This was said at the aquaculture sessions at the Alltech ONE Conference, held this week in Lexington, Kentucky. Speaking at this session, Philip Lyons, global manager Aquaculture Research at Alltech Coppens emphasized the complexity of fish nutrition, compared to monogastric or ruminant nutrition. “We are dealing with a growing number of fish species we farm, all having different nutrient requirements, intestinal morphologies and raising conditions. This has consequences for the speed of innovation within the field of fish nutrition and science”.
Yet, Lyons sees a lot of catch-up in the field of fish nutrition in the last few years, moving aquaculture up on the so-called R&D/innovation ladder. Lyons explains: “This ‘ladder’ - or research trajectory - has 8 phases, going from phase 1 (simple formulation using crude nutrient and gross energy values) to more advanced formulation using precise growth modeling and ileal protein digestibility (phase 5) all the way up to nutrigenomics, automated feeding, data analytics and computer vision (phase 8). While pigs and poultry have already reached phase 8, the innovation level of Nile tilapia, rainbow trout and Atlantic salmon is still around phase 5. If we combine all aquaculture species, we are even at phase 3-4. But we are now moving into the next phases fast with many fish species, which is really exciting.”
From net energy to functional diets
A great example of innovation development is the use of net energy models instead of working with digestible energy values. “Working with digestible energy means you basically assume that all the protein, fat and carbohydrates within the diet are utilized in the same way. Net energy takes that step further and actually assumes that these nutrients are utilized differently, resulting in a far more precise measurement of growth performance. This gives the farmer a clear model of what to expect from a given feed. For rainbow trout, we are already using the net energy values in our formulation, and there are a number of exciting projects in this field that are developing net energy models for more fish species. It is complicated because all species are different, but the impact is huge, both from a performance and sustainability standpoint,” Lyons explained.
Lyons also sees a lot of opportunity in the field of the microbiome (what is the function of the gut bacteria, for example), the use of enzymes in fish diets (can we apply them more often) and the development of functional diets (designing specific/precision diets for different conditions or varieties within one species). Lyons explained that “enzymes are still an underutilized technology within aquaculture, because of the challenges around enzymes during extrusion. Yet, if we are able to overcome this and include more enzymes, there is huge potential to make fish diets more digestible and sustainable”.
In the field of functional diets, Alltech Coppens developed a tailored diet for rainbow trout to improve fat digestibility during winter conditions. “As trout diets have a fair amount of fat, cold temperatures lead to solidification of the fat and lower digestibility of the feed. With our feed, we managed to get a 7% increase in fat digestibility during low temperatures, directly improving feed conversion ratio levels,” said Lyons.
Focus on flexibility and sustainability
Improving digestibility and more precise feeding all lead to more efficient diets and better use of the raw materials we use. When it comes to the replacement of marine ingredients in the road to more sustainable diets, Lyons had a clear message. “We have to stop searching for single magic bullet ingredients to replace fishmeal. It should be about flexible formulation, using all the raw materials we have available and doing this in a more sustainable way at the same time. It is more a case of adding ingredients instead of replacing ingredients. We really have to change this narrative and perception that persists through the industry.”
Maud Valkenaars, nutritional researcher at Alltech Coppens, and also speaker at the event, delved a bit deeper into this topic and explained that “in the past, fish diets were formulated on crude protein and fat levels, wheat, fishmeal and fish oil. But at the moment, the formulation is based on nutrient digestibility levels and amino acid profiles among others, coming from a wider range of protein sources.”
Valkenaars addressed that the novel ingredients on the market, such as single-cell protein, insect meal and algae, are considered sustainable options for fish diets, although the price is still relatively high for these new ingredients. “But we shouldn't forget the opportunity of replacing marine ingredients from the wild catch by using more fish trimmings (fish byproducts). This is a sustainable and circular way of looking at marine ingredients and awareness of using these byproducts is growing. At Alltech Coppens, we have already replaced 80% of our marine sourced ingredients with fish trimmings,” Valkenaars said.
LCA: A necessity in the future
According to Valkenaars, the aquaculture sector is moving towards using more Life Cycle Assessment (LCA), a method to quantify the environmental impact of a certain product and to support sustainable decision making. Valkenaars explained that “there is an increased focus on transparency and sustainability of food production. And we need to be able to quantify the effect that global food production has on the planet. At Alltech Coppens, we started by calculating the carbon footprint per raw material. But sustainability is much more than carbon footprint only, it should also include things such as damage to human health, ecosystems and resource availability. For our LCA calculations, we even added an extra one: the damage to marine resource sustainability. This allows us to also take into account the fish stocks depletion. When we add this data to our feed formulation software, we can quantify the total sustainability score for all the feeds we produce and investigate the potential of the diets in real farm conditions. If you have a sustainable diet, but still have a high FCR in your fish, it is still not sustainable.”
Valkenaars foresees that using LCA in aquaculture will become a necessity in the near future, instead of a luxury. “This requires that we all move in the same direction, are transparent and develop a standardized quantification system in sustainability scoring. Now it is our time to take our position in this as a sector,” she concluded.
