Abstract
Background:
Common carp (Cyprinus carpio) are a nutritionally valuable species with high demand in local and regional markets.

Aim:
This study evaluated the effects of dietary pumpkin seed (Cucurbita pepo) supplementation on the health status and immune response of farmed C. carpio challenged with Vibrio parahaemolyticus.

Methods:
Pumpkin seeds were selected for their rich content of essential nutrients and potential immunostimulatory properties. Seventy-two healthy fish (average weight 85.16 ± 0.10 g) were randomly assigned to four dietary groups receiving 0%, 1%, 2%, or 3% pumpkin seed powder for 12 weeks. Fish were fed to near satiation twice daily. After 56 days, a 3-hour crowding stress test (40 kg/m³) followed by 24 hours of recovery was performed. Key parameters assessed included growth performance, feed efficiency, hematological and biochemical markers, serum lysozyme activity, body composition, and immune-antioxidant response. Following this, 12 fish per group were intraperitoneally injected with V. parahaemolyticus, and mortality was recorded.

Results:
Fish fed pumpkin seed-supplemented diets, particularly at the 2% level, showed significant improvements in growth, immune markers, feed utilization, and survival rate post-challenge compared to the control group.

Conclusion:
These findings suggest that pumpkin seed supplementation enhances immune function and disease resistance in C. carpio, supporting its use as a functional ingredient in aquafeed formulations.

Key words: Medicinal herbs; Pumpkin seed; Cucurbita pepo; Cyprinus carpio; Vibrio parahaemolyticus.