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Research Project: Improving Nutrient Utilization to Increase the Production Efficiency and Sustainability of Rainbow Trout Aquaculture

Location: Small Grains and Potato Germplasm Research

Title: Optimizing growth and mitochondrial function in rainbow trout, Oncorhynchus mykiss through eco-friendly dietary and changes in water temperature regimen strategies

Author
item IDENYI, J. - West Virginia State University
item ABDALLAH, H. - West Virginia State University
item ADEYEMI, A. - West Virginia State University
item HUBER, D. - West Virginia State University
item GANNAM, A. - Us Fish And Wildlife Service
item Sealey, Wendy
item IGWE, D. - Cornell University
item EYA, J. - West Virginia State University

Submitted to: Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2024
Publication Date: 9/10/2024
Citation: Idenyi, J.N., Abdallah, H., Adeyemi, A.D., Huber, D.H., Gannam, A., Sealey, W.M., Igwe, D.O., Eya, J.C. 2024. Optimizing growth and mitochondrial function in rainbow trout, Oncorhynchus mykiss through eco-friendly dietary and changes in water temperature regimen strategies. Aquaculture. 595:741591. https://doi.org/10.1016/j.aquaculture.2024.741591.
DOI: https://doi.org/10.1016/j.aquaculture.2024.741591

Interpretive Summary: Finding suitable alternatives to fish meal and fish oil in fish diets remains a threat to the sustainable production of rainbow trout. Global warming compounds this threat because growth, nutrient utilization, and the ability to cope with stress are all negatively affected by increasing water temperature. To investigate the interactive effects of diet and water temperature, USDA ARS physiologist at Bozeman Fish Technology Center collaborated with researchers at West Virginia State University to examine growth metabolism in rainbow trout fed different plant-based oil and protein sources and cultured at different water temperatures. Results indicate that both temperature and diet affect growth. These findings underscore the importance of considering these factors in the development of plant-based aquafeeds in order to optimize growth and productivity.

Technical Abstract: Developing sustainable aquaculture practices remains a challenge, notably finding suitable alternatives to marine ingredients in carnivorous fish diets such as rainbow trout (Oncorhynchus mykiss), which is an ecologically and economically significant aquaculture species. Therefore, we investigated the impact of sustainable ingredients and water temperature manipulations on rainbow trout growth, body composition, mitochondrial enzymatic activity, and gene expression. A total of 432 fish were fed four isocaloric, isolipidic, and isonitrogenous diets comprised of 40% crude protein and 20% lipid and formulated as diet 1 (Animal-based protein + 25% fish oil/ 50% plant oil/ 25% animal oil), or diet 2 (Animal-based protein + 100% plant oil), or diet 3 (Plant-based protein + 25% fish oil/ 50% plant oil/25% animal oil), or diet 4 (Plant-based protein +100% plant oil) at 14 °C or 18 °C or 20 °C water temperature. Results showed growth rate (percent weigh gain (PWG) and specific growth rate (SGR), feed efficiency (FE), and feed intake (FI) were significantly (P<0.05) higher in fish reared at 14 °C and 18 °C compared to 20 °C. The PWG, FE, FI, and SGR levels were significantly (P<0.05) higher for fish fed diets 1 and 2 than those fed diets 3 and 4. Dietary composition influenced protein, moisture, lipids, and energy contents in fish, while temperature affected protein, moisture, and lipid contents. For protein, lipid, and energy contents, temperature-diet interactions were significant (P<0.05). In different tissues (muscle, liver and intestine), the mitochondrial enzymatic activities varied. Only complex V activity in the liver was affected by diet, while complexes II, III, and V activities were significantly (P<0.05) affected by temperature. A temperature-dietary interaction was observed for complex V. The temperature regimens, but not the composition of the diet, affected muscle mitochondrial enzymatic activities. There were significant (P<0.05) effects of temperature on complex III, IV, and citrate synthase activities in the intestine, whereas dietary composition had no significant impact (P>0.05). Based on diet main effect, temperature main effect, and diet-temperature interactions, selected genes were expressed differently in different tissues. The nd1, cox2, cytb, cox1, and atp6 genes were influenced by diet and temperature in muscle tissue. There were also differences in gene expression patterns in liver and intestine tissues based on diet and temperature. Overall, the results of this study showed that both temperature and dietary composition had significant effects on growth performance characteristics, proximate composition, mitochondrial enzymatic activities, and gene expression levels in rainbow trout. These findings underscore the importance of considering these factors in the development of plant-based aquafeeds in order to optimize growth and productivity.