BLOG: Half the breeding is in the feeding – food for thought

I know this blog is about feeding and nutrition, but I feel it’s important – in order to get the focus of the comment right – to point out the areas in which the gains have been made from their program thus far. The most significant gains have been made in conformity. Firstly, they’ve eliminating the bottom end of the spawning batch. This was the end that took the longest to grow and took up so much less-than-optimal productive fish space. The second gain they registered was that they reduced the number of times they had to grade by 33%.  Grading was a high cost, labour intensive operation that finished up costing a couple of days of growth while the fish settled down.  Thirdly, the program had improved the conformation as well as the consistency of the fish, which gave them a greater return per fish space, as well as a marketing edge.

The comment that my colleague made was that half the breeding was in the feeding. Now this brings us to the diets that are available. And how much work has gone into them from a phase feeding point of view.  Salmonoids have been farmed for decades and the diets available have been road tested over that time. I can remember the bad old days when the pellets were steam pressed and gave a feed conversion efficiency of 2:1, on a good day. Now the industry norm, using extruded rations and species and, to a point, age specific diets, is around half that, but how much better could it be?

I’m talking aquaculture here when I say other intensive animal protein industries have developed a very scientific approach to diets. A sophisticated pig farmer, for instance, will change his diet every fortnight, and will have a different ration for gilts and sows and a different ration for winter and summer feeding.

Once the average fish farmer gets the fry from the hatchery he will feed two diets: a rearing/weaning diet and a growers’ diet.  Or more accurately, those are the two diets available.  While there are some excellent post larval and nursery diets around, they seem to cut out at just over a millimetre. The larger pellet sizes are limited in nutrition profiles – as in one ration feeds all sizes.

Which in turn should raise the question: how much growth is being missed at those crucial early stages by not having adequate diets available? Those early stages when daily body weight gains are in the vicinity of 10% – and more – and the juvenile fish are doubling their size in less than a week.

The corollary to that of course is, what growth potential will be missed from feeding inadequate diets to the genetically improved fish that are starting to come through for some species? Fish that have superior economic potential to the run of hatchery seedstock that, at this stage, is still the norm available for most farmers.

Look, I’ll be the first to agree that with all the different species grown, it’s neigh on commercially impossible to design and manufacture species-specific phase feeding diets for all of the whole aquaculture industry. What I am saying is that one, the pig and poultry growers have incorporated phase feeding into their farming operations. And two, the streamlining of genetic potential in fish farming has started. When one of Australia’s most progressive barramundi hatchery operators and growers makes the comment that half the breeding is in the feeding, it might be time for the feed industry to review the situation.