Scientists tested whether salmon could eat food made from microbes and plants instead of traditional fish oil. They fed different groups of Atlantic salmon for 16 weeks and then studied how their bodies processed fats. The good news: salmon fed a mix of microbial oil and canola oil showed similar fat metabolism to salmon eating regular fish oil. This matters because fishing for fish oil isn’t sustainable, but growing microbes in labs is. The research suggests we can feed farmed salmon more eco-friendly food without hurting their health or nutrition.

The Quick Take

  • What they studied: Can we replace fish oil in salmon feed with oil made from microbes and canola oil without changing how salmon’s bodies work?
  • Who participated: Atlantic salmon (farm fish) were divided into four groups eating different types of oil for 16 weeks. The abstract doesn’t specify exact numbers of fish.
  • Key finding: Salmon eating 10% microbial oil mixed with 10% canola oil showed fat metabolism patterns almost identical to salmon eating traditional fish oil, suggesting successful replacement.
  • What it means for you: If you eat farmed salmon, future fish may be raised on more sustainable food sources without losing nutritional quality. This is still early research, but it points toward more environmentally friendly aquaculture.

The Research Details

Researchers divided salmon into four groups, each eating different combinations of oils for 16 weeks. Group 1 ate traditional fish oil (20%). Group 2 ate half fish oil and half canola oil (10% each). Group 3 ate mostly canola oil with some microbial oil (15% canola + 5% microbial). Group 4 ate equal parts canola and microbial oil (10% each). After 16 weeks, scientists removed liver and muscle tissue and analyzed them using advanced lab techniques to see how the different oils affected fat processing and which genes were turned on or off.

This approach is important because it looks at both what genes are active (gene expression) and what types of fats are actually present in the fish’s tissues (lipidomics). This two-part approach gives a complete picture of how the fish’s body adapted to the new food sources.

The study used controlled diets with equal calories and protein, meaning differences came from the oil sources alone. The researchers used advanced molecular analysis techniques. However, the abstract doesn’t specify how many fish were studied, which is important information for understanding the study’s strength. The study lasted 16 weeks, which is a reasonable timeframe for observing metabolic changes in fish.

What the Results Show

The most important finding is that salmon eating 10% microbial oil plus 10% canola oil showed fat metabolism patterns nearly identical to salmon eating traditional fish oil. This suggests that microbial oil can successfully replace fish oil in salmon feed. The salmon’s livers showed changes in how they stored and processed fats depending on the diet, with some diets promoting more fat storage than others. The genes controlling fat-making were more active in salmon eating the plant and microbial oil combinations compared to those eating fish oil. Muscle tissue showed more subtle changes, but still responded differently to each diet type.

Salmon eating diets with less omega-3 fatty acids (the healthy fats found in fish) showed higher activity of inflammatory markers, suggesting that omega-3 levels matter for reducing inflammation. The different oil combinations changed how the fish’s cell membranes were structured, particularly affecting the balance between two types of phospholipids (PE and PC), which influence how flexible and functional cell membranes are.

This research builds on growing interest in sustainable aquaculture feeds. Previous studies suggested alternative oils might work, but this study provides detailed molecular evidence of how salmon bodies actually adapt. The finding that 10% microbial oil works well aligns with the goal of reducing dependence on wild-caught fish for aquaculture feed.

The study doesn’t specify the exact number of salmon used, making it hard to judge statistical strength. The research only lasted 16 weeks, so we don’t know long-term effects. The study focused on salmon biology, not on whether humans eating this salmon would notice nutritional differences. We also don’t know how different salmon populations might respond differently to these feeds.

The Bottom Line

Based on this research, microbial oil appears promising as a sustainable replacement for fish oil in salmon feed (moderate confidence level). The 10% microbial oil + 10% canola oil combination seems most effective. However, this is one study, and more research is needed before widespread adoption.

Aquaculture companies and fish farmers should pay attention to these findings as they work toward sustainable practices. Consumers interested in environmentally friendly seafood may eventually benefit. People concerned about omega-3 intake should note that salmon fed alternative oils had lower omega-3 levels, which might matter for their nutritional value.

The metabolic changes observed in this study occurred within 16 weeks, suggesting relatively quick adaptation. However, long-term effects over months or years remain unknown.

Want to Apply This Research?

  • Track weekly salmon consumption and note the source/brand when possible. As sustainable salmon becomes available, users can log whether they’re eating traditionally-fed or sustainably-fed salmon and monitor any perceived differences in energy levels or inflammation markers.
  • Users can search for and choose farmed salmon labeled as fed sustainable or plant-based diets when shopping. They can also track their omega-3 intake from various sources (salmon, supplements, other fish) to ensure adequate levels if eating alternative-fed salmon.
  • Over 8-12 weeks of eating sustainable-fed salmon, users could track energy levels, joint health, skin quality, and inflammatory markers (if they have access to testing) to observe personal effects. This creates a personal experiment aligned with the 16-week study timeframe.

This research is preliminary and focuses on salmon biology, not human nutrition. While the findings suggest microbial oil can replace fish oil in salmon feed, more research is needed before widespread implementation. If you have concerns about omega-3 intake or fish consumption, consult a healthcare provider or registered dietitian. This study was conducted in controlled laboratory conditions and may not reflect real-world aquaculture practices. Always verify product labels and sourcing information when purchasing farmed salmon.