Sources, quantification techniques, associated hazards, and control measures of mycotoxin contamination of aquafeed.

With the productive intensification of fish farming, the partial or total replacement of fishmeal by ingredients of plant origin became a reality within the feed industry, with the aim of reducing costs. However, this practice increased the impact of mycotoxin contamination. Studies have shown that mycotoxins can induce various disorders in fish, such as cellular and organic alterations, as well as impair functional and morphological development, and, in more severe cases, mortality. Thus, studies have been conducted to evaluate and develop strategies to prevent the formation of mycotoxins, as well as to induce their elimination, inactivation or reduction of their availability in feed.

Mitigation of aflatoxin B1 in fish feed by peroxidase from soybean meal.

Potential of the enzyme peroxidase (PO) from soybean meal to mitigate aflatoxin B1 (AFB1) in fish feed was evaluated. Reaction parameters studied in the wet stage of the feed production process were enzyme activity (0.01-0.1 U/g), temperature (20-36 °C), time (0-8 h) and humidity content (40-70%). Feed was produced in conformity with the National Research Council and spiked with AFB1 at 10 ng/g. Any residual concentration of AFB1 in the diet was extracted by the QuEChERS method and quantified by a liquid chromatograph with a fluorescence detector. AFB1 mitigation of 90% was reached when feed production conditions were 0.035 U/g, 32 °C, 6 h and 70% humidity. Therefore, application of PO to the feed industry may be considered a promising tool for mitigation of AFB1, considering its toxicity and frequent occurrence. In addition, it guarantees safe food for consumers of fish farming products, as AFB1 can bioaccumulate in the food chain. It also provides an alternative use for soybean meal that would previously be discarded.

Evaluation of Interactions of Added Soybean Peroxidase with Other Nutrients Present in Fish Feeds Using an In Vitro Digestive Simulation.

Peroxidase (PO) has been applied in different areas of industrial biotechnology, including the control of contaminants like aflatoxin B1 in fish feeds. However, its potential negative interactions with the macro and micro components of feeds have not been evaluated. The aim of this study was to evaluate the impact of PO's addition to a feed on compounds like fatty acids and polyphenols using an in vitro simulation of the digestive tract of the tilapia. The influence on fatty acids was determined by changes in the peroxide index, with the feed including PO presenting values four times higher than those of the control feed. On the other hand, the in vitro digestive simulation also evidenced an effect of PO on the bioaccessibility of polyphenols significantly influenced by the total digestion time and temperature. The bioaccessibility of polyphenol ranged from 2.09 to 16.23 µmol of the total Trolox equivalent antioxidant capacity for the combinations evaluated in the study. The greatest bioaccessibility was observed at the central point under the following conditions of digestive hydrolysis: pH of 7, 30 °C, 4.5 h of digestive hydrolysis and an absence of PO.

Occurrence and bioacessibility of mycotoxins in fish feed.

In this study Aflatoxin B1 (AFB1), ochratoxin A (OTA) and zearalenone (ZEN) occurrence in fish feed, regarding its chemical composition, were investigated. Besides, AFB1 bioaccessibility to fish was evaluated by in vitro digestion. Mycotoxins were extracted by QuEChERS and quantified by HPLC-FLD. Results showed that 93.3% of the samples were contaminated at maximum levels of 16.5, 31.6, and 322 µg/kg in the cases of AFB1, OTA, and ZEN, respectively. A positive correlation between OTA, ZEN contamination, and lipid content was observed. Risk estimation of feed consumption by fish at the highest levels of AFB1, OTA, and ZEN shows that the younger the fish, the higher the risk of exposure to mycotoxins. The AFB1 bioaccessibility assay showed that 85% of this mycotoxin may be absorbed by fish. Therefore, establishing maximum levels in the fishing sector is fundamental to contribute to feed quality and nutritional safety of fish species.

Peroxidase as a simultaneous degradation agent of ochratoxin A and zearalenone applied to model solution and beer.

The aim of this study was to evaluate the action of the commercial peroxidase (POD) enzyme (Armoracia rusticana) on the simultaneous degradation of ochratoxin A (OTA) and zearalenone (ZEA) in model solution and beer. For this purpose, the reaction parameters for POD action were optimized, POD application in the degradation of mycotoxins in model solution and beer was evaluated and the kinetic parameters of POD were defined (Michaelis-Menten constant - KM and maximal velocity - Vmax). In the reaction conditions (pH 7, ionic strength of 25 mM, incubation at 30 °C, addition of 26 mM H2O2 and 1 mM potassium ion), POD (0.6 U mL-1) presented the maximum activity for simultaneous degradation of OTA and ZEA of 27.0 and 64.9%, respectively, in model solution after 360 min. The application of POD in beer resulted in the simultaneous degradation of OTA and ZEA of 4.8 and 10.9%, respectively. The kinetic parameters KM and Vmax for degradation of OTA and ZEA were 50 and 10,710 nM and 0.168 and 72 nM min-1, respectively. Therefore, POD can be a promising alternative to mitigate the contamination of OTA and ZEA in model solution and beer, minimizing their effects in humans.

Aflatoxin M1 and B1 in Colombian milk powder and estimated risk exposure.

Aflatoxin M1 (AFM1) and aflatoxin B1 (AFB1) were determined in 51 milk powder samples purchased from different grocery stores located in the Caribbean region of Colombia. Analysis was conducted using QuEChERS extraction and high-performance liquid chromatography with fluorescence detection. Results from the analytical method showed recovery ranges from 65% to 110% and relative standard deviations lower than 20%. AFM1 was detected in 100% of the milk samples (0.20-1.19 µg/kg) and 55% exceeded the maximum level in milk (0.5 µg/kg) set by the Colombian and European regulations. AFB1 was not detected in any of the analysed samples. Considering the measured contamination the maximum AFM1 level that can be ingested by consumption of milk powder is 0.007-0.013 µg/person/day. These values are above the average dietary intake estimated in Latin America according to the Joint FAO/WHO Expert Committee, which is 0.0035 µg/person/day.