Development of a Direct Competitive ELISA Kit for Detecting Deoxynivalenol Contamination in Wheat
- This study was conducted to develop a self-assembled direct competitive enzyme-linked immunosorbent assay (dcELISA) kit for the detection of deoxynivalenol (DON) in food and feed grains.
- Based on the preparation of anti-DON monoclonal antibodies, we established a standard curve with dcELISA and optimized the detection conditions.
- The performance of the kit was evaluated by comparison with high-performance liquid chromatography (HPLC). The minimum detection limit of DON with the kit was 0.62 ng/mL, the linear range was from 1.0 to 113.24 ng/mL and the half-maximal inhibition concentration (IC50) was 6.61 ng/mL in the working buffer; there was a limit of detection (LOD) of 62 ng/g, and the detection range was from 100 to 11324 ng/g in authentic agricultural samples.
- We examined four samples of wheat bran, wheat flour, corn flour and corn for DON recovery. The average recovery was in the range of 77.1% to 107.0%, and the relative standard deviation (RSD) ranged from 4.2% to 11.9%. In addition, the kit has the advantages of high specificity, good stability, a long effective life and negligible sample matrix interference. Finally, wheat samples from farms in the six provinces of Henan, Anhui, Hebei, Shandong, Jiangsu and Gansu in China were analyzed by the kit.
- A total of 30 samples were randomly checked (five samples in each province), and the results were in good agreement with the standardized HPLC method.
- These tests showed that the dcELISA kit had good performance and met relevant technical requirements, and it had the characteristics of accuracy, reliability, convenience and high-throughput screening for DON detection. Therefore, the developed kit is suitable for rapid screening of DON in marketed products.
Comparison of four commercially available ELISA kits for diagnosis of Fasciola hepatica in Irish cattle.
Fasciola hepatica is a liver parasite of mammals and it results in poor welfare outcomes and economic losses in ruminants. While faecal egg count is the test most commonly used for diagnosis, it does not indicate presence of migrating immature stages.
Serological techniques increase sensitivity at all stages of the liver fluke infection. The aim of this study was to compare four commercially available ELISA tests for the diagnosis of F. hepatica. For this purpose, we tested three sample types; (i) known F. hepatica status sera from an experimental infection for the comparison of sensitivities and specificities, (ii) sera from pre- and post-flukicide-treated (albendazole, closantel, nitroxynil and triclabendazole) beef cattle to contrast the differences of seropositivity before and after treatment, and (iii) bulk tank milk samples from dairy herds sampled during high and low F.
hepatica exposure periods for assessing seasonal variations with the four tests available. Samples were tested using ELISA kits supplied by four manufacturers (Ildana Biotech, IDEXX, Svanova, and Bio-X). Samples were analysed simultaneously and in duplicate. In the control population Ildana, IDEXX and Bio-X presented 100% sensitivity (Se) and specificity (Sp), Svanovir presented a Se of 59% and a Sp of 96%. In flukicide-treated beef cattle, kits highlighted decreasing antibody levels 90 days post-treatment in variable degrees.
Finally, bulk milk showed a significant decrease in ELISA value between high and low fluke exposure periods with all tests studied.Se and Sp found in the present study, confirm that Ildana, IDEXX and Bio-X are accurate for the detection of F. hepatica exposure in Irish cattle. Svanovir Se and Sp in this population, indicate that a larger study is necessary to confirm this test characteristic in Irish herds.
In post-treatment use, Bio-X showed a consistent and significant decrease of ELISA value in all groups treated, denoting to be a reliable tool for assessing treatment effect at 90 days post-treatment. Finally, all tests showed to be a reliable tool for the F. hepatica monitoring of high and low exposure seasons, using bulk tank milk samples.