Much like in other species of animals, stress in aquaculture can significantly impact fish and shrimp production. When fish and shrimp become stressed, they often expend additional energy and nutrients fighting against the stressor and any resulting inflammation, regardless of what may be causing the stress. This will lead to fewer nutrients and lower levels of energy available for growth and performance, ultimately resulting in lower market weights.
One common cause of stress in aquaculture is high stocking density. High stocking densities increase the probability of fish sustaining a skin lesion or injury, which can lead to bacterial or pathogenic infections that cause illness.
Stress can also be caused by environmental changes such as poor water quality or drastic swings in water temperature and/or salinity.
Water Quality Important for Fish and Shrimp Production
Water quality is essential to fish and shrimp production. If oxygen levels are not optimal, fish and shrimp may become stressed due to limited oxygen availability, which can affect their swimming, feeding activity and nutrient metabolism, ultimately restricting growth.
Both fish and shrimp exhibit reductions in immune parameters when exposed to environmental stressors, such as changes in water salinity and temperature, resulting in reduced resistance to pathogens.
Changes in salinity and water temperature have a huge impact on farmed shrimp, affecting their growth, molting and survival. When transferred to low-salinity waters, white shrimp L. vannamei showed marked decreases in hemocyte counts, phenoloxidase activity, respiratory burst and superoxide dismutase activity, all important markers of innate immunity.
Increased water temperature may also result in metabolic stress and cause serious damage to cold-blooded fish species. Elevated water temperatures result in increased oxygen consumption and may influence several redox-related biomarkers and redox homeostasis of fish.
Optimize Aquaculture Nutrition with Performance Trace Minerals
Fish have both enzymatic and non-enzymatic antioxidative defense systems against reactive oxygen species (ROS)-related damage. Antioxidative enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase scavenge free radicals and contribute to the body’s enzymatic antioxidative defenses.
These enzymes require trace minerals like selenium, iron, copper, zinc and manganese for optimal activity. Inadequate dietary intake of these trace minerals may compromise the effectiveness of these antioxidant defense mechanisms. Activity of glutathione peroxidase (GPx) significantly increased in European seabass supplemented with Zinpro Performance Minerals® at one-half the level of inorganic trace minerals, indicating that Zinpro Performance Minerals (in particular Availa®Se vs. Selenite), is more effective in sustaining antioxidant capacity in European seabass.
Adding Zinpro Performance Minerals to aquaculture nutrition programs can help improve the innate and adaptive immune responses as well as antioxidant functions. It is essential to formulate functional feed that optimizes growth performance and enhances the capacity of fish and shrimp to minimize stress. Research has revealed that replacing inorganic sources of zinc in shrimp diets with Availa® Zn yielded 5% more growth after eight weeks. Replacing zinc with Availa-Zn and inorganic selenium with Availa-Se increased hemocyte count and phenoloxidase activity, both key biomarkers of shrimp immune response.
Another key performance parameter is mortality. In one study, partially replacing inorganic sources of trace minerals with Zinpro Performance Minerals reduced cumulative mortality in shrimp by about 20% seven days after being challenged with Vibrio harveyi. The mortality rate dropped further when inorganic trace mineral sources were replaced entirely with Zinpro Performance Minerals.
Functional feeds supplemented with performance trace minerals contribute to enhancing the fish and shrimp’s abilities to cope with stressful situations such as disease, handling, transport and vaccinations.
For more research study details, download the Essential Trace Minerals for Exceptional Performance brochure.
Performance Trace Minerals Improve Aquaculture Ability to Respond
Zinpro Performance Trace Minerals can significantly improve the ability of shrimp and fish to mount a rapid and robust immune response when under disease and stress pressure. This may result in higher growth rates, reduced mortality and improved overall health in aquaculture production systems.
For more information about including performance trace minerals in your aquaculture nutrition program, contact a Zinpro representative today.