Viral and bacterial diseases remain the leading cause of economic losses in shrimp aquaculture and continue to constrain the industry’s growth. Many of these outbreaks can be traced to the use of natural feeds in broodstock maturation systems. Fresh feeds such as polychaetes, squid, mussels, clams, and Artemia biomass commonly comprise more than two-thirds of the maturation diet, yet many of these natural ingredients are potential carriers of major shrimp pathogens.
Wild polychaetes are especially risky and have been identified as vectors for White Spot Syndrome Virus (WSSV), Acute Hepatopancreatic Necrosis Disease (AHPND), and the microsporidian parasite Enterocytozoon hepatopenaei (EHP). Mussels and clams have also been implicated as sources of WSSV, AHPND, and Vibrio. Artemia biomass from China has been identified as a potential vector for EHP and Vibrio. Even warm-water squid has tested positive for AHPND. Because hatcheries supply nearly all of the postlarvae used by shrimp farms, the introduction of pathogens through infected maturation feeds can result in widespread and costly disease transmission throughout the production chain.
Although these losses provide strong motivation to reduce reliance on risky natural foods, many hatchery managers remain reluctant to adopt prepared diets, believing that natural feeds are essential for successful maturation and larval rearing. However, this perception is outdated. Modern formulated maturation diets can be designed to closely match the nutritional profiles of natural ingredients. While no commercial product yet replaces all natural feeds without some reduction in fecundity, several formulations have successfully replaced 100% of polychaetes and bivalves with minimal effects on spawning performance. Eliminating the riskiest components of the diet has been shown to reduce bacterial loads and improve naupliar survival during larval rearing.
Although complete replacement of natural feeds is not yet feasible, hatchery managers can take practical steps to mitigate biosecurity risks. Replacing wild polychaetes with SPF farm-raised sources and implementing PCR testing of all fresh feed batches prior to use are effective preventive measures. Proper freezing of natural feeds at −10°C to −20°C can significantly reduce Vibrio counts, and freezing at −20°C prevents polar tube extrusion in EHP spores. Finally, treating nauplii with iodine and/or ozone before stocking can help interrupt vertical transmission of bacteria and EHP from broodstock to nauplii.
These measures, combined with the replacement of the riskiest fresh maturation feeds with formulated maturation diets, offer a practical and effective path toward improved hatchery biosecurity and healthier, more resilient shrimp production systems.