Abstract: This study investigated the effects of Lactobacillus supplementation in drinking water on the intestinal and immune organs in broiler breeders during the late laying period. The aim is to provide a theoretical basis for the application of Lactobacillus in poultry husbandry. A total of 360 healthy Silkie fowls（Black⁃boned chickens），aged 38 weeks with average weight of（2.4±0.1）kg，were randomly assigned to a control group and a treatment group，each with 6 replicates of 30 birds per replicate. The control group was provided withnormal drinking water，while the treatment group wasgiven a Lactobacillus nutrient solution（2 kg/t，with a viable bacterial count of 3×109 CFU/g） in their drinking water. Following a 7⁃day adaptation period，the experimental trial lasted 65 days. Results demonstrated that，compared to the control group，at day 30，the relative weight and organ index of the jejunum and cecumin the Lactobacillus ⁃ supplemented group were significantly increased （P<0.05）. At day 65，there was no significant difference in the intestinal organ index or relative weight between groups（P>0.05），but the thymus organ index was significantly increased（P<0.05），and other immune organ index showed a tendency for improvement. These findings indicate that adding Lactobacillus to drinking water can mitigate age⁃related decline of intestinal organs and enhance immune organ function in late⁃laying broiler breeders.

Key words: Lactobacillus, Broiler Breeders, Organ Index, Late Laying Period

摘要： 该文探讨了饮水中添加乳酸菌对产蛋后期肉种鸡肠道器官和免疫器官的影响，旨 在为乳酸菌的应用提供理论依据。试验选取38周龄、体重接近（2.4±0.1）kg的健康竹丝鸡360 只，随机分为对照组和试验组，每组设6个重复，每个重复30只鸡。对照组使用正常饮水，试 验组在饮水中添加2 kg/t乳酸菌营养液（活菌数为3×109 CFU/g）。预试期7 d，试验期65 d。结 果表明：与对照组相比，在第30 天时，乳酸菌添加组的空肠、盲肠器官相对重量和器官指数显 著增加（P<0.05）。在第65 天时，乳酸菌添加组肠道器官指数及相对重量无显著差异（P> 0.05），但胸腺器官指数显著提高（P<0.05），其他免疫器官指数呈现改善趋势。该研究结果表 明，饮水中添加乳酸菌能够一定程度缓解产蛋后期肉种鸡肠道器官的衰老，并有助于提升免 疫器官的功能。

关键词: 乳酸菌, 肉种鸡, 器官指数, 产蛋后期