Location: Small Grains and Potato Germplasm Research
Project Number: 2050-21310-006-006-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 19, 2019
End Date: Aug 18, 2024
Objective:
The overall objective of this collaborative research is to improve competitiveness of rainbow trout production. This will involve evaluation of gene expression, proteomic and metabolomic differences, microbiota differences and performance of trout fed various alternate protein and lipid sources, direct fed microbials, and immunostimulants, while also identifying differences between trout strains and selected/non-selected lines.
The collaborative research between ARS and the Cooperator will focus on the following three objectives:
1) Identify rainbow trout families with improved phenotypes for growth, fillet fatty acid composition, and utilization of a grain-based fish feed through dietary modification and genetic selection.
2) Conduct feeding trials in support of optimizing feed formulations to develop commercial trout feeds based on oilseed and grain products without inclusion of marine protein and/or oil.
3) Conduct physiological studies with direct fed microbials and immunostimulants in support of optimizing mucosal health, immune function, and functionality for improved trout performance.
Approach:
Collaborative research will focus on obtaining information to better identify differences in physiological and biochemical mechanisms driving production traits of trout from selected and non-selected lines fed conventional or all-plant protein/oil diets and to characterize the mucosal microbial community using non-culture dependent techniques (new generation high-throughput technologies). Through development of a better understanding of the effects of specific ingredients, diet formulations, direct fed microbials, and immunostimulants on the mucosal microbial community and fish physiology, strategies can be developed to optimize fish health and performance.
Objective 1: Rainbow trout from prior brood years are maintained by the Cooperator and reared to maturity as two-year old fish. The Cooperator’s staff will monitor fish for maturity and spawn them based on the ARS spawning matrix,with individual crosses (one male and one female) made by Cooperator staff. After fertilization, each egg batch will be incubated in an individual Heath incubation tray to maintain cross identity. The Cooperator will maintain eggs, fry, and fish to an average weight of 5g, following Cooperator IACUC protocols. At this point, fish from each cross will be evaluated for a five-month performance according to ARS protocols approved by the Cooperator IACUC. Over this period, numbers of fish will be reduced at several weight points by weighing each individual fish from each cross, eventually leading to the final selection of trout retained for future broodstock. Each of these fish will be implanted with a PIT-tag for identification.
Objective 2: The Cooperator will to conduct feeding trials to evaluate the effects of supplementing plant-based feeds with nutritive and non-nutritive dietary ingredients on fish performance. Specific trials to be conducted include evaluation of plant-based oils, cholesterol, emulsifiers, and taurine on metabolic signaling, nutrient utilization, and fish performance.
Objective 3: The Cooperator and ARS will continue research on the effects of diet and trout strain on the structure of the gut microbial community. This effort will include assessment of the transcriptome, gut immune function, and histological evaluation of the distal intestine in the context of development and characterization of distal enteritis. Studies will also address the effects of direct fed microbials and immunostimulants in support of improving trout health and performance.
