Thursday, June 11, 2015

11/06/2015: Alternatives to achieve the sustainability challenge in shrimp production: Sodium Butyrate

by Alvaro Ortiz, Aquaculture Product Manager, Norel SA, Spain

First published in International Aquafeed, May-June 2015

Although aquaculture is always referred to as the future solution to feed the nine billion people estimated in world population by 2050, there are still many complications to overcome.

Shrimp production plays a key role in aquaculture. Diseases such as Acute Hepatopancreatic Necrosis Syndrome (AHPNS) and related outbreaks recently reported in India, together with raw material prices volatility are two major problems that need prompt solutions if we do not want to succumb achieving the sustainability challenge.

Despite this, the outlook is positive. Although China, Mexico and Thailand are reporting lower productions than forecasted for 2014, the volume traded during the first half of the last year in the international shrimp market increased by five to six percent compared with the same time period in 2013. In terms of farmed shrimp production, positive trends have been posted so far in Ecuador, Indonesia, Vietnam and India.

Forecast in India
The official forecast in India suggests that farmed shrimp production, dominated by Vannamei, may increase by 10 to 20 percent during the current fiscal year (April 2014-March 2015), and Brazil farmed shrimp production is expected to grow 18 percent (Intrafish, and FAO Globefish).

Pathologies are going to be present throughout this year and fish meal/oil prices are not going to help to create an idyllic scenario; in early December 2014, IMARPE confirmed its recommendation after a second survey that there should be no quota issued for the second fishing season.

Antibiotics growth promoters, AGP’s are under surveillance because of suspicions they create resistance to pathologic bacteria creating “superbugs” causing 25,000 deaths per year in Europe, 38,000 deaths in Thailand and 23,000 deaths per year in the EEUU. The overall impact cost is estimated to be US$35 billion in the EEUU (sources: ECDC 2007, Pumart et al 2012, US CDC 2013).

To overcome all these challenges, a new generation of additives is being thoroughly studied: the natural growth promoters (NGPs). Also termed non-antibiotic growth promoters, NGPs are feed additives contemplating different categories as salts of organic acids, probiotics, prebiotics, phytogenic or yeast. In addition to the beneficial effects in terms of health status and performance, NGPs supplementation does not usually bear any risk regarding bacterial resistance or undesired residues in the edible fish product. 

Several publications have addressed the effects of short chain fatty acids (SCFA) and their salts on the health and performance of fish. These SCFA are commonly known by their specific antimicrobial activity. However the effects of SCFA go beyond modification of gut microflora. Other benefits such as: improved digestive enzyme activity, increased pancreatic secretion, enhanced development of intestinal epithelium and intestinal barrier integrity, or anti-inflammatory properties (Gálfi and Bokori 1990; Le Gall et al. 2009), have been described and attributed to likely causes of enhanced performance, particularly when supplementing butyric acid in its sodium salt form.

Butyric acid is naturally produced and present within the intestine of both carnivores and herbivores fish (Holben et al. 2002; Mountfort 2002). It is very well known how the anti-inflammatory effect of butyric acid can prevent the presence of enteritis in salmon when part of the dietary fishmeal is substituted by soybean meal. This additive could therefore be useful to help reducing the diet costs when fishmeal prices or availability become unpractical, facilitating a higher inclusion of vegetable raw materials, by means of increasing their digestibility and counteracting anti-nutritional effects.

Regarding its pathogen inhibition capabilities, in a recent study conducted by Katsetsart University (Thailand) and Norel S.A. different compounds were tested to assess its inhibition and bactericidal activity against marine shrimp pathogenic bacteria.

Gustor Aqua (Sodium Butyrate) was tested in this study against V. parahaemolyticus.
A strong inhibitory effect was found for Gustor Aqua both at pH=5 and pH=6 against V. parahaemolyticus, microorganism suspect of causing AHPNS.

In another study
In another study, butyric acid was compared against the most common SCFA exhibiting a greater inhibition capacity (University of Santiago and Norel SA), less quantity of butyric was needed to inhibit the same concentration of pathogens. 

Knowing that sodium butyrate might be of great help in the important shrimp farming industry, Norel wanted to test the additive on-the-field and a trial was conducted in a commercial shrimp farm in Honduras.

Gustor Aqua (protected sodium butyrate) was tested to determine the effect of the additive in performance parameters. The initial density was around 31 shrimp/m2. Ponds supplemented with Gustor Aqua completed the fattening period with 35 percent more biomass, the final yield (kg/ha) in those ponds was 26 percent higher. Feed conversion ratio was also influenced by adding the additive, being 2,033 in the control ponds and 1,590 in the sodium butyrate supplemented group.

Gustor Aqua positively influenced animals’ performance and in addition, their health status is boosted as the higher survival rate reflects. The combination of both variables yields better economic results.

Read the magazine 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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