This piece was first published in International Aquafeed Magazine - July 2021 issue

About twenty years ago, when I was younger and a much less experienced scientist, I was fortunate enough to work alongside some of the best aquaculture nutrition scientists in the world. One of those scientists was Dr Geoff Allan, who at the time was leading a nationally coordinated effort by the Australian government and local feed industry to research the application of alternative ingredients in aquaculture feeds. What I learnt from Geoff was the structured and systematic way in which the science of ingredient assessment needs to be undertaken. Something that has stuck with me to this very day. Even now and having had the opportunity to work with so many science leaders across the world, that research program still resonates today in terms of its impacts. 

From that experience, Geoff and I wrote a review to capture the things we had learned and what worked well for us, as well as some of the pitfalls and mistakes we noted along the way. We published that work back in 2007 [Aquaculture Nutrition 13, 17-34], and it became a bit of a seminal landmark in the aquaculture nutrition domain as it was the first time that the science of ingredient assessment was clearly described in a structured and systematic way. What we had proposed was a series of five key steps: Characterisation > Palatability > Digestibility > Utilisation > Functionality. The order in which we proposed the steps being just as important as the steps themselves. We had noted from our own experience, as well as the increasing volume of work in the domain, that people jumping straight into growth studies, without defining the effects of palatability and digestibility usually just described the effects of those two parameters, but without the ability to define the effect of either. The other critical problem we had noted was that scientists across the world had launched into the endeavour of “fishmeal replacement”, but in most cases never clearly defined what they were working with, let alone what they were replacing. Something we thought was akin to trying to measure something, but never telling anyone what the units of measurement were.

Roll onto the present day, and ingredient assessment science in aquaculture is facing something of a renaissance with lots of new proteins and oils emerging. So, I recently reviewed the science landscape to see how things have changed, only to note that in many cases the same mistakes are still being made. Mindful of this I decided to revisit that old review of Geoff’s and mine and wrote a revised version last year [Aquaculture Nutrition 26, 1871-1883]. This time though, I included some illustrated examples of the reasoning behind our series of five key steps in the hope that folk may understand the points better. Maybe I am being hopeful that it will help the next generation take us that leap forward, or at the very least help us make some sense of the past.

Dr Brett Glencross