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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATION OF NUTRITIONAL, GENETIC AND PHYSIOLOGICAL APPROACHES TO IMPROVE PRODUCTION EFFICIENCY OF RAINBOW TROUT Title: EVALUATING THE EXPRESSION OF METABOLIC, IMMUNOLOGIC, AND MUSCLE DEVELOPMENT FACTORS AND THEIR RELATIONSHIP TO GROWTH AND DIETARY UTILIZATION

Authors
item Overturf, Kenneth
item Johansen, Katherine - FORMER USDA ARS EMPLOYEE
item Frank, Karen

Submitted to: Book of Abstracts Aquaculture America
Publication Type: Proceedings
Publication Acceptance Date: September 15, 2005
Publication Date: February 13, 2006
Repository URL: http://riley.nal.usda.gov/nal_web/digi/submission.html
Citation: Overturf, K., Johansen, K. and Frank, K., (2006) Evaluating the expression of metabolic, immunologic, and muscle development factors and their relationship to growth and dietary utilization. Book of abstracts Aquaculture America, Pg 220

Interpretive Summary: Studies involving fish utilization of formulated diets, genetic improvement, and evaluation of disease resistance rely heavily on monitoring physical parameters such as overall weight gain, condition factor, and fillet weight. These measurements do provide valuable information, in a general manner, in regards to variation between control and treatment groups. However, studies have shown that diet formulation in which fish meal has been replaced with alternative sources in rainbow trout can lead to effects such as loss of appetite, intestinal damage, weakened immune function leading to disease outbreaks, and noticeable physical alterations (splotchy discoloration and fin erosion). Before new diet formulations can be widely recommended, they must be evaluated for their effects on fish physiology and health. Furthermore, studies evaluating growth have found that in most cases the largest fish tend to deposit more fat and the meat texture can be of a less firm quality than that of other smaller individuals. And finally, in experiments attempting to determine immunological reactions in response to pathogens, stress or diets, interpretation of results can be confusing when attempting to relate the different responses and their levels. The recent availability of genome sequence for trout and other species now allows for the generation of assays for determining expression analysis of genes of interest. These methods allow for the monitoring of specific aspects involved with physical changes observed within the experiment. The majority of information regarding physiology, immunology, and metabolism comes from research performed in other animal models, but this can now be used to evaluate on a molecular level the changes occurring in aquaculture species. We have developed more than 50 assays in our lab examining muscle development, immunology, and metabolism. In some experiments there is a high correlation between level of gene expression and treatment. Our next step is determining the relationship for protein level and activity with gene expression for different assays.

Technical Abstract: Studies involving fish utilization of formulated diets, genetic improvement, and evaluation of disease resistance rely heavily on monitoring physical parameters such as overall weight gain, condition factor, and fillet weight. These measurements do provide valuable information, in a general manner, in regards to variation between control and treatment groups. However, studies have shown that diet formulation in which fish meal has been replaced with alternative sources in rainbow trout can lead to effects such as loss of appetite, intestinal damage, weakened immune function leading to disease outbreaks, and noticeable physical alterations (splotchy discoloration and fin erosion). Before new diet formulations can be widely recommended, they must be evaluated for their effects on fish physiology and health. Furthermore, studies evaluating growth have found that in most cases the largest fish tend to deposit more fat and the meat texture can be of a less firm quality than that of other smaller individuals. And finally, in experiments attempting to determine immunological reactions in response to pathogens, stress or diets, interpretation of results can be confusing when attempting to relate the different responses and their levels. The recent availability of genome sequence for trout and other species now allows for the generation of assays for determining expression analysis of genes of interest. These methods allow for the monitoring of specific aspects involved with physical changes observed within the experiment. The majority of information regarding physiology, immunology, and metabolism comes from research performed in other animal models, but this can now be used to evaluate on a molecular level the changes occurring in aquaculture species. We have developed more than 50 assays in our lab examining muscle development, immunology, and metabolism. In some experiments there is a high correlation between level of gene expression and treatment. Our next step is determining the relationship for protein level and activity with gene expression for different assays.

Last Modified: 10/31/2014
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