Leandro Castro, Peter Van Wyk, Jennifer Doherty, Brittany Ploof and Morgan Prescott
Zeigler Bros.
Shrimp larval nutrition has undergone significant advancements over the years, reflecting continuous improvements in management practices, knowledge of nutritional requirements, and sustainability considerations. From natural feeds to the introduction of formulated diets and the development of functional feeds, the journey has been marked by innovation and adaptation to meet the changing demands of the industry. However, challenges persist, particularly in the use of microalgae as an important nutritional source for the early stages of shrimp.
Despite their nutritional benefits, microalgae present significant disadvantages, including high costs, nutritional variability, unpredictable production, and contamination risks. Addressing these challenges requires an innovative solution that can provide the nutritional benefits of microalgae in a more efficient, cost-effective way, with enhanced biosecurity.
After extensive research and testing to tackle these challenges, Zeigler has created EZ Larva Ultra, a significant advancement in shrimp larval nutrition. It offers a liquid microencapsulated diet that combines the benefits of microalgae with improved stability, digestibility, and biosecurity.
The science behind EZ Larva Ultra
EZ Larva Ultra utilizes advanced microencapsulation processes that are the result of years of research to improve upon pre-existing methods. The latest technology has led to an 8% increase in protein and a 25% increase in lipids, based on dry weight.
This advanced microencapsulation technology provides a superior nutrient delivery system, offering several significant advantages. Microencapsulation protects the active ingredients, preserving essential nutrients and ensuring their stability and bioavailability, while also reducing nutrient waste and promoting greater feeding efficiency.
It also allows controlled nutrient release during digestion, optimizing absorption in different segments of the larval digestive tract, thus improving the overall health and growth of the organisms. Additionally, this enhanced microencapsulation increases nutritional stability during storage and transport, ensuring a long shelf life.
The buoyancy of larval diets plays a central role in the performance of these products and was an important aspect of the development process for the new product. The previous generation of EZ Larva had a 100% sedimentation rate after 60 minutes, whereas the improved EZ Larva Ultra demonstrated excellent particle suspension even after 120 minutes (Fig. 1).
Better buoyancy ensures a more even distribution of feed in the water column, reducing waste and competition for food, while also improving water quality and reducing stress on the organisms. This positively contributes to their overall health and harvest performance.
EZ Larva Ultra is the most advanced functional feed available today. A range of functional compounds is incorporated into the EZ Larva Ultra formulation, specifically developed for the unique properties of liquid diets. One of the components consists of organic acids, which offer several significant benefits. Their antimicrobial properties play a crucial role in controlling pathogens, thereby reducing the incidence of diseases and maintaining shrimp health at optimal levels.
Organic acids can also reduce stress in organisms, which is particularly important during periods of environmental fluctuations or frequent handling of the shrimp. By modulating stress hormones and strengthening the immune system of the shrimp, organic acids help minimize the negative effects of stress, increase disease resistance, and improve resilience to changing environmental conditions.
Another component of the health package is Vitality Pak (Vpak), a compound added to all Zeigler larval diets. Vpak is a blend of ingredients that enhances the natural immune response capabilities of shrimp in any system and at any stage of culture.
One of the most significant advancements of EZ Larva Ultra is the inclusion of probiotics incorporated into different components of the diet’s unique structure. Using advanced techniques, Zeigler’s R&D team developed methods to deliver specific probiotic strains to targeted areas of activity. One set of probiotic bacteria (Rescue) is included in EZ Larva Ultra to improve gut health, while another set (Remediate) is included to improve water quality.
Rescue contains 1.5 x 107 CFU/g of four unique Bacillus spp. strains, selected for their efficacy in controlling six common strains of Vibrio spp., including Vibrio parahaemolyticus. Rescue is incorporated into the microcapsule for delivery to the intestine via ingestion.
Meanwhile, Remediate, is composed of another unique set of probiotic Bacillus species selected for their ability to digest organic material and reduce ammonia levels. Remediate is incorporated into the liquid fraction of EZ Larva Ultra, enabling it to be delivered into the water column when the product is added to the tank. By offering EZ Larva Ultra to larvae, hatchery managers proactively address multiple threats to the health and well-being of the crop.
Rescue and Remediate are proven commercial probiotics from Zeigler that have undergone significant testing in both laboratory and commercial settings and are increasingly popular in several key markets across Asia.
