Aquaculture ponds contain many types of microorganisms, including pathogenic bacteria. Infection by these bacteria can cause disease and disrupt metabolism in farmed species like the shrimp Penaeus vannamei. However, the metabolic changes at each infection stage and the effects of metabolite supplementation on infected P. vannamei remain unknown. To learn more, researchers recently collected gastrointestinal tract samples from healthy, diseased, and moribund (dying) P. vannamei. The diseased and dying shrimp were primarily infected with the bacteria Vibrio parahaemolyticus and Vibrio harveyi and exhibited dysregulation of important metabolites and their associated enzymes. The diseased shrimp had high levels of taurine and related enzymes, while the dying shrimp had high levels of hypoxanthine and related enzymes. In addition, higher taurine levels were strongly correlated with lower abundance of the Vibrio pathogens, suggesting a protective effect of this metabolite. In a challenge experiment, supplementation with taurine improved the survival of shrimp against V. parahaemolyticus infection, primarily by increasing the expression of the taurine pathway enzymes cysteine dioxygenase and cysteine sulfinic acid decarboxylase. Although the exact mechanism needs to be determined, the findings reveal that taurine supplementation can enhance shrimp immunity, providing insights that may help improve crustacean aquaculture.