18th December

Breakthrough in shrimp farming

Stefan Kraan, Scientific Director, Ocean Harvest Technology

The black tiger prawn, Penaeus monodon, is a marine crustacean widely reared for food in Asia and is often the one that ends up on your restaurant plate.

At approximately 36 centimetres in length and weighing up to 650 grams this is the world's largest species of prawn. P. monodon is also the most widely cultured prawn species in the world, although it is gradually losing ground to the whiteleg shrimp, Litopenaeus vannamei. Over 900,000 tonnes are consumed annually, worth about $USD 5 billion, two-thirds of which is farmed

Frozen head-on, head-off, and peeled shrimp used to be the major export products to the main markets in the USA, EU and Japan. In financial value, Penaeus monodon is the most important traded aquaculture commodity in Asia.

Disease issues
Being the case with every type of monoculture, major disease problems are always a threat, either from viral Whitespote Disease (WSD) and Yellowhead Disease (YHV) or bacterial Vibrio campbellii .

No chemicals or drugs are yet available to treat such viral infections. Nevertheless, through good management of pond, water and feed, together with close monitoring of the health status of stock inputs, the impact of disease can be greatly reduced.

Outbreaks of the most serious virus disease nearly always occur following dramatic changes in parameters such as water temperature, salinity, dissolved oxygen and water hardness. In some cases, antibiotics and other pharmaceuticals have been used to treat these viruses but their usage comes with a high price and with little success.

Solution
Oceanfeed™-shrimp is the first marine natural and sustainable functional feed ingredient derived from macroalgae. Unique blending and processing guarantees that all bioactive ingredients are present in the final end product and can replace the mineral and vitamin premix.

A number of reports in the literature have shown some degree of success in improving the clinical outcome of shrimp in viral and bacterial challenges by administering immunostimulants and algal extracts.*

When supplemented to the diet, fucoidan – a seaweed component -partially protected shrimp from White Spot Syndrom Virus (WSSV) infection **. Oceanfeed™- shrimp contains a plethora of natural bioactive compounds which, when incorporated into the diet, can modulate several functions and assist in the control of chronic diseases and viral infections in farmed shrimp.

It also allows for disease-free farmed shrimp to be reared in a more natural and sustainable way, thus easing concerns about environmental impact and sustainability.

Trial results
OHT recently finalised trials using Penaeus monodon with the objective of researching the effects of Oceanfeed™-shrimp on growth, FCR, and viral and bacterial diseases. Tests were also done to assess the improvement of the clinical outcome of P. monodon shrimp challenged with WSSV and Vibrio after feeding on a diet supplemented with Oceanfeed™-Shrimp. 

Growth tests were performed by CreveTec-AFT Research Center in biofloc recirculation systems. Challenge tests were performed by the Shrimp Research Group of the University of Ghent in Belgium.

Four different diets (with identical protein and lipid levels) were tested, incorporating 5 and 10% inclusions of Oceanfeed™-Shrimp and two diets with yeast included.

Results after the two-month trials showed that inclusion of 10% of Oceanfeed™-shrimp (OF10-shrimp) without the addition of yeast was the best diet of the four tested diets and was able to replace the mineral vitamin premix.

Moreover, shrimp fed with 10% inclusion of OF-shrimp were 2.8% heavier than reference shrimp fed with the standard reference diet at the end of the trial. This would translate into a 2.8 tonne increased yield per 100 tonnes of shrimp.

The Feed Conversion Ratio (corrected for mortalities) was 0.08 better with 10% inclusion of OF-shrimp. This is 8 tonnes of feed per 100 tonnes of shrimp that would be saved. Mortalities also improved on the OF10 feed by 1.67%. This is 1.67 tonnes shrimp per 100 tonnes. There was a strong effect in the OF10 diet when challenged with Whitespot Viral Disease and the bacterial disease Vibrio with a 40% and 20% lower mortality respectively compared to the control diet.

At the end of the trial, non-challenged shrimp were tasted by a large UK seafood retailer. The trials showed that OF10 shrimp were significantly better in taste and texture than reference diet shrimp.

Global issues
In 1810 the world population was approximately 1 billion; today, the figure is upwards of 7 billion, and by 2050 it is expected to top 9 billion. Food is therefore going to be incredibly important!

Currently food production is primarily land-based, despite the fact that 71% of the earth’s surface is covered by oceans. That leaves roughly 26% of the earth to support human life, animal life, vegetative life and agricultural production.

It is estimated that less than 3% of the earth’s surface is being utilised as arable land. The green revolution has made 3% of the planet incredibly productive. But can it grow? Even more importantly, is it sustainable? The platform (food production) may not be burning, yet, but it is getting quite crowded. What if 10% of the ocean could be used to grow seafood? Shrimp farming will no doubt form a large part of this seafood production.

We are at the cross roads of a blue revolution, and Ocean Harvest Technology has developed feed ingredients from macroalgae to help develop this in a more sustainable way and to lessen the need and dependency on chemicals and additives. A perfect example is the effects of Oceanfeed™-shrimp in shrimp farming.
 
*(Itami et al., 1998; Takahashi et al., 2000; Chang et al., 2003)
** (Chotigeat et al., 2004; Huang et al., 2006)

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