ProtoNutrition, Robustness, Oxygen and Omega-3 in Salmon (ProtoROOS)

Lead Research Organisation: UNIVERSITY OF EXETER
Department Name: Biosciences


Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

Technical Summary

Our hypotheses are that prior nutritional history (proto-nutrition) has an impact on subsequent nutritional requirements as the fish seeks to obtain a net level of key nutrients in their system to sustain growth. Additionally, that the occurrence of "challenging" environmental conditions, through hypoxia (and reciprocal CO2 increase), impacts nutritional responses, not by changing the animals demands per se, but rather by an overall down-regulation of feed intake resulting in an apparent need for an increased nutrient concentration in the feed. These hypotheses contend that nutritional requirements for fish should be expressed as a function of their daily nutrient demand relative to total energy intake and growth demands (akin to a recommended daily intake, RDI), not as a proportion of the diet as has historically been the case. This is a major conceptual shift in the notion of nutritional requirements in the aquaculture domain.
By addressing both hypotheses, we will improve our ability to manage the nutritional requirements of Atlantic salmon more effectively and efficiently through their lifecycle. This will enable greater utilisation of sustainable feeds formulated with very low levels of marine ingredients, through that better understanding the complexities associated with essential nutrient demands and how to supply them. There are elements of the nutritional programming concept in parts of this project in that we will, for the first time, test the hypothesis that proto-nutrition during the salmon's freshwater phase of life will have an impact on subsequent requirements. Specifically, that the potential fortification of a salmon's diet when it is young may allow a reduction in demands later in life during a more resource demanding stage. This will have huge implications for how much of the finite marine resources will need to be used in satisfying the animals requirements at the more resource-use-intensive later stages during the seawater phase of production

Planned Impact

See Lead Proposal from Stirling
Description Lab experiments were completed to examine whether challenging environmental conditions in fish farms (such as low oxygen) influence a fish's response to diet by changing how well they utilise nutrients or alter their appetite. To
examine this Atlantic salmon were fed one of two different diets, containing either low or high levels of the 'healthy' long-chain polyunsaturated omega-3 fatty acids (n-3 LC-PUFA), and either maintained in normal or low oxygen environmental conditions. The largest influence observed, as expected, was that low oxygen conditions reduced growth rate, which was due to those fish having a reduced appetite and eating less food. Previous studies had suggested that low oxygen conditions also influence the effect of dietary omega-3 fatty acids. However, the current study clarified that the benefits of these omega-3 fatty acids are almost entirely due to the effect they have on appetite, rather than specifically being beneficial as an 'essential' nutrient. This changes how aquaculture nutrition considers the importance of these omega-3 fatty acids in helping farmed fish cope with low oxygen conditions.
Exploitation Route See submission from the lead PI at Stirling University.
Sectors Agriculture

Food and Drink


Description Keynote Talk and Debate at Aquaculture Workshop in The Netherlands 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Keynote Talk (by Prof. Rod Wilson): "Physiological impacts of carbon dioxide in fish"
2021 Workshop on Fish Nutrition, Aquaculture Systems and Water Quality
18th-21st October 2021, Wageningen.
Audience: ~200 early career researchers and academics and aquaculture industry reps in aquaculture-related research
Year(s) Of Engagement Activity 2021