Friday, August 19, 2016

19/08/2016: Aqua feeds in the Sea bream farming industry

by Diogo Thomaz, Stella Adamidou, Dr Florian Nagel & Dr Hanno Slawski – Aller Aqua Group

A brief history of sea bream nutrition: Sea bream and Sea bass farming started in the early eighties in the Mediterranean, at a time where knowledge about the nutritional requirements of these species was practically inexistent. 

At that time only cold-pelleted feeds were manufactured with a small number of ingredients such as wheat, fishmeal, fish oil, soya and a variety of plant oils and meat meals.  

Dr Florian Nagal, Aller Aqua Research
Protein origin was mainly from fish and animals, and inclusion levels in the diets were very high, exceeding 50 percent. Fat content was very low, below 12 percent, and the main issue was to form a pellet, which could be consumed by the fish. 

As years passed, technologies evolved and from cold pelleted feeds we went one step further to steam-pelleted diets; in the mid 90s extruded feeds started to be produced extensively, turning the page in the history of fish feeds. 

The introduction of extruders
Extruders increased flexibility on the number, the type and the quantities of raw materials formulators could use. At the same time the new technology offered a number of options on the physical characteristics of feeds and improved digestibility of ingredients. Meanwhile academic and company researchers were working on the nutritional requirements of the species and the industry was continuously trying new formulas.

Extruders were the tools for the evolution of feeds. From gross protein, amino acids and fat levels, we moved to digestible protein/digestible energy requirements and from fixed diets to flexible diets. Fishmeal and fish oil substitution took place at the top of the feed companies’ agenda, research and EU funding projects and price and availability started to fluctuate considerably, adding some risk to feed production and cost.
In the year 2000 (until 2013), EU decided to ban land-based animal meals and turn the industry, that was struggling to find the best substitution for fish meal, exclusively to plant protein and fat sources. The need to reduce fishmeal and fish oil, combined with the EU ban, caused a number of changes in feed formulation.

Sea bream
Very soon it was discovered that Sea bass’ and Sea bream’s tolerance to plant materials were impressively high, but still lower than the tolerance of cold and fresh water species such as trout. 

As feeds were changing, the bass and bream industry in the Mediterranean kept growing rapidly, from a few tons in the early 80s to over 300,000 tons, increasing in biomass load and fish density but also health issues. Higher levels of premixes and a large number of additives are being 

Dr Florian Nagel, Aller Aqua Research used to cover different types of issues, such as liver and gut health, immune system enhancement, and pathology issues, all of which are types of stress, but also feed palatability and digestibility. 

Today we are at a stage where fishmeal-free diets are discussed and tested commercially for some carnivorous species and this seems to be the inevitable future of fish feeds.

In the best case scenario, fishmeal and fish oil supply will be stable over the next few years, demand will always be higher than supply, and prices will have be on the rise, whilst aquaculture production will increase together with the demand for more fish feeds.

Read the full article HERE.

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