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BEANS AND AQUACULTURE a partnership for more sustainable foods systems


Dr Pietro Iannetta, Agroecologist do not usually start articles with personal notes. However, I do like breaking from the constraints of protocol. I do this as I think it may be worthwhile to share what directs and motivates scientists such as I, those who study agricultural ecology which is to examine the relationships between the exploitation of natural (and unnatural) resources for food. For example, this week I have listened to Sir David Attenborough’s Scars of Evolution (BBC, Radio 4), a fascinating exploration of two conflicting theories of human evolution as being from either that of aquatic ape, as opposed to the earlier savanna based theory. Until recently, the savanna hypothesis had largely been accepted with significant ramifications upon the relative importance Western society places on meat as a protein source, as opposed to that obtained from the marine food chain. Yet, the evidence now seems irrefutable that evolution of the humans, or more correctly their defining feature, their brain, was dependent upon essential fatty acids and nutrients that can only be sourced in the marine food chain. And evidence from modern day nutrition studies show that the same essential fatty acids and nutrients still help maintain good human brain function. Yet, just this week a friend, seemingly intelligent argued that “we have evolved to eat meat, not vegetables”. In response, I shared my opinion on his version of reality (results not shown here), and I share this short conversation as just one personal and recent example which highlights the societal challenge: the cultural stereotyping of diet reinforced my popular dogma. So, we face global food systems which have become preoccupied with intensive meat production, and its associated nutrient use inefficiencies and devastating negative environmental impacts. This preoccupation is underpinned by our dependency on man-made inorganic nitrogenous fertiliser which is exploited to cultivate the feed-crops for intensive meat production (See ‘Livestock’s Long Shadow,’ 2006). The polarisation of our food production systems seems inextricably linked to the polarisation of diets with additional negative impacts on well-being and the associated costs of impaired health. This cascade of dependencies, upon meat

production plus the nitrogen fertiliser and the non-renewable energy (fossil fuels) required to manufacture that fertiliser, is not sustainable, or sensible. Even if it were possible to manufacture nitrogen fertiliser from renewable energy sources, say wind power, this would still not encourage natural chemical cycling in-field. Evidence has shown that legume-dependant organic production in rain fed agricultural systems on near-pH neutral soils is only 5 percent less productive than conventional intensive production (Seufert et al., 2012). This success is achieved despite the use of crop varieties bred for high inorganic fertiliser (and pesticide) inputs. Such data has the power to influence a step-change towards more-sustainable legume-based food production systems, which encourage natural chemical cycling. However, here again I must digress since I have used the work legume, and it has also become clear to me that many members of the public are unaware of legumes. For example, consider that most people have some appreciation that a balanced meal might consist of a plate on which rests three main food types - protein, vegetables and carbohydrates. However, the source of the nitrogen (fertiliser) to produce all three is rarely considered. Further, it is not taught that this essential nitrogen could be provided naturally via a process called biological nitrogen fixation. This process exists in terrestrial and aquatic systems and is the means by which legumes may convert inert atmospheric nitrogen into biologically accessible forms, ammonia initially and so to proteins.

The use of Faba beans for farmed salmon production

So, with this foundation established I shall return to my original objective which is to share the findings of the £2.6 million Innovate UK-Industry funded project “Beans4feeds”, which ended in early 2016. The project's formal title, “Development of protein-rich and starch-rich fractions from faba beans for salmon and terrestrial animal production,” respectively, disguises its largely commercial aim. This was to encourage the production of home grown legumes in the form of faba- or field-beans (Vicia faba L.), for farmed salmon production. Faba bean kernels, beans with

38 | September | October 2016 - International Aquafeed

SEP | OCT 2016 - International Aquafeed