Larval shrimp nutrition has come a long way. While we are still fine-tuning our knowledge of the nutritional requirements of larval shrimp, our knowledge-base has developed to the point where hatcheries have many high quality larval feeds to choose from. Nevertheless, many challenges remain. Shrimp diseases continue to be the biggest challenge for the shrimp industry and many of these diseases originate in hatcheries. Vibriosis, in particular, is a challenge for hatchery operators. It is well-documented that live feeds such as Artemia are an important vector for the introduction Vibrio into the larval rearing tank. Treating vibriosis and other bacterial pathogens with antibiotics leads to antibiotic resistance and is not a sustainable strategy.
Zeigler researchers have been working on developing feeds to supplement or replace live feeds with functional feeds that support the shrimp immune system, contribute to a healthy gut microbiome, limit the development of populations of pathogenic bacteria, and improve digestive efficiency. Research efforts at Zeigler Bros. are focused on how to incorporate function feed ingredients such as probiotics, immunostimulants, organic acids, essential oils, and antioxidants into larval diets to maximize their efficacy in promoting shrimp health. Micro-encapsulated liquid feeds provide an ideal vehicle to deliver these functional feed ingredients in a premium larval diet. The low temperature manufacturing process allows probiotics and other temperature sensitive ingredients to be included in the diets with no loss in viability effectiveness. Microencapsulation prevents the leaching of ingredients into the water, ensuring delivery into the guts of the shrimp where their effectiveness is maximized. Ingredients targeted for the gut can be incorporated in the microcapsules, while ingredients for targeting the tank environment can be incorporated into the liquid fraction.
Microencapsulated liquid feeds are ideal for replacing live feeds. It is well-documented that Artemia nauplii are a major vector for the introduction of Vibrio and the supply of cysts is at risk due to the drying up of saline lakes where Artemia cysts are harvested. Liquid micro-encapsulated diets can successfully replace 100% of the Artemia in larval shrimp diets and significantly reduce Vibrio loads in larval rearing systems. While high quality algae are essential in the early larval stages, maintaining an adequate volume of high quality algae can be challenging, especially during certain months of the year. A major research focus for Zeigler Bros. is the development of cost-effective liquid feeds that allow for significant reduction in the amount of algae required for successful production of post-larvae. Micro-encapsulated liquid feeds can be manufactured with nutritional profiles that are nearly identical to the nutritional profiles of diatoms like Thallasiossira, and with very small particle sizes that allow the capsules to be readily consumed by early stage zoea larvae. Nutrition research is leading the way to more biosecure and sustainable larval rearing systems and healthier larvae, without antibiotics.