The aim of the present study is to estimate a functional feed additive, lemon peel fermented with Lactobacillus plantarum (FLP), for shrimp health. Four experimental diets containing 0%, 1%, 2%, and 3% FLP were each fed to triplicate groups of white shrimp (initial weight: 2.37±0.01 g) in a recirculation system for 8 weeks. Weight gain, feed efficiency, and survival were not significantly affected (p<0.05) by the dietary treatments. Total hemocyte count was higher in shrimp fed diets with 1% and 2% FLP than that in shrimp fed the 0% FLP control diet. Shrimp fed the diet with 2% FLP exhibited higher hemolymph pro-phenoloxidase activity than shrimp fed the control diet. Intestinal Lactobacillus plantarum increased but Streptococcus equinus decreased with the increment of dietary FLP levels. After 72-hours challenge with Vibrio alginolyticus, survival was higher in shrimp fed diets with 2% and 3% FLP than that in shrimp fed the control diet. Results indicate that lemon peel fermented with L. plantarum can be used as a functional feed additive for Pacific white shrimp. A level of 2% FLP is suggested to be included in shrimp diet to enhance non-specific growth and resistance to V. alginolyticus.