Background: Using bacterial (probiotic) strains can influence beneficial health statuses, e.g., through dairy products; however, they must be assessed as safe before consumption; broiler rabbits represent a suitable model for this purpose. This study evaluated the safety and effect (functionality) of the dairy-derived, plantaricin-producing strain Lactiplantibacillus plantarum LP17L/1 using broiler rabbits. The following parameters were assessed to evaluate safety and functionality: microbiota, phagocytic activity (non-specific immunity parameter), blood serum biochemistry, oxidative stress enzyme, growth performance, cecal hydrolytic activity, and jejunal morphometry. Methods: Previously validated methods were used for the analyses. The appropriate administrations approved the experiments. Results: Although only up to 1.0 colony forming unit (CFU)/g (log10) LP17L/1 reached the gastrointestinal tract of the rabbits, the total lactic acid bacteria and amylolytic streptococci were significantly increased (p 0.001). The other microbiota were not influenced, meaning there was no negative influence on phagocytic activity, growth parameters, and biochemistry in the analyzed blood serum. Conversely, lower GPx values were measured in the experimental group than in the control group, meaning LP17L/1 did not induce oxidative stress. LP17L/1 caused an increase in villi length to crypt depth ratio, while hydrolytic activity was also significantly increased (p 0.01, p 0.001). Conclusions: L. plantarum LP17L/1 was confirmed as safe. Regarding the functionality, no negative influence on the microbiota was noted, and the tested parameters were not negatively influenced. Demonstrating that the LP17L/1 strain is safe provides further chances for its industrial application. Additional studies are being conducted.