Bacterial diseases continue to challenge productivity in many shrimp farms. Recently, acute hepatopancreatic necrosis disease (AHPND), caused by pathogenic strains of Vibrio parahaemolyticus (VPAHPND), has significantly impacted shrimp farmers economically. This disease has also driven an increase in antibiotic use in Asia.

Plant-based feed additives—phytogenics—are now being seen as promising alternatives to antibiotics for managing bacterial diseases. Pineapple extracts are one of the candidates mainly due to bromelain (BM) which is of particular interest due to its antibacterial properties. Malaysian researchers investigated the efficacy of a bromelain-based additive in shrimp feeds to enhance growth performance and disease resistance to AHPND.

A 28-day feeding trial using quadruplicate groups of Penaeus vannamei was conducted to evaluate the efficacy of BM on growth, gut microbiota and resistance to AHPND. Dietary 1% or 2% BM enhanced growth of shrimp which was significantly (P < 0.05) higher at 2% BM compared to control (0% BM).

In the first AHPND challenge, shrimp survival (mean ± SE) fed 1% or 2% BM were 84.8 ± 3.8% and 78.3 ± 2.5%, respectively, and significantly higher compared to the positive control group (69.6 ± 1.8%).

Surviving shrimp were then re-grouped into triplicates and fed the control diet for 14 days. This wash-out period was used to determine if prior dietary BM had a longer-term effect on shrimp health. In the second AHPND challenge, shrimp survival previously fed 1% or 2% BM were 71.1 ± 9.7% and 73.3 ± 3.8%, respectively, and significantly higher compared to the control group (51.1 ± 2.2%).

Hepatopancreas showed less damage and harbored significantly lower Vibrio counts in shrimp fed BM-added diets. Dietary BM modulated the stomach bacterial community and imparted the highest alpha diversity. At the phylum level, Proteobacteria, Actinobacteria and Bacteroidetes were the main groups across treatments but with varying relative abundance. Luteolibacter, Paracoccus, Planctomyces and Demequina were identified as the main contributors for the diversity differences observed among treatment groups. The relative abundance of Luteolibacter was significantly enriched and Vibrio bacteria significantly lowered in the stomach of the BM-added groups.

Researchers concluded that dietary bromelain induced modulation of the stomach microbiota of shrimp which potentially enhanced its resistance to AHPND-causing V. parahaemolyticus.

Reference:

Ng, Wing-Keong, Mong, Mei-Ling, Dietary Bromelain From Pineapple Extracts Enhanced Growth Performance and Modulated Stomach Microbiota Which Provided Longer-Term Protection to Penaeus vannamei Against Acute Hepatopancreatic Necrosis Disease (AHPND) Caused by Vibrio parahaemolyticus, Aquaculture Research, 2024, 6492170, 14 pages, 2024. https://doi.org/10.1155/2024/6492170