Effective microbial management is essential for successful shrimp farming and involves biosecurity, feed and water management, and microbial product application.
Gut microbiota plays a key role in nutrient absorption, immunity, and disease resistance. Studies show differences in gut microbes between healthy shrimp and those with diseases like AHPND or EHP, but the complex relationship between environment, pathogens, and microbiota is not fully understood. Probiotics can enhance gut health, digestion, and immunity, and are delivered via water, feed, or non-nutritional methods. Bacillus-based probiotics were shown to improve shrimp survival during laboratory vibrio challenge test (de la Peña et al., 2024; Hostins et al.).
An important point to consider is the reduced appetite of shrimp under stressful conditions, i.e. environment or disease. Maintaining a healthy microflora or reducing the risk of the pathogen becoming dominant in the microbiome is difficult when the shrimp stops eating. When shrimp are not feeding properly, the effectiveness of probiotics is greatly diminished because the probiotics must be ingested in adequate amounts to have a positive impact, and without proper feed intake, their delivery becomes increasingly difficult. Furthermore, the higher the number of active Bacillus cells delivered to the shrimp, the stronger the effect on the growth, survival, and immune parameters (Omar et al., 2024).
Innovative modes of delivery must be used, stimulating the shrimp to ingest despite their reduced appetite. Besides adjusting farming protocols and probiotic application, another alternative to face such challenge is to deliver the probiotics in a non-feed matrix which might be complementary to feed but especially formulated targeting high attractability and the grazing behaviour of shrimp. By aligning nutritional and behavioural aspects, we can create a powerful tool to bring probiotics to the shrimp gut, modulating the microflora in a more targeted way, reducing pathogen levels in the gut and potentializing the benefits of probiotics in challenging conditions.
de la Peña et al. (2024). In vitro and in vivo evaluation of the efficacies of commercial probiotics and disinfectant against acute hepatopancreatic necrosis disease and luminescent vibriosis in Litopenaeus vannamei. Res. Vet. Sc., 171, 105204.
Hostins et al. (2019). Managing input C/N ratio to reduce the risk of Acute Hepatopancreatic Necrosis Disease (AHPND) outbreaks in biofloc systems–A laboratory study. Aquaculture, 508, 60-65.
Omar et al. (2024). Effects of the putative probiotics Bacillus licheniformis, Bacillus pumilus, and Bacillus subtilis on white leg shrimp, Litopenaeus vannamei, immune response, gut histology, water quality, and growth performance. Open Vet J. 14(1):144-153.