Monday, September 11, 2017

12/09/2017: Functional feed additives to enhance the digestive and metabolic capabilities of fish and shrimp, a ‘must-have’ in today’s aquafeed

by Peter Coutteau, PhD, Sam Ceulemans and Alexander van Halteren Nutriad International, Belgium

Aquaculture is the fastest growing industry producing animal protein


Still, aquafeed production only represents four to five percent of global animal feed production and is fragmented over many species and countries around the globe.

This lack of critical mass limits research developments, particularly for tropical species of fish and shrimp. At the same time, the young aquaculture industry suffers from several bottlenecks that must be solved to maintain its sustainable growth and satisfy growing global demands for fish and shrimp.
 


Solving these bottlenecks requires multi-disciplinary work and combined progress on different areas including breeding programs, vaccine development, farm technology, husbandry, zonal hygiene management, and nutrition.

At Nutriad, we believe that functional feed additives, powered by natural, bio-active compounds with specific functional properties, are an important component to solve these key issues. Strong fluctuations of feed ingredient prices, sometimes in combination with low market prices at the farm gate, have repeatedly affected the profitability of all bulk species, including shrimp, marine fish, trout and pangasius.

As a result, optimising cost-efficiency of feed is a major issue for aquaculture producers. For carnivorous species such as salmonids, marine fish and shrimp, formulating feed using increasingly reduced levels of fishmeal and fish oil, without affecting performance nor health status under production conditions, has proven to be a challenge.

The upcoming new generation of aqua feeds are using significantly lower levels of marine ingredients. This has been achieved by the use of alternative ingredients, mostly proteins and fats derived from plant crops, in combination with feed additives which enhance the digestive and metabolic capabilities of the fish and shrimp to deal with these “unnatural” ingredients in their diet.

Increased nutrient utilisation efficiency is key to achieve more cost-efficient feeds
Functional feed additives that enhance digestive and metabolic processes are crucial to make novel feed formulations work within the limitations of the digestive system of fish and shrimp. Potential products for improving digestion and feed utilisation in fish include phytobiotic compounds, organic acids, enzymes, and natural emulsifiers.

However, it is difficult to predict the functionality of many of these products for a wide range of fish species, covering carnivorous, omnivorous, and herbivorous feeding habits, marine/freshwater habitats, cold/tropical climates, and extremely different feed formulations.

At Nutriad, a continuous programme of empiric screening for important aquaculture species aims at identifying promising compounds for application in aquaculture. Our research has mainly focused on compounds that are heat-stable in order to facilitate application under practical processing conditions for aquafeed.

In omnivorous fish such as tilapia and catfish, digestive aids have shown interesting results to improve nutrient utilisation from cheap ingredients and improve economics of farming and filet processing.

Lin & Wu (2014) demonstrated that the dietary protein level could be reduced in tilapia feeds by supplementing a feed additive capable of enhancing nutrient utilisation. Tilapia fed two percent less protein and supplemented with a digestive/metabolic enhancer, showed even better performance in terms of growth, feed conversion ratio, protein efficiency and retention, and fileting yield compared to control fish.

Furthermore, fish fed the enhanced low protein diet showed lower levels of visceral fat and plasma triglycerides, but enhanced activity of the enzyme G6PDH, which indicated effects on lipid and carbohydrate metabolism (Table. 1).

The metabolic effects can explain the release of non-protein energy, which in turn results in protein sparing and more effective utilisation of protein for muscle growth.

For carnivorous fish such as marine fish and trout, digestibility enhancers adjust for decreased digestibility, particularly of dietary fat and energy, for fish fed feeds containing low levels of fishmeal and high levels of vegetable proteins.

Also, digestive/metabolic enhancers allow to formulate lower fat levels in high energy feeds without affecting performance whereas improving liver health.


Read the full article, HERE.

The Aquaculturists
This blog is maintained by The Aquaculturists staff and is supported by the
magazine International Aquafeed which is published by
Perendale Publishers Ltd

For additional daily news from aquaculture around the world: aquaculture-news

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