A challenge trial of Rescue was conducted to evaluate the probiotic’s ability to prevent the growth of V. harveyi and V. parahaemolyticus colonies in the intestines of shrimp. Over 27 days, the shrimp were exposed to these pathogens while using Rescue as a prevention strategy. The treatment with Rescue against V. harveyi showed a 50% increase in survival compared to the control treatment (Rescue: 67%; Control: 44%).
When challenged with V. parahaemolyticus, the treatment demonstrated a 42% higher survival rate than the control (Rescue: 66%; Control: 47%). These results demonstrate the significant benefits that EZ Larva Ultra offers by delivering highly effective probiotics like Rescue, precisely when they are most needed.
The science behind our innovation
With nearly 90 years of history as an innovator and pioneer in the production of feeds for aquatic organisms, Zeigler has developed extensive knowledge in nutrition, formulation, and the manufacturing of shrimp diets, especially during the early stages. Nearly a decade ago, Zeigler opened the Zeigler Aquaculture Research Center (ZARC), where many innovative products, such as EZ Larva Ultra, were developed. The laboratory features testing systems for each stage of shrimp development. Organism evaluation techniques were designed to eliminate human influence on the results of the comparative treatments.
Advanced algorithms prevent even the slightest differences in formulation strategies, as well as manufacturing process choices and adjustments, from affecting the performance of the diets during trials. This knowledge provides precise analysis of performance in critical phases, such as the shrimp larval stages.
ZARC studies comparing EZ Larva Ultra with the previous generation of EZ Larva demonstrated a higher harvested biomass (1,264.25 mg vs. 876.63 mg), providing shrimp with a greater final average weight (0.60 mg vs. 0.50 mg) and improved feed efficiency (0.44 mg of weight gained/mg offered vs. 0.31 mg of weight gained/mg offered).
Additionally, organisms fed this new product showed higher survival rates (70% vs. 58%) and a superior larval development index (6.86 vs. 6.69). After confirming the efficacy of EZ Larva Ultra at ZARC, it was tested in a commercial larviculture environment in Brazil. Nine 26-L tanks were filled at a density of 145 nauplii/L each.
The control treatment used a combination of dry larval feeds and competitor liquid diets. In the test treatment, EZ Larva Ultra replaced 25% of the dry diets. Organisms fed with EZ Larva Ultra showed a 7% higher survival rate and generated 12% more revenue than the control treatment. Applying these results in an economic analysis model, the EZ Larva Ultra treatment generated 15% more profitability, a very positive outcome when incorporating this new product into the diet protocol (Fig. 4).
Microscopic comparisons of the organisms were also an important feature of the trial. Under magnification, shrimp in the EZ Larva Ultra treatment showed a greater accumulation of lipids compared to those in the control treatment (Fig. 5). These fat droplets in shrimp larvae serve as essential energy reserves, supporting metabolic functions and aiding in the development of vital organs. They provide concentrated energy, crucial for growth, survival, and overall health during the larval stages, contributing to the development of robust and resilient shrimp. This may have been a key factor in the survival differences observed between the treatments.
To further challenge EZ Larva Ultra, another study was conducted to provide a comparison with microalgae. In this trial at ZARC, EZ Larva Ultra replaced 50% of the microalgae in Z1 and 100% in Z2 and subsequent stages. Although no statistical difference was identified in the average weight, statistical differences were observed in organisms fed with EZ Larva Ultra, showing better survival and final biomass.
Conclusion
These results demonstrate the potential of including high-quality liquid diets to replace a large portion of algae use in the early stages of shrimp larviculture. EZ Larva Ultra represents a paradigm shift in shrimp larval nutrition by combining the benefits of microalgae, advanced microencapsulation technology, and the latest innovations in functional feeds. With its superior performance, enhanced stability, and targeted delivery of nutrients and functional compounds, EZ Larva Ultra sets a new standard for shrimp larviculture worldwide.
By combining EZ Larva Ultra with EZ Artemia Ultra, shrimp postlarvae hatcheries can maximize the nutritional innovation that Zeigler offers, ensuring high quality nutrition and achieving optimal growth results with healthier shrimp, increasing production outcomes and generating greater profitability. With Zeigler’s commitment to innovation and sustainability, the future of shrimp aquaculture looks more promising than ever.
Hatchery Feed & Management Vol 12 Issue 4 2024
