This piece authored by Dr Brett Glencross was published in International Aquafeed Magazine in May 2023

Predicting the future is always full of uncertainties. However, when working out which options to take, it is always important to understand where you currently are and where we have been before you try and work out where you might end up. In essence it is something of a navigation exercise. It was in this light that an article was recently published in the Journal of the World Aquaculture Society that charts the history and prospects in aquaculture nutrition research. The work was the outcome of a four-year journey with the United Nations Food and Agricultural Organisation (FAO), where I was asked to assemble a global team to examine three key themes that underpin the feeds and feeding process (requirements/ ingredients/ management) and to review them in terms of that past–present–future context.

Whilst undertaking this review, it was noted that the top seven cultured species groups (carps, tilapia, catfish, shrimp, other freshwater fish spp., salmonids, and marine fish spp.) collectively comprise close to 90% of all aquaculture production and therefore these species, and the science underpinning them, formed the focus of the article. One of the things noted with these seven groups was that the use of compounded feeds was not equally applied among each. Indeed, the largest group by volume, the carps are still mostly produced in small-scale extensive, semi-intensive, and integrated polyculture systems with little to no manufactured feed inputs. Importantly, things like feed specifications, ingredient choices, and feeding management were noted to vary across each of the groups, but also with substantial variation regionally across the world. However, increasingly it was noted that each of these species' groups is moving towards intensive production, where a greater reliance on feed is commanded.

In terms of reviewing the past 20 years of research into feed technology, it was noted that there had been substantial progress made in improving feeds and feeding technologies for most species. Some of the biggest gains had been made through improvements in feed conversion efficiency (through a better understanding of requirements and improved feed management) and ingredient sustainability (through increased capability to use a wider range of ingredients) were two notable achievements. Although the requirements of many of the main aquaculture species are now well understood, there remains much to do in defining requirements for many of the species being farmed in the developing world. There is an increasing need to be more precise in what we prescribe as the required levels of essential nutrients and various additives in the diet based on age, genotype, environment, and health status. We see this emerging as a “precision nutrition” approach to farming aquaculture species.

Notably, there remains a further need to diversify our ingredient options to provide greater resilience to feed supply. Increasingly the sustainability of different feed ingredient sources, including the influence of possible climate change impacts, is becoming a growing issue. It was clearly identified that what is needed to sustain future feed production are sustainable sources of cost-effective protein, some essential amino acid additives, some omega-3 fatty acid resources, and various minerals and vitamin additives. While the use of new and varied ingredients will mean that food safety remains a priority issue throughout the world. It was noted that feed manufacturing has evolved from a simplistic exercise to a highly complex science with state-of-the-art engineering. However, the application of this technology has not been consistent, as there is still widespread use of pelleting, mash, and trash fish feeding throughout the developing world. Similarly, we see a growing dichotomy in feed management between the developed and developing world, with a high reliance on manual skilled labour in the developing world, whereas more advanced aquaculture systems are becoming increasingly reliant on automated computer-controlled feeding systems.

In terms of the scientific journey, that we have embarked on over the past 20 years, we can see that science has underpinned massive changes in how we feed our fish. The ability to produce animals with the lowest FCR’s of any domesticated animal species is a clear testament to this progress. However, the path before us now highlights that it is the resources we need to use (the ingredients) that is perhaps our most urgent priority to address. Hopefully sowing the seeds of science will help us deliver a better future in that regard too.