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FEATURE

quality may be of great importance, especially for shrimpexporting countries, as it directly affects shelf life. The study by Burgos-Hernández et al. in 2005 also confirmed that FB1 causes histological changes in the shrimp hepatopancreas as a result of alterations in trypsin and collagenase activity. Mexía-Salazar et al. (2008) also observed marked histological changes in the hepatopancreas, as well as necrotic tissue, in shrimp fed 500 µg FB1/kg. These authors also observed changes in both the electrophoretic patterns and the thermodynamic properties of the myosin extracted from shrimp exposed to FB1.

Marine species as more susceptible

All aquaculture species tested for sensitivity to FUM to date have been omnivorous or herbivorous, and all have been freshwater species, with the exception of whiteleg shrimp. High levels of FUM have been measured in plant meals commonly used for carnivorous marine species, but there have been no studies investigating the possible effect of FUM on marine species. To fill this knowledge gap, two trials were carried out in marine species, where there is potential to use plant meals. One of the studies was conducted with gilthead seabream (Sparus aurata), one of the most important aquaculture species farmed in Europe and a good model to study the effect of FUM on carnivorous marine species. In this study, which is still being evaluated, triplicate groups of 35 gilthead seabream (315 fish in total), with a mean initial body weight (IBW) of 28.8 ± 2.1 g were fed one of three experimental diets for 60 days. The experimental diets were: FUM 1, containing 168 µg FUM/kg feed; FUM 2, containing 333 µg FUM/kg; and a control diet, free of mycotoxins. Preliminary results indicate that the FUM inclusion levels

Table 1: Effect of FUM on the main growth indicators in gilthead seabream (Sparus aurata), compared to the control diet. FBW

SGR

FCR

FI

PER

FUM 1

11.4%

8.2%

17.5%

10.9%

14.9%

FUM 2

15.7%

11.9%

19.3%

9.5%

16.1%

Table 2: Effect of FUM on the main growth indicators in turbot (compared to the control group). FBW FUM 0.5

0.7%

FUM 1.0

10.7%

FUM 2.0

15.2%

FUM 5.0

17.7%

SGR

FCR

FI

PER

1.0%

7.6%

5.3%

7.3%

13.4%

28.7%

6.9%

22.5%

20.6%

32.0%

1.7%

24.4%

24.5%

42.5%

9.6%

29.8%

tested affect total growth. Table 1 summarises the effect of FUM at 168 and 333 µg/kg feed on the main growth indicators: final body weight (FBW), specific growth rate (SGR), feed conversion ratio (FCR), feed intake (FI) and protein efficiency ratio (PER), compared to the control diet. The FUM levels tested did not affect survival rates. A second study was carried out in turbot (Psetta maxima; formerly Scophthalmus maximus), a benthic carnivorous species, considered to be the most important flatfish species farmed in Europe and one with a great potential for East Asia. In this study, which is still being evaluated, triplicate groups of 30 turbot (450 fish in total) with a mean initial body weight (IBW) of 83.7 ± 2.9 g were fed diets containing 0.5, 1.0, 2.0 or 5.0 mg FUM/kg for 63 days (diets labeled FUM 0.5, FUM 1.0, FUM 2.0 and FUM 5.0, respectively).

Future proofing your aqua feed production starts with co-creating the perfect fit. Let’s build or upgrade your aqua feed mill

All great ideas start with a dialogue. What’s your ambition? We at van Aarsen believe that sharing know-how and co-creation are essential in finding the perfect fit. Whether you are looking to modernize or expand your aqua feed production, want to replace aging machinery with future-proof innovations, or need advice in the planning and setup of a completely new aqua feed mill, Van Aarsen is the knowledge partner for you. Take a look at our website.

www.aarsen.com/process/aqua-feed

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DEC 2018 - International Aquafeed magazine  

DEC 2018 - International Aquafeed magazine