In terms of sustainability, fish feed remains one of the finfish aquaculture industry's greatest challenges. To alleviate pressure on wild stocks, there is a growing need for aquaculture to reduce and ideally eliminate fish meal and fish oil from carnivorous fish feeds.
Innovation requires feed that provides minimal inputs – the essential and limited nutrients required by the fish, whilst maximising production of quality fish fillets. At the 2016 Aquaculture Canada and Coldwater Harvest Conference held in St John’s Newfoundland, Dr Stefanie Colombo, a postdoctoral research fellow based at Ryerson University, explained how her work involving genomics is helping the industry achieve just that.
In the search for alternative feeds, land-based plant ingredients are considered to offer both environmental and economic benefits. However, they tend not to be high in many of the nutritional requirements of carnivorous finfish, such as the omega-3's eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which, amongst other things, are essential for brain and heart functioning in vertebrates. Whilst carnivorous fish can generally create their own EPA and DHA from the omega-3 precursor, the level at which they can do so is fairly limited. In the natural environment, most of the EPA and DHA come from the fish’s diet – other fish.
Reducing the EPA and DHA from farmed fish diets can impact fish health, as well as reduce some of the human health benefits associated with eating fish. One plant-based candidate for an alternative carnivorous fish-feed ingredient is camelina, a flowering plant that is in the same family as mustards and cabbages. Camelina is fairly unique in the terrestrial plant world in that it contains naturally high levels of omega-3, however it does not supply the EPA and DHA found in the natural diet of carnivorous fish – and the traditional fish-based feed used in carnivorous fish aquaculture.
By genetically engineering camelina, Dr Colombo argues, we could produce plant-based oil with omega-3 levels that matches those found in marine-based diets.
This article was written for (and can be read in full at) The Fish Site.