Project Number: 6420-32000-021-00
Project Type: Appropriated

Start Date: Dec 14, 2004
End Date: Dec 13, 2009

Objective:
Objective 1 - Examine the effect of alternative protein sources and dietary nutrients on stress response, immune response, and disease resistance of fish. Objective 2 - Evaluate the effect of immunostimulants and probiotics on fish stress resistance, immune response and disease resistance. Objective 3 - a) Determine the optimum dietary level of marine fish oil and feeding duration necessary to optimize n-3 highly unsaturated fatty acids (n-3 HUFA) content in fillets of channel catfish and b) Determine the relationship between n-3 HUFA content in diets and the catfish vitamin E requirement with regard to stress, the immune response, and disease resistance.

Approach:
Fish farmers in the U.S. reported that disease related mortality represents the major economic loss to the aquaculture industry. Historically, antibiotics and chemicals have been used to treat diseases in aquatic animals. However, given the fact that diseased fish eat poorly, only a limited number of FDA approved and efficacious drugs/chemicals are available for treatment, and the increasing problem of emerging drug-resistant pathogens and the resultant food and environmental contamination, disease prevention is a better means of controlling infectious diseases. Nutrition has proved to be a key factor in maintaining fish health. All essential nutrients are required in diets in adequate quantity to promote growth, sustain health, and maintain the ability of fish to withstand stress and resist disease-causing agents. Dietary modulation of stress and immune responses has been accomplished in numerious terrestrial animals as well as in some fish species using various approaches, including use of additives and supplementation of certain essential nutrients at levels above the minimum requirements for growth. In this proposed project, we will investigate the effect of alternative protein sources, selected dietary nutrients, immunostimulants and their interactions, and probiotics on fish health. This project will lead to discovery of compounds, nutrients, non-nutrient dietary additives, probiotic microorganisms, and their concentrations and interactions that are effective in increasing stress resistance, immune responses,and resistance to infectious diseases of channel catfish and Nile tilapia. Research will also be conducted to define dietary levels of fish oil and feeding duration to optimize highly unsaturated fatty acid content in catfish fillets. The outcome of this project will lead to increased demand for alternative protein sources and development of least-cost diets to improve growth and fish health and value-added catfish products to improve human health will be available for consumers.