关键词: 乳酸菌, 肉种鸡, 器官指数, 产蛋后期

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