesterol level. Dietary supplementation with COS significantly decreased serum triglyceride level compared with birds fed the control diet. Moreover, COS significantly increased total antioxidative capacity and significantly decreased malondialdehyde level in serum, but had no significance on the activities of antioxidant enzymes. The only change in blood immune response compounds observed in this study was a significantly increased concentration of C3 when laying hens were fed COS supplemented diets. In conclusion, COS could improve laying performance and egg quality in hens during the late laying period. Inclusion of COS in the diet might be beneficial to hens’ health by lowering serum lipids, enhancing antioxidant activity and slightly enhancing immune ability. HIGHLIGHTS COS improved laying performance and egg quality in hens during the late laying period. Inclusion of COS in the diet might be beneficial to hens’ health by lowering serum lipids, enhancing the antioxidant activity and slightly enhancing immune ability. The optimum concentration of COS is 75 mg/kg in the basal diet in order to achieve an increased egg production, egg quality and health condition.

中文翻译：

---

添加壳寡糖对产蛋后期蛋鸡产蛋性能、蛋品质、血液生化、抗氧化能力和免疫力的影响

摘要 在这项为期 10 周的试验中，研究了在蛋鸡日粮中添加壳寡糖 (COS) 对产蛋后期产蛋量、蛋品质、血液生化、抗氧化能力和免疫力的影响。将3000只52周龄的丰达1号蛋鸡随机分配到3个处理组，每组5个重复，每组200只。治疗包括仅基础饮食或补充有 75 或 125 mg/kg COS 的基础饮食。饲喂两种 COS 补充日粮的母鸡与对照鸡相比，母鸡日产蛋量、产蛋量和饲料转化率都有所提高。较高水平的 COS 补充剂对蛋壳强度和蛋壳厚度产生积极影响，但显着降低蛋黄颜色。还发现添加 125 mg/kg COS 可显着增加血清白蛋白含量并显着降低血清胆固醇水平。与饲喂对照日粮的鸡相比，日粮中添加 COS 显着降低了血清甘油三酯水平。此外，COS显着提高总抗氧化能力，显着降低血清丙二醛水平，但对抗氧化酶活性无显着影响。在本研究中观察到的血液免疫反应化合物的唯一变化是当蛋鸡喂食 COS 补充日粮时 C3 的浓度显着增加。综上所述，COS可以提高蛋鸡产蛋后期的产蛋性能和蛋品质。在日粮中加入 COS 可能通过降低血脂对母鸡的健康有益，增强抗氧化活性，略微增强免疫能力。亮点 COS 提高了母鸡产蛋后期的产蛋性能和蛋质量。在日粮中加入COS可能通过降低血脂、增强抗氧化活性和略微增强免疫能力对母鸡的健康有益。基础日粮中 COS 的最佳浓度为 75 mg/kg，以提高产蛋量、产蛋质量和健康状况。