FEATURE
Fumonisins in aquaculture:
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The most sensitive species by Rui A Gonçalves, Biomin Holding, Austria
n aquaculture, fumonisins (FUM) have generally been associated with reduced growth rate, feed consumption and feed efficiency, and impaired sphingolipid metabolism. Fumonisin toxicity is related to this ability to inhibit sphinganine (sphingosine) N-acyltransferase (ceramide synthase), a key enzyme in lipid metabolism, disrupting this pathway. This is due to the long-chain hydrocarbon unit (similar to that of sphingosine and sphinganine) in these mycotoxins, which plays a role in their toxicity.
Sensitivity of freshwater species
Little information is available on the effects of fumonisins on aquaculture species, and most research focuses on freshwater species. The channel catfish (Ictalurus punctatus) is the most widely studied species. These fish can tolerate relatively high levels of FUM, with a sensitivity level of around 10 mg fumonisin B1 (FB1)/kg feed. Adverse effects of fumonisin-contaminated diets have also been reported in carp (Cyprinus carpio L.): various experiments have observed scattered lesions in the exocrine and endocrine pancreas, and interrenal tissue, probably due to ischemia and/or increased endothelial permeability. In another study by Pepeljnjak et al., 2003, one-year-old carp were fed pellets containing 500, 5,000 or 150,000 µg FB1/
Overview of the experimental conditions
kg body weight, resulting in weight loss and alterations in hematological and biochemical parameters in target organs. Tuan et al. (2003) demonstrated that feeding FB1 to tropical species at 10, 40, 70 and 150 mg/kg feed for 8 weeks affected growth in Nile tilapia (Oreochromis niloticus) fingerlings. In this experiment, average weight gain in fish fed diets containing 40,000 µg FB1/kg or more were lower. Hematocrit was only reduced in the tilapia given 150,000 µg FB1/kg feed. The ratio of free sphinganine to free sphingosine (Sa:So ratio) in the liver increased at 150,000 µg FB1/kg feed.
Pacific whiteleg shrimp
To the author’s knowledge, the only crustacean species studied to date with respect to sensitivity to FUM is the Pacific whiteleg shrimp (Litopenaeus vannamei). Despite slight variations in testing levels, the few studies available suggest that Litopenaeus vannamei is much more sensitive to FB1 than previously described in freshwater species. García-Morales et al. (2013) have shown that soluble muscle protein concentration was reduced, and changes were observed in the thermodynamic properties of myosin, after 30 days’ exposure to FUM in Pacific whiteleg shrimp fed 20 to 200 µg FB1/kg feed. The same authors reported marked histological changes in the tissues of shrimp fed a diet containing 200 µg FB1/kg feed, and changes in meat quality after 12 days of ice storage in fish fed more than 600 µg FUM/kg feed. The effect of FUM on muscle
Water parameters being controlled during experimental period
22 | December 2018 - International Aquafeed