Wednesday, February 14, 2018

15/02/2018: Do tilapia really need these high dietary protein levels?

by Abdel-Fattah M. El-Sayed, professor Oceanography Department, Faculty of Science, Alexandria University, Egypt

abdelfatah.youssif@alexu.edu.eg

Tilapia are freshwater cichlid fishes that, while native to Africa, were introduced into many tropical, subtropical and temperate regions of the world during the second half of the 20th century. They are among the most important farmed fishes in the world, second only to carps.


Global tilapia aquaculture has witnessed significant expansion during the past three decades. As a result, the global production of farmed tilapia boosted from 383,654 tonnes in 1990 (2.28 percent of total aquaculture production) to 5,670,981 tonnes in 2015, representing 7.4 percent of global aquaculture (excluding aquatic plants) and 11.63 percent of total finfish aquaculture.
 


Semi-intensive tilapia culture has been adopted in various parts of the world, either in monoculture or polyculture systems. Semi-intensive tilapia culture with other herbivorous/omnivorous fish such, as carps and mullets has seen significant expansion, particularly among small-scale farmers in Asia, Africa and Latin America. Under semi-intensive culture systems, tilapia requires about 25 percent crude protein (cp) or even less. This is because these fish can meet part of their protein requirement from the natural food available in the pond through pond fertilisation. In intensive farming systems, this level might be increased to 28-32 percent during grow out phases.

There has been a rapid, global industrialisation of tilapia production in recent years, accompanied by a gradual shift in tilapia culture from traditional, low-input, semi-intensive systems to more intensive farming practices, with an increasing dependence on formulated feeds. In many regions, this has created a disparity between seed supplies and demand, and a concomitant increase in demand for formulated feed.

In parallel with tilapia culture expansion, tilapia feed industry has witnessed substantial growth during the past three decades. Piles of studies have also been accumulating on the development of commercial, cost effective tilapia feeds and best feed and feeding practices. The accumulated knowledge reveals that tilapia require about 40 percent protein during their early larval stages, reduced to 25-32 percent during pre-grower and grower periods. These levels have been adopted in commercial extruded tilapia feed production worldwide for many years; and still applied in many parts of the world.

However, in recent years, some commercial tilapia feed producers have sharply increased the protein, and sometimes lipid, levels in extruded tilapia feeds, far beyond their reported requirements. I do not know whether this increase is justifiable, despite the sharp increase in the prices of feed ingredient, particularly protein source (fish meal, oil seed meals, animal by-product meals, etc.).

As a result of this increase in protein (and, sometimes, lipid) levels in tilapia feeds, prices of these feeds have sharply increased, particularly in Africa. For example, retail price of tilapia starter feed in Tanzania (> 44% protein) ranged from 1400-2700 USD/tonne in 2017. In Kenya, 57 percent starter tilapia feed (Skretting) costed 4000-4900 USD/tonne in October 2017 (depending on particle size). Retail price of feed crumbles (48% cp) was 3000 USD/ tonne, while the price of grow out feed (35-38% cp) was 1300-1360 USD/tonne. Of course, these prices are extremely high, to the limit that enforced many fish famers in different parts in Africa to abandon fish farming.


Read the full article, HERE.

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