The effect of feed additive ethoxyquin on tilapia growth performance and potential secondary hazard to consumers

Ethoxyquin(EQ)is a widely used feed additives for aquaculture,but the potential hazard to fish and consumers are not fully understood.In this work,EQ was applied to tilapia fed with either high-fat or low-fat feed,and the changes in growth performance and intestinal barrier integrality of genetically improved farmed tilapia was observed.Additionally,the microbiota in the intestinal content and flesh was analyzed by 16S rDNA sequencing,and the flesh metabolites was measured by LC-MS/MS untargeted metabolomics.In the low-fat group,EQ increased weight gain and feed conversion rate,but reduced survival rate.In the high-fat group,only weight gain decreased,and there was no significant effect on feed conversion rate and survival rate.Additionally,the intestinal villi and microbiota diversity was impaired in both feeding conditions.Microbiota analysis revealed that EQ resulted in different composition and lower diversity of the flesh microbiota and upregulated the proportion of potential pathogens.EQ also changed the flesh metabolome,decreasing beneficial metabolites and increasing potential harmful components.This work elucidated the effect of EQ on growth performance of tilapia and implied that it has adverse effects on tilapia and may be passed on to consumers.

Analysis of ethoxyquin and its oxidation products in swine tissues by gas chromatography-tandem mass spectrometry for evaluating the feed-toanimal tissue transfer of ethoxyquin and its metabolites

Background:Ethoxyquin(EQ)is a common antioxidant which is widely used in animal feed.But the supplement of EQ in animal feed may lead to the residues of EQ and its major oxidation products:ethoxyquin quinone imine(EQI)and ethoxyquin dimer(EQDM)in animal tissue.Thus,it would pose potential health hazards to consumers.However,the method for the simultaneous determination of EQ,EQI and EQDM in animal tissues is currently not available,and the accumulation extend of these chemicals in animal tissues after EQ administration remains to be evaluated.Results:A gas chromatography-tandem mass spectrometry method was successfully developed for the simultaneous determination of EQ,EQI and EQDM in swine tissues.The quantitative limits of EQ,EQI and EQDM can achieve to 0.5,5.0 and 5.0μg/kg in swine tissues,respectively.The spiked-recovery ratios of the three analytes(5–2000μg/kg)were in the range of 64.7%–100.7%with relative standard deviations below 11.6%.Moreover,the utilization of this method for the analysis of actual swine tissue samples revealed that the application of commercial EQ additive in swine diet would produce the residues of all the three chemicals(EQ,EQI and EQDM)in fat,kidney,liver and muscle.Conclusions:The assay accuracy and precision of this GC-MS/MS method can meet the requirement of quantitative analysis.Meanwhile,the safety of EQ as a feed additive should be seriously considered with regard to food safety concerns since the oxidation product of EQ may have potential carcinogenicity.

Effects of Angelica sinensis extracts on lipid oxidation in fish feeds and growth performance of juvenile Jian carp(Cyprinus carpio var. Jian)

The study was to explore the effect of the extracts of Angelica sinensis(EAs) on lipid oxidation in fish feeds compared with ethoxyquin(EQ) and the effect of dietary EAs on growth performance of carp(Cyprinus carpio var. Jian). Firstly, fish feeds were respectively added with EQ, and ethyl ether extract ethyl acetate extract(EAE), acetone extract, ethanol extract(EE) and aqueous extract(AQE) of Angelica sinensis, except for the control. The results showed that EAs and EQ inhibited lipid oxidation in fish feed(P < 0.05). Of all of the examined EAs, EAE showed the strongest protective effects against lipid oxidation(P < 0.05). Moreover, EAE at high concentrations showed a stronger effect on lipid oxidation compared with EQ(P < 0.05). Then, 7 experimental diets respectively supplemented with 0.0, 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 g/kg of EAE were fed to the respective treatment groups for 30 d. Four replicates were performed for each treatment group; 20 carp(mean weight: 12.10 ± 0.13 g) were in each replicate. The result indicated that dietary EAE improved the growth performance in carp(P < 0.05). The appropriate con centration of EAE for carp growth was estimated to be 3.643 g/kg diet. Thus, EAE could be used as a natural antioxidant in feeds for Jian carp.

Chemometrics-assisted excitation-emission fluorescence spectroscopy for simultaneous determination of ethoxyquin and tert-butylhydroquinone in biological fluid samples

A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix （EEM） fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin （EQ） and tert-butylhydroquinone （TBHQ） contents in biological fluid samples was developed. After a simple data preprocessing that was to insert zeros below the first-order Rayleigh scattering, the second-order calibration method based on the alternating normalization-weighed error （ANWE） algorithm was used to deal with EEM data. Via the introduced ＂second-order advantage＂, the individual con- centrations of the analytes of interest could be obtained even in the presence of uncalibrated interferences. The experimental concentration ranges for the analytes were as follows： EQ, from 4.58 to 20.6 p.g mL-1 in plasma and from 6.87 to 20.6 gg mL-1 in urine; TBHQ, from 4.49 to 20.2 ~tg mL-1 in plasma and from 6.73 to 22.4 I.tg mL-l in urine. The recoveries from spiked bi- ological fluid samples were in the ranges of 92.8%-106.2% for EQ and 94.6%-107.2% for TBHQ. These results demonstrate that the three-dimensional EEM fluorescence with second-order calibration method is a powerful tool for obtaining both EQ and TBHQ quantitative results in plasma and urine samples, and could be applied to more complex matrices